weak spark which is causing my car to run extremely rich

[ALP584]

Well here is my problem, I have identified the problem as weak spark which is causing my car to run extremely rich. However it is not that simple !

The motor has 25 break in miles and is FULLY BUILT

2.4L
BJ SMIM
280's
Wiseco pistons
Eagle rods
650 fic
Aeromotive
rewired 255

etc and the list goes on and on I checked the motor after 25 miles just to see if perhaps it could a bad rebuild causing this. To my surprise all cylinders after 25 miles have exactly 180 psi across. I have ruled out the engine entirely, because it sounds awesome like a new engine should.

I run a maf-t 3 inch and already checked if it was a maf problem and it is not since I used a stock maf and still the same problem. I checked the ecu but found no leaky capacitors and the ecu has DSMLINK on it that works flawlessly. I tried swapping cas,maf,power transistor, wires,the plugs are ngk 7's gapped properly, also the coils were swapped for suppousedly good ones with the same result the spark is weak. When I tired to drive the car it will build boost and fall and break up almost any time I build boost and sputter. I have meticuously checked every where for a boost leak and found nothing. I am fairly certain that my car runs the way it does because the spark is very weak. I have even swapped the injectors with 450's with no luck. I have even checked timing and it is dead on. I am running out of ideas here! and the car will not IDLE at all it just dies and then it is hard to start the car back up. Also when I did the old school method of checking each spark seperately each fire fine but they are very weak compared to a friend of mines my spark is like a dim star and his spark is like the north star. Well hope someone can tackle this with some good ideas

P.S everything was fine previously when my 2.0L was in the car, that motor had rod bearing failure so I pulled the motor, and the car sat for 6 months put everything back together and now this ! also please do realize that I did tripple check all the maft and dsmlink settings they are fine.

Thanks

 

[ROOKIE1]

You check timing by marks or with a light ? Are you sure that when you removed the cas it was aligned properly .

 

[ALP584]

I checked timing manually rotated the engine to see if all marks lined up and they do perfectly, also if timing was off I would not get 180 across with timing off it would be lower in my situation, I do not have balanceshafts in my car and when I lined up the timing marks I pulled the cas and it was lined up all the way so the cas is not off and it does get power to it. The spark is weak that could be attributed to timing but timing is fine and I switched coil packs and did the same unless the other coil pack was bad as well.

Thanks

Alen

 

[peypey's ride]

I would say check out your power transister. It my be bad and sending a weak signal. Find a spare if you got one and just switch them out and see what happens.

 

[ALP584]

I replaced the power transistor and it did not change the situation and per the volt meter I am getting powet to both the transistor and the coil pack

 

[sbengineering]

check to see if the ignition is getting the correct voltage.

 

[ALP584]

Both the coil pack and the power transistor are getting power from the harness to the units themselves as per the volt meter.

 

[sbengineering]

Both the coil pack and the power transistor are getting power from the harness to the units themselves as per the volt meter.

but are they getting the right amount of voltage.

 

[oldman]

1. How did you check for boost leaks?

2. There are two types of timing, valve and ignition. You have checked valve timing (timing belt marks) but you have not checked ignition timing (CAS, with a timing light).

3. How about posting a Link log.

 

[ALP584]

As far as the voltage goes from the connectors to the coil packs it is fine I checked it with a voltmeter with my haynes manual plus I had a buddy of mine which is very knowledgeable with circuitry and dsm's overall check my coils, transistor and coil pack and confirmed they are fine. As far as dsm timing goes the cas timing is perfectly aligned with a timing gun and the timing is ground with dsmlink and set to 5 and with unground fluctuates around 8-10 per link. I do not have a log yet, because I looked at the stream on and everything is set right and seemed to be fine as far as idle.

 

[oldman]

How did you check for boost leaks? Post a log anyway.

 

[ALP584]

I went to a hardware store bought a pcv plastic coupler drilled a hole in it inserted a tire valve in it siliconed it all around, purchased a sillicone coupler that fits on my turbo inlrt and my 2g t elbow. Pressure checked both with my buddy watching my boost gauge going to 20 psi it held it for about 45 seconds till it dropped off with no leaks anywhere. I will post a log as soon as I can.

Thank you wisemen so far...

 

[nc90awd]

Are all you ground wires hooked up? The one's on the intake manifold, fire wall, tranny ect. Make sure the grounds are clean and making a good connection.

 

[ALP584]

I have one going from the BJ SMIM to the firewall, one going to the firewall from the tranny and one going from the battery negative terminal to the firewall. I do not have the ground hooked up to the exhaust since it is a full 3 inch SS Buschur exhaust and the stock ground is frail, however that did not cause any issues before what so ever with the old engine. None of the grounds seem to be damaged visually other than the exhaust ground but I do not believe that is the issue since it did not bother the engine before.

 

[luv2rallye]

Weak spark on all plugs is usually a weak coil. Just because a coil's resistance checks out ok does not mean it is necessarily good. Also did you move the coil from it's stock location? Other causes can be bad grounds, poor plug wires, or power transistors that have too slow turn off times (incorrectly connecting a capacitor here will also do this). Also look at the coil in the dark to make sure spark is not jumping to ground around it.

 

[ALP584]

Since I have a SMIM I had to move the coil pack, it sits on top of the BJ SMIM on a special bracket I fabricated out of aluminum both of th coils sit on top of the SMIM between runners 3 and 2. That is all I can think of now I used also Nology wires and switched to Magnacore wires with no luck still weak spark

 

[luv2rallye]

Occasionally I've heard of cases where moving the coil location produced weak spark. Possibly the magnetic field needs to be close to the head's metal. Yet I've also heard other cases where even moving it to the firewall has not been a problem. I'm sure it depends on the year, design, etc. Since you changed all this it may be your problem (in fact the sheet metal may be acting as a shield). If you can relocate it to be bolted onto the head this may do better. Even if all you do is temporaily try this just to see if it helps. If you can't, try bolting some heavy wide (must be wide - 1" or wider) wire mesh braid from the coil's bracket to the head to help transfer the higher frequency magnetic field (although this may not work - bolting to the head is best).

 

[laserspeeddemon]

Just out of curiousity, what are you gapping at?

 

[ALP584]

I got a jdm vr-4 coil pack plugged it in my car and all my problems went away, thank you for all the helpfull insight guys!

 

[oldman]

Awesome.......good work luv2rallye.