except the idle should rise when you find the vac leak, not stumble....I found several leaks that way....
hopefully someone can help
Thread Starter
Intermediate
Joined: May 2015
Posts: 37
Likes: 1
From: Princeton West Virginia
hopefully someone can help
I have been working on a 86E corvette that I purchased about a month ago, been updating everything and getting back to working order. I have came to an issue I can not figure out and hoping that someone can help. So I finally got everything back together on the motor after replacing the fuel injectors, and fuel pressure regulator. I start up vehicle and while its running, if you give it a little gas, just push down on pedal just a little bit, like if you were pulling out, it acts like it wants to die, but if you open it up on the throttle it acts fine, also acts fine just sitting there, just does it when you barely push down the pedal. What would cause this? Would it be a dirty or bad throttle body? Or throttle body sensor? I cant figure out.. please help.......
Instructor
Joined: Nov 2005
Posts: 214
Likes: 6
From: West Valley City UT
just used this technique on another car, no leaks, so i replaced the fuel filter. that solved my problem.Make sure you don't get a false positive by spraying near your air filter, because that will stumble your car as well.
Instructor
Joined: Nov 2005
Posts: 214
Likes: 6
From: West Valley City UT
Drifting
Joined: Jun 2013
Posts: 1,590
Likes: 60
From: ft myers FL/Munising MI
guessing spraying on a vac leak seals the air out and raises the idle...into the tb itself would replace the gas which is a higher octane....on my car, it raised the idle when I found a leak....
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Jun 2013
Posts: 341
Likes: 2
Besides any leaks, are the injectors OK and correct for your car? That and the FPR is what actually changed so look hard there. What's the fuel pressure? Are all the sensors hooked back up correctly? I forgot one once and the car ran rough. Did you disconnect and reconnect the battery? When I ran without a sensor I think the computer learned to deal with it and the battery disconnect fixed it once I reconnected it.
I did my TPI several times and used regular gaskets with that purple gasket sealer and haven't had a problem.
I did my TPI several times and used regular gaskets with that purple gasket sealer and haven't had a problem.
Thread Starter
Intermediate
Joined: May 2015
Posts: 37
Likes: 1
From: Princeton West Virginia
I've checked all vacuum lines, they are all fine, replaced every line. I have also have new fuel filter, new fuel regulator, I haven't checked my fuel injectors but I did get new Bosch injectors when I first started this process and was putting the car back together. Anything else anyone can think of? Like I said it idling it's fine, then if you just give a little gas it seems like it's going to die. I did let someone else look at it today to see if he could notice anything, he said he thought he heard a knocking noise from a fuel injector. How can I tell if the fuel injectors are good? How can I check to see if they are sticking? Also is there any chance that it could be something else? Please help... Giving me a major headache trying to figure this out.. Thank you
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
That's normal.
You can check your injectors by measuring the resistance of the coils. Remove the connector and the coils should measure about 15 ohms. Check all of them and if any are quite a bit lower than the others then you have a problem. Best to replace all if one or more are bad. Sometimes injectors will check OK when cold and then fail when hot, so check them both ways.
You can check your injectors by measuring the resistance of the coils. Remove the connector and the coils should measure about 15 ohms. Check all of them and if any are quite a bit lower than the others then you have a problem. Best to replace all if one or more are bad. Sometimes injectors will check OK when cold and then fail when hot, so check them both ways.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
If no vacuum leaks or CEL:
When changing over to Bosch 3's from FIC:
When starting the vehicle for the first time allow it to idle for 15 minutes before driving.
Suggest disconnecting the battery for several seconds to base line the ECU then follow the above procedure.
If the issue persists check the TPS setting. Key on engine off (KOEO) voltage @ the TPS
should be .54 volts. To check/adjust the TPS you will need 2 stick pins + a digital VOM.
The TPS check/adjust procedure is well documented on this forum.
Good luck.
Edit: Ghoastrider1 is faster than I am
When changing over to Bosch 3's from FIC:
When starting the vehicle for the first time allow it to idle for 15 minutes before driving.
Suggest disconnecting the battery for several seconds to base line the ECU then follow the above procedure.
If the issue persists check the TPS setting. Key on engine off (KOEO) voltage @ the TPS
should be .54 volts. To check/adjust the TPS you will need 2 stick pins + a digital VOM.
The TPS check/adjust procedure is well documented on this forum.
Good luck.
Edit: Ghoastrider1 is faster than I am
Last edited by Churchkey; May 19, 2015 at 07:54 AM.
Team Owner
Joined: Dec 2012
Posts: 30,427
Likes: 1,609
From: Outside the Quick Stop N.J.
