Help Please

John Robinson · May 5, 2006

I posted earlier being stranded when my car quit running. Today I had the codes checked and it did not have any codes. The engine turns over fine.

I have checked all the fuses for the fuel pump and ignition and they were fine.

I even tried a different key and disconnected the battery to reset the ECM.

Has anybody had this kind of experience? Any thoughts would be much appreciated. I am looking at fuel pressure,pumps, relays etc. some direction from you folks would help with this mystery.

I apologize if in my previous post I offended the CAC group. I noticed I had a lot of people look at my post but only 3 responded to me. I have found the tech advice here at CAC Superior to what is available elsewhere and so if in my ignorance I have performed a no no please let me know.

vetteboy86 · May 5, 2006

Never cause for offense here. Why dont you check to see if you have fire down to the plugs. I know they make spark checkers for lawn mowers and other various things, so they probably have one for cars. This is what I would check first. Fuel should be easy to check. Just key the car up with a fuel pressure guage hooked up to the fuel rail and check to see if the system builds pressure. Make sure you check to see if the plugs are getting spark.

John Robinson · May 5, 2006

Thanks

I have been reading my shop manual. I certainly will look for a spark checker and a fuel pressure Gage. With all the relays etc in control of the engine running I am somewhat overwhelmed. Boy they sure are different than a lawn mower to fix.

jmccloud · May 7, 2006

No Start

A test method:
Crank the engine for several seconds or a minute.
Pull the plug that's easiest to reach.
Check to see if it's wet. If not, probably a no-fuel problem. Fix the fuel pump.
Then dry things out if they're wet.
Put the plug into the wire connector and 'ground' the plug by laying it on the block or intake, making sure that the metal hex is in good contact with the block (put a brick on it) in such a way that you can see the spark gap.
Have someone crank the engine and look for a spark. No spark; check the opti, cap, rotor, wires, power to the opti, etc. On newer GM cars, there's a circuit that inhibits power to the distributor or opti if the oil pressuer is low (except during start-up). Check this circuit too - you'll need a Helms manual for the specific year of your car (other manual's won't be adequate).
You're most likely missing either fuel or spark; go from there.
But, if you have both, the spark is probable way out of time due to cross fire in the 'Opti' so look there. Or, worse yet, the timing chain has jumped and the spark is completely out of time with the cam/crank. This disaster often produces unusually fast cranking speed. A compression test will show really poor results too.
Hope this helps.
BTW welcome to a great forum, they helped me with some tough ones.

SPANISHVETTS · May 7, 2006

Sorry that I did not see this before.
Being a 93 the odds are that the Opti has crapped* but that is the easy way out. With a no start condition on any motor go back to basics and assume nothing.
To start you need air, fuel and spark in the right order.

Pull off the air filter and try to start it… you will not believe how many blocked air cleaners we have seen.
Pull off a spark plug wire, stick it on a good spark plug, ground the spark plug and try to start the beast. Do you have Spark?
Push the Schrader valve on the fuel rail with a screwdriver and see if fuel sprays out. (if the gas does not get in your beer and eyes you do not have enough fuel pressure)
Open the GM service manual and follow the flow chart down from the condition you discovered with the above test. DO NOT skip a single steep.
Replace the Opti.

*we had a 93 for 2 years… replaced 2 Opti sparks.

vette-dude · May 8, 2006

John,

In your previous post you said that you hosed/washed down the engine. The replies said that most likely the optispark has crapped out on you. Nothing has changed. The optispark is most likely the culprit. They are expensive and when one goes bad we all want it to be something else but it doesn't work that way unfortunately. It never hurts to ask a question. If you need more info, use the search button at the top of the page and enter optispark and you will find more information then you can process. Good luck and remember NEVER HOSE DOWN AN ENGINE WITH AN OPTISPARK IGNITION!! I hope it is something else but it is doubtful.

Randy

John Robinson · May 8, 2006

The latest infor

I had the car taken to mechanic I have known for 30 years. He called today to say it is the ECM and he has one on order. I should know Wed if that is what it is. I am still confused why I did not have a code. I will post again if that is the fix. I will still have the orginal wires and plugs and a small oil weep on the front of the engine. Someday I will tackle those problems. :confused

SPANISHVETTS · May 8, 2006

If it is the ECM the next round is on me and I do not buy many rounds.

Even on the race cars I have never seen a true ECM failure... there was always another problem and on LT1s that problem is named OPTI.

Please let us know the outcome, I would love to be wrong about this.

John Robinson · May 8, 2006

Diagnosis

I just talked to the mechanic and he said that he is not getting a signal to the enjectors He has run the diagnostics and it leads to the ECM. A re manufactured AC Delco unit is on order and I will post if it fixes the problem. I would be as happy as a hog in a full slop trough if that is all it is.

I also asked the mechanic what he would charge to change the oil and filter and use Mobil 1 Synthetic Oil and lube the chassis. He said he would do it for $38.00. I can't go to Wal Mart and buy the oil and filter for that price. One of those might as well the wife does'nt need to know about.

:J

jmccloud · May 8, 2006

ECM?

I had one GM car whose ECM died (not a Corvette). The key was that the Service Engine light did NOT come on when checking for codes (shorting the two leads on the ADL connector).
And it did NOT have any codes.
It could be as simple as the ECM loosing its ground; or it could be a dead ECM.
Your symptoms are similar to mine but not exactly the same. Occasionally the car would start then run for only a few seconds.
New ECM (about $100) and it ran fine.
Good luck.

SPANISHVETTS · May 9, 2006

John Robinson said:
I also asked the mechanic what he would charge to change the oil and filter and use Mobil 1 Synthetic Oil and lube the chassis. He said he would do it for $38.00. I can't go to Wal Mart and buy the oil and filter for that price. :J

adMy wholesale price on Mobile 1 in Spain is almost $8/qt and that is buying the stuff in 55 gal drums...Would your mechanic make a house call to Europe?

If the ECM is dead odds are that some thing else killed it. Keep us posted.

vette-dude · May 9, 2006

SPANISHVETTS said:
adMy wholesale price on Mobile 1 in Spain is almost $8/qt and that is buying the stuff in 55 gal drums...Would your mechanic make a house call to Europe?

If the ECM is dead odds are that some thing else killed it. Keep us posted.

John,

I agree with our friend from Spain. Certainly hope that the ECM takes care of the problem. Stranger things have happened to these computerized systems. If the optispark isn't the culprit then forgive me for attempting to lead you in the wrong direction. ;shrug

It is pretty hard to analyze a problem in cyberspace but in 90% of the situations you have, the opti has taken a crap. Good luck.

Randy

gmjunkie · May 9, 2006

jmccloud said:
I had one GM car whose ECM died (not a Corvette). The key was that the Service Engine light did NOT come on when checking for codes (shorting the two leads on the ADL connector).
And it did NOT have any codes.
It could be as simple as the ECM loosing its ground; or it could be a dead ECM.
Your symptoms are similar to mine but not exactly the same. Occasionally the car would start then run for only a few seconds.
New ECM (about $100) and it ran fine.
Good luck.

ECM will Almost Never tell on Itself!!!!! It will give false Codes,Random Codes,or No Codes!!! They can Screw with your Head till you have All of your hair pulled OUT!! (SEE Avatar) I have replaced LOTS of ECM's!! Never a Opti!! I wash and detail the hell out of every used Vette I get!!!! Trick is NEVER try to Start or turn on key, till you have removed the Opti Cap and throughly Dried it out with Compressed air and Heat Gun !!! The Fire jump'n in um, Kills um!! :upthumbs

John Robinson · May 9, 2006

I agree about OPti

I washed the engine but I had read enough posts to know to protect the opti with two garbage bags stuffed in the cavity around the opti. That having been said When it failed I was sure it was the opti and still am crossing my fingers that the ecm will fix it. I hate to fix something by just throwing money and parts at it. Thats why I had it towed to a garage that could diagnose the whole system. I figured he was going to tell me it is the opti and I planned at that point to pay to have it flat bedded back to my garage where I could work on it. I still will have to get to it at some time for the wires and plugs and oil leak.:cry

Stay posted I will post the results of the ecm change. :beer

vette-dude · May 9, 2006

gmjunkie said:
ECM will Almost Never tell on Itself!!!!! It will give false Codes,Random Codes,or No Codes!!! They can Screw with your Head till you have All of your hair pulled OUT!! (SEE Avatar) I have replaced LOTS of ECM's!! Never a Opti!! I wash and detail the hell out of every used Vette I get!!!! Trick is NEVER try to Start or turn on key, till you have removed the Opti Cap and throughly Dried it out with Compressed air and Heat Gun !!! The Fire jump'n in um, Kills um!!

You mean you finally have electricity or are you still running that Model T powered generator??? :L

Randy

SPANISHVETTS · May 9, 2006

gmjunkie said:
ECM will Almost Never tell on Itself!!!!! It will give false Codes,Random Codes,or No Codes!!! They can Screw with your Head till you have All of your hair pulled OUT!! (SEE Avatar) I have replaced LOTS of ECM's!! Never a Opti!! I wash and detail the hell out of every used Vette I get!!!! Trick is NEVER try to Start or turn on key, till you have removed the Opti Cap and throughly Dried it out with Compressed air and Heat Gun !!! The Fire jump'n in um, Kills um!!

Between your dead ECMs and my burnt OPTIs we probably have enough old parts to build a new FORD. ;LOL