Not Starting, need help diagnosing.

[brittxmx3]

I bought my car (93 GS V6 5sp unmodified) knowing it did not start and I am running through the diagnosis process; here are the symptons:

Car would start, run for a few seconds then die.

It sounded sweet before it died.

Then I had it start, it was idling so after it had reached running temperature I blipped the throttle, it sounded a bit rough for a moment and then it died.

Since then it shows no sign of it starting whatsoever.

So I checked the fuel pump and relay via the diagnostic box (they are fine). Cleaned, then replaced the VAF, checked the intake system for cracks/leaks and found nothing.

So now I am heading for the ECU and distributor. So my question is, how can I check to see if the problem lies in the distributor? I took the cap off, cleaned up the contacts and end of the rotor arm which were pretty awful to no effect and it was running sweetly before (momentarily) so that was clutching at straws. If I pull a plug and find it does spark, that still does not answer my question as to whether it is the distributor or ECU (if they are the culprit), same if I find no spark.

Or of course I may be barking up the wrong tree so any suggestions are welcome.

I popped off the timing belt cover and the belt is in good condition.

Thank you for any responses.

[Ryan]

Sounds like a classic distributor to me.

I'm too lazy at this exact moment to write it out for you, but if you use the search function, you'll find it.

[davmac]

Sounds like you know how to pull diagnostic codes and luckily you don't need to start the car to do so. Please see what codes you are getting and post them. There are several that would suggest distributor as the culprit but you may have another unrelated problem.

Other things to check:
spark plugs - pull these because it is easy and gives some indication of engine condition by their appearance NGK copper plugs work great and are cheap so you might just replace them so you know they are good
spark plug wires - at least check resistance or if you can replace them unless you know they are new
Air intake tube and the miles of vaacum tubing. You need to carefully inspect to be sure no hose is disconnected and the air intake tube is not cracked and leaking.
Connectors on the throttle body: IAC (underneath) and TPS (along the side) - make sure these connections are solid
Adjust TPS (search at this site)

[Daninski]

Swap out the disty and you should be gold, however taking out a spark plug and checking for spark would be the optimal starting point I think.

[crazycanadian]

3 things you need for a car to start... Spark, fuel and compression.... Since the car runs well when it does run I'd say you are loosing either spark or fuel... And I wouldn't bet on any mechanical problems with the motor...

Go buy your self a cheap $5 spark tester that allows you to open up the gap... This will help tell you if you have enough spark to actually fire the cylinders... Using a spark plug hanging out side of the cylinder only gives you half the picture....

If you have spark and its not firing, then check for fuel pressure... (don't just crack a line see it spray and say hey I have pressure) If you don't have a gauge actually disconnect the line, run it into a bucket get someone to crank it or at least turn the key on and see if fuel poors out at a good rate....

If you have spark and fuel pressure but still not starting you'll need to check injector pulse... This is easy to do with a test light... Unclip and injector, loop the light between both terminals and see if the light blinks when you crank it...

If you have answers to all of that, then you can get better answers as to what the problem is...

[brittxmx3]

Thanks for all the help. Pulled a plug, no spark.

So pulled the distributor, looks like some water has got into it at some point:



So time to order another distributor, will post back here as soon as I have installed one.

To answer some of the questions. From the diagnostic box I could not pull any codes, the check engine light goes out after a while. Spark plugs look fine, they were replaced 1,500 miles ago apparently when the car had quite a service; including a new clutch and the brakes were overhauled.

List of jobs getting shorter...

[brittxmx3]

Switched out the distributor and still not getting a spark. Unfortunately someone has spliced the loom here and there, so I may have to re-do the splices. Hate cars that have been messed around with like this! However it did start before so I will assume it is not a splice issue.

I was planning on doing the HEI mod, so I will get that done and see if that makes any difference. Just hoped I could get it working first so I was not wondering if the HEI mod was bad.

[Daninski]

Not surprising you had water in the disty the gasket is missing between the cap and disty body. Check again for spark, if the new disty is a good one doing a HEI mod won't fix your problem.

Edit; Have you checked your main engine fuse yet?

[brittxmx3]

Going to hook a test light up to the plug entering the distributor to see if it is getting a signal from the ECU. Yeah I realise if the distributor is good the HEI will make no difference, but at the moment I cannot make the call that it is good. So as I am doing the HEI anyway, may as well see if it cures it.

[crazycanadian]

The test light trick would only work if you are hooked up to the coil... not sure where you are hooked in...

Get a wiring diagram and do the basics.. check for power and ground... If you have that but still have no spark then you'll need a lab scope to go further..

Also while you are at it.. did you have the cap off and just make sure when cranking that the dizzy is rotating??

[brittxmx3]

Well finally had some time to do a bit of work, good job I do not need this car until June! Did the HEI upgrade and now I have a spark, but not a very convincing spark. I was not happy with the way I installed the post in the distributor cap and I used an old distributor cap and did not replace the rotor arm. So now I am thinking of re-doing the cap with a new cap and getting a new rotor arm. I am also thinking of taking the positive feed to the coil to a relay and running a new feed direct from the battery through the relay; so I am sure of a good 12v at the coil.

I did try playing with the timing a bit and managed to get hit by the high voltage whilst twisting the distributor, so something is definitely not quite right. My wires are pretty awful too. Maybe a combination of all of the above and new wires will yield a better spark.

Oh when I yanked a plug I could smell fresh gas on it.