MSD ignition wire compatibility question

[Victor Charlie]

I wonder if I have a problem due to "upgraded" spark plug wires and would appreciate some advice.

here's the story: I have a few simple performance mods, new low resistance MSD wires. New copper plugs were selected and gaped per writeup on this site (but I can't find the specs at the moment).

There are few weird related problems:

1) puzzling intermittent starting problem. Car won't start if it stalls while warm, or sometimes just won't atart warm. Starts and runs great 3 hrs later.
2) timing gun has trouble picking up a signal unless the no 1 wire is perfectly seated in the coil back, even then it seems to miss a flash, though the engine doesn't sound like it is misfiring.
3) car idles and runs well with ignition set to 20 deg BTDC, idles slower but sort of okay at 10 deg. Timing gun has setting for DIS.
4)visually have spark, but it might have missed a few times, when I was watching it, hard to be sure.
5) no evident spark advance when engine check jumper is removed.

Thes things aren't a problem: coil packs and ignitor test fine with DVM tests. Fuel pump seems to be working fine when pinching return line. I checked all the voltage tests at the ECU and all were normal except the AC signal.

Reground cams appear to be timed correctly. Engine runs really great once started, very smooth and powerful across the RPM range.

Boosted to 11.5 psi. Stock coils, ignitor, '89 ECU.

I am willing to upgrade the coils and/ or ignitor if it is likely to help with starting, or go back to stock wires if that is the problem. I hadn't planned a piggyback ECU until I had the car running reliably without one.

What would be the best setup to make this car run reliably as street car?

 

[cuel]

Make the contacts on the coil side of the wire fit better. I had to spread them open a bit to get a better fit on the cap for my n/a. I'm pretty sure I've seen other people here having a loose fit at the cap/coils with msd wires. Hope it helps.

 

[Victor Charlie]

Make the contacts on the coil side of the wire fit better. I had to spread them open a bit to get a better fit on the cap for my n/a. I'm pretty sure I've seen other people here having a loose fit at the cap/coils with msd wires. Hope it helps.

Thanks, I just did that and it definitely was better, but not perfect, misses occasionally at idle. I'm driving it now. I will fuss with it some more to improve the contact. I won't really know unless it fails to start again.

I'm still interested in any opinions on whether there would be a benefit to upgrading the ignitor or coil pack.

 

[jetjock]

No, not at that boost level. Nor do I think your starting problems are ignition related. And did you check for codes before setting timing?

 

[Victor Charlie]

No, not at that boost level. Nor do I think your starting problems are ignition related. And did you check for codes before setting timing?

Sweet, thanks for jumping in boss.

Yes. There was a code 51 only. Not sure why since the voltage tests were normal.

 

[cuel]

Might check your cps connection and harness for brittle or frayed wiring, or bad connections. Seems fairly common for an intermittent start issue on the GTE. Might post up your voltage readings for the tps, to, just to be sure.

 

[jetjock]

As I suspected. Timing can't be done if 51 is set, at least if it's been set by the TPS. No wonder your timing is goofy...

 

[Victor Charlie]

As I suspected. Timing can't be done if 51 is set, at least if it's been set by the TPS. No wonder your timing is goofy...

Thanks for the pointer, I'll investigate further tomorrow.

 

[jetjock]

Good luck. When you jumper the diag block the ECU sets idle speed and prevents the ESA system from working. These things will only happen if the idle contact in the TPS is closed. Your code 51 implies it isn't. I say implied because 51 can be set by a couple of other things that don't prevent timing (AC on for example) but the TPS is far and away the most common cause and that'll prevent initial timing from being set. It's why timing should never be attempted without first checking the MIL. Doing so verifies 1) the ecu is in diag mode and 2) it's able to set timing.

 

[MKIIISupraGuy]

I just read this and saw the last post about code 51, which is what my car had when I checked codes today, trying to figure out my issues and all. Nice to know it's timing related. I sure am glad I read this forum, because that would explain a lot ..lol. Sorry about butting in guys, just saw the relevance and could'nt resist.

 

[jetjock]

Yep, it's probably why Victor Charlie's timing has gone Tango Uniform

 

[Victor Charlie]

Yep, it's probably why Victor Charlie's timing has gone Tango Uniform

Maybe, but I did check the TPS via ECU input voltages per TSRM and all the inputs were per spec.

Also, the AC input IS messed up. It reads around 4 V when the AC is off, and 0v when the AC is turned on, so that may well be the cause of the code 51.

Unfortunately, the tire dealer didn't torque the lug nuts and the wheel almost fell off last night, stud was sheared off. So now it is in the shop while we negotiate responsibility and I can't work on it for a while.

 

[Victor Charlie]

Sorry not to have a definite answer, I hate leaving my own thread hanging. I set the timing to 15deg BTDC, where it was before, never resolved the AC problem, fussed with some wires to the CPS, cranked with the EFI fuse out, reinserted the fuse, and now it is running great and starting fine, so I'm not sure what made the difference. It will hold for winter. Maybe multiple factors with a new engine had to be resolved to get it starting consistently. Enough of this thread, thanks for the help.