New member here - been meaning to join, finally decided it was time, especially with my current issues!
Background - I have a 89 formula 350 that I had a 383 built for. I still have the TPI, but with a ported upper plenum, slp runners, and an edlebroc lower manifold, 58mm BBK TB, AFPR and 24 lb SVO injectors. The CPU has not been retuned yet, plan was to get it running then take it to the shop for a tune. I started the car for the first time yesterday and it starts, but does not run longer than 3-6 seconds, then turns off.
What I have done -
1. Adjusted tps voltage to .56
2. Replaced the IAC
3. Adjusted timing (just trying the dist in differnt places) but I can not set the timing because the car does not run long enough.
4. Checked fuel pressure.
5. Just looked over the harnesses/plugs, etc.
6. Put the car in diag mode by jumping A and B on the diag port, waiting 30 seconds, then starting the car - no help.
I did notice that when I have the key on and turn the dist from one extreme to another I get a sound like relays pulling in and a fuel pump running kind of sound.
Any ideas?
Thanks in advance- looking forward to meeting more 3rd gen owners
Background - I have a 89 formula 350 that I had a 383 built for. I still have the TPI, but with a ported upper plenum, slp runners, and an edlebroc lower manifold, 58mm BBK TB, AFPR and 24 lb SVO injectors. The CPU has not been retuned yet, plan was to get it running then take it to the shop for a tune. I started the car for the first time yesterday and it starts, but does not run longer than 3-6 seconds, then turns off.
What I have done -
1. Adjusted tps voltage to .56
2. Replaced the IAC
3. Adjusted timing (just trying the dist in differnt places) but I can not set the timing because the car does not run long enough.
4. Checked fuel pressure.
5. Just looked over the harnesses/plugs, etc.
6. Put the car in diag mode by jumping A and B on the diag port, waiting 30 seconds, then starting the car - no help.
I did notice that when I have the key on and turn the dist from one extreme to another I get a sound like relays pulling in and a fuel pump running kind of sound.
Any ideas?
Thanks in advance- looking forward to meeting more 3rd gen owners
Former Sponsor
Since you have a MAF system, the car should be able to run on a stock tune.
Couple of things come to mind...
Don't start the car with the A and B terminals jumpered, you can damage the ECM by doing so.
Your 24 lb injectors are going to be adding more fuel than what your ECM is anticipating since the stock prom is set for 22 lb injectors. Lower your fuel pressure several pounds from stock spec (43 psi with key on, engine off) to try to compensate for that until you can get the injector size fixed in the prom.
To set your timing roughly, just pull the cap off the distributor with cyl one at TDC. You should see the rotor pointing near the plug wire for cylinder number one. This would be near 0 degrees of spark advance. You can try to advance a small amount by hand. You'll know if you've gone too far when the engine cranks slowly, as if the battery was weak. This means you are at about 15 degrees advanced.
Has any work been done on the valves recently?
Can you get a vacuum reading when you start the engine?
Couple of things come to mind...
Don't start the car with the A and B terminals jumpered, you can damage the ECM by doing so.
Your 24 lb injectors are going to be adding more fuel than what your ECM is anticipating since the stock prom is set for 22 lb injectors. Lower your fuel pressure several pounds from stock spec (43 psi with key on, engine off) to try to compensate for that until you can get the injector size fixed in the prom.
To set your timing roughly, just pull the cap off the distributor with cyl one at TDC. You should see the rotor pointing near the plug wire for cylinder number one. This would be near 0 degrees of spark advance. You can try to advance a small amount by hand. You'll know if you've gone too far when the engine cranks slowly, as if the battery was weak. This means you are at about 15 degrees advanced.
Has any work been done on the valves recently?
Can you get a vacuum reading when you start the engine?
Quote:
Originally posted by 92blue
Since you have a MAF system, the car should be able to run on a stock tune.
Couple of things come to mind...
Don't start the car with the A and B terminals jumpered, you can damage the ECM by doing so.
Your 24 lb injectors are going to be adding more fuel than what your ECM is anticipating since the stock prom is set for 22 lb injectors. Lower your fuel pressure several pounds from stock spec (43 psi with key on, engine off) to try to compensate for that until you can get the injector size fixed in the prom.
To set your timing roughly, just pull the cap off the distributor with cyl one at TDC. You should see the rotor pointing near the plug wire for cylinder number one. This would be near 0 degrees of spark advance. You can try to advance a small amount by hand. You'll know if you've gone too far when the engine cranks slowly, as if the battery was weak. This means you are at about 15 degrees advanced.
Has any work been done on the valves recently?
Can you get a vacuum reading when you start the engine?
Thanks for the response!Originally posted by 92blue
Since you have a MAF system, the car should be able to run on a stock tune.
Couple of things come to mind...
Don't start the car with the A and B terminals jumpered, you can damage the ECM by doing so.
Your 24 lb injectors are going to be adding more fuel than what your ECM is anticipating since the stock prom is set for 22 lb injectors. Lower your fuel pressure several pounds from stock spec (43 psi with key on, engine off) to try to compensate for that until you can get the injector size fixed in the prom.
To set your timing roughly, just pull the cap off the distributor with cyl one at TDC. You should see the rotor pointing near the plug wire for cylinder number one. This would be near 0 degrees of spark advance. You can try to advance a small amount by hand. You'll know if you've gone too far when the engine cranks slowly, as if the battery was weak. This means you are at about 15 degrees advanced.
Has any work been done on the valves recently?
Can you get a vacuum reading when you start the engine?
I took the jumper out after waiting 30 sec, then started it - I thought that was safe? I;ll check the FPR Key on and see what I have - the only time I checked it before was with the vac unplugged, and I had 50 then. I am hoping to be in the low 40's with vac applied, but I need to make sure. I also need to watch the guage when I start the car to make sure the pressure isn't dropping off.
On the valves - they were set up when the 383 was built (this is a new motor and this is the first time it was started. I was told it was ready to go.
By vac reading, do you mean that I should just pull a vac hose and connect a gauge? I have not done that
Former Sponsor
Your problem might very well be your fuel pressure then. Your 24 lb injectors at 50 psi will behave like 25.7 lb injectors. That means you are adding roughly 15% more fuel than what the factory tune calls for due to your larger injectors and higher fuel pressure.
With the vacuum disconnected, lower your fuel pressure to about 38 psi. Your 24 lb injectors should flow 22.xx lbs at that psi, which should let you get the car running.
Yes, I was referring to disconnecting a vacuum line, and hooking up a vacuum gauge. Low vacuum indicates you may have a problem with excessively retarded timing, fuel mixture that is very far off, incorrectly adjusted valves, timing chain off a tooth, and then the list jumps into cam problems.
With the vacuum disconnected, lower your fuel pressure to about 38 psi. Your 24 lb injectors should flow 22.xx lbs at that psi, which should let you get the car running.
Yes, I was referring to disconnecting a vacuum line, and hooking up a vacuum gauge. Low vacuum indicates you may have a problem with excessively retarded timing, fuel mixture that is very far off, incorrectly adjusted valves, timing chain off a tooth, and then the list jumps into cam problems.
Senior Member
The car being MAF may not make it as tollerant to changes as you might think. My GTA no longer idles until the O2 sensor warms up and all I did is swap to a ZZ4 cam. If you do not hold the pedal down some or the butterflys open until the ECM hits closed loop it will stall out.