weak spark

[gravesdu_99]

Well I believe that I have a big problem with weak spark. I have a 1jz with brand new coils and stinger ems. I keep foiling plugs out after about 20-30 minutes run time. I have tested the grounds going to the motor with a multimeter and they read normal. I'm not sure how to get a reading from the coil plug itself or from the ignitor. I have heard that the ignitors never go bad. Maybe I got an unlucky one. So I'll looking for other possibilites and maybe a way to test the coil clips and the ignitor.

 

[Freshmaker]

is the stinger tuned? can you verify the AFR's arn't your problem?

What spark plug gap are you running?

 

[gravesdu_99]

car was tuned and running for about 6 months, then just out of no where started fowling plugs. The afr's are in the right range and the plugs are gapped at .030. I checked my cam sensors and they are both at 1114 ohms. The wires on the sensors look pretty bad so I'm going to redo those.

 

[suprahero]

Fill out the template in this thread and lets see how your setup compares to ours.
http://www.supramania.com/forums/showthread.php?t=99709

 

[Freshmaker]

Its so hard to diagnose a standalone through the internet. It is possible you have a setup issue(coils, dwell time, etc), but since I don't have stinger specific experience I can't help with that.

What kind of driving does it take to fowl the plugs? idling? no boost? 20 psi?

What temp was the car tuned in? What temp(atmosphere) are you fowling plugs at? If there is a big difference, your air temp ignition compensation map might be way off.

 

[gravesdu_99]

Yeah theres a lot to take into consideration. Thats why I made a point that the car had been running fine over 6 months with no problems. I was hoping that by adding the stinger people would just rule out the ecu's normal caps problems.

The motor is fouling plugs running off boost. I took it to a tuner and he even had problems fouling plugs. The guy was an ass and didn't want to look into it though. Needless to say I won't be going there again.

 

[gravesdu_99]

changed the cam connectors out today and still have weak spark. It looks like on the very first crank that the spark is strong then it goes away. Any one else have any ideas or anything for me to check.

 

[gravesdu_99]

another question. I took a mutlimeter and checked the connectors for the coils. I get power when I use a different ground, but when I try to put the multimeter on the power and the ground of the connector I get nothing. The spark plugs do spark and the car runs. But like i said it fouls all the plugs out very quickly and the spark looks very small. Is this just a JZ thing for the very small spark or is it just me.

 

[10secdream]

What plugs are you running? I have found that on my setup and in my climate that I cannot use BKR7E's for the life of me. They will always foul up after a couple of days and my tune is rock solid. I have since switched to BKR6E's and have zero problems with fouling. I am also running 20-24 psi of boost with meth injection.

 

[tsupra]

how good is your ground from the engine head to the body or to the battery? it needs to be a fairly heavy wire, at least a 10 gauge or better an 8, and the point where it attaches to the body needs to be clean and paint free.

 

[suprahero]

Just thought I'd check in and see if the problem is still happening. Hopefully you'll get it worked out.

 

[gravesdu_99]

how good is your ground from the engine head to the body or to the battery? it needs to be a fairly heavy wire, at least a 10 gauge or better an 8, and the point where it attaches to the body needs to be clean and paint free.

yeah, I ran an 8 gauge wire from the battery to the head. With a muiltmeter I checked all the grounds on the motor and they all came out the same voltage as the battery. Can somebody tell me if I should be getting a ground and power at the end of the coil connector. So that way I know if I need to start taking my harness apart to look for a broken or burnt wire. So far this is the list

New coils
New cam connectors with wire leads
New plugs gapped .025
Grounded the ignitor (found on supraforums)
Checked grounds

 

[tsupra]

yeah, I ran an 8 gauge wire from the battery to the head. With a muiltmeter I checked all the grounds on the motor and they all came out the same voltage as the battery. Can somebody tell me if I should be getting a ground and power at the end of the coil connector. So that way I know if I need to start taking my harness apart to look for a broken or burnt wire. So far this is the list

New coils
New cam connectors with wire leads
New plugs gapped .025
Grounded the ignitor (found on supraforums)
Checked grounds

you should have a wire with 12 volts on it with the key on and a wire that goes to the igniter. the wire going to the igniter isn't exactly a ground wire but does provide a path for current to flow. when that current flow stops is when you get spark. http://www.autoshop101.com/forms/h39.pdf has a decent explanation of how it works. is the point that you attached the 8 gauge wire at the head clean? one thing to remember with aluminum is that it oxidizes very quickly, the second you stop cleaning it it oxidizes and oxidized aluminum conducts very poorly. give it a good clean with a scotchbrite pad and put some antiseize compound on it before putting the wire back. not saying that that's your problem but it's fairly quick and easy to do and can't hurt.

 

[gravesdu_99]

Okay thanks, thats exactly what I was looking for.

 

[gravesdu_99]

Okay I checked all the clips to the coils and they are getting 12+ volts on the wire that is on with the ignition. I guess my next check is to check the wires going to the ignitior. Can some one some me which wires to check on the ignitior. Also will I was watching the spark from the plug I can see where it is still weak but also speratic (sp?). It jumps all over the plug and thats from a brand new plug.

I'm thinking maybe a melted wire or something. Like I said this all happened within about 10 minutes. The car went from driving fine to running like shit. And I had previous been driving the car for about 6 months with no problems.

 

[gravesdu_99]

would timing have anything to do with it. I just have the timing set at tdc. Should I have it set at something else like 10 deg retard, or 10 deg advance.

 

[10secdream]

I have mine set at 10 Deg BTDC. Also what gap are you running your plugs? Even with an ignition amplifer I had to gap my plugs down to 0.020 in order to run 23-25psi.

 

[gravesdu_99]

i have the plugs gapped down to .025