LT1 Problem. Please help.
Thread Starter
Staging Lane
Joined: Oct 2008
Posts: 68
Likes: 0
LT1 Problem. Please help. So recently I have rebuilt the top end of the motor. Added headers, and deleted all of the EGR crap. After putting it all back together, sometimes I am able to get it to crank and other times I am not. Once cranked it idles fine for a bit, then falls on it's face and dies. During this time I cannot give it any throttle or it will immediately die. I rebuilt my opti with an MSD kit that I had laying around and I know 100% that the opti is on correctly. It is a 95 so it's keyed. I have triple checked all of my grounds as well.
Is it possible that my valves are not adjusted correctly? Bad TPS or other sensor? Please help.
Forgot to add that if I spray starting fluid it will idle and rev just fine. No misses or anything.
Is it possible that my valves are not adjusted correctly? Bad TPS or other sensor? Please help.
Forgot to add that if I spray starting fluid it will idle and rev just fine. No misses or anything.
Last edited by davidhouston23; Jun 2, 2010 at 02:33 PM. Reason: Forgot :(
Thread Starter
Staging Lane
Joined: Oct 2008
Posts: 68
Likes: 0
All new gaskets. There is a check engine light on, though I have no way to scan it. I would assume it has something to do with deleting the EGR as it wasn't on before the rebuild. I have not checked the pressure at the rail, but when I push the valve on the regulator gas comes out. I will get a gauge and test it.
For 95's with the obd1 system and obd2 connector.....you can scan them with an Actron CP9185 scan tool. They retail around $250, but you may be able to talk your local parts store into letting you borrow one, or leave a deposit. They are the only handheld scanner I know of that works. It will also record a few seconds of run time and give readouts for each sensor. Check out my thread "Running very rich" for and example of the information it will give you. You can also buy a cable for about $75 and download free software to do the same thing. I'm planning on going that route, but had to borrow the scan tool because I didn't have time to wait on the cable.
Also....I agree that it sounds like your problem is fuel related. Let us know how that fuel pressure checks out. If you don't have a pressure tester, you can put a deposit on one as a loaner tool at your nearest Auto Zone. They refund you 100% when you return it.
Also....I agree that it sounds like your problem is fuel related. Let us know how that fuel pressure checks out. If you don't have a pressure tester, you can put a deposit on one as a loaner tool at your nearest Auto Zone. They refund you 100% when you return it.
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Launching!
Joined: Jan 2007
Posts: 233
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From: Mooresville,NC
If you can unbolt the rail and take out the assembly with injectors, I think that would work the best. I'd just have some new o-rings for the injectors handy incase you rip one taking it apart or putting it together. Are you wanting to actually clean the rails out with a chemical or just make sure they aren't clogged with something?
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Staging Lane
Joined: Oct 2008
Posts: 68
Likes: 0
I went to harbor freight and bought a cheapie fuel pressure tester. I hooked it up to the fuel rail and immediately saw 5PSI. When turning the key on and attempting to start the car the fuel pressure does not move. When I spray starting fluid the car will stay running, and the fuel pressure does not move either. I am going to try and hook the tester directly to the fuel pump and see what it reads then, as there is a new fuel filter on the car.
I did test the regulator as well, was told to unplug the vacuum line and if gas shot out then it was bad. No gas shot out, so i'm assuming the regulator is fine.
The odd thing is that if I disconnect the fuel lines from the rail while there is pressure in the system, it shoots out like crazy, so I figured it had more than 5PSI. Same then when you push in on the schrader valve, gas shoots out.
Thanks for any help guys, this is getting annoying.
I did test the regulator as well, was told to unplug the vacuum line and if gas shot out then it was bad. No gas shot out, so i'm assuming the regulator is fine.
The odd thing is that if I disconnect the fuel lines from the rail while there is pressure in the system, it shoots out like crazy, so I figured it had more than 5PSI. Same then when you push in on the schrader valve, gas shoots out.
Thanks for any help guys, this is getting annoying.
Launching!
Joined: Jan 2007
Posts: 233
Likes: 0
From: Mooresville,NC
I'm not sure but I think 5 psi at the rail and not changing after trying to crank it would mean the pump is probably going bad. I just changed my pump last weekend and it had like 8psi with the key on but then if I did key off to key on again it would go up about 3-4 psi each time. I changed it and it starts on the first try everytime. Before it took 2-3 times of cycling the key, which tells me the pressure is now high enough even though I did not put a gauge on it since the new pump to see exactly what the psi is.
