90 gsx running problems

[idahos_1G]

so i just picked up a 90 gsx awd turbo. it has a 3 inch downpipe and 3 inch cat back exhuast. other than that all stock. it has a really rough idle and is gettin really bad gas millage it will kill a 1/4 take of gas driving to work and back which is a 15 mile round trip and its on the highway so not much stop and go. the idle will vary. it will idle at about 400-500 sounding like its running on 2 cylinders but once u give it gas it runs great. other time it will idle at about 800 and sound like its running on 3 cylinders. when your driving it around it runs very good. i started with the fuel system new filter and i put in a walbro 255 that it came with. it had really bad gas in it so i thought that that would be a start. than checked for vacuum leaks found a couple fixed them but no change. sprayed around the intake and hit a spot around the injector and the intake to the head. i have a new intake gasket for it just want to find out if thats really it. the intake box has been cut open on top. o also it runs like crap when its cold. so can someone help me out here. maybe a sensor or somthing im missing? thanks alot.

mike

 

[toyotaturbo]

I didn't see you mention an adjustable fuel pressure regulator. If you don't have one, you should get one. With a 255lph fuel pump, it will overrun the stock regulator and the car will run like garbage (if at all). Check your spark plugs and wires definitely. After your basic tune up items have been addressed, start getting into deeper issues such as cam angle sensor, coil pack, power transistor pack, and the ecu.

 

[blueninteytwo]

as far as adjustable FPR, Aeromotive makes a good one, and if you plan on running a strut tower brace, get a firewall relocate kit. also pick up a pressure gauge that screws right into the top of the aeromotive. will save you hassles down the road when doing either a big turbo upgrade or just trying to get to the bottom of a phantom problem, you can just check the gauge and eliminate fuel system issues (example: no start condition)

as far as wonky idle, the IAC's (idle air controller) in these cars are horrible. some people swear that a product called sea-foam (search, it's in the forums) helps with smoothing out the idle, along with taking the throttle body out and giving it a thorough cleaning (especially where the throttle butterfly meets the body)... if both of those don't help, then look at the IAC as the culprit.

 

[idahos_1G]

alright guys ill check into to that and ill get back to u .

 

[idahos_1G]

no i dont have a fpr. im gettin a wideband next week and i have a safc. so ill do some tuning and dataloging shorty. i unpluged the maf and it raised the ilde by a couple hunderd about 200-300 but still idle like junk. it idled like this before i put the fuel pump in. i dont know much about dsm. well i know enough. and im good with cars so i guess its just time to spend a couple hours on it and pluck away at it. well there is a small leak where the mani meets the head missing a bolt. i got to find one for it and throw it on. so well try that aswell. no check engine lights. well if the light is even plugged in. the car was a mess when i got it. how do i run for codes it being obd1?