will not idle on own !!!!!
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 32
Likes: 0
From: CHIPMAN ALBERTA
will not idle on own !!!!!
Hello out there in corvette land.I have a problem with my 1994 Corvette LT-1 manual trans.Engine ran excellent before work that i recently done,looking for more power of course !!!What i did was i replaced the opti spark to a MSD with new wires,i changed the intake maniflod to a 7107 eldebrock air gap model,also ceramic headers,cat back exhaust,new 2 in dual core radiator.Now at start up the engine revs to approx 3000 rpm and then stals,everytime !!I checked the spark plug wiring several times,not nice doing that ,but checked several times,all are going to correct cylinders.One thing i noticed was very rich exhaust smell.!!!!!!!!!! Has Anyone out there had the same problem and what did you do to fix this problem.Please get back to me with any info,it would be greatly appreciated,Thanks and have a good day..
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
This sound like a reasonable place to start or at least a related area that the problem might be.
Of all the parts you replaced, it does not sound like none of them could cause your problem except the manifold or related area. Make sure the EGR is OK and not open.
If by some chance it is idle air (IAC) related, the PMC might be confused as to where to set it (with all the new stuff added). You might start by disconnecting the battery for 30 seconds to re-set the PCM. There is also a FSM factory procedure to re-set the PCM for the IAC.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
If it revs to 3000, might not be getting any fuel or too much air. I would put a fuel pressure gauge on it and make sure that is OK.
Also inspect the mating of the throttle body, action of the throttle, make sure it is clean and look at the TPS (throttle position sensor) to make sure it is connected correctly.
I would also measure the voltage coming off the wiper to make sure it can change thru its range (approx 0.4 - 4 .5 volts).
Also inspect the mating of the throttle body, action of the throttle, make sure it is clean and look at the TPS (throttle position sensor) to make sure it is connected correctly.
I would also measure the voltage coming off the wiper to make sure it can change thru its range (approx 0.4 - 4 .5 volts).
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 32
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From: CHIPMAN ALBERTA
Hello again ,tryed all checks ,all seems ok ,i was wandering though ,on the 7107 air gap intake manifold,does it take a special size of intake manifold gasket ? matched to stock LT-1 heads ??Also maybe engine is getting 2much air and not enough fuel with all new performance upgrades i installed,maybe it needs 26 lb injectors up from the stock 24 lb ?? Does anyone know info on this before i go and remove intake and change injectors,Thanks
Pro
Joined: May 2008
Posts: 670
Likes: 56
I read somewhere else (unfortunately can't remember where) that someone got an Edelbrock air gap LT1 manifold that was off where the intake mates to the heads and it caused a tremendous vacuum leak that does sound like your problem. Your 24lb injectors should be fine with the few mods you have made. Can you put a vacuum gauge on it and read your vacuum?
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Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Add my vote to the vacuum leak theory- if too much air is being taken in, the ECM tries to compensate by increasing the fuel pulse width. I also agree that you should pull codes, even if the service light is not on.
Drifting
Joined: Sep 2002
Posts: 1,642
Likes: 0
From: Suwanee,Ga
Hello out there in corvette land.I have a problem with my 1994 Corvette LT-1 manual trans.Engine ran excellent before work that i recently done,looking for more power of course !!!What i did was i replaced the opti spark to a MSD with new wires,i changed the intake maniflod to a 7107 eldebrock air gap model,also ceramic headers,cat back exhaust,new 2 in dual core radiator.Now at start up the engine revs to approx 3000 rpm and then stals,everytime !!I checked the spark plug wiring several times,not nice doing that ,but checked several times,all are going to correct cylinders.One thing i noticed was very rich exhaust smell.!!!!!!!!!! Has Anyone out there had the same problem and what did you do to fix this problem.Please get back to me with any info,it would be greatly appreciated,Thanks and have a good day..
Sounds like the AIC, at least for the idle problem.
You did re-installed the O2 sensors? Eh...
Double check the MSD instructions? Have zero experience with MSD/ Opti sparks, but sure sounds like a likely place for a weird problem??
Codes Is it Throwing any codes??
TJM
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 32
Likes: 0
From: CHIPMAN ALBERTA
Hello again ,it is very cold up here in Edmonton Alberta Canada,but once it gets nice out n i will checking for codes and possiblely removal of the new air gap intake manifold.Has anyone out there had any problems with new intake manifolds being warped ????
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 32
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From: CHIPMAN ALBERTA
Hello again out there,another question about my problem that i am having [will not idle ]-i finally had time to check codes from the computer using the cross terminals from 16 pin connector,codes that came up are -H12 -H16 -H48 -H64 -AND H65,i know what they mean but how does a person eliminate them ?Please if anyone has info PLEASE get back to me in regards to this problem.Thank you.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Hello again out there,another question about my problem that i am having [will not idle ]-i finally had time to check codes from the computer using the cross terminals from 16 pin connector,codes that came up are -H12 -H16 -H48 -H64 -AND H65,i know what they mean but how does a person eliminate them ?Please if anyone has info PLEASE get back to me in regards to this problem.Thank you.
