454 Tbi High Idle

All TBI assemblies are flow bench tested, calibrated and idle adjusted which makes for easy installation. i have put all new sensors on the engine. she starts at about 2500 rpm and finally comes down to 1200 rpm after awhile. Choose top quality brands AC Delco, API, Delphi, Forecast, Replacement, Standard Motor Products, Walker. I have a 1987 Chevy 1 ton with a tbi 454 and when I am trying to drive at slow speeds or like around in a parking lot the idle takes some time to slow after you push the clutch in it won't return to idle fast enough. If the RPM's raise up then you have a vacuum leak at the point you sprayed at. 1995 K3500, (454), Computer commanding high idletoo high Discussion in ' Engine Performance + Maintenance ' started by 454/4X4 , Jun 25, 2013. The engine has a little over 500 miles on it. It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. The truck is an 1989 Chevy 1 Ton Extended cab Dually (Older Bodystyle) Engine is 454 7. 7 tib's, the iac threads into the tbi and has a square shaped plug. 93' K5 Blazer 5. It measures atmospheric pressure as opposed to vacuum in the manifold. When I start the truck the idle stays at 1800 rpm's until it warms up then drops down to 11-1200 rpm's and wont drop any lower. This Edelbrock cam kit produced 540 HP & 530 ft-lbs. 89' V3500 TBI 454, TH400. Find your performance intake manifold now! Highlighting a comprehensive catalog of performance intake manifold available on sale this week. The 92 454 TBI engine I messed with the upper bushing was quite worn and allowed the pickup teeth to touch. Mid and High Rpm power loss and bogging. shut it off and restart it and ran fine all the way home. Drive great and idles perfect at stop signs. Truck starts and runs fine at first. 4L TBI and I am experiencing some strange problems. Please include TBI number (location of number is circled below) and enter all the required information about your TBI and Boat in the text boxes below. could not tell you why idle is high. The idle will relearn if you put the vehicle in drive and allow the idle to come down with all accessories off for about two to three minutes. The sensor basically looks at idle or closed throttle (IDL) and throttle angle opening (VTA). I researched and found it should be connected to the j port and I will need to drill tbi and connect a little hose and fitting on outside of tbi. Past approx 1/4 throttle angle the deflector side of the throttle body will start allowing air thru. It would down shift into 1st. Anywaydid you actually try mashing it down and releasing it to get the choke off? Sounds about right, you put a load on it by putting it in gear, the idle fellif you take your foot off the brake it'll probably do about 25mph (at least our 454 does on high idle). This Edelbrock cam kit produced 540 HP & 530 ft-lbs. 800-900 in gear. Matthew Myers 7 месяцев назад These have 2 temp sensors, one by the thermostat housing which is the one that tells the injector whst the temp is. Again, runs smooth at idle and even Revs smoothly but only when the truck is in park. 454 Big Block Chevy Turn-Key Crate Engine With 550 HP GM performance Gen VI 454 4 bolt main Chevy block Block painted with 3 coats of high temp ceramic engine paint customer's choice of color. Install the map sensor upgrade from the speed shop to provide the increased fuel flow needed for a high performance TBI engine. Two fuel injectors mounted on top of the throttle body inject fuel into the motor. Silverado & Fullsize Pick-ups - 89 454 TBI Stumbles and other - Hello everyone I have a truck which has cost close to 1,500 in repairs so far and they still have not found the problem I brought it in for. 82 1824270300-7 6. Been having a surge thats been driving me nuts. seems fine so I plug the box in and she seems a little rich at idle so I lean it out till she sound good and then run to the. Over all good system BUT one thing I noticed was that there was a flat spot in the throttle near full throttle. Check all the vacuum hoses. seems fine so I plug the box in and she seems a little rich at idle so I lean it out till she sound good and then run to the. 4 Engines 1985-91 (w/o the 4L60-E or 4L80-E transmissions): Our harness upgrades to the 1988-90 CK truck computer. I have checked for vacuum leaks cant find any. The "minimum idle speed" must be less than the "target idle speed", otherwise, during normal operation, the IAC pintle could bottom out on the air passage seat of the TBI, and damage will occur to the stepper motor of the IAC control. runs rough and feels starved for fuel when in drive and under any sort of load, barely drivable. Choose top quality brands AC Delco, API, Delphi, Forecast, Replacement, Standard Motor Products, Walker. Self taught, barely backyard mech status, for the love of the game. Do you think the adjustable map sensor would help with this? I am also having idle surging issues as well. May just need a new pump. Usually when a ignition module or pickup coil starts to go out the tach (if it has one) will start to jump around for no reason and spit/sputter on heavy acceration. 7 TBI Cold start flooding issue Hey gang new here and in need of some help. Tranny shift problems. This is a common problem on the 454 "most" of the time it is the TBI gasket. I had been experiencing some engine sputtering and stalling when the engine was under load, noticed alot going up hills. Do you think the adjustable map sensor would help with this? I am also having idle surging issues as well. As shown in the picture, these items are located at the back left (right if your standing in front of the car) of the engine, behind the inlet manifold. Hello, my name's Ryan, new user with my first square body. It would down shift into 1st. Keep in mind, this is a truck 454 so RPMs generally are low, I rarely rev it over 2500 and it sees a fair amount of idle time. My tach (did the moonie to needle swap) would indicate 1000rpm or so which drove me nuts and I did all kinds of things trying to fix it. 7) with TBI. If the code comes back you may have to replace the Electric Throttle Control Actuator (Motor) to repair the problem. 87 chevy 350, tbi rebuilt, idle and rev - youtube Jun 24, 2012 Just rebuilt the tbi injectors, 5 in tips and 8 in cherry bombs. A pressure drop of more than 1 psi under these conditions indicates an issue with the fuel delivery system. in the chilton book it tells you idle is autmaticly adjusted through the computer so thers not a hell of alot you can do it about it but it says if absolutely needed you can remove this seal behind the stop screw. 99 k3500 dually 7. The Chevrolet 454 engine was a part of the 2nd generation of Chevrolet big block engines. 454 SS build: Suggestions for 400-450 hp TBI (Read 11063 times) If you want a 400 hp truck sell the big block truck and go get a high performance small block. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. Unlike a port fuel injection system, that sprays fuel into the intake manifold runner just above the intake valve, the injectors in this system spray fuel directly into the throttle body. its a 1991 r3500 gmc (1980's body style crew cab dually tbi 454 4l80e) Original motor broke the crank and threw 2 rods. 7 EFI 350 MAG MPI 6. i am a compotent fab guy and do pretty good with mechanicals as well, but i cant figure out what the heck is going on with my 454 tbi. As of 2015, Chevrolet suggests a retail price of about $7,200. in the chilton book it tells you idle is autmaticly adjusted through the computer so thers not a hell of alot you can do it about it but it says if absolutely needed you can remove this seal behind the stop screw. 4 barrel tbi installation page 1 installation of howell engine developments high performance 2 & 4 bbl throttle body fuel injection on engines originally equipped with carburetors this system is based on the production gm (chevrolet) throttle body fuel injection system and electronics used from 1987-91, on 305, 350, and 454 v-8 engines. As I have it set right now, my idle at park is in the high 700s and my desired idle in gear is set at about 700 cold (80 degrees) and gradually lowers to 590 once engine temp reaches 160 degrees. The TPS itself is simply a linear variable resistor that when driven by the ECU produces a linear voltage in a 0-5 volt range, 0 volts being idle and up to 5 volts representing. Engine is a TBI 454 7. Here's a bunch of things that you should check after confirming the base timing with a light. This patented design greatly improves torque over a wide rpm range, especially off-idle through 5500 rpm. Recently my truck has developed a high idle problem. I have checked for leaks and it doesnt have any. 3 v6 TBI within the Automotive Support forums, part of the Tech Support Forum category. « on: May 13, 2011, 11:02:55 PM » Ok well first off I'm new to the sight so hello to everybody and I apologize for asking a question that might have already been answered. 5 inches at 950, more vacuum than my bone stock 97 7. We Can Promise You the Curb Idle will be Set for a Plug-N-Play Setup. Start by disconnecting and plugging the brake vacuum booster hose. com The intake is Edelbrock for a carb with an adapter form a 454 TBI engine. 4 Engines 1985-91 (w/o the 4L60-E or 4L80-E transmissions): Our harness upgrades to the 1988-90 CK truck computer. As I have it set right now, my idle at park is in the high 700s and my desired idle in gear is set at about 700 cold (80 degrees) and gradually lowers to 590 once engine temp reaches 160 degrees. Just the other day out of the blue it starting missing bad under a load. 7L, 350 MAG, 5. It would pull just fine until I floored it and then it seemed to loose power. I'mpretty sure Tim's is a throttle body injection like mine. Recently I started experiencing backfires on my 454, so the first thing I did is read all the related threads posted on this board, and began checking the recommended items (carb, distributor, vacumn leaks, valve springs, etc). TBI for GMC Motorhomes. 87 would be a very early version tbi so it will be similar. 81 17113099 Idle Air Control $ 151. 99 k3500 dually 7. This will keep the idle fuel adjustment easier to tune and also keep engine from running on when shut off. 3L High Idle Problems - Need Help! Can you help me figure out my 1998 4. 99$ 19010615 Delco High Mount Starter 358. Direct shipping means you get it fast and our experienced new engine center employees know most of the accessories that you may need to finish your repower or new engine installation. The throttle blades are closed and it appears to have too - Answered by a verified Chevy Mechanic We use cookies to give you the best possible experience on our website. Some TBI and MFI conversion systems also include electronic ignition timing control for select distributors or crank triggers, and facilitate control of power adders like nitrous oxide, and we have units that are both gasoline and E85 compatible. 454 Runs Rough. Check the vacuum advance because if it is not working the timing could be too far advanced and the diaphragm may have a air leak creating a lean mixture. The problem is that the engine idles fast and I have to step on the brake firmly at stop signs to hold it from creeping forward. 3L TBI V6 from a salvage yard. but there is an adjustment. Been on quite the gremlin hunt going on a month. 7 Idle surging,stalling in the alt. The largest GM TBI unit was provided on the BBC 7. The engine has a little over 500 miles on it. Here's a bunch of things that you should check after confirming the base timing with a light. 4L/454 Standard Motor Idle Air Control (IAC) Valves and get Free Shipping on Orders Over $99 at Summit Racing! Standard Motor Products replacement idle air control valves help you get maximum fuel efficiency and powe. The iac on my 454 tbi unit is held on with two screws and has a flat 4 wire connector, identical to the plug on the ignition module. I thinks it should idle about 600 and Ive been keeping the tranny in neutral at stops but other people have to drive this and I dont want to. When shifting into drive, engine runs at idle rpm, when throttle is pushed down to come off idle, engine coughs & dies. I have checked for leaks and it doesnt have any. We usually refer to an exhaust backfire as a "backfire", and backfiring through the carb as "spitting" or "coughing". I hooked up a digital timing light and the RPM was 2200 and the timing mark was 25 degrees. 2 weeks later. Didnt want to idle normally, the rpms changed. They are in a general most-likely-to-occur order. 4) on a 350 (5. 87 would be a very early version tbi so it will be similar. 1995 K3500, (454), Computer commanding high idletoo high Discussion in ' Engine Performance + Maintenance ' started by 454/4X4 , Jun 25, 2013. The vehicle ran perfectly as long as it wasn't idling. Can't get my 454's idle below 800 rpm, during warm-up it will run at 1100-1200rpm then drop down to 800. How do I convert to carb from TBI? I have a 454 1994 and would like to get rid of the brain to have a stand alone engine and trans. of torque when used with #7163 intake and #60559 cylinder heads on a 454 engine. 050 cam lift). I spoke with an ex-454 owner last night via telephone. 1) To me, its dumb to have it idle so high if it still is going to stall when dropped in gear, 2) My first thought is that the cam has too much duration & overlap, and this is why its stalling at anything below 950 rpm. I have checked for leaks and it doesnt have any. Again, runs smooth at idle and even Revs smoothly but only when the truck is in park. The sensor basically looks at idle or closed throttle (IDL) and throttle angle opening (VTA). Please include TBI number (location of number is circled below) and enter all the required information about your TBI and Boat in the text boxes below. Things that might help with a project like this. I have never owned a TBI that didn't have this go bad at some point. The Chevrolet TBI (throttle body injection) Performer manifolds are dual-plane, low-rise intake manifolds with a 180° firing order and a patented runner design that delivers outstanding performance with crisp throttle response. Re: 454 XL TBI rpm issue Post by km1125 » Mon Jul 01, 2019 3:04 pm 390Express wrote: Source of the post From what I can tell from digging into the MEFI 1-2 diagnostic manual, there's nothing in the ECU that provides a higher idle, that would otherwise make it stall later. I have a 94 454 TBI and was chasing what i thought was a high idle. A pressure drop of more than 1 psi under these conditions indicates an issue with the fuel delivery system. 1) Start the engine and let it idle in park for 3 minutes. and the stock tbi unit flows pretty good from factory but some do manage to fit a 454 tbi ontop for more cfm. 87 chevy 350, tbi rebuilt, idle and rev - youtube Jun 24, 2012 Just rebuilt the tbi injectors, 5 in tips and 8 in cherry bombs. Topic: 1990 P30 454 TBI Rough Idle when cold Posted By: cutlas on 05/22/07 08:10am When I start the engine cold it idles like it has a big cam and the exhaust smells of gas. New High Quality TPS New High Quality IAC Valve Reconditioned injector pod and fuel nut fittings Complete overhaul kit used in the process with mounting flange gasket included for your installation on your intake ATTENTION: There are multiple casting numbers used. Page 1 of 2 1 2 Next >. The problem is that the engine idles fast and I have to step on the brake firmly at stop signs to hold it from creeping forward. I constantly have high idle at start up its like 1500rpms for about 2 seconds than down to about 1200rpms till it warms up than down to about 1050rpms. 91 350 TBI rough idle and no power at all i recently aquired a 91 chevy C2500 with a new rebuilt 350 tbi. After driving for a while (approx 30 miles) when I shut off the truck and re-start it the idle is really fast. Chevy Blazer idle is too low, then when come to a stop is very high for a few seconds. On my SOB, a '91 Rockwood 28' I had the 454 with factory fuel injection. The sensor basically looks at idle or closed throttle (IDL) and throttle angle opening (VTA). MoPar did this trick back in the early emissions days. Changed the gasket on the throttle body, adjusted the idle screw. When the air is hot, the thermistor has a low resistance, which rises as the air temperature cools. I have a 1993 Chevy 1/2ton pickup 2wd with a 5. I found a 2. 7 tbI I have replaced every sensor on motor had igniton timing redone. MERCRUISER HORN WARNING SYSTEMS 90-898301003 JUNE 2007 Page 5 / 10 Models All MEFI-3 V-6 and V-8 Sterndrive and Inboards 4. The ECM uses non-volatile memory to keep track of the IAC position when the engine and ECM are turned off. 99 k3500 dually 7. Cleaning the throttle body allowed more air to enter the engine, and the computer is compensating by adding more fuel. I have a 93' Chevy K5 Blazer that developed a cold start issue just recently since the temps have started hitting the 40's at night here in Eastern Washington state. No MAF sensor or O2 sensors on this TBI 454 engineit's a 1ton. Over all good system BUT one thing I noticed was that there was a flat spot in the throttle near full throttle. its a 1991 r3500 gmc (1980's body style crew cab dually tbi 454 4l80e) Original motor broke the crank and threw 2 rods. V8 Propane Kit Holley 650hp High Horsepower Performance Complete Conversion 14. The idle is controlled by the ecm via the AIC valve, a stepper motor. A 'divorced' exhaust crossover port heated well-choke thermostat coil was used to provide cleaner and faster engine warm-up. No Misfire Diagnostic Trouble Codes. Two fuel injectors mounted on top of the throttle body inject fuel into the motor. Just getting it to act right at startup is a struggle. I have checked for leaks and it doesnt have any. I live in western Canada, and have since made several trips into the rockies. 91 thru 96 B-body Model Specific. We manufacture and design many of our own parts. at idle the voltage goes from 12 to 14 just bouncing around , i tryed the the MAF sensor cleaning and it helped somewhat i have already. Find 1995 CHEVROLET 7. 7) with TBI. The 6DFC & 6DGC both work on the 6DFC xdf file, and 90% of the parameters work for the 6DFD & 6DGD, however I will get a revised xdf for the FD&GD. Welcome to TBI CHIPS throttle body injection services. Just the other day out of the blue it starting missing bad under a load. The engine runs fine when cold but as it warms up it starts to "surge" at idle and when you come to a stop it acts like it wants to stall then it grabs. Buy Nos Rochester Delco Rochester online, high quality at wholesale prices. Anywaydid you actually try mashing it down and releasing it to get the choke off? Sounds about right, you put a load on it by putting it in gear, the idle fellif you take your foot off the brake it'll probably do about 25mph (at least our 454 does on high idle). Recently I started experiencing backfires on my 454, so the first thing I did is read all the related threads posted on this board, and began checking the recommended items (carb, distributor, vacumn leaks, valve springs, etc). Looks like a bad casting of the crank (looks like the crank had been cracked half way for some time) Ran great, but in its final weeks was getting only 6-8 mpg and a little down on power. My new rebuild with a larger cam and tbi has the truck not idling correctly. TPI is a fuel injection system that uses individual injectors for each cylinder that are mounted in the intake manifold and usually ends up looking much different than a traditional carbureted setup. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading. The Blue Knight Bosch Gen III fuel injector is 1. Also Fits Big Block 454 7. This may result in an unusually high or low idle speed, or in some cases a surging idle speed that repeatedly climbs and falls. 1992 Merc 454 7. The truck has 190K miles on it and runs fine other than a misfire. After installing new intake gaskets, (the egr part was completely clogged, but the oil valley looked super clean) car now has a weird idle problem. The engine has started to idle very high. the engine is an 86. 3L TBI V6 from a salvage yard. Fast idle and idle control is determined by the air regulator, the Auxiliary Air Control (AAC) valve and the F. Mine was out of adjustment. Hi i am new to this forum and in desperate need of advice. EVERY BODY wants to change injectors. After driving for a while (approx 30 miles) when I shut off the truck and re-start it the idle is really fast. Self taught, barely backyard mech status, for the love of the game. Replacing the TPS and the IAC on the 91 GMC C3500. 00 trying to find the problem for this. Starts cold no prob, runs and idles fine until its warm and in park or nuetral. For example, my tow rig is a 1989 Dually with a 454. One tan and one black. You will also notice the IAC is bottomed out closed or searching (depending on how bad the leak is). When not in gear, it idles around 1000, however when in gear it hovers around 300-500 at best. I have an 87 Suburban, 454 TBI that idles at about 1400 rpm. The problem turned out to ce the distributor. It would down shift into 1st. On my SOB, a '91 Rockwood 28' I had the 454 with factory fuel injection. I've also seen where excessive carbon build up under the TBI could cause a problem like you describe. Junkyard TBI. GM TPI Swap. 93' K5 Blazer 5. He still has to figure out how to make an intake plenum and filter system. and it cleared up. Listed below is a group classification for the custom (or high) performance camshafts listed in this catalog – (the durations shown are based on. mine was really loose. Rough idle but otherwise runs fantastic (1993 Chevrolet C1500) Truck runs great when driving down the road and idles smooth for a couple minutes after coming to a stop. Setting the 454SS TBI idle speed Two settings to double check on the TBI are: 1) the min. Find Replacement Car & Truck Parts For Sale. Looking for help please, 1998 5. com View Cart | My Account. Suitable for street and off-road use, the 454 HO big block crate engine by Chevrolet is able to produce 425 horsepower at 5250 rpm. Made the idle surge or just higher at times depending on what mood the TPS was in. Silverado & Fullsize Pick-ups - 1988 454 tbi not running like a 454 - Its a 88 k3500 4x4 with the 454 tbi and when i bought it it sat for two years. i am a compotent fab guy and do pretty good with mechanicals as well, but i cant figure out what the heck is going on with my 454 tbi. at idle the voltage goes from 12 to 14 just bouncing around , i tryed the the MAF sensor cleaning and it helped somewhat i have already. 4L/454 Standard Motor Idle Air Control (IAC) Valves and get Free Shipping on Orders Over $99 at Summit Racing! Standard Motor Products replacement idle air control valves help you get maximum fuel efficiency and powe. This is why more modern cars with carburetors (mostly 80's and early 90's cars) had idle stop solenoids that completely close the throttle plates off when the key is switched-off which completely shuts the fuel and air off, thus preventing run-on from happening. I constantly have high idle at start up its like 1500rpms for about 2 seconds than down to about 1200rpms till it warms up than down to about 1050rpms. I think the 454 iac wiring has to do with the iac itself. Starts up, high idle comes on and than goes down. 7 liter with 260'000 miles on it. How do I convert to carb from TBI? I have a 454 1994 and would like to get rid of the brain to have a stand alone engine and trans. I thinks it should idle about 600 and Ive been keeping the tranny in neutral at stops but other people have to drive this and I dont want to. they were pretty strong, not vortec 454 strong, but they got the job done. 7L TBI Mercruiser with Bravo 3 drive on a Sig 260. The engine has a little over 500 miles on it. The truck has 190K miles on it and runs fine other than a misfire. I have an 87 Suburban, 454 TBI that idles at about 1400 rpm. We usually refer to an exhaust backfire as a "backfire", and backfiring through the carb as "spitting" or "coughing". I thinks it should idle about 600 and Ive been keeping the tranny in neutral at stops but other people have to drive this and I dont want to. You cannot adjust the idle speed with a setscrew or any other mechnical adjustment. GM Vortec 8100: The 454's Forgotten Big Brother This trio depicts (left to right) the 203 (high-torque, stock-idle quality, emissions-compliant, safe with stock piston crowns), the 206 (for. 7L engines is shown on the right. If the goal is getting the best of both worlds in a street and strip cam. Take off the cap and check the shaft for sideway movement. Okay if anyone saw my last thread I had a few problems. 7L) engines. This may result in an unusually high or low idle speed, or in some cases a surging idle speed that repeatedly climbs and falls. Things that might help with a project like this:. 4 wont idle, floods out after a few seconds,replaced everything from fuel pump to tbi presure reg,injectors. It will idle fine for a while then idle to 350-400 rpm almost die then rev back up and idle fine and repeat. P0507 CHEVROLET Tech Notes If there are no intake leaks, clean throttle body, adjust engine idle and erase engine code. Check and repair all defective cracked vacuum lines. Tranny shift problems. Spray WD 40 around the base of the TBI and if idle speeds up it is the gasket. Check O2 sensor for a false rich reading which will cause ECM to lean the mixture to compensate. 6mm or about 1/16 inch longer than most replacement fuel injectors for the GM 7. The Big Block Chevy 454 is a great engine. I was going to add a worked TBI from a 454 that would support another 100HP, but never got. Silverado & Fullsize Pick-ups - 1988 454 tbi not running like a 454 - Its a 88 k3500 4x4 with the 454 tbi and when i bought it it sat for two years. Engine Idle Is Too Low Or Stalls Dirty Throttle Body. For that period it was GM's answer to a carb and I think they worked better than a carb, but they came with their own problems. Edelbrock Intake Manifold 3764; Performer Rectangular Port Dual Plane Idle to 5500 RPM Satin Aluminum for 1987-1990 Chevy 454 BBC | Star / PerformanceParts. Reset Idle Learn = The Idle Air Learning can be reset to a default value (16 steps) - by setting this control value to 1, and turning the key off and waiting for the system to completely power down. The GM TBI is a speed-density system, which assumes the engine ingests a given amount of air at wide-open throttle. This is why more modern cars with carburetors (mostly 80's and early 90's cars) had idle stop solenoids that completely close the throttle plates off when the key is switched-off which completely shuts the fuel and air off, thus preventing run-on from happening. I have replaced the idle control valve/soleniod but this didn't make a difference. Normally the static idle is factory set, when I first started the 454 after major changes to the engine and a rebuilt TB it idled too slowly. 0L) and LO5 (5. No point in checking the timing unless that is unplugged. It has an adjustable pressure regulator, a fast idle solenoid, and barb fitting for the fuel inlet and return. Setting IAC (Idle air control) valve I saw this video , and wonder about his words of "wisdom. '91 Chevy 350 TBI surging at idle and stumbling at speed Howdy - My father in law's '91 Chevy was running poorly, so we put new plugs, wires, cap and rotor on it, and it's running better, but it it still surging at idle. I have replaced the fuel pump, distributor, coil, cap, rotor, plugs wires. 66k on the odometer. Pictured with electric choke does come with hot air choke. 0 intake, 1-3/4" long tube headers, 750 Holley Street demon, Return style regulator, Fuel pressure set at 5psi, stock HEI, Summit cast steel roller tip rockers, mild 454 Vortec roller cam (and matching. In the fall i did a bunch of stuff to my 350. 7 efi tbi tpi NIB Mercruiser 305/350/454/50 2. I recently picked up a 95 suburban. After installing new intake gaskets, (the egr part was completely clogged, but the oil valley looked super clean) car now has a weird idle problem. Just the other day out of the blue it starting missing bad under a load. Start by disconnecting and plugging the brake vacuum booster hose. 7) with TBI. Rough idle but otherwise runs fantastic (1993 Chevrolet C1500) Truck runs great when driving down the road and idles smooth for a couple minutes after coming to a stop. Power was up significantly, with output boosted to 507 hp at 5,700, though peak torque actually dropped slightly to 538 lb-ft at 4,000 rpm. The chevy 454 is in a 1988 sportscoach pathfinder rv. 4:Poor Idle, Very shaky idle, or no idle at all If you want to check your EGR manually you sometimes can, however the EGR is only meant to be opened under normal operation temperature in excess of 2300-2500 RPMs , so unless you meet these conditions it is not a good way to manually check the plunger valve for movment. New High Quality TPS New High Quality IAC Valve Reconditioned injector pod and fuel nut fittings Complete overhaul kit used in the process with mounting flange gasket included for your installation on your intake ATTENTION: There are multiple casting numbers used. As soon as you take your foot off the pedal, it will die, you can't get it to go since you have to idle the truck to get it into gear. A less than $3 fix if you can do it yourself. 7L engines is shown on the right. 454 Throttle Body Did you recognize that driving an all new auto off the lot quickly and considerably drops its worth? From an economic viewpoint, acquiring an utilized motor vehicle is a better choice. Extra air getting in the engine will speed up the idle. I have a 1993 Chevy 1/2ton pickup 2wd with a 5. Running Problems. (fast idle control device) valve. in the chilton book it tells you idle is autmaticly adjusted through the computer so thers not a hell of alot you can do it about it but it says if absolutely needed you can remove this seal behind the stop screw. Checking and adjusting the TPS (throttle position sensor) on the 91 GMC C3500 dually with a 454 big block V8 7. You cannot adjust the idle speed with a setscrew or any other mechnical adjustment. 4L TBI and I am experiencing some strange problems. I start it and it idles at 1450. Save on Nos Rochester Delco Rochester, all qualified orders over $50 gets free shipping. '91 Chevy 350 TBI surging at idle and stumbling at speed Howdy - My father in law's '91 Chevy was running poorly, so we put new plugs, wires, cap and rotor on it, and it's running better, but it it still surging at idle. Pro-M EFI makes tuning for forced induction super easy. Take off the cap and check the shaft for sideway movement. It will eventually learn it on its own, but it may take over a week of driving, during which time you will experience high and low idle speeds and possibly rough idle. Welcome to TBI CHIPS throttle body injection services. Rough Idle causing a Misfire Condition Case Study. Check it for interference. Re: Marine power 454 tbi boats are weird for normal car people to diagnose as we ofter forget things like one rotates in the opposite direction and all timing components do as well. The Vortec 7400 L21 was a commercial version of the Chevrolet Big-Block engine used in the medium duty truck platform. In that case it had been modified for performance and the headers created so much heat that they caused the problem. Check the vacuum advance because if it is not working the timing could be too far advanced and the diaphragm may have a air leak creating a lean mixture. 073; Metering Rods: Primary-50M, Secondary-DR. checked the timing, spark plugs& wires, rotor & cap, checked to see if the. Lately I've made some changes in hopes of bumping up the idle pressure a bit. As a single solution, or partnered with products from other Holley companies we can give you the edge you need over the competition!.