LT-1 issue

[ss3011]

Make sure the MAP sensor wiring, and sensor is OK. If you removed the sensor, from last year, make sure the seal to the intake is in good condition.

[John Nechiporchik]

I'll check that . I did remove it since last year.

[Jim Whitehead]

Use a OHMS meter and sweep test the TPS sensor.

[Alan Roehrich]

If the fuel pressure drops fairly soon and/or quickly after you shut the vehicle off, you need to test fuel pressure and volume, as well as determine whether or not the fuel pump used has a check valve. If fuel pressure did not drop when the car ran before, but does now, I suspect the pump is supposed to have a check valve, and there is now a problem.

[Dyno]

Broken ignition rotor.

[John Nechiporchik]

Dyno, Brand new MSDcap and rotor.
Alan, How would a faulty check valve in the pump react?
Will check the TPS for sweep again. Checked it in the fall and it was OK.

Re-terminated 3 TPS leads as the old terminals seemed loose. This did not solve problem. Also pulled back timing to 36......no difference.

[Alan Roehrich]

The check valve retains fuel pressure after the pump is turned off. For example, a stock or stock replacement pump will usually retain 90% or so pressure for several minutes. If your pump retained a significant amount of pressure last year, for a significant period of time, and this year it bleeds off a substantial amount of pressure fairly quickly, then something significant has changed. Since that change is accompanied by a performance/driveability problem, that is where you should look first.

I would think, and I may be wrong, that 45 psi is a little low. It would seem to me that you'd want to run closer to 55-60 psi if you can build that much pressure, and use a shorter duty cycle on the injector to maintain the A/F ratio the engine likes.

[Dave Noll]

Originally Posted by John Nechiporchik

Re-terminated 3 TPS leads .

Umm ..... just a thought. The wire's didn't get mixed up did they ?