car starts but runs rough then dies?

[2gDSM6bolt]

i have a 97 with a 6 bolt swap and have been having some issues. every once in a while i will have a really bad miss at 3000 rpms and it won't let it rev past this. if you unhook the neg. battery cable it clears up for a month or two. thats really not the problem but i thought it might have something to do with whats going on. i went to lunch today and when i got back in the car it runs really rough for a second then dies out. if you unhook the battery cable now the car will stay running but extemely rough and can't be driven. then if you turn it off and try to start again back to running for a second then dying. any suggestions?

 

[allezgrand]

When you did the 6 bolt swap, which electronics did you swap? If you have all 1G electronics being run by a 2G ECU, you are going to run into problems. Do you have a CEL error? Have you scanned for codes?

 

[2gDSM6bolt]

the swap was done by a previous owner by fist racing in houston. i can't get a hold of a code reader but i did find that two cylinders aren't getting spark. i tried swapping the coils to see if it changed which cylinders aren't getting spark but it didn't. could it be the ignintion module. also it will start and run fine once when it is the first cold start of the day but after that it runs on two cylinders

 

[NHerron]

You can test the igntion power transistor with this guide if both your coils are good (search how to test coils if not sure)

http://www.dsmtuners.com/forums/articles-electrical-wiring/229419-how-test-power-transistors.html

 

[Twinturbo120]

Im running into the same issue. It runs on two cylinders only even though I have spark and fuel. These cars man...I tell ya

 

[2gDSM6bolt]

Tried a new ignition module and same problem starts once and then when I kill it, it runs on 2 cylinder again

 

[NHerron]

Have you traced the wires for the coils for proper voltage. The coils could be fine but a may have bad connection to one of coils. That's assuming its running on two cylinders due to lack of spark.

 

[2gDSM6bolt]

Will try that but wouldn't it always run on two cylinders instead of after that initial start?

 

[NHerron]

Small electronics such as semiconductors can fail when heated up, like that link notes why to use a heat source to test electronics. I realize you replaced the power transistor already. Are you 100% sure it's not getting spark when this happens or can it just be running very rough / choppy and not realize it

 

[2gDSM6bolt]

We pulled the plugs while starting it and the middle two cylinders weren't sparking but the others were

 

[NHerron]

Somethings up with one of the coils. That being the coil, wiring to that coil, or power transistor

1/4 has their own coil same as 2/3. Sorry to state the obvious but the fault is in that area

 

[2gDSM6bolt]

I agree that was my first thought also but I swapped the coils around and the same cylinders don't have spark. That's what is confusing me. And it still doesn't make sense why it starts and runs perfectly fine at first

just scanned the car today and i came up with 4 codes. it came up with P0340, P0443, P1105, and P0403. any ideas?

 

[NHerron]

This link will sum up P0403 & P0443. Those specific codes won't cause your issues though. The codes are electronics related, being the solenoid itself, the wires supplying to solenoid, or possibly the ECU
http://www.dsmtuners.com/forums/electrical-tech/435665-what-check-next.html

Same thing with P1105, fuel pressure solenoid. Since you have all those codes, the previous owner probably left all of it disconnected. If you have emissions, you'd have to get that fixed eventually or you won't pass inspection. But as far as driveabily, most likely these codes are not your issue

But code P0340 is a problem. You need to investigate the wiring for the CAS. Since it's a 6 bolt swap, you'll have the CAS on the cylinder head, passenger side, near the throttle body either camo green or black in color. Trace the wires first to make sure the previous owner didn't do a shady wiring job. They should be soldered, heatshrinked and possibly some kind of wire shielding. If good there, buy a new CAS from the classifieds. They are cheap usually for sale every week @ $20-$30 shipped
OBD-II Trouble Code: P0340 Camshaft Position Sensor Circuit Malfunction
RRE Instructions

 

[2gDSM6bolt]

yeah just checked that out, he had some wire nuts and the wiring seemed ok. i have two extra cas from a previous dsm, but one is the type with just wires no harness connection and the other has the small harness connection so i will try to find one and try that out because i got a hold of the guy i sold my old dsm and got some extra coils and tried and it didn't help. thanks for the help i will let yall know when i swap out the cas