Ok i'm hoping someone can point me in the right direction here. This is for the '93 in the sig. I'm not running the SC right now because I'm waiting for $$ to rebuild it. I got a pcm4less tune to run without it. The car runs great when it first starts up. The tires spin no problem 1st and 2nd. But as it warms up it progressivly starts to run worse. It doent act like its going to stall or anything but it has a great lack of power especially uphill under a load. At 200* it wont even spin the tires and I cant even chirp second. I dont expect it to be extremely fast givin' the low compression pistons and the blower cam but it feels like a real dog. I have the air filter mounted on the intake tube where the charger mounts and it runs right past the driver side header. Could this heat the air up so much that it runs horrible? I can even switch the old chip back in thats tuned for 10psi and it runs decent until it warms up. I dont think its an open/closed loop thing because it seems progressive. Could it be running so rich it starts misfiring? It doesnt blow much smoke out at all unless im idling for a while. Also I put new stock plugs in when I removed the charger so they would be the right heat range. Gapped a .052. I have an areomotive A1000 with 42lb injectors. The fuel pressure is 38-48 at idle and climbs under WOT. I also have a fuel management system but that only activated under boost and its switched off anyway. Let me know what info you need. No trouble codes either. I know the best thing to do would be fix the charger and dyno tune it but it should run decent the way its set up. Any help is appreciated. Thanks Nathan

 

Anyone??

 

Hook up a fuel pressure guage and see if your fuel psi drops when your car is hot.

You could also have an intake manifold leak.

You need to get the car scanned when its hot to see if there is any retard as well.

 

Thanks for the reply.

I have an autometer FP gauge hooked up all the time. The pressure never drops.

Its not a MAF car so would an intake leak make it run horrible?

I have a scanner and it doesn't retard the timing when hot just sitting still and revving it but I didn't check under load. Thats a good idea. I'll try it tomorrow.

Thanks for a few ideas because I'm fresh out. It takes a small amount of oil once in a while also. I guess that could point towards an intake gasket leak.
Nathan

 

I'd like to know what you find out. Someone over here has the same problem as well. Temp stays the same throughout but the power definetly drops over a period of time.

 

Let me know too, My z runs like crap when it's hot, low rpm and under load

 

My Z is like that too....
It will run great for the first 15mins and everything feels fine with light pedal and after those 15mins I feel like it needs more gas and its not as smooth...

 

I'm starting to think it has something to do with the timing being retarded. I'm going the hook the scanner up when I get home from school tonight. I'll post my results.

 

Thought I found the possible problem today when trying to diagnose a new starter/no crank problem. The harness that goes behind the passanger side header was burnt through. One ground wire was completely through, another ground, the Knock Sensor wire, and the ignition wire to the starter were almost all the way through. I fixed all the wires which fixed the starter but the wire on the knock sensor had no effect on engine performance. The scanner will have to wait until tomorrow.

 

Good to know...THANKS FOR THE INFO!