jfb

That is a good sign, but a better test is the one I described, bring a grounded wire close to an unplugged spark plug boot and see if you get a snappy at least 1/2" spark during cranking. Weak spark can prevent your engine from starting. Your 93 has an Opti-spark distributor and spark timing is taken care of by the distributor with no marks on the flywheel to check spark timing and no means to change the timing.
What fuel pressure did you measure? How long did it hold after you turned the ignition off?
Do you have injector pulses on each cylinder bank when cranking?
What happened when you sprayed starter spray into the MAF?
What cylinder pressure did you record?

JAKE

[QUOTE=jfb;1574924849]You do testing to reveal what vital element is missing that prevents the engine from running. I don't accept that every vital element is there (hot spark, spark timing, fuel and air and in the correct ratio, and cylinder compression) and yet the engine will not start. Somewhere you have failed to test one or more of these elements.

Did you have at least 1/2" of spark?
What was the spark timing?
What was the fuel pressure and how long did it hold up?
Did you see injector pulses on each cylinder bank?
What happened when you sprayed starter fluid into the MAF and then cranked the engine?
What cylinder pressure did you measure?

I understand your frustration and myself and others would still like to help you get your engine running. Giving up will fix nothing!!!!!!!!!!!!![/QUOTE]

I totally agree but if he's actually given up there's not much we can do.

Jake

JAKE

That'll show you the spark is traveling down the wire but won't give you a visual indication of its intensity. The distance the spark can jump to ground and its color help more.

Jake

surfer93

Well throwing money at it did not work, lets diagnose.

With some one in the car turning the key, pull the injector plugs off and check for voltage.

ECM's rarely go out completely, also I have found them everywhere. When I looked for one for my 93, I found 6-7 places with them in stock.

Did you check for an injector(s) stuck open, i.e. OHM the injectors to see if they went out or clamp off the return line to check for open injector or bad FPR?

I have a 93 and just got rid of a 92 and I can say they are not hard to diagnose, if you use the FSM.

FSM has really good steps to diagnose problems like this. I do not have mine with me or I would help you more, but ask someone with a 92-93 FSM to send you the No Start diagnosing procedures.

93cruiser

My icm went out completely. However it did give 3 miles of notice that it was going out.
FWIW

dmclaws

OK............so let's just say "if" I tested the spark as descirbed and it was weak. Does this indicate the opti is bad?

As for the injectors they were checked for voltage & were OHMed out 2 weekends ago. Checked out fine.

dmclaws

Thinking back over the past 1-1/2 years, let me add a couple of more bits of information and see if it has anything to do with the issue................

Back in the fall of last year the AC compressor stopped. When I took it to the repair shop I was told it was the compressor. Did not get fixed and AC still does not work. On or about this same time the horn stopped working.

Also, I can't pin point the time although I believe it was earlier this year when I noticed a distinct electrical type burning smell like plastic. I could not see or identify anything at this time and the car basically ran fine until this latest issue.

Between January and March of last year the car would selectively start (approximately 6 times). It would start everytime upon jumping and finally in March I replaced the battery. There were no other starting issues until the end of June of this year. As my son has been driving the vehicle daily I seldom drove for the past year. However, there were a few occasions when I noticed a slight hesitation when taking off from a light although nothing really caught my attention.

The car has 120k miles and the 1st opti was replaced at around 75k in March of 2004. The opti I just installed was purchased from Mid-America.

Don't know if any of this helps.

surfer93

Injectors can be bad and still OHM out perfect, you can get impurities in your fuel and block open or clog injectors.

Did you have your coil tested?

Did you check your TPS?

Have you checked FP while cranking engine?
When my pump went south, car would idle for a second, then die.

Check voltage at injectors to make sure they are pulsating and not constant voltage?

Did you check the ECM connectors?

dmclaws

Coil replaced 3 weeks ago.

Not sure how to check TPS

FP was good but did not monitor while cranking.

Not sure what you mean by pulsating injectors

ECM connectors have been on and off several times

surfer93

Coil replaced 3 weeks ago.

Not sure how to check TPS
Do a search on it or PM Toptechx6

FP was good but did not monitor while cranking.
How do you know it is good then?

Not sure what you mean by pulsating injectors
Injectors fire via an electrical pulse, if you are getting constant voltage, ECM is most likely bad

ECM connectors have been on and off several times
But have you checked for broken/bent pins or bad wires?

JAKE

An EGR valve sticking open can cause a low A/F ratio during cranking. This can cause a no start condition.

Unless the engine enters Clear Flood mode at the first indication of flooding condition a no start condition may result. Clear Flood means your foot pressing the accelerator pedal to the floor; shuts off the injectors.

Check duct work between MAF sensor and throttle body for air leaks

A malfunctioning MAF may cause a no start or stall after start condition. Disconnect MAF and the PCM will default to speed density to calculate load and airflow. If this results in a start, and the connections to the MAF are okay, replace the MAF.

Improper fuel system pressure (41-47 psi is the recommended range needed) will result in one of these: Engine cranks but won't start; cuts out (which may feel like an ignition problem); poor fuel economy; loss of power; hesitation, and error codes.

Many other tests can be done but they call for a scan tool, test light, etc.

Hope this helps.

Jake

JAKE

If it gets to that, check with ECKLERS, TPIS and even one of the re-programmers many of us use, like PCMFORLESS or SOLOMON.

The PCM takes care of all the timing issues; it's not adjustable except by re-programming the computer.

BTW, what year are we discussing? Oh, I see now, a 93; got it.

Jake

surfer93

92-93 are speed density, so no MAF.

JAKE

Ah, yes! So right away that makes me ask has the MAP sensor been checked? I'm not all that familiar with Speed Density systems but I DO KNOW how sensitive they can be to mods.

There should be a Trouble-Shooting Section in your FSM on how to check the MAP sensor for proper operation. If you don't have FSM for your year getting one would be at the top of my list - believe me this won't be the last time you'll need it.

Now, we need to kick around the smell of smoke, etc., you posted on earlier. Makes me wonder what wiring damage was done when that happened.

Could be something that took time to surface as opposed to an immediate failure. I think we need to look more closely into that incident.

Did you ever track down the cause?

In what part of the engine compartment did this happen?

Has anything in the car stopped working since then?

Anything that's become erratic, intermittent, etc?

Jake

dmclaws

Catching up from the 8th...........
* I'll check the TPS
* I'll retest the FP
* How do you test the injectors?
* The ECM pins/wires all check out OK

As for the burnt electrical smell I actually smelled this inside the car. However, the horn does not work nor does the AC. I tried to give somewhat of a 2 year timeline a couple of weeks ago as to a few issues related to the car. I've owned it for over 7 years and it has performed flawless until 2 motnhs ago and has been sitting ever since.

94vettelover2

$1000 & I'll come get it.You already verified you have spark.Now buy or rent a noid light set from a auto parts store & check for injector pulse.I'm assuming you have compression as the car would sometimes start before.Is your security light flashing?Try using a newer ignition key or have a spare made.Post your fuel pressure readings.If you rent a fuel pressure tester from an auto parts store,keep in mind that it could be faulty as its not well taken care of & is not a quality made part compared with a Snap-on or other high quality fuel pressure tester.I had this happen to me when I rented a fuel pressure tester from an automotive parts store to check for a running issue.The car would start & run but the tester read zero pressureHang in there

jfb

A fuel pressure gauge costs about $12. You can make your own noid light with an LED (light emitting diode) and a series 680 ohm resistor. You must connect it with the correct polarity to the injector socket. You can try it both ways. When cranking, the noid light should pulse. Try spraying starter fluid to see if the engine will start on it. If it does, then you have a fuel delivery or quality problem. Fuel pressure should be 35-42 psi and it should hold up for at least 1/2 hr with the ign off, this tells you that the injectors are not leaking, nor the fuel pressure regulator has a defective check valve. Fuel pressure should hold relatively constant during cranking and engine running. Take a grounded wire and hold it near the boot of an unplugged spark plug wire and have someone crank the engine a few revs. You should see a snappy at least 1/2" spark. Engines won't start on weak spark.

dmclaws

Answer this..............when spraying starter fluid into the intake, flames blew back out. The car appeared to want to start.

Burned the hair off my right arm!!!!!!!

Mikes1991

Check your grounds. There is a ground behind the battery tray and one on the block by the starter I believe. Clean them up and use a little dieletric grease. Also check the wiring harness to the opti scuff the contacts with a neddle and check for resistance. Did you scan for codes on the ecm and ccm to scan codes for ecm ground ab terminals and turn key to run position for the ccm ground a to g. Also try tapping your ecu a few times lightly to see if it starts. I can shut my car off by tapping mine. My ecu goes out tom for repairs. My local pep boys rep is sending mine to borg warner overnight shipping and tested and fixed for only a 125 bucks so Im going with that deal. Dont give up just be systematic and when your tired of it testing etc just walk away for awhile and come back latter thats what Ive ben doing as I have had a similar problem only now I have narrowed it down but man did I have to do a lot of testing. What about the fuses are they all good. Keep us posted as this helps everyone else to learn. Best of luck

Mike

Mikes1991

so there is spark in the cylinders at least lol