I was only showing off for a minute or so...

[DJ 95 Formula]

So for the first time in a very long time I did a couple burn outs showing off to my wife. My first burnout was nice and the second was on its way to being better when all of a sudden I hear a pop from the engine bay and the bird loses engine power and stalls. Mind you its very dark out, I jump out. pop the hood and using my cell phone try to inspect the engine bay. No fluids are found on the ground or splattered anywhere else. After my visual inspection finds nothing I decided to try to start the car again. I turn the key, and that brandy new starter rotates the engine with a vengeance but the car does not sound like or appear to be starting. I let off the ignition and the car is running, very lopey, like a car that is running out of gas or a timing mistake. It won't run for more than a few seconds though.
The next day with the sun at my back I visually inspected the motor again and can't seem to find anything standing out. Still no fluids on the ground or anything.
So where to begin?? The engine rotates, and will start but very lopey and will only run for a few seconds, pressing the accelerator helps nothing.

Thanks,

DJ

[Joe 1320]

Is there a check engine light?

I would check for spark at each plug. it could be the optispark took a crap.

[Craig 94 TA GT]

My guess is that you grenaded your optispark. The pop could have been fuel loading up, then igniting somewhere in the exhaust manifolds.

But in order to properly diagnose, you need a scanner. Check for codes to see if its the optispark distributer. Also, check to see if you have proper spark - you can do this a number of ways, through the plug wire, plug, or a timing light. It could also be the ICM or coil.

If you verified spark is there, get a fuel pressure gauge to see if you have fuel going to the rails and injectors. You should see a minimum 37+ at idle and 5-7 more with the vacuum line removed from the fuel pressure regulator. It's located on the back of the intake manifold with a hose attached to the side of the intake manifold.

What RPM were you doing your burnout at?

EDIT: Joe beat me to it!

[DJ 95 Formula]

thanks for pointers

The check engine light is on, problem with that is that it has been on since my cat backed up a while ago. After fixing that cat I never reset the computer and the light never cleared on its own from that day.

The pop definitely sounded like fuel in the exhaust manifolds so I think you are right about that.

Here is where I really kick myself in the ass... I replaced the water pump earlier this summer and due to $ at the time decided not to replace the Opti while I was in there.

That particular burnout I am not certain of the RPM other than red range. At first I hit the rev limiter and backed off but I know I was still up there, 5000+.

[Injuneer]

If the SES light was on after you fixed the cat, you didn't cure the problem that turned the light on in the first place. If you fix a problem, the code will stay in history, and the SES light will go out. If it was still on you should have scanned it again. It still had (and still has) an active trouble code. Even the stored code will self-clear if you've solved the problem and it does not happen again in 50 or so "drive cycles". Its a mistake to drive it with the SES light on.

You need to scan it.

Is it possible the "pop" was a true "backfire", with excess fuel in the cylinders exploding at the wrong time (intake valve open) and blowing back into the intake manifold? Make sure the inlet elbow isn't blown off the throttle body. Make sure the vacuum lines are all still connected. Check the wires in the MAF sensor for damage.

An upset in the Opti, carbon tracking, cross-firing, failing optical signals can cause the engine to backfire through the manifold.

[DJ 95 Formula]

lesson learned the hard way

I have certainly learned my lesson now about the SES light. I have put off long enough getting the cable for my laptop. I just ordered one last night and will get it scanned ASAP. I have been putting off a few things like the coolant level sensor is not working as the coolant is full but I still receive the dummy light in the car... So i might take care of that now that I will be in the area again....

I am convinced the pop I heard did come from the intake. The lopey idle came right after the pop.

[Craig 94 TA GT]

Fred mentioned a great point - check the MAF. Remove the connector to the MAF to get it to run in speed density mode. Try to run it like this. It will throw the SES light and store an MAF code, but if the MAF is the problem, it should run with it unplugged.

[DJ 95 Formula]

It just keeps gettin better

SO, I had gone and physically checked the MAF and the connector was already unplugged. Now I don't know if I happened to unplug it back when my cat plugged up on me or what. I really do not remember unplugging or removing the MAF. I am thinking though that it has been unplugged from about the time the cat backed up. Using Freescan today, thanks to my awesome new cable, i received the Code 48 for MAF system failure. Since I found it unplugged I decided to plug it in but the car wont start up more than a couple of dieselly idles before it konks out again. That is the only code that I appear to be getting.

If I plug the MAF in, reset the codes through freescan, would that clear the code temporarily or possibly permanently if the MAF is not a problem?

The car will not start up so so I don't believe all sensors are turning on right away. If there were other codes I imagine I would be seeing more as I have not performed any type of reset since this issue began.

for the heck of it I am attaching two files zipped together. The status log file and the engine data log file. One item that sticks out to me right now is the desired idle being over 3000, what is that all about?

For now my next step is going to be taking apart the air intake right up to the throttle body just to check for anything out of the ordinary. I am also going to check fuel pressure once the fuel pumps kicks on and off. Unfortuniately I can not check anything while running because it will not start. I can barely get the couple seconds of lopey idle now that the car is nice and cold I am guessing.


Thanks, DJ

[Craig 94 TA GT]

You are correct - if you reset the codes, plug in the MAF and run it, the MAF code should not re-appear if it's in working condition.

I can't tell one thing from your scan because the car is not running. The desired idle is fine - it is dependent on conditions of your car. Not running will have some default value set. Is it possible just to crank it over while scanning? If it catches for a second or two, maybe something will stick out. However, we probably wouldn't see much, since it's just starting.

EDIT: I cross referenced my scans with the car off and noticed one thing really stands out. Not sure if means anything but your injector pulse widths are at 40. I'm not sure if it still opens with the car off, but mine are 0 when off. Are your injectors stock? I also notice that your timing is set at 7 degrees when off? Mine is also 0. I wonder if these are differences in the '95 PCM, or if something's up with those items on your car. If you can get a fuel pressure gauge, that would be great.

[DJ 95 Formula]

update

Attached are logs from todays test. I confirmed spark on the 3 front plugs on the drivers side. I didn't jam my hand around for the rest yet. Attached is the log files from ECU while trying to start and you can see where I press the gas pedal as well. There are some different readings here that I didn't get the first time.

I might try to check the rest of the plugs though I think I am going to send the car off to a shop soon.

Drop the .txt off the csv file to open it into excel.

DJ

[Craig 94 TA GT]

Are you trying to start it when the RPMs go up? If so, I'm almost certain your opti is shot? Fred is an expert on this, so you might want to wait for his opinion, but it really looks like it's the opti is dead. Your RPMs are so low - your cap and rotor might still work, but the optical sensor might be destroyed. What also gets me is your injector PWs. They're so ridiculously high, I don't understand what's the deal. Maybe in '94 to '95, Freescan changed something, but I'm used to seeing 2 or 3 pw at idle. If that really is ms, your injectors are open so ridicously long, then it goes to 0, and back up to 70s.

[DJ 95 Formula]

answers

When the car does start.. only for a second or two, I cannot actually hear or tell because of how barely it is running. When I let off the ignition the motor diesels and stalls almost immediately with a spuddering almost intake backfiring sound. I am trying to make sure it is the Opti which I figured if I get spark on every cable then it might not be.. I am worrying there is something thrown or blown in the valve train.

I guess the answer to your first question is it is highly possible I am still trying to start it when the engine actually fires and begins its dieseling. The engine never appears to fire and take off in excess of the spin of the starter.

Checking on fuel pressure.

DJ

[Craig 94 TA GT]

So in the scan, the RPMs showing 100-200 RPM is it actually it trying to start? I'm not too knowledgeable on the opti, but I'm wondering if it's possible to still have spark, but a no-start condition if the optical sensor is messed up. Say the opti is reading the crank is in the wrong position, or not reading at all - I don't know if that's possible to cause a situation like this?

[FTA1995]

If the optical sensor is jazzed up enough, the pcm will not send a sig to the ICM to fire the coil, BUT that's only if the pcm recognizes an optical sensor failure. Try this out of curiosity, disconnect the vacuum harnes to the opti at the manifold and the other part from the intake. Blow into the manifold end without the check valve. listen for any type of tiny plastic sounding rattles in the body of the Opti. In my sace, i blew mine badly enough to where I was actually blowing pieces of opticrap out of the intake elbow side hose. If that happens, go with the opti. Otherwise until then, as fred said, scan scan scan.

[FTA1995]

When the car does start.. only for a second or two, I cannot actually hear or tell because of how barely it is running. When I let off the ignition the motor diesels and stalls almost immediately with a spuddering almost intake backfiring sound. I am trying to make sure it is the Opti which I figured if I get spark on every cable then it might not be.. I am worrying there is something thrown or blown in the valve train.

I guess the answer to your first question is it is highly possible I am still trying to start it when the engine actually fires and begins its dieseling. The engine never appears to fire and take off in excess of the spin of the starter.

Checking on fuel pressure.

DJ

Whoa whoa whoa, the motor 'diesels?' There is no way that can happen in a fuel injected car, unless there is a very large amount of fuel blowing past the injector pintles AND some really heavy combustion chamber burs. I tried to look at your second log file, but its way too unorganized to read for me. Since it seems like you're till kind of dead ended here, I would suggest hooking up a small cheap inductive timing light. see what your timing is while cranking, on that note,have you checked for spark at plug level? If you have no spark or a messed up spark at any given plug, test for spark at the coil. I use an old plug and a screwdriver to ground it out, don't shock yourself.

Post your cranking timing that you find, if you get a reading at all. You'll probably have to post a timing mark kit on your balancer, doubt it will already have one but you might.