Abubaca

iTrader: (3)

Guys I'm stumped. Had the car for 20 years and while I don't know everything, I normally know what I'm doing. Right Now I'm stumped.

Background. Car was unhooked from battery for 6 weeks while being painted. -Battery IS charged, in fact we tried a brand new batt. No joy.

Components. Car is being run by a Holley HP EFI ECU, however with regard to ignition, it functions the same as stock, with the only connection being the same 4 pin connector to the back of the ignition module.
I'm running an MSD 6a with a blaster coil, however I can, and have switched back to the stock ignition to rule out issues in the past by bypassing the MSD box. It functions just fine ...and I have done that now, but still no start.

Here's what I know.
I DO have 12v to the coil. Have NOT checked if I have 12v going to the Ignition Module, FROM the coil. Could be the coil.

I know the ECU is NOT getting a signal from the distributor/module. The Holley software shows no signal received. I've tried 4 modules and 2 distributors, so it SHOULD be sending a signal. What I do NOT know is if there is in fact actually a signal and something's up with the ECU? -OR, if it's possible it's too weak of a signal. I talking with Holley as to how to test for a signal.
I know there's supposed to be an AC signal coming from the VR sensor in the dizzy, into the ignition module, then out to the ECU, but I don't know what kind of signal is coming out of the ignition module, so I don't know how to test it.

Right now my plans are to pickup a replacement coil, and to try and test that crank signal going to the Holley and see what's up there.

Here is my question...if you're still with me:
With 15* base timing at the cap, even with no ECU controlling timing, should I still see spark at the plugs? No fuel of course, since the ECU thinks no spark, but should I still have a base 15* degrees of timing, and SEE a spark at the plug?
....or is everything coming from the ECU? Meaning even with a powered coil, ready to fire, no ECU means no spark?

....it would help point the finger at the ECU or the ignition system as the culprit.

skinny z

Any luck? This arrangement is still using the distributor to tell the ECU what the crank position yes?

Abubaca

iTrader: (3)

Yes, crank signal comes straight from the distributor like stock. With regard to ignition, there's no difference with the Holley. It's just a different ECU under the dash. Same igntion module, same 4 pin connector going in between. Same black and grey connectors on the coil....everything the same. ....and keep in mind the car RAN. It's been up and running with the new engine/Holley ECU for well over a year.

skinny z

Considering that it was a running vehicle, this sort of points to a poor connection somewhere wouldn't you think? Some corrosion over carry over from being in paint and getting into somewhere it shouldn't. Seeing as you can bypass the ignition module via the MSD and have the same results sort of eliminates that portion of the circuit.

On my MSD 6AL equipped car, plugging the twisted pair cable from the box to the distributor with reversed polarity has created a no start condition for me. The connector is keyed to prevent this reversal but somehow I managed to get it backwards.

Just thinking out loud here with the hopes of twigging something in your investigation.
And bumping the thread.

Abubaca

iTrader: (3)

Well I do agree that since minimal changes were made, it does look like some sort of bad connection, ground, etc. etc. Rest assured I've checked, but of course I can't rule out something small that I missed.

On the other hand....with the ECU not getting a signal, it pretty much points to the ignition system, assuming the ECU is functioning properly. .....and I've replaced most of it.

I'd like to check for signal coming out of the ignition module, but I'm not sure exactly what I'm looking for, and I don't wanna start guessing.

Only things I can think of at this point are to check that signal.....and check the coil.

RBob

iTrader: (1)

I'm not sure how the Holley ECU handles the spark during cranking. The stock ECM opens the EST/BYPASS line which forces the ICM to control the spark. This has the spark occurring at the base timing.

Can replicate this by physically opening the EST/BYPASS connector.

As for the signal from the ICM to the ECM (REF high), it is a 0 - 5 volt square wave.

RBob.

Abubaca

iTrader: (3)

Can I measure that with a multi-meter? I will google that...Thanks!

My understanding is that it's the same as stock....but I'm far from an electrical genius. Fortunately, I've brought pictures. This is literally what I have wired up now after bypassing the MSD box. They don't show two pink and two white to the coil, but it's the same. They just don't show the the switched power as pink, which it is, and they don't show the tach out wire.

The red lines block out things the generic harness has, but I'm not using. The yellow black (A) wire is where I'm seeing no signal, so says the fancy Holley software. That's what I want to measure. See if it's a problem in sending...or in receiving. Ground is well....ground. Does wire (B) and wire (H) make sense to you? Is that same as the GM ECM? You said to open the EST/Bypass. Looks like Holley as slightly different terminology. That essentially means base timing at cranking, right? Essentially the ECU would receive the proper signal and open the circuit, right? Would that be B or H? .

I still wouldn't have timing control, but I could isolate the problem to either the ignition system not sending a signal or the ECU not receiving.

I appreciate ANY help!!!!!!!!!!!!!!!

Thanks!!!!!!!!!

scooter

iTrader: (11)

I have limited experience with my Holley setup, but have you tried saving your config and re doing the initial setup? With all the replacements you have done, but the ECM seems suspect, maybe it just "forgot" what was configured? I had to redo my setup once, but I don't remember exactly why.

Abubaca

iTrader: (3)

I've reflashed the ECU with a few of my most recent tunes. They're all fairly similar, and they all ran very well. -and they all had the same ignition configurations.

scooter

iTrader: (11)

I know someone that had to send his ECU back to Holley to have it fixed. I don't know exactly why though.

RBob

iTrader: (1)

The YEL/BLK wire is the REF Hi from the distributor to the ECM. During cranking I would expect a DVM to show in the 2.4 - 2.5 volt range (DC scale).

Yes, they are the same as GM, but I don't know if the holley ECU controls things the same as GM did. Wire B is the EST/BYPASS, the OEM harness has a single wire connector to open to set the base timing.

Wire H is the EST signal from the ECU to the distributor. This tells the distributor when to dwell and when to fire the coil. Note that OEM, this is only done once the engine is 'running.' Until running the EST signal is clamped to ground by the ICM.

OEM ECM opens the EST/BYPASS line at key-on, engine-off. Then closes the connection once the engine is running over 400 RPM.

Note the pink & white 2-wire pigtail between the ICM and ignition coil. They are known to go bad, mostly at the coil connector. The stress on the wire can cause the wires break inside of the insulation.

RBob.

Abubaca

iTrader: (3)

Gotcha. Lot of info, and a few things to try but it all makes sense. Won't get a chance to trouble shoot for a few days. Ugh.

THANK YOU!!!!!!

IROCZman15

iTrader: (25)

not 100% sure about Holley but i know that they own MSD and MSD allows you to send back your computer/ignition parts for testing and repair.

A about 6 months ago my MSD Digital-6 ignition control box just failed out of the blue. I had driven the car about 45 minutes from a car show. Parked it in the driveway, washed it and cleaned it. went to put it away and no start. no spark. box was flashing a red light instead of a solid. tested everything else around the ignition system only to determine that the box was bad. Called MSD tech, sent the box in. A few weeks later they tested it and found two blown circuits. $55 later plus shipping it was back in my car. During the time period when the box stopped working and when it was back in the car I just plugged the stock ignition wiring connectors back together and the car ran and got me around just fine. I just could not use nitrous since that box controls the timing retard etc.

So, if you do all your tests for voltage and continuity across the coil, etc etc, and think it may be the MSD box or the Holley ECu, call their tech line and see what they say. They might have a fix for ya and if not they can give you an RMA# and just ship the equipment to them for testing. If they find there is no problem they will send it back to you.

Abubaca

iTrader: (3)

Glad to hear that worked out for ya and they were able to help. Yeah.....I've heard good things about their customer service, and thus far that's been my experience. Just hoping NOT to have to send the ECU in.

maroe624

I picked up a Sniper with everything including Hyperspark dis and box from a sketchy dude in a motel parking lot for 500. Gave it to me in a dirty beat up box with bunch of extra crap, could not believe it surely something had to be wrong with it. Never had an issue with it, ran great, started up every time. Sucks that it's given you such grief bro.

Abubaca

iTrader: (3)

Saw your reply and realized I never updated. Was NOT the Holley. Ended up being the gray/black pigtail that plugs into the coil. Not sure exactly what wire was bad, as I replaced the whole pigtail.