Symptom - Car will run fine 90% of the time. Sometimes, after the car is warmed up and running great, I will shut it off to get gas or somthing like that. When I go to restart, I get the SES light and as soon as I hit the gas, the car dies. Sometimes it will crank right up, sometimes not.

Ok, this has been going on for months and I'm finally narrowing it down and only getting one code...code 54.

#54 = Low voltage at fuel pump
Low voltage at fuel pump relay
Output failure at quad driver module

What is the quad driver relay? This is the only part of this code that has not been replaced in the last 6 months.


How do I go about testing those three things and whats the best plasce to start?

 

check yoru connections at your fuel pump relay. i purchased a welbro 255lph kit. when i purchased it, i opted to get the additional wiring harness.
http://www.racetronix.com/product/RX..._Pump_Kit.html
it is supposed to help the pump out alot. i also have the factory fuel pump that i had that was working really good. hit me at jonnyblaze4_2k1@yahoo.com if your at all interested.

 

Just been told that the quad driver module is actually inside the ECM itself. I'm beginning to think that the new ECM they installed is a piece of junk. I think I'll take it oua dn run it down to the dealership.

 

Test the signal at the fuel pump voltage sensing input to insure that you have at least 11.8V when the pump is running.



If you do, go here:

http://www.batauto.com/articles/quaddriver.shtml

 

Vader - Thanks for the link, but I have one question. Does the TPI system have a Quad Drivers Module? I looked on the chart and it only shows a 5.7TBI...no TPI.

 

Aye, Rock

A.F.A.I.K., the carbed cars had the quad drivers with sensing circuits. TPI did not. Your error code should be for the fuel pump voltage.

 

Alright, finally got everything put back together and found the connectors I needed to rebuild the FP relay harness. However, no freakin luck...got more problems.

Replaced the fuse for ECM near the battery
Replaced FP relay and FP relay harness
Start car, starts right up, but I get an SES notice
Turn car off, pull code 54 again
Start car, starts great, runs, no SES light
Turn car off, try to start again and it won;t start
Pull code 54 again
Try to start again and no SES light at all, even at acc
ECM fuse is blown again
Pulled relay, tried another relay
Blew another fuse as soon as I plugged it in

Somebody tell me some good news. Heck, I'll even take bad news, anything.

 

Just for clarity, have you replaced or disconnected the oil pressure switch to take it out of the circuit? It could be shorting internally and pulling down the FP circuit voltage.

 

No, haven't done that yet. Right now i can;t keep the fuses from blowing out. If the Oil switch is shorting internally, would that cause the fuses to blow out like that?

Oh, one more thing...where is the oil pressure switch?

 

The problem seems to be coming from either the orange or the red wire from the fuel pump relay. One of the two is grounding on somehting causing me to keep blowing fuses. How feasable would it be to cut those two dead and simply run new wires?

 

Eye,

I'm not certain on your '89, but an '86 has the pressure switch right next to the distributor. There is a "T" fitting that plumbs it to the oil pressure transducer for the dash gauge. Newer cars have a switch on the left side of the block, down near the oil filter. Yours could be either place, but if the fuse is blowing immediately, that could be at fault. Take it out of the circuit to see. You should be able to simply unplug it.

 

The quaddriver is present in TBI and TPI ECMs.

What harness did you replace and why?
If you are blowing the ECM fuse, then if you have throttle body injection, check the 2 injector wires and see if they have rubbed on the throttle body.

 

Dirtrocker - Thank you for the help, but I do have a TPI motor.

Vadar - I appreciate the pic, it;s so much easier to have a pic when dealing with stuff like this. I'll check it out tonight.

 

Maybe tonight will yield something, I'll give the O/P switch a try and trace over the rest of the F/P wiring as well.