dropping a cylinder

[dsmtalontsi95]

I have a 2g with a 6bolt swap. For some reason if you rev the car at 3500 I drop cylinger 3, it also causes the tack to jump up about 500 rpm (the needle on the tach, not the motor). So far I've changed out cas, coil pack, and wires. The car runs fine until you rev to 3500 and drop 3 even if you let off the cylinder never comes back. If you turn the car off and start it right back up it's fine (all 4). We can pull the wire and it has spark after it drops that cylinder (pulled the wire while the car was running). That leads me to beleave that its the injector. What tells the injector to fire? The only thing I have left to check is the ecu unless you guys know of anything else that could cause this issue.

 

[ktmrider]

The Transistor or Injector Resistor packs can cause that, you try those yet?!?
When the tach jumps around it is usually the transistor power pack going/gone bad.

 

[iceman69510]

Typically the transistor pack will drop two at a time though, since it is dual fire, 1 and 4, and 2 and 3 fire together.

 

Are you running DSMLink? Do you have the Random Misfires disabled?

 

[dsmtalontsi95]

I don't have link installed yet. I wanted the car running well before install. What are/where are the injector pack and transistor pack, I'll try those tonight. The tach only jumps once the cylinder has been lost.

 

[prove_it]

swap your injectors around and see if the problem follows. Correct me if I'm wrong but I think The injectors get power and ground from the ECU. If you have spark then it's a fuel issue. Since it happens at the same time everytime then it's going to be the computer, the wiring or the injector for some reason. Swap injectors around if no change try swapping a different ecu in and see what happens. If still does the same check your harness.

It's a weird problem, that's for sure.

 

Quoting dsmtalontsi95:
I don't have link installed yet.


It sounds like Random Misfire to me. You aren't getting a P0300 MIL code from it? /ubbthreads/images/graemlins/confused.gif Does it do it when the engine is cold, or only after it has warmed up?

 

[dsmtalontsi95]

It's a brand new motor so I let it warm up first. I tried to install link lastnight and the 95 ecu started to fry.

 

That's IC112, which controls both the BCS solenoid and the FPR solenoid. It looks like the burn may be towards the front of the chip, so it would be the BCS/wastegate solenoid. If the solenoid is shorted, or the wires to the solenoid get melted/shorted together, that is what happens. I doubt it has anything to do with the DSMLink.

 

[dsmtalontsi95]

Could I just un clip them? I did yesterday and reinstalled the ecu and nothing happened, it didn't start to smoke or melt or anything. Should I not do that again?

 

If you aren't using either the BCS or FPR solenoids, I would just wiggle the IC back and forth until the leads break off, and leave it that way. The chip is already popped, so its doing no good for you.