Engine Diagnostic HELP!!

[Aspect]

Background: 95 MTX became more difficult to start, requiring more cranking time than normal, and occasionally when driving would buck when the throttle was first pushed down. Then it began to run rough at an idle and you could smell raw gas (catless y-pipe)and see black smoke. It would smooth out within a couple of minutes. Then the check engine light came on. When this situation would happen, the first response from the motor when the gas was pushed down was to try to die.

Engine Check Codes (Key On, Engine Off) 543, 118

So, I then replaced the ECT sensor. It started up quickly and seemed to run fine. It did buck on me once as I drove off shortly (within 100 Yards of the house). So I drove it back to the house. Thinking it may have been something the ECU had learned, I removed the negative cable, turned the lights on, and waited about 1 hour. I waited that long for the coolant temp to drop so I could top it off after replacing the ECT.

New Problem: When I reconnected the battery and tried to start the vehicle, it just turns over. After a few seconds of cranking, the raw gas smell returned. It never did fire back up. I ran the codes again and got a 116 (ECT out of range).

Please HELP!!!!

 

[BlackOnBlackATX]

well code 543 is for your fuel pump, which does sound like it could be the source of your problems possibly. have you tried to test your pump or fuel pressure or anything?

 

[Aspect]

Ist that the code you would receive if the engine had stalled? Which it has.

 

[BlackOnBlackATX]

Aspect:
Ist that the code you would receive if the engine had stalled? Which it has.

::shrugs:: i dunno, perhaps it is. luckily ive never had that problem. but if its taking a while to crank over all the time wouldnt it be a good idea to check the fuel pressure anyway?

 

[Aspect]

Agreed....does anyone have this process documented?

 

[BlackOnBlackATX]

Aspect:
Agreed....does anyone have this process documented?

there should be something in the search about checking it but all you really have to do is get the appropriate gauge and hook it up to your schrader valve on your fuel rail. when the car is idling you should be between 28 and 33 psi. let us know how it goes. you can probably rent the gauge from autozone.

 

[Aspect]

BlackOnBlackATX:

Aspect:
Agreed....does anyone have this process documented?

there should be something in the search about checking it but all you really have to do is get the appropriate gauge and hook it up to your schrader valve on your fuel rail. when the car is idling you should be between 28 and 33 psi. let us know how it goes. you can probably rent the gauge from autozone.

Well, I first have to get it running to check it. It will not run right now.

 

[sdpatt]

The 543 indicates that the fuel pump is not even getting power at times through the integrated relay control module. There may be an electrical discontinuity in the power supply to or from the ICRM. When the car cranks but doesn't start, do you hear the fuel pump run for at least 1.5 seconds? Try turning the ignition key to ON (not START) and listen for the pump. You should hear a high pitched whine for 1.5 seconds from the fuel tank. If no whine, did you hear a "click" from the ICRM above the radiator? If no click, the ICRM or the power source to it is suspect. If you hear a "click" but the pump doesn't run, either the pump or the connection to it is not in operable condition.

 

[BlackOnBlackATX]

Aspect:
Well, I first have to get it running to check it. It will not run right now.

ah ****, sorry i forgot. but scott hit on the head what i could not articulate at first. let us know how it goes.

 

[Aspect]

As I recall, (the car is 87 miles from me right now, but I will have my father verify it for me) when the key is initially turned forward, I do remember hearing the pump prime. I also want to verify the 54X code. It may have been a 542 instead of the 543. Either way, since I can readily smell gas fumes once I start cranking, could the FPR be a culprit? If so, how would I verify it? Especially without it currently starting.

 

[TYSHO]

DTC 542 indicates that one of the following has occured:

No start:
-Interia Fuel Shutoff (IFS) switch was not reset or electrically opened (if in secondary circuit).
-Open circuit between the fuel pump and FPM circuit connection to the power-to-pump circuit.
-Poor fuel pump ground.
-Fuel pump electrically open.

DTC 543 indicates a fuel pump secondary circuit failure between the B(+) supply and the FPM connection to power-to-pump circuit.

possible causes:

No start:
-Open circuit between the B(+) supply and the FPM connection to the power-to-pump circuit.
-Fuel pump relay contacts always open.


DTC 118 indicates that the corresponding sensor signal is greater than the Self-Test maximum. Maximum is 4.6 volts.

Possible causes:
-Open in harness
-Faulty connection
-Faulty sensor
-Faulty PCM

DTC 116 indicates that the corresponding sensor is out of Self-Test range. Correct range of measure is 0.3 to 3.7 volts.

Possible causes:
-Low coolant level
-Faulty harness connector
-Faulty sensor


From the last test you took regarding the 116, I'd focus on the last 3 possible causes. All of this information was from the KOEO test results as you said it was.

<small>[ July 08, 2003, 08:34 PM: Message edited by: TYSHO ]</small>