<img src="/forums/images/graemlins/frown.gif" alt="" />

Only the 2nd time in our roughly 12 years together. Can't complain too much I guess.

I drove my Monty to work yesterday. Cranked right up in the morning and had no issues on the way there. But when I tried to start her at the end of the day she wouldn't start. The starter motor is getting plenty of juice. It's turning the motor at normal speed but the engine won't start.

I know its silly to say "my car won't start. What's wrong?" but I do have some specific questions.

Some info first:
I have had intermittent hesitation or momentary losses of power over the last 4-5 months. Usually just barely noticeable. Check Engine light has been coming on for about the same amount of time. Code is "Throttle Position Sensor / Idle Speed Switch". I wouldn't think this is related to my current problem.

Again, don't think this is related but...when I was testing the TPS (VM measured resistance within normal range) I unplugged the connector to it. I realized as I was troubleshooting my no-start that I never plugged it back in. I plugged it in and tried to crank again. No difference. I thought maybe the ecu had freaked out trying to compensate for no signal so I disconnected the neg batt terminal to reset the ecu. No difference.

So now my newbie questions:

1) Even with all the repeated start attempts I could not smell fuel anywhere. Even took air filter out and couldn't smell fuel in air intake hose. This is a fuel-injected engine, is fuel smell from engine flooding something I should be able to detect? I know that applies to carb'd engines but does it apply here?

2) I suspect a global problem with either ignition system or fuel delivery system. What's the best way to narrow it down?

3) Any other things I should check? I checked ignition wires, sured up all vacuum lines and connectors I could find.

Thanks for any suggestions and sorry for the long post.

-Ray

Check for spark at plugs first. Disable fuel pump, remove one plug and ground, then crank engine. Need bright blue spark for ignition.

Neutral safety switch?

I don't think the engine would turn over if NSS problem.

Thanks!

PCC: Will check for spark tonight after work.

LR: Yeah, I occasionally do have that problem, but engine won't turn in that case.

If it cranks for several turns (5-10 sec) and you don't smell fuel (from outside of the car), then I'm thinking fuel. The engine may not be getting fuel(pump relay, pump or injectors not firing may be the cause).

The guys are correct though to tell you to check for spark first. No spark, no fire. No fuel, no fire. Could be either.

Do the Gen I V6s have the fuel pump test jumper in the engine bay?

Test for spark. If the ecu does not see spark (tach signal), it will not inject fuel. You should smell fuel at the tailpipe if it is injecting and not firing. Test the ecu for codes. If nothing at all, ecu is dead (probably leaking caps).

Fuel pump test connector is either near the timing connector (dside firewall?, can't remember color - see fsm wiring diagram - just had a brain poot, and it may be near the ecu somewhere). If you supply 12v+, the fuel pump is supposed to run. With the engine off, you should hear it. If you remove the solenoid connector from the starter and put the key in start, you should hear the fuel pump run, and you've just tested the FI/ecu/fuel pump relay as well, another possiblity.

THe wiring under/around the coil and bracket are suspects, as is the power transistor on the coil bracket (the square black thing). The power transistor is what triggers the coil to spark by breaking the coil ground path, which act sends the tach signal to the ecu and the tach. Does the tach show any action while cranking?

aha!

Will try to find that test connector (smart idea to include that in the design). No fuel smell at tailpipe or anywhere else so pump is not running. Will also inspect components around the coil. There is no tach movement when cranking. After d/c'ing neg battery term and reconnecting ecu reads normal.

Great info and thanks everyone! Well, I'm home with the sinus cooties so back at work she still sits. I will report back on the findings and process for future newbs.

You guys are amazing.

Fuel Pump Test Connector





Just to be clear, are you talking about 2 different methods of testing? Or do you need to disconnect the starter solenoid connector to use the 12v test connector?

I finally had a little time and energy at work yesterday...but not tools <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> . So I unplugged one of the plug wires and placed a test lead between the spark plug and the plug wire and saw a spark. It was a bright blue color, but not as thick or intense as I would have expected. It was about the thickness of a piece of sewing thread. That sound all right? I could stick a multimeter in there and measure current / voltage if anyone knows what figures I should be looking for. I'll dig around and see if I can find that info.

For lack of tools to go any further, I also pulled the cargo area carpet and had a coworker listen at the access plate for pump noise and nothing was detected that way.

I won't be able to work on it again till Monday. Going to price a new pump / relay in the meantime I guess...