Car not starting, how to diagnose

Madman_DSM · 10-17-2009, 06:14 PM

My car refused to start today. I drew few laps around the city, stopped, went outside, came back and no go.

Disconnected the battery, ran KOEO test, error 542 "Fuel Pump circuit open; PCM to motor"/"Fuel pump open, bad ground or always on - - ". From the sound it seems that fuel pump is not working during KOEO.

I've seen this code before, but the car was running fine. Now it won't start, it'll crank for hours, but no start.

The fuse under hood is not damaged. The car was hitting with electricity when I was getting out of it after cranking. Now it doesn't do that.

Do you know how to find an open wire if it's the case or what should I diagnose?

Where is the fuel pump wiring going through?

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PRO50SC · 10-17-2009, 08:49 PM

First you need to determine why it's not starting. Is it b/c there is no spark, or no fuel? What have you checked?

mjr46 · 10-17-2009, 10:49 PM

http://sbftech.com/index.php/topic,588.0.html

Madman_DSM · 10-18-2009, 08:23 AM

Quote:

Originally Posted by PRO50SC

First you need to determine why it's not starting. Is it b/c there is no spark, or no fuel? What have you checked?

No fuel, it was sort of sputtering at first, then it was just turning over, also, no pump sound, and 542 code. Sorry I didn't make it clear.

After going through a lot of wires I traced it down aftermarket immobilizer (secret switch) problem, now the car is running again.

Quote:

Originally Posted by mjr46

http://sbftech.com/index.php/topic,588.0.html

Thank you, this is a very useful link. I will bookmark it. Since I don't repair cars every day I tend to get sidetracked by some stupid, unrelated symptoms most of the time.

Still, I will have to check that 542 code though, because it seems it's persistent even the car runs just fine. It's quite possible that guys who were adding the immobilizers and alarms, did something wrong. I will reset the codes and if they'll come back I'll have to do some wire tracing.

By the way, do you know where the fuel pump relay is on a '95 GT?

mjr46 · 10-18-2009, 08:31 AM

the fuel pump relay in a sn-95 is incorporatted as part of the CCRM = constant control relay module and is the black box on a bracket on the passanger front side by radiator