Need help from experienced mechanic

[skyline084]

I have an rb25, and would like someone to help me diagnose the problem with it.

[Krazykouki]

What the problem?

[skyline084]

Here's how the problem occurred, which started a week ago
First time I noticed it, it just stalled. But than fired up and ran perfect.
Next it would hesitate, backfire and stall. Start up and run fine.
Than it started to do it a couple times a day.
Now it won't even start and keep an idle, it turns over and will fire but die instantly.

The motor ran good for months and this just came out of no where, and within a week, about 3 or 4 days of driving, it's done.

Replaced the MAF and did nothing.
I'm gonna use the service manual to check voltage/continuity on CAS, MAF, coilpacks..
The fuel pump primes, car fires up, but this problem just took control.. so any advice on what to check will be appreciated.

[Krazykouki]

Is the ecu throwing any codes?

[skyline084]

It's giving code 54. which is to check A/T circuit to ecu. Which is weird b.c mine is a manual.

[Krazykouki]

Take the CAS out but leave it plugged in...turn it while the ignition switch is on and see if you can hear the injectors firing.

Also, make sure your engine has a good ground.

[TheRBguy]

Definately sounds like either a bad sensor or a power or grounding issue somewhere.

[skyline084]

Okay, I have a couple solid grounds right off the block to the frame, but I'll check all grounds as well. I cut the stock water temp sensor and just taped it off b.c I'm using the aftermarket one now. Could that be affecting anything?
one problem with taking the cas out and spinning it.. how do i get it back to its original position?

[Krazykouki]

Okay, I have a couple solid grounds right off the block to the frame, but I'll check all grounds as well. I cut the stock water temp sensor and just taped it off b.c I'm using the aftermarket one now. Could that be affecting anything?
one problem with taking the cas out and spinning it.. how do i get it back to its original position?

Did you cut the 2 wire coolant sensor? If you cut the one with 2 wires, that will have a bad effect on the running condition.

To get the CAS back to the original position you would have to use a timing light.

[skyline084]

na i cut the one thin blue wire for the stock temp.
Does the CAS reset every 360 degrees? so would I be able to just make a mark on the CAS (say 12 oclock) than just spin it back to that mark when I'm finished?

[julio]

Definately sounds like either a bad sensor or a power or grounding issue somewhere.

+1, intermittent issues usually are.

[skyline084]

okay , so check cas, maf... igniter and coil should be fine though because it fires up.. right?

[skyline084]

I checked all 4 wires for voltage on CAS connector. No voltage. I have continuity between the two blue wires though.

[skyline084]

Okay, found out that my EGI fuse went bad. Now, do the blue and green relays have different amp rage?

[Carl H]

eh, across the terminals there is about a 10ohm difference iirc with the relays... I've used them interchangeably tho.
Typically an egi fuse being blown will cause this problem like you found, replacing them seems to be the fix.
Occasionally the power draw will spike and blow the fuse, seen it on a few cars now.

[skyline084]

I put a blue relay in place of egi and thought it fixed it because the car started good and idled. Until I gave it gas, then it bogged out and died.

[Krazykouki]

Has the ECU ever been modified?

[skyline084]

I haven't done anything to it since I've had it, I don't know about previous owner

[Carl H]

have you pulled codes from the ecu (assuming that wiring is proper and it will allow for code storage)?

[skyline084]

It was throwing code 54. (A/T circuit to ECU) Weird b.c I have a manual..
The ECU has also thrown other codes in the past, but I resolved them.
I'm pretty sure all the wiring was done right, don't forget the car ran for months with out a problem, than all of a sudden this stalling issue occurs. 4 days of driving later, bam, problem took over. Car won't even stay at idle.
Than replaced EGI, car fires right up and idles for ten minutes until I give it heavy gas, it hesitates than stalls again.
Now I'm back to square one

[skyline084]

can someone with a s13 240 check something fast for me?
If you can..
On the EGI relay(GREEN one on left) Can you check if you get full 12v at #2 , and #3 on Relay Terminal.
Thanks