280z: another problem

[280zgod]

Hey all. I finally got my entirely new exhaust sytem from MSA. The whole deal, headers, and the twice pipes exhaust system. I had them professionally installed and the car runs like crap. My Nissan 720 pickup is now faster then my Z i almost cried i mean 650$ to screw up my Z? Anyways just wanted to explain the situation before I asked if anyone has had a similiar problem? thanks please help me!

[280zgod]

here are the symptoms if that will help: must idle at 2000rpm or else it will die but it may also idle at 500rpm and jump sporadically, extremely slow accel, on decel the rpm stays at 2000rpm unless the gear you are in is at a higher rpm range, it is running hotter now then it did with the stock setup and the headers i bought are ceramic coated and supposed to help cool the engine, every now and then it lags during accel: thats all i can think of thanks again. Another note my egr valve is disconnected from the thermostat thingy.but it is still fully on the manifold

[gema]

What did you disconnect/remove during the install? Is the car FI or Carbs? Not sure if these cars have O2 sensors in the exhaust? All I know is my 240z

[TomoHawk]

It sounds likethe muffler guy may have disconnected something needed to run well.

[280zgod]

I have FI i removed the egr valve thats all and the exhaust guy didnt have acces to under the hood so to speak the hood was down and the car was locked he didnt disconnect anything and about O2 sensors i thought it did but im guessing that what i thought was the O2 sensor was really the catalyst sensor haha other then that i didnt disconnect anything else to my knowledge oh yes but one strange thing on reinstalling my fixed gas tank ive noticed that the fuel guage isnt working any longer even though me and my friend charted the wires and rehooked everything like it was so would the guage and wires saying i have no fuel cause the FI to run wrong? i know this is alot of stuff to ask for but im really mad that my car ran better stock and after having it out of commision for like 5 months now that makes it even worse im sure alot of you sympathize and thanks for your help its much appreciated

[280zgod]

haha well after fiddling with my car a bit and reattaching the egr it will now idle correctly but it still has no power

[SteveK]

FI systems generally have a lamda sensor (O2) installed early on in the system (usually around the collector), most aftermarket L series headers dont have the threaded hole and it has to be added -- did you do that or was it already installed and if so did you fit the lamda sensor.

Without the Lamda sensor the ECU cannot get an accurate read of the mixture burned and as a result cannot alter the mixture to suit.

[TomoHawk]

I wish my 280Z had one of those to fix my mixture problem. Soot is practically dripping out of the tailpipe.

[280zgod]

there is no O2 sensor on my car with FI that is all i ahve to say about that

[2ManyZs]

I think I'd go back to basics and start from there....

Such as:

Was the intake removed or moved at all during the header installation? If so, check all the intake plumbing, especially the rubber boots that connect the AFM to the throttle body.

Check all the vacuum lines.

Check to see if the timing is still OK, maybe someone bumped the distributor and the distributor is loose enough for it to have moved slightly.

Double check all the electrical connections on the intake and around the coil, distributor, and throttle body.

Double check for an intake leak at the head, use some starting fluid and spray around the base of the intake while idling.

BTW, what color are the plugs?

[mdbrandy]

Originally posted by SteveK

FI systems generally have a lamda sensor (O2) installed early on in the system (usually around the collector), most aftermarket L series headers dont have the threaded hole and it has to be added --

The Z's didn't use an O2 sensor in the FI system until the '79 280ZX.

[SteveK]

Thanks mdbrandy

It wasnt clear to me what 280zgod had or had not got, so it was a point of elimination which is now eliminated.