who can figure this one out? 1,2 cyl not burning like 3,4 ???

[r1jlewis]

I'm stumped on this now. S15 SR, new bottom end (rods, pistons and rings), new HG W/arp's, fresh valve job, HKS cams, Greddy springs, bla bla. Now on with the story, compression all between 135-145 accross the board, leak down reads 100in 92 out accross the board. Each one you can feel air out the oil cap so head is sealing good. Problem is that cyl 1 and 2 just don't burn like 3,4! 1,2 are still almost all black while 3,4 are white. Swapped injectors 1,2 to 3,4 and coil packs 1,2 to 3,4. No change, stays with the cylinders. Ohm reading on injectors are all same. All new plugs, tried swaping, no help. ECU is a AEM EMS and shows output same accross the board. Pull coil packs and can hear good fire accross the board. Removed injector harness and check all conections look great. All Ohmed out normal. AEM says it's not the ECU, CFTurbo says it is. Just now baffeled! Car still runs fine, but still staying out of the boost until full dyno tune is completed, but i can't do that until it's burning the same accross the board. Any ideas???

[highmilehatch]

I have zero experience with AEM, but I've heard of the injector drivers going bad sometimes. Do you have a stock ECU and injectors you can plug in to rule it out?

[IanS]

Id say its an ECU issue, unless somthing is mechanically wrong with the lifters for cylinders one and two causing them not to allow enough air in. What are you running for cams, and are you still using HLAs?

[NissanMaster]

Yo,Pull the injector rail without disconnecting fuel lines or release of fuel pressure,you may have injector leak down at the pintale of the injectors;Also with the fuel lines pressurized install a pressure gauge clamp off both fuel lines & observe how fast you lose pressure,some loss is normal. I recently had a 2000 Q45 with Cyl #3 Misfire Code,fouled plug & good coil.replacing the #3 injector got all 8 poppin,reset self learning control,checked base idle,verified Frt O2 modulations & checked TPS on/off.Good Luck! BSR 4 Ever!

I'm stumped on this now. S15 SR, new bottom end (rods, pistons and rings), new HG W/arp's, fresh valve job, HKS cams, Greddy springs, bla bla. Now on with the story, compression all between 135-145 accross the board, leak down reads 100in 92 out accross the board. Each one you can feel air out the oil cap so head is sealing good. Problem is that cyl 1 and 2 just don't burn like 3,4! 1,2 are still almost all black while 3,4 are white. Swapped injectors 1,2 to 3,4 and coil packs 1,2 to 3,4. No change, stays with the cylinders. Ohm reading on injectors are all same. All new plugs, tried swaping, no help. ECU is a AEM EMS and shows output same accross the board. Pull coil packs and can hear good fire accross the board. Removed injector harness and check all conections look great. All Ohmed out normal. AEM says it's not the ECU, CFTurbo says it is. Just now baffeled! Car still runs fine, but still staying out of the boost until full dyno tune is completed, but i can't do that until it's burning the same accross the board. Any ideas???

[r1jlewis]

Using stage 2 cams 256in 264 out with stock HLA's. I pulled the HLA's out also and checked them and all looked good. Then i rebled them and put em back in. My FPR leaks down a little but stays close to 38psi. Has normal leak down. All injector orings are new and looks great. If it was an injector leak problem, then it would of followed the injector. i'm going to Oscope the signal into the injectors and coils to see if all the input signals are even across the board. It's just wierd!

[r1jlewis]

I wish i had my stock ecu and injetors. that would be a quick definate rule out. Anybody got one hanging around??

[IanS]

Using stage 2 cams 256in 264 out with stock HLA's. I pulled the HLA's out also and checked them and all looked good. Then i rebled them and put em back in. My FPR leaks down a little but stays close to 38psi. Has normal leak down. All injector orings are new and looks great. If it was an injector leak problem, then it would of followed the injector. i'm going to Oscope the signal into the injectors and coils to see if all the input signals are even across the board. It's just wierd!

good luck with the Oscope, if that doesnt lead you in the right direction I will be thoroughly stumped.

[doridori23]

Any results from your Oh-so-silly-scope? Very useful tool and if it does indeed indicat teh ECM then i would call AEM back and be nice at first and tell them what you have done first then the oscilloscope's results. Kindly state that you simply want to exchange as you have always had good luck with AEM and do not want to change over to another company. If they are still being poopoo heads then ask for a supervisor. When you get him explain it all again while remaining calm (yelling will just get you ignored) if he is being iffy tell him you'll being the car to Hawthorn and if they can find a problem other than the ECM then you'll pay the labor rate but if it is indeed the ECM you wan the ECM, shipping costs, missed time from work, and per-diem for your stay.

[r1jlewis]

Well, i checked it out last night. One problem is that i'm using a Scopemeter, which is still an Oscope but it's very slow in reacting to anything unlike a normal Oscope that i'm used to using. I never found a good looking square wave signal. The top of the peek just sloped back down instead of a nice straight square drop off signal. I did call them earlier but left a message. I'm going to see if they will do a diagnostic on it and give me a tear down. AEM did state yesterday that only recently they incorporated a full 100% test procedure. I did have a problem with it once but it was a different problem. One other issue i have with it is that my A/C doesn't cycle any more so wasn't sure if it was just a setting or the ECU wasn't doing it's job. Think it's back off to AEM again. I'll get back with the results. Why can't it just work the first time!!

[S14-KOUKI-MONSTER]

What up Justin. Hope you get it squared away asap. Lifters would've been my firt guess, but you already tried that I see. In reply to your email, yes I will send you pics when I get it painted. My buddy has been booked solid with tatooing and air-brushing, and I've been bugging him to re-finish and paint it for a few weeks now.

Jordan

[r1jlewis]

well guys, just got the ems back from aem and they said it was fine. they did upgrade something inside of it, cause now it's a higher rev level and now has a mod # to it. don't think that's going to change anything though. nissan thought it might have a leak on the intake gasket between 1 and 2 but that's seems a little far fetched to be causing that kind of problem. Not really sure where to look from here. any other ideas?