dmclaws

I probably should have signed on months ago.............anyhow, here it goes.

About a month ago my son went to start the car and it would not fire, (has been running fine). The next day it fired right up. Later that day he began to drive the car and got about 1 mile from home when it died...............towed back to the house. After reading on-line it looked obvious that it was the optispark. I ordered one from Mid-America and installed last weekend................car still WILL NOT Start! Between yesterday and today I've tested all I could based on tech manuals and on-line support. I'm so fed up right now I'd sell the damn thing if an offer was made.

Any thoughts?

toptechx6

What testing have you done? I don't see any mention of attempts to isolate the cause of the no start. Are there any codes in the ECM? Have you checked the fuel pressure? Have you checked for spark to the plugs?

PS: I'll offer $100 as is!

dmclaws

This is what bothers me. The testing has been limited but still points to the optispark although it was what was just replaced. The only code showing the last time I checked was 2-4. Fuel pressure is good.

toptechx6

Do you have a factory service manual?
If testing shows an opti code and you have replaced it I would carefully inspect the wiring and connectors in the circuit.
There is no code 2-4, code 24 is for the vehicle speed sensor.Have you checked for spark to the plugs?

aminnich

Assuming you are getting no spark then check the pigtail that connects to the opti and to the harness under the right fuel rail cover. Among other things you can unplug both ends and OHM it out. Along the same lines are you positive the coil to opti is fully seated?

dmclaws

Toptechx6................correct, the code was 24.


Aminnich.....................the pigtail to the opti was 5v as noted what to test from the manual. And YES..............I spent the morning insuring the coil plug was seated to the opti.

dmclaws

Update.................I checked for spark with a tester and there is a spark. Same issue though............car will not turn over.

HlhnEast

Can we push it on my trailer? $105.00 cash money!

seriously dont forget the fuel side, make sure to test the pressure. Check fuel filter.

Good luck!

jfb

What do you mean by, "car will not turn over"? Turning over refers to the starter cranking the engine.
Automobile engines require hot spark, spark at the right time, fuel and air and in the correct ratio and cylinder compression in order to start and continue to run. When they can be cranked and won't start, that is the time to do standard diagnostic tests to find out what is missing that prevents the engine from running.
Use a timing light while someone cranks to see if you have spark and spark at the right time. Bring a grounded wire close to an unplugged plug wire boot while someone cranks. You should have a snappy at least 1/2" spark. Measure the fuel pressure, it should be 35-42 psi and it should hold up for at least 1/2 hr with the ign off. If it falls rapidly you may have leaky fuel injectors or defective check valve in the fuel pressure regulator. Use a noid light (available at parts stores) and test an injector socket on each cylinder bank while someone cranks, it should pulse during cranking. You can make your own light with an LED (light emitting diode) and a series 680 ohm resistor. The homemade light must be connected with the proper polarity to work. Spray starting fluid into the MAF and see if the engine will start. If it does, you have a fuel delivery problem.
You have only tested spark and you too easily become discouraged. To find out why it won't start you have to test ALL the things an engine requires to start and continue running. Come back and tell us what you found with all these tests so we can offer more help.

timmy 93

Have you checked the ICM and the coil ?

rodj

http://www.mainstreamtopics.com/foru...p?showtopic=78

Lemme

How does the fuel pressure drop normally when the ignition is turned off? Does the fuel make its way back to the fuel tank somehow?

sailorsteve

Unlike gases, liquids are not compressible. The pressure in the fuel system will drop without any fuel being returned to the tank.

gbrtng

Lacking an ignition analyzer, I replaced a weak coil on a friend's 92 and solved this problem. His was refusing to start on damp days.

dmclaws

Thanks for all the responses...........I've simply given up. The car can sit and rot as far as I'm concerned! Totally fed up after 4 weeks of testing.

jfb

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!!!!!!!!!!!!!

ChrisLT1conv

check the icm and the coil. A coil s only about 20 bucks so you might want to just buy one

dmclaws

Already replaced the coil last month. I'm leading toward the ECM or timing. The ECM is about impossible to find and I have no clue about timing..............don't know what to look for or how to adjust.

sailorsteve

Timing is not adjustable on the LT1. But you can be sure you have a good spark by putting a spare plug into a plug wire, laying it on a grounded spot, and cranking while watching the plug.

dmclaws

I used an inline spark tester and spark was there.