WOT info need...... HELP!
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Instructor
Joined: Jun 2013
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From: hanceville al
WOT info need...... HELP!
OK I have a 1990 L98 I just installed a edelbrock high flow lower intake manifold and runners had the plentum ported and added a 52mm throttle body. After finding top dead center for timing the car started right up and immedately went to wide open throttle. I thought that the blades on the throttle body may have been stuck, nope. I went so far as to even disconnect the cabling to the throttle body. I double checked the plenum runners bolts to make sure they are tight and all vaccum lines are connected. I cant start the car to try and trouble shoot because it WOT's. I mean idol to max red line in 2 seconds. Any idea's?
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Instructor
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From: hanceville al
Thanks you guys for the replies. The cables are currently disconected from the throttle body and the car revs up to WOT almost instantly. Will the IAC cause this???? I would think it would take one heck of a vaccum leak to cause this symptom.
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From: hanceville al
I have not done that yet Im working on it now I can say that I started the car with the TS out and it still did the same thing. This car is a soeed density car so I dont have to set the voltage like earlier models, plug and play. I have the IAC pull off the new TB what am I looking for? It is a new IAC just put it on last year.
Drifting
Joined: May 2013
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From: Reno Nevada
Speed density huh? Probably gots a Moates adapter with my chip in it too?
Something is telling the ecm to add fuel. Even with timing really advanced it wouldn't got wot. At idle you should be somewhere close .60 volts at the tps. If, for some reason it was reading 4 volts plus it would think the throttle is open. Hook datamaster to it and replay watching the devices.
Something is telling the ecm to add fuel. Even with timing really advanced it wouldn't got wot. At idle you should be somewhere close .60 volts at the tps. If, for some reason it was reading 4 volts plus it would think the throttle is open. Hook datamaster to it and replay watching the devices.
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Thread Starter
Instructor
Joined: Jun 2013
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From: hanceville al
Just hooked up original TB with no change, I dont have data masters on my new computer but I do have the moates addapter, I need to find out is it works with windows 7. Also I cant log but only a few seconds because Im afraid of engine damage. That does leed to a good question if it were a massive vaccum leak it would not cause the ECU to increase fuel would it?
Drifting
Joined: May 2013
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From: Reno Nevada
What you're describing is more than a vacuum leak. I tried to call you, but you must have a new number. Think about this. There's always power to the injectors, and the ecm completes a ground to pulse them. What if this ground has been compromised and the injectors just keep firing?
Le Mans Master
Joined: Feb 2005
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From: Clearwater Florida
What you're describing is more than a vacuum leak. I tried to call you, but you must have a new number. Think about this. There's always power to the injectors, and the ecm completes a ground to pulse them. What if this ground has been compromised and the injectors just keep firing?
Race Director
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From: moraga ca
The tps could be reading 5 volts and injectors firing to the max but the engine wouldn't rev unless the fuel is matched with enough air to create a mixture that will fire.
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Instructor
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From: hanceville al
How can I check my TBS it is a speed density model and as far as I know it is a plug and play sensor. I cant see having a vaccum leak large enough to make the car rev to max RPMs in 2 seconds, but I think maybe the TBS maybe stuck and creating a WOT issue.
Race Director
Joined: Apr 2002
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From: Anaheim CA
Short terminals A & B on the ALDL connector and turn on the ignition. That will cause the IAC to close. Unplug it while the ignition is still on (the computer will reset it if you turn off the ignition). Now the only way air can get into the engine is through the throttle body bores. If you're still going to high RPMs then you must have a vacuum leak.
As far as I am aware, only LT1s had non-adjustable TPS sensors. You can tell by looking at the mounting screw area. If there are slots there then it's adjustable.
As far as I am aware, only LT1s had non-adjustable TPS sensors. You can tell by looking at the mounting screw area. If there are slots there then it's adjustable.
Racer
Joined: Jun 2006
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Do a search for Edelbrock runners. Quite a few have had problems because the runners do not mount flush to the plenum. I have seen two sets in the last year that have had to have the top flange ground down level to fit properly, no such problems with SLP runners.
Remove the plenum and then dry fit it without the plenum gaskets, if you see any uneven gaps you found your problem.
Remove the plenum and then dry fit it without the plenum gaskets, if you see any uneven gaps you found your problem.
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Instructor
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From: hanceville al
Thanks for all comments, yep the EGR valve is installed, I will try and close the IAC as recomended and that stinks to here that as much oney as that set up was people are having issues.
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Instructor
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From: hanceville al
OK so I have tried every thing memtioned in this tread, I even put a volt meter on the TPS and it seemed fine. The tach works when it wants to so I did not trust the readings it was giving so I bought a new tach and it shows the car is running at 4100 RPMS. Can a vacuum leak cause the car to run that high??
