Intermittent no start condition - Page 2

Steve Williams · 09-16-2013, 11:17 PM

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 · 09-17-2013, 12:02 AM

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 · 09-17-2013, 01:07 AM

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 · 09-17-2013, 09:27 AM

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 · 09-17-2013, 09:35 AM

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 · 09-17-2013, 09:55 AM

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

John Nechiporchik · 09-17-2013, 09:58 AM

Thanks. I'll check out the MSD instructions.

buzzinhalfdozen · 09-17-2013, 10:23 AM

Yeah quick search looks like it does have the LED, hopefully it's in a position that you can see it. Without the crank input I'd imagine you will have neither spark or fuel activity. As SS3011 stated your set up MAY require a cam sync input to operate again not knowing your system it is merely a guess,any way of finding out how it's set up? Do you know who installed and set up the system, that would answer alot of questions. Again IMO I'd start by verifying the LED is blinking first.Good luck. Joe

Rich Biebel · 09-17-2013, 11:01 AM

I ran my LT-1 with an Accel gen VII and a crank trigger.

I used an MSD 7al2 until it failed and than an MSD Digital 6

I did not send the crank trigger into the Accel ECU..

I ran it just like any std non efi engine. Timing was locked and set at the trigger.

I felt since I was new at this ....it was simpler and it was...

I gutted a stock distributer and added an MSD cap and rotor...

So my fuel pump and ignition were basically outside of the ECU...

The injectors of course have to run for the engine to start...

The tests Rob said to do should reveal the problem.....but you have to get it to NOT start first....

A cam sync sensor as I recall was only needed if your were running your EFI as a sequential firing order.....

P.S. I could not get my car to even start the first time I tried......wiring issue. ECU to MSD....

John Nechiporchik · 09-17-2013, 11:14 AM

Spoke with the previous owner/builder.
The Accell Calmap only controls the fuel map. The other functions(timing, rev limiters etc) are managed thru the MSD box. Rich, this appears to be similiar to your set-up.

I wiil get a spark tester and noid light tonight and perform the tests that Rob indicated.
Is there a universal noid light or do I need to buy the kit that has injector brand specific lights? I believe my injectors are Bosch.

09-16-2013, 11:17 PM	#11
Steve Williams Member Join Date: Aug 2007 Location: Detroit, Michigan Posts: 352 Likes: 0 Liked 1 Time in 1 Post	Re: Intermittent no start condition 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.

09-17-2013, 12:02 AM	#12
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: Intermittent no start condition 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.

09-17-2013, 01:07 AM	#13
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,093 Likes: 162 Liked 219 Times in 79 Posts	Re: Intermittent no start condition 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. Last edited by Rob Petrie E395; 09-17-2013 at 01:32 AM.

09-17-2013, 09:27 AM	#14
John Nechiporchik Member Join Date: Mar 2007 Location: Grosse Ile Mi. Posts: 315 Likes: 74 Liked 12 Times in 6 Posts	Re: Intermittent no start condition 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.

09-17-2013, 09:35 AM	#15
John Nechiporchik Member Join Date: Mar 2007 Location: Grosse Ile Mi. Posts: 315 Likes: 74 Liked 12 Times in 6 Posts	Re: Intermittent no start condition 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!!

09-17-2013, 09:55 AM	#16
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 985 Likes: 0 Liked 12 Times in 9 Posts	Re: Intermittent no start condition 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 __________________ Joe Buchanan SS/BX 3117

09-17-2013, 09:58 AM	#17
John Nechiporchik Member Join Date: Mar 2007 Location: Grosse Ile Mi. Posts: 315 Likes: 74 Liked 12 Times in 6 Posts	Re: Intermittent no start condition Thanks. I'll check out the MSD instructions.

09-17-2013, 10:23 AM	#18
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 985 Likes: 0 Liked 12 Times in 9 Posts	Re: Intermittent no start condition Yeah quick search looks like it does have the LED, hopefully it's in a position that you can see it. Without the crank input I'd imagine you will have neither spark or fuel activity. As SS3011 stated your set up MAY require a cam sync input to operate again not knowing your system it is merely a guess,any way of finding out how it's set up? Do you know who installed and set up the system, that would answer alot of questions. Again IMO I'd start by verifying the LED is blinking first.Good luck. Joe __________________ Joe Buchanan SS/BX 3117 Last edited by buzzinhalfdozen; 09-17-2013 at 10:28 AM.

09-17-2013, 11:01 AM	#19
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,275 Likes: 25 Liked 510 Times in 200 Posts	Re: Intermittent no start condition I ran my LT-1 with an Accel gen VII and a crank trigger. I used an MSD 7al2 until it failed and than an MSD Digital 6 I did not send the crank trigger into the Accel ECU.. I ran it just like any std non efi engine. Timing was locked and set at the trigger. I felt since I was new at this ....it was simpler and it was... I gutted a stock distributer and added an MSD cap and rotor... So my fuel pump and ignition were basically outside of the ECU... The injectors of course have to run for the engine to start... The tests Rob said to do should reveal the problem.....but you have to get it to NOT start first.... A cam sync sensor as I recall was only needed if your were running your EFI as a sequential firing order..... P.S. I could not get my car to even start the first time I tried......wiring issue. ECU to MSD.... __________________ Rich Biebel S/C 1479 Last edited by Rich Biebel; 09-17-2013 at 11:11 AM.

09-17-2013, 11:14 AM	#20
John Nechiporchik Member Join Date: Mar 2007 Location: Grosse Ile Mi. Posts: 315 Likes: 74 Liked 12 Times in 6 Posts	Re: Intermittent no start condition Spoke with the previous owner/builder. The Accell Calmap only controls the fuel map. The other functions(timing, rev limiters etc) are managed thru the MSD box. Rich, this appears to be similiar to your set-up. I wiil get a spark tester and noid light tonight and perform the tests that Rob indicated. Is there a universal noid light or do I need to buy the kit that has injector brand specific lights? I believe my injectors are Bosch.