Question about 1990 Nissan 300ZX
Hi there i have a 1990 300zx fairladyz. its non-turbo. the timing belt snapped recently which me and my dad managed to replace.the car started ok but was running ruff. so we knew that we had bent valves . we opened the engine , found out 2 exhaust valves and 2 inlet valves were bent in cylinders 4 and 6 . got the heads refaced , valves reseated . we put in new water pump , idler pullys , tensioner pulley , timing belt . car started fine but the engine rpm was a bit high . we played with the crank angle sensor and t.p.s also to get a little lower rpm , but still not very happy. the car sometimes doesnt wanna start , and i noticed that i have to quickly start car without any speed appication . which does help so iam thinking that the fuel mixture is too rich. ive ordered the consult cable from ebay US to acheive a better tunning. now my exhausts have also given up so i have to replace them. the engine sounds pretty good when the car is running. yeh the important bit also is that as soon as you wanna engage in gear (auto) and take off the car stalls a bit and then goes. it stalls everytime i wanna take off. please help .
The reason it's stalling out is because of the adjustments you made to the CAS and TPS. You need to reset the CAS where it was, since when you rotate this sensor, you change the ignition timing. As for the TPS, that also needs to be reset to how it was. The way to adjust the idle on this engine is with a screw on the idle air control valve (IACV). At the back corner of the engine, on top on the driver's side, the IACV is bolted on. If you crouch down next to the driver's fender and look straight in at the IACV (with a flashlight) you will see a screw recessed in there, with the head pointing toward you. That's the idle adjustment screw. With the engine running, AFTER you have reset the CAS and TPS, turn this screw until you are able to set a warm-engine idle of roughly 750 RPM. Messing with TPS voltage and ignition timing is a sure-fire way to stall or blow up your engine.
Posted on Oct 19, 2008
U need to do as j_del says... only a couple things he missed. to properly adjust the idle, u need to warm the car up to normal operating temp, unplug the iacv then turn screw to adjust. u want it to idle about 650-700, all else he says is true.
Posted on Jun 13, 2009
With 10 years experience in a Nissan dealership, I agree with j_del... you shouldn't mess with the CAS and TPS... but I'm not sure that messing with the IACV will properly correct this issue.
Did you check for vacuum leaks? The idle speed should not have changed after you replaced all these parts. But, a vacuum leak would lead to the higher idle speed and stalling you described. There's lots of vacuum lines on these engines and it's easy to miss one. Propane enrichment is one way to look, but I prefer to let the engine idle and spray small amounts of carb cleaner (any parts store) around different areas of the engine and listen for a change in idle speed. That'll help you pinpoint the source. Again, do this AFTER you reset the CAS and TPS.
Posted on Oct 29, 2008
I have a 90 300zx non turbo auto the tranny shift late from first to second in normal driving is there a way to adjust the kickdown or what controls when to shift
Posted on Jul 02, 2010
I am overhauling ma engine. anyone knows wer to find the timing specs or diagram? im on the process of putting ma timing belt on. altho i have marked ma timing gear, i just wanna check it on the specs.. thank you
Posted on Jun 16, 2009
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Posted on Jan 02, 2017
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