Testing coils on a coil over plug system?

[art leong]

Originally Posted by Adger Smith

Art,
Getting worse with heat and better when cool.... I still think Coil Temp affect has to be something in the electical controls.. Coils or sensors that time the electrical cycles being bad. I Still think the 2 step circuits in your computer are not working correctly. I would talk to the guy that did that and try to get it deactivated...completely. Get it running as a foot brake set up and then go back to the 2 step.

First I deactivated it in the ecu, then I removed the wiring from it.
I'm trying to get it back to running right without the 2 step. I ran fine before. I had it idling at 1000 rpms, drop it in gear and hold 900 rpms. When that comes back. Then I'll tackle the 2 step.

Originally Posted by buzzinhalfdozen

Art, the LS1 coil pinout is A= ground, B=low reference to PCM, C=coil control PCM, D=Ign power or B+ The low reference on terminal B is the PCM ground for the coil. Hope this helps. BTW you stated that this all seemed to start after using the launch funtion in the ECU, in what manner does your system limit RPM? does it do Ign. only, fuel only or a combination of these?

The launch control function can cut spark, fuel or timing. I was told for the N/A just to use the spark. It worked flawlessly in neutral but went ballistic when against the converter.

[buzzinhalfdozen]

Art, not sure I would spend any time looking at Crank or cam triggers, as they would just make the engine quit no matter what. Did you get your spark checker if so do you have nice blue spark from all coils? I asked before about MAP sensor... what does it read? Do you have any tuning tables that use the MAP input to change fuel or timing perhaps coil on time based on MAP or fuel enrichment based on MAP sensor? Can you "see" in real time what timing and pulse width is being commanded by the ECU?Also can you view your Crank sensor count in real time, sometimes referred to as Wheel dbug counts?

[art leong]

Originally Posted by buzzinhalfdozen

Art, not sure I would spend any time looking at Crank or cam triggers, as they would just make the engine quit no matter what. Did you get your spark checker if so do you have nice blue spark from all coils? I asked before about MAP sensor... what does it read? Do you have any tuning tables that use the MAP input to change fuel or timing perhaps coil on time based on MAP or fuel enrichment based on MAP sensor? Can you "see" in real time what timing and pulse width is being commanded by the ECU?Also can you view your Crank sensor count in real time, sometimes referred to as Wheel dbug counts?

The ecu is programmed to use the map sensor and the tps to change timing and fuel.
The map sensor is in the ecu. It has a calibrate function, and it matches the internal bap sensor. According to the datalogs the map reading changes seem to be right. I can hook up a seperate map sensor. I don't know is I have a wheel debug option.
I just checked the wiring for the coils and it seems to be correct But I did notice that I get 11.8 volts at the pos side of the coil (ignition on) when I get 12.5 at the battery. This is going to require more inspection. This is without the fuel pump on only the ecu and (heated) wideband O2 sensor is energized. I'm wondering why an ecu takes that much voltage when I might try to disconect the O2 sensor and see what happens.

[buzzinhalfdozen]

Art, if you have 12.5 volts at battery and 11.8 volts at coil you are seeing voltage drop in that circuit, what voltage does the coil have when it's running?

[art leong]

Originally Posted by buzzinhalfdozen

Art, if you have 12.5 volts at battery and 11.8 volts at coil you are seeing voltage drop in that circuit, what voltage does the coil have when it's running?

The only thing on is the O2 sensor and the ECU. I'll check it with the O2 sensor unplugged
When the car starts and runs the voltage goes to 13.9

[buzzinhalfdozen]

Art, yes the heater in the 02 does require a bit of amperage, so that's most likely where your voltage is going. You said you datalogged your engine while this is happening what inj. pulse are you seeing how bout coil dwell and calculated timing? you should be seeing some sort of change in these, what happens cto the 02 reading?

[Adger Smith]

Joe,
What I don't understand is he is getting lean 02's even when he is going rich on the settings. I keep thinking it is something to do with the coils not having good enough output (or a signal) to fire the plugs and he has more 02 in the pipe because the engine is an air pump when the plug doesn't fire... ???
Sensors don't read raw fuel, but they read raw air...right? Any ideas?

[buzzinhalfdozen]

Adger, you are correct if a cyl. misfires it is "read" by the 02 as lean. There are a few thigs that can cause an unwanted lean condition, obviously a miss as we discussed, fuel pressure, low injector pulsewidth, a radical timing change I believe could also induce this issue as would a vacuum leak. For this engine to quit it has to be losing...1 the correct amount of fuel...2 the correct amount of spark as well as at the correct time. Now thaty being said, Art has indicated that he's put a timing lite on it and all looks good, what the timing is doing just proir to stall may be unknown, say forsome strange reason the ECU decides to drastically retard the timing.... what happens, or say the ECU decides to decrease the coil dwell time what happens? The same can be said for the injector control if for some reason it decreases the pulsewidth what happens? Any of these things can cause the symptom he's got. As a starting point I would log injector pulse width... coil dwell time... ECU calculated Ign. timing, also the crank trigger wheel counts as well as the cam sync trigger if available. Another handy tool I use quite often is an inline spark checker as well as a "noid" lite. While carefully observing these during the event it can be apparent that the coil quits... then the engine stalls or you see the noid lite quit flashing then the engine stalls, this happens very quickly but with an engine that repeats the failure quite often it's easy to pick out. Have a problematic car now from another shop that just quits at times, by using my lab scope I noticed that at times the 18X crank signal gets erratic, gonna replace that and see if it's fixed. Wish I were close enough to go help ART first hand however I belkieve he's got the smarts to locate this issue.

[Ed Wright]

If it is better with a muffler, it makes me wonder, is it in closed loop? First, that is not what you want. Second, if you insist on closed loop make sure you have the minimum closed loop RPM to something like 4000 RPM. You DO NOT want the ECU making fuel corrections at lower RPM with open collectors. Pulling oxygen back in the collector during the overlap cycle with big race cams. It will make false corrections due to the O2 "seeing" thar oxygen and returning a false lean indication to the ECU, causing a very rich mixture.
Are the spark plugs black after an extended idle?

[art leong]

Originally Posted by Ed Wright

If it is better with a muffler, it makes me wonder, is it in closed loop? First, that is not what you want. Second, if you insist on closed loop make sure you have the minimum closed loop RPM to something like 4000 RPM. You DO NOT want the ECU making fuel corrections at lower RPM with open collectors. Pulling oxygen back in the collector during the overlap cycle with big race cams. It will make false corrections due to the O2 "seeing" thar oxygen and returning a false lean indication to the ECU, causing a very rich mixture.
Are the spark plugs black after an extended idle?

Open loop. Only using the O2 sensor for dataloging and manual quick tune. The O2 sensor is in the collector so it does not read acurately at any thing below 3500. I have put a 2 foot curved extension on the collector to get the idle settings close.
The plugs look dark but not sooty or wet. They look like they have always looked.