Intermittent no start condition

[John Nechiporchik]

Rich, I did test the coil immediately after experiencing the no-start condition. I placed the spark tester between the coil and the coil wire. Spark was there. I did not, however, test it on the other side of the coil wire (your process). I will do that tomorrow. That would eliminate or validate a bad coil wire. I will go through all the wiring this weekend....after I do the noid test.
I will find a noid between now and the weekend.
Thanks.

[buzzinhalfdozen]

Originally Posted by John Nechiporchik

Rich, I did test the coil immediately after experiencing the no-start condition. I placed the spark tester between the coil and the coil wire. Spark was there. I did not, however, test it on the other side of the coil wire (your process). I will do that tomorrow. That would eliminate or validate a bad coil wire. I will go through all the wiring this weekend....after I do the noid test.
I will find a noid between now and the weekend.
Thanks.

Having spark coming out of the coil indicates you indeed do have the necc. trigger to initiate spark. Where you tested it isn't an issue, you've proven that the MSD portion is operational. I really doubt you would have a bad coil wire causing this as you would have other symptoms. Though it is a good idea to regularly change the coil wire as all the spark energy is directed thru it as opposed to single events thru the plug wires. Seems as though you are down to correct signaling to EFI controller or the controoler itself, BTW how are your injectors powered? The ECU merely provides the ground, if your power to the injectors is erratic you'll see the same issue. Joe

[John Nechiporchik]

Joe, I need to find out how the injectors are powered. There are enough wires under the dash that it will take some time to figure all this out. Also, crawling under the dash is an event in itself!
I talked to MSD again today...and I will do a resistance check on the crank trigger pick-up tomorrow. He said the reading should be between 65-85 Ohms. With this and a noid test, I should have enough info to determine the source of the problem....then finding the root cause may be another journey.

[buzzinhalfdozen]

John, having a spare crank sensor is a good idea regardless, however it seems apparent that it is not the cause of your problem, unless of course your no start "fixed" itself during your test. Do you know what switch you turn on to power the injectors? This would narrow the search a bit. As I've stated I'm not familiar with your system however can you "real time " communicate with it via a laptop and if so does it display any active parameters? Such as engine RPM? If so then you could monitor for RPM while attempting to start which I would expect to see, then during a no start event see if it is in fact displaying RPM. Hope this isn't too confusing. Joe

[John Nechiporchik]

Joe, Don't know which switch fires the injectors. I will assume it's either the ignition or fuel pump switch. Will be part of my "trace the wires" event tomorrow night and this weekend.
Relative to your other comments, I'm not familiar enough with the laptop interaction with the ECU to understand what you mean. This stuff is all new to me.

[buzzinhalfdozen]

Ok, can we assume that you have had the laptop connected at all? If so then you'll just have to look around and see what info is displayed, but I'd bet you'll be able to see engine rpm. That would help in determining whether the ECU "thinks" the engine is running. I would like for you to have comm. via laptop as soon as you can as it may help find the issue.Quickest way to find the power source I would think is to use a test light at the injector connector and start trying switches, the 1 that makes the lite come on is it, then it's a matter of tracing that 1 circuit. Once you get a bit more info you'll be fine, knowing how things are wired up is a huge step in the right direction.Please keep us updated on your progress and good luck. Joe

[Mike Pearson]

Just freshened my engine. Now it won't start. No spark at the plugs. How do you check the pick up on the crank trigger with an ohm meter. Using a 7AL box and crank trigger. Carburetor set up. Just looking for some ideas. The coil is nearly new. The MSD parts are older but have been real reliable.