Intermittent no start condition

[FED 387]

try any other coil other than another a MSD 8261 if you are going to run more than a lap every hour or two just to see if that is the problem--- for repeat operation much like stock/super stock/ bracket cars go DO NOT USE the MSD 8261 it will usually do what you are describing---an MSD 8251 will not cause the symptoms you are describing---an MSD8261 coil gets so hot internally with repeat operation it breaks down due to the heat--- if you ran the car for a lap then shut it down for a while say 30 +minutes then ran another lap you MIGHT be OK but the MSD 8261 coil is not designed for lap after lap

[Steve Williams]

You mentioned fuel pressure....Does it give you 45psi when it cranks? Does it fall off? To bleed off that quickly upon shut off doesn't seem right to me. You also need to have 40psi minimum with the engine running to effectively fire the injector. Less than that and it can create problems. If we can get Ed Wright to chime in, he has a good deal of knowledge on these engines. Much more than me I suspect. One thing I failed to mention in my last post, is to check your grounds and wiring going to and from your crank trigger/ICM and coil, to include the weather connectors. If there is problems in either of these two circuits of wiring (bad ground or short while cranking), it can create a problem in having enough voltage to fire the engine off or a weak signal. I fought this condition for three weeks before stumbling across my problem.

[ss3011]

If you key on the DFI controller it should cycle the fuel pump for a couple of seconds then turn off until it cranks sees engine rpm above a certain rpm. If fuel pressure doesn't build up enough and you crank too soon, it might not build enough fuel pressure to run. I used an Accel conversion pressure regulator on my LT1. It used to hold full pressure for 30 mins or more after shutdown. You either have a leaking regulator or dirty fuel injectors that are leaking down. Also is your Opti-spark still hooked up ? There should be a connector in the Opti-spark that picks up the signal for timing the fueling. Depends on how your DFI is configured. Might want to check the connectors and wires. Does your Opti-spark have the ventilation system installed ? The later Opti-sparks had a vent system to prevent moisture from building up and corroding the components inside.

[Rob Petrie E395]

Get a spark tester. It looks like a spark plug with a clip on the side (get the one that looks like a spark plug not the cheap plastic adjustable one if possible you will now what I mean when you see it). Unplug the coil wire and put the clip on your coil terminal and plug the coil wire on the spark tester like you would a spark plug wire. So that the spark tester is inline between the coil and the coil wire. While your at it get a noid light too. If you are not familiar with what a noid light is is plugs into the harness connector that plugs onto the injector. You can buy both of these tools at any auto parts store for probably twenty bucks or less. Then try to start the car until it does not want to start. You will know right away when you are trying to start it if it has spark because you will hear the spark tester snapping. If you have spark and it wont start quickly unhook a injector harness from a injector and plug in the noid light and crank it over. It should flash when cranking. This will allow you to figure out weather it is a injector pulse, spark or both problem. I dont have Accell system I use Holley, FAST and GM stuff on my cars. Does the Accell system use the OPTI for a crank signal or do you have a crank trigger?
Edit I just re read your posts so I know know it has a crank trigger. So See if one of the above is acting up (no injector pulse or no spark). Could be alot of things but we can figure out alot from knowing the results of the above tests. IE if its just no injector pulse or just no spark could be some things. IF it does not have spark and injector pulse it narrows it down some. Let me know what you come up with and I would be happy to try and help.

[John Nechiporchik]

Rob, I will get a spark tester and noid light tonight and run the tests. I'll post results.

Thanks for the tips. Testing these systems is a lot better than starting to throw money at parts.

[John Nechiporchik]

Steve and SS 3011
Sunday when the engine was running, the fuel pressure was rock steady at 45psi.

Also, the set up has a crank trigger and I have no knowledge as to the questions SS raised on the signal source and timing of signal.
I'm hoping the problem lies in the coil, regulator or perhaps crank trigger as these are relatively easy (but not cheap) fixes. The tests Rob suggested will provide some direction. If this is an ECU based issue.....that's a whole different scenario!!

[buzzinhalfdozen]

I may be wrong but I seem to recall the digital 7's having an LED on them that when blinking during cranking indicate it's seeing a trigger (crank sensor input), you may want to read the instruction manual on that. If it's in fact the case and you're seeing it blink, that would indicate to me that the triggering is working correctly. I'm not familiar with your system but most merely piggyback off the MSD for RPM (trigger) events which it needs to operate. Would be a quick way of determining what side to look at spark or fuel. Joe