Missing

[rsTurboLaser]

I've replaced the coil pack, spark plugs, wires. ive checked the timing (spot on) and looked for boost leaks (none) , ive swapped an ecu, injectors, and a ta unit from a friends car, volts are at steady 14.4 with the car on. I have basically stock everything besides some free mods like hacked air can, boost controller, rewired fuel pump. Its missing all over the place at idle and part throttle
(probably full throttle too just dont notice it). I bought the car a year ago and it didnt do this but for the last couple of months it just started acting up and im running out of ideas.
suggestions?

 

[DSMcrazy3]

I would recommend checking or replacing the EGR unit. Those can sometimes lead to misfire.

 

[rsTurboLaser]

not the egr. i just did the emissions clean up and it still does it. possibly fuel pump?

 

[Coup D E'Tat]

I'm wondering if it's a wiring problem at this point. Tomorrow, I want to pull apart the wiring that runs to the coil pack and see if anything is obviously off. If not, I guess we'll have to start tracing everything back to the origin.

 

[peregrine]

check your relay on the fuel pump rewire.

 

[Defiant]

I've replaced the coil pack, spark plugs,

What exact spark plugs, and what gap?

 

[Coup D E'Tat]

BPR6ES', gapped to .028"

 

[Old Mitsu Tech]

First of all, when did you notice the miss? Was it a natural phenomenon or did you notice it after something was done to the car? Most commonly on the eclipses and mine too is the spark plug boot that goes down into the head will perforate and cause missing. Is the missing one cylinder or all? Under acceleration or all the time? Do you have a check engine light that is on? If so, I need to know the code or codes stored. Misses can be very awe inspiring to say the least. If it does it at idle or can be reproduced while the car is stationary, I would scope the ignition to see what your kv reading is. I would do a snap kv to see if the system is up to the task of heavy load. I have also seen "new" wires that were worse than the ones I took off. The ecu and the igniter could be a contributor as they both have direct effect on the system. I would scope the injector ground side to see the pattern and see if it acts abnormal. This could signal a bad ecu. I have seen this more than once. Check the primary input to the coil with a scope and see if the pattern skews while the engine is missing. If you know someone with a Vantage handheld scope, I would recommend that as it will tell you the connection points, the pattern references and let you check for transients that will never show up on a dvom. It is also vehicle specific which is a plus. One last thought. At night or in a dark room which has great ventilation or exhaust tube handy, remove the plug cover and check for little blue sparks. use a spray bottle with water on the secondary ignition. This would help locate any weak insulation. If that doesn't work, take a 12 volt test light on a good ground and hold it near the secondary ignition system. Rub it around the wires, the coils and such. This sometimes finds a weak leak in the insulation. BTW, the plug boot that goes into the head will sometimes have a whitish place with a little black dot in it. Look for it and if you have one, that could be your source. Let me know if this helps. Rick

 

[Coup D E'Tat]

First of all, when did you notice the miss? Was it a natural phenomenon or did you notice it after something was done to the car? Most commonly on the eclipses and mine too is the spark plug boot that goes down into the head will perforate and cause missing. Is the missing one cylinder or all? Under acceleration or all the time? Do you have a check engine light that is on? If so, I need to know the code or codes stored. Misses can be very awe inspiring to say the least. If it does it at idle or can be reproduced while the car is stationary, I would scope the ignition to see what your kv reading is. I would do a snap kv to see if the system is up to the task of heavy load. I have also seen "new" wires that were worse than the ones I took off. The ecu and the igniter could be a contributor as they both have direct effect on the system. I would scope the injector ground side to see the pattern and see if it acts abnormal. This could signal a bad ecu. I have seen this more than once. Check the primary input to the coil with a scope and see if the pattern skews while the engine is missing. If you know someone with a Vantage handheld scope, I would recommend that as it will tell you the connection points, the pattern references and let you check for transients that will never show up on a dvom. It is also vehicle specific which is a plus. One last thought. At night or in a dark room which has great ventilation or exhaust tube handy, remove the plug cover and check for little blue sparks. use a spray bottle with water on the secondary ignition. This would help locate any weak insulation. If that doesn't work, take a 12 volt test light on a good ground and hold it near the secondary ignition system. Rub it around the wires, the coils and such. This sometimes finds a weak leak in the insulation. BTW, the plug boot that goes into the head will sometimes have a whitish place with a little black dot in it. Look for it and if you have one, that could be your source. Let me know if this helps. Rick

Rick,

the miss came about suddenly. I highly doubt the ECU being the culprit. As I stated earlier, we swapped in a lot of known working parts, so the wiring is what still stands out to me.

No CEL's, misses at idle and cruising, and is not load dependent. Wire 4 does not miss, only 1-3.

The plug wires are NGK's, and every boot on them is fine.

Later today (hopefully,) I'm going to check out some of the wiring.