To reset base idle...

[JMK]

I have a '94 with the 3.9L. There are a few issues I have with it right now. The first is that I have low fuel pressure (about 30psi at idle) and it drops to 0 on shut down. It bleeds down in the time it takes me to kill her and to get back to the gauge. The book tells me to R2 the pressure regulator. Its been hard to start lately. It usually takes a good 5-10 seconds of cranking to get her running. The last issue is that apon engine start she idles at roughly 1800 RPM for a moment then kicks down in increments of roughly 250RPM until it reaches its true idle. That lasts for about 30 seconds. The cute little code display I have under passenger seat shows 48, which says to reset base idle. Cool. I have a few questions based on this info: Could these problems related? Do I need to adjust the base idle when it is at 1800 or wait for it to settle to 600-700? I would think the latter. Is there anything else going into this that I should know before hand?

Thanks

JMK

 

[vray]

I would check fuel pump, fuel filter before anything else. The fuel pressure procedure is posted but I can't remember which thread, try the search function... Fix the fuel pressure issue and the rest of the problems may go away with any luck.

 

[JMK]

I would check fuel pump, fuel filter before anything else. The fuel pressure procedure is posted but I can't remember which thread, try the search function... Fix the fuel pressure issue and the rest of the problems may go away with any luck.

The fuel pump and filter are more or less new. About 15 months for the pump and 6 for the filter. There are 2 procedures for fuel pressure checks. One is at the fuel rail. The other is at the fuel filter (this one I have not doen as I dont have the correct fitting for it.) As mentioned in my previous post I am getting a code 48 which leads to the stepper motor/base idle and further to tests 15 and 16 of continuity test procedure. Whatever that is... Apon further investigation code 48 also suggests a possible problem with the speed sensor. Which refers you to test 25 of continuity test procedure, and I have no idea what that is or what it entails. I would much rather leave luck out of it if I can help it.

JMK

 

[ptschram]

You have badly leaking fuel injectors. Clamp the supply line while it has pressure and if it bleeds down, it is the injectors. If it holds pressure, it's the pump.

 

[JMK]

You have badly leaking fuel injectors. Clamp the supply line while it has pressure and if it bleeds down, it is the injectors. If it holds pressure, it's the pump.

Thanks I will try that.

JMK

 

[JMK]

Ok changing out the fuel pump assy fixed the problem. How does low fuel pressure effect the idle speed on start?

Thanks once agian.

JMK