jollyroger927

Hey guys, my friend has just picked up a ls1 swapped 240sx track car. The nissan harness has been completely removed and it is all re wired. My background involves 4 cylinder turbo engines so this is really the first v8 im working on, im very excited but not sure where to start. I've been researching over the last couple weeks about these motors and these swaps. He bought this car knowing that there was a misfire issue.

So I start engine for the first time at my garage. The idle for a cold start is around 2.5k. When I rev it up, the revs will come down SLOWLY back to 2-2.5k. When i say slowly i mean ridiculously slow. So I unplugged what I assume was the idle air control valve, because it stopped this problem right away. Idle still stays around 2k even when pretty warm (above 140)

I took the car out on the road and it ran great. Other then the high idle the car seemed to be running exactly as it should, maybe some slight misses climbing the rpm band but nothing drastically wrong. Then the car was completely warmed up. Thats when the misfires started happening. The car had about a quarter or less of its power now, it could barely move. The idle was around 600rpms and would stall.

I think this problem has alot to do with the o2 sensors not being there. The previous owner said that you can disable these in the ECU (which he said he did)and the car can function without them, can someone clarify this a I cant find any info on deleting o2 sensors from these engines.

Some info about the car: Fuel pump has its own switch, fan has its own switch, maf is plugged in, new spark plugs, some type of long tube headers to straight pipes no mufflers. If there are any other questions let me know.

Sorry if this is in the wrong section guys, and i appreciate any help you can send my way!! Ill also try to get some pics up for you guys.

i r teh noobz

iTrader: (4)

You can delete the rear O2s, but I'd suggest keeping the fronts (unless you run open loop all the time).

My car ran fine for 3 weeks with no O2s while I waited for my exhaust guy. Does this car have an OBD2 port? Any codes showing up?

jollyroger927

Im going to the shop tomorrow im gonna bring my laptop and plug in, see what happens. Its got the plug just haven't checked it yet. I think im gonna get some o2's and see if i can wire them in.

jollyroger927

Went to start the car up today, cold start has the same misfire problem now and wont idle. Gonna bring laptop down tomorrow to attempt to check the codes.