i need help here since other forums are mean.....90 GSX prob

[da1085]

well i have a 90 gsx with a jdm motor installed in it.

im having problem with rpm gauge....i know 90 model are the odd one out from the group but i have looked at the wiring and it looks good.

problem is all my gauges work until i hit boost. once i hit boost, my rpm goes to zero.

i have some after market gauges. according to my boost gauge i can sustain 9psi solidly.


what should i do to fix my rpm weirdness under boost?

[RedGalant2k1]

sounds like a wiring issue.

I would go back to the wiring and try to trace each wire starting point to ending point.

Curiously what kind of gauges are you using?

And does that include RPM, and Speedo gauges?

[Shadow19]

Maybe.. Just maybe.. Your rpm gauge cant keep up with how fast the engine revs when you start spooling.... Id try either a new gauge cluster or an aftermarket rpm gauge.... But being the anal person i am.. Id stick with a stock look and just get a diferent clister.. I hope this helps..

[seth98esT]

9psi is weak, 11psi is stock. You can run 14-15psi safely on stock fuel.

Sounds like you have a short of some sort. I assume you didnt do the wiring. What CAS are you using? What ECU? The 90 definitely has different wiring then hte 91-94. I had a 90 awd 5spd at one point, but stock motor.

[Sleepervr-4]

Seth is correct about wiring being different in the 90 models. If I were you I would post it on www.galantvr4.org Those guys are more familiar with the 6th gen galant. This site is really for 7th, 8th & 9th gen galants.

[da1085]

well the cluster is from the car which is stock also....i mean the rpm works perfect untill bust comes in. where should i look for this wiring(CAS or other stuff)?

also why would i be only at 9psi if stock is 11-12? like what would keep me at 9psi? i have the BCS hooked in so i should not be opening the wastgate at stock setting for it.


oh by the way everything should be from a 90 1G.

[da1085]

i searched the other site and they really didnt have anything that solves my rpm problem.

any ideas? just post it and ill check it out on my car.

[RedGalant2k1]

I'd inspect anything related to the RPM gauge and wiring. My guess at full boost if the rpm gauge is on a vacuum line it could be thrown off. What was it like before installing the boost gauge?

[da1085]

well i've had this problem since the day i got the car running(bought the car as a shell then had a jdm motor installed)


the boost gauge did not have any effect on the roblem...i beleive the rpm receives an electronic signal from the coils but then it doesn't seem that my coils are bad.

[RedGalant2k1]

Well lets backup a little.

Since you bought it what has been done?

[da1085]

it was a stock 90 GSX with blown motor and turbo......

instead of tryin to fix the motor i went ahead and bought a JDM motor and trans. i had that installed.


everything works except this rpm weriness......i really want it fixed since i dont want to over rev the motor....car runs great...but like seth said my psi is weak since im at 9 psi stable. stock psi is 11-12 but my wastegate opens up im gueassing arund 9psi.


i have the yellow top JDM set up. it came with yellow injectors and a 16g turbo stock.