ULTM8Z

So back in February, I posted about a system voltage spike to ~16V that seemed to make the car run stronger, until I found the issue and corrected it.

https://www.thirdgen.org/forums/diy-...injectors.html

Well, I think the ignition coil may have been on the way out and this spike in the system voltage somehow momentarily compensated for it.

The car has been running strong since then, but like I said, I could never replicate the power level I felt that day no matter how much tuning.

So I figured since the issue was something electrical, I'd go after the ignition coil.

Bingo!

I bought a Pertronix flame thrower coil and immediately got that power back.

Interesting thing now is I've been having to pull fuel back out all over the place in the calibration as a result. I had been richening AE, VE, and PE and to some extent it helped, but with the new coil, it's too rich...

The car is responding to calibration changes much better now that the ignition is back up to par.

BTW, I e-mailed Pertronix to see about what I should expect if I bought their module as well. I'm reading around the net where people are saying the module and coil should be matched. I currently have a factory GM module.

What do you guys think?

whatif3387

I'm also running the same ICM and a pertronix distributor. Please post their response when they get back to you. I've always wondered how they compared to a GM ignition control module.

CORV3TT3

Glad it worked out!



^ This is true!

The only thing that may be more maddening is having a bad connector between functioning parts. I had a bad connector on my WB and it drove my tune in circles. I thought I had an exhaust leak for the longest time. And a bad O2 sensor... LOL

ULTM8Z

Wow, another revelation... (I've been starting to really think about the ignition system after the coil swap proved so effective).

Curious about the grounding scheme of the distributor, I took the distributor out, drilled a small hole in the bottom of housing and mounted a braided ground strap. Then took the other end of the strap and hooked it up to the back of the cylinder head (the same head that has the main engine ground strap).

I'll be damned.... I actually felt a performance improvement. And proving to myself it's not my imagination, the BLM's dropped again forcing a whopping~7% reduction in VE's mostly in the mid-range. The coil swap forced about a ~5% reduction. So overall, the improvement in the ignition resulted in a huge power increase while needing roughly 10-12% less fuel. My guess is my mpg also improved significantly as well.

This was definitely unexpected even though I thought it was worth a shot... I would have thought the metal-to-metal connections with the bare metal manifold, clamp, and dizzy housing would have been a good enough ground for the distributor. But I suppose the path through the manifold, and the manifold bolts (which actually have anti-sieze on them) may not have been sufficiently conductive path.

Moral of the story is make sure your ignition systems have adequate grounds!!

Man, I CANNOT WAIT until the next dyno day over here...

Dominic Sorresso

Makes u wonder what would happen with using CnP ignition?

htrdbmr

Are you using a small or large cap HEI?

ULTM8Z

It's a large cap.

ULTM8Z

Probably a dumb question once you tell me what it is, but what's a CnP ignition?

CORV3TT3

Coil-on-Plug

CORV3TT3

FWIW- I've had terrible luck with coils from Autozone, NAPA, O'Reilley's, and Advance.

RBob

iTrader: (1)

Coil-Near-Plug, such as used on the LSx engines.

RBob.

Fast355

iTrader: (2)

My 1997 350 Vortec Express van had noticeably lost grunt, was running a bit rough cruising down the highway in overdrive and had some occasional misfiring that was too sporadic to turn on the Service Engine Soon light. Got some cold, wet weather and when I went to start it, the engine refused to fire, just sat there and turned over. Very weak spark when I started my diagnostic checks. Immediately blamed the cap and rotor as they are bad about having issues. Pulled the coil wire off the distributor and tested the spark, still very weak. Sprayed some DW40 over the top of the coil and the engine started. Swapped coils with the coil that came off my Mercruiser intake manifold. Immediately picked up a huge amount of low-end torque and my short term fuel trims were -20 to 25% on both banks until my long trims leveled out about -10 to -15%. I had also been masking a bad/weak ignition setup with extra fuel.

I ended up still having the sporadic misfire and that turned out to be a worn/knife edged distributor drive gear. At WOT it would run fine, at higher RPM/low load like crusing down the highway in 3rd gear trailing the throttle coming down hill with a trailer it would miss noticeably.





I also wonder how my engine would run with the EFI Connection 24x reluctor and CNP ignition. I have seen the results of a PCM/Ignition system swap on a 450 HP LT1 engine that gained over 25 HP and nearly matching torque numbers across the whole RPM range. I am sure some of it is from the PCM and better fuel management, but I bet a large chunk of the power gain is from having a hotter spark by having longer dwell time for the individual coils.

Dominic Sorresso

Fast,

I recall Grumpy suggesting that the CnP was responsible for a significant part of the power coming from LSx based motors. Perhaps RBob can verify that but I remember Bruce telling me that during a phone conversation when he was converting his GN to CnP. One reason why I have trying to find a way of adapting that to the LT-5. I suspect a high revving motor would benefit from having individual coils and hotter spark.

JP86SS

iTrader: (1)

Damn, I think you've pointed to the weak spot in my system too!
Covering with too much fuel..., odd grounding of dizzy case (small cap), can't get power I had before coil change,module change, cap rotor plugs and wires make no difference. Every time I'd play ignition parts, BLM changed as described.
Going to do some testing this weekend on the dizzy grounding for sure.

Thanks for sharing the experiences.
Jp

ULTM8Z

Lol... I seem to get all the wierd crap happening to me...

So when I/we finally figure it out, I post it up so hopefully others don't have to slog through it like I do.

I'm very close to publishing my Miniram start bin 2.0. Just having to fine tune a few areas in the bin.

ULTM8Z

Got a reply from Pertronix... it's a little open ended though. They don't seem to be saying for sure I'll see any improvement...

You should match the coil with the module; they are designed to work together for a hotter spark and you may see improved performance or fuel economy gains or both. HEI modules are very reliable and we don't see many issues with them.

CORV3TT3

RBob- has anyone integrated EFI Connection's 24x system with EBL? CnP is a direction I've kicked around for a future mod... just wondering if it's been done yet.


ULTM8Z- sorry of this hijacks your thread. Just figured as we are on the topic of spark, coils, and distributors that I'd ask. Hope that's okay.

ULTM8Z

No worries... I'm interested as well!

CORV3TT3

There is a system EFI Connetcion sells for carbed motors.

I understand the ECMs used for EBL Flash / P4 don't drive DIS systems... but was wondering if the carb system could be adapted since it is more of a stand alone.

But I've probably answered my own question... I mean, the 6AL could run it- but wouldn't talk with the ECM the way it would need to.

RBob

iTrader: (1)

The 24x system is based on the LS1 PCM. No, won't work with a current EBL system. Could likely use an external interface box to do so, but most would still go with the LS1 PCM.

Oh but they do. No problem running a GM DIS system with an EBL system. So far every EBL SFI-6 Flash ECM is running a factory DIS set up.

If I can ever find the trigger wheel I'm going to retro-fit a car with DIS running an EBL Flash ECM (TBI). I put it someplace 'safe' so it wouldn't get damaged or lost...

RBob.

ULTM8Z

More from Pertronix when I pressed on the "may" part of the earlier reply...

If your old coil was weak (low output) and you installed a new coil you would feel the improvement; it’s not the case for the module, If your engine is well maintained (tuned up) you may not feel the improvements.

I'm probably not going to try their module... I'm skeptical I'll see anything that'd be worth the money.

whatif3387

I was hoping they would share with you some info as far as how the ICM causes the SA to advance or retard at certain RPMs compared to say a GM 369 and the other GM tbi icms...