Weird engine misfire and tach issue

[sprocket2005]

Ive got a 97 awd with a 6 bolt swap and dsm link. I was driving it home from work today and on my way home it suddenly starting running terribly and my tach dropped down to less than half of what it should be reading. (i can tell by my oil pressure gauge) Anyways, the engine lost about all power and the tach dropped down to about 1200 - 1500 rpms while cruising on the highway at 60mph in 5th gear, also my wideband started saying that its running lean and it almost seemed as if it were running on 2 cylinders or something, it wont idle, it tries to idle, but at extremely low rpms and stalls after a second or two. I BARELY got home and am not sure what to think or do, or where to start. Anyone have any ideas as to what it could be?? Normally, i would start checking for a boost leak or something but i dont think a boost leak would make my tach do this.. (btw, it did not throw an engine light)

 

[DSMsamurai666]

I've had something like this happen to me twice in two different cars. It was a fuel problem both times. I'd say for some reason your cylinders aren't getting enough fuel. You must have some type of impedence somewhere between the tank and the injectors. The simplest place to start is with the fuel filter. When did you change it last?

 

[Muzda]

Sounds like a spark issue, maybe the coilpack dropping a coil or something electrical cutting one of the coils signals. A friend of mine had this exact problem last week. I forgot what he did to fix it, but I'll ask him when I see him next.

 

[luv2rallye]

With the tach reading half you're running on 2 cylinders (either 1&4 or 2&3). Check for bad coil or power transistor at links shown here: http://www.dsmtuners.com/forums/pro...art-no-fuel-prime-no-spark.html#post151265626

 

[Boost_Addict_88]

I've experienced this as well. It was a fuel problem for me. Start with cylinder 1 (closest to timing) and start unplugging the electrical to the injectors with the car running. If it dies then it works, but if its still running the same, then there's a problem. If this is your issue, unplug the battery and ECU, let sit for 5-15 minutes, then plug it back in. The car may run like crap at first, but give it 5-10 minutes, as the ECU is trying to relearn everything. Try this then report back.

 

[gsxalex]

I had a similar problem recently after swapping an intake manifold. I carelessly had my ignition wires tangled up with my fuel injector wires, and possible with the coil wires. The weird thing is that it ran fine until an hour later i was doing a pull on the freeway and it all went haywire. My tach was jumping around all over the place and the car ran like shit.

I poppped my hood, and noticed the mess right away. After a quick sorting of wires i had it running perfect again.

Im not sure how it would be a fuel problem, but to me it seems most likely an ignition problem.
let us know what you find.

 

[sprocket2005]

It turns out it was just a bad connection on this sensor.. Im not real sure what the sensor is but i disconnected it and sprayed it out with electronic cleaner and its running normal now.

 

[justin90gsx]

thats your transistor! thanks for showing your problem!

 

[sprocket2005]

Yeah, I actually wasnt doing as good as i thought i was, yesterday I cleaned the transistor up and started the engine and let it warm up and it ran good for about 20 mins then i shut it off and let it alone, but today i took it down the road and it started missing badly again before i even made it a mile away from home. I opened the hood and wiggled the pigtail going into the transistor and it started working again, then another 1/2 mile or so and it did it again, so i popped the hood and wiggled the pigtail and it started idling normal but before i could get back into my car it started missing again. I disconnected the pigtail and looked down into it and it was clean, the transistor was too, so i disconnected plug wire 1 and tryed to start it, but it wouldnt start so i reconnected #1 and disconnected #2, it started after that and while it was trying so hard to stay running i reconnected #2 wire and it made no difference it was still missing terribly. I disconnected the transistor once i limped her home and took it inside and looked at it, its pretty clean and there are marks on each of the 7 prongs that show that it had a good connection. Idk if the transistor went bad or what, do transistors go bad often???? or is it pretty common for them to go bad???? I also am not real sure where the transistor is supposed to bolt to, the guy that put the motor in my car bolted it to the intake manifold with only one bolt holding it against the manifold. It says on the transistor TAC GND so that would explain the tac issues. Heres the pics of the transistor, and if you look at the one pic you can see where the entire mating area between the transistor and the intake manifold was, its marked by the bolt hole on the left side. Is there somewhere else i should mount the transistor, maybe for a better ground, or should i just get a different one and put it back where it was????

 

[sprocket2005]

the pics....