car not starting - please HELP!!!

Hi all,

I'm hoping some of you technical gurus over there can help me with a problem we are having with my '91 vr4 here in aus.
I blew a motor so swapped it out with a JDM motor out of a facelift RS VR4 front cut ('91 model). I took the ECU out of the front cut and put ECMlink into it. I have seen that motor running in the front cut before I purchased it so I know it works. we are using the wiring harness that was originally in my car and using the jap motor.

The problem is that the car wont start. we have checked the ECU in another car and it starts and runs that car fine.

we have tried/tested/replaced the following
-plugs
-leads
-coils
-ignitor
-TPS
-CAS
-injectors
-inlet mani gasket
-throttle body gasket

changing all of the above changed nothing on the car, it just keeps cranking.

we have verified that it has spark, and the injectors are ticking.

we have done a compression test and the results came back 142-146-148-150, which is within tolerance

we have pinned out the ECU and wiring harness to make sure that each wire is going to the correct spot in the loom. we did have some broken/shorted wires which we have fixed and we are now 98% confident that the loom is not the issue.

we have checked, double checked and triple checked the timing and the marks line up spot on.

the only thing that is different to stock is that we haven't got any of the solenoids plugged in on the wiring loom (boost/fuel pressure/etc) and we have removed all aircon and heater components from the car, both behind the dash and in the engine bay. and when I removed the units from behind the dash I cut the plugs off the loom.

this has 3 of us stumped on what it could be. if anyone can shed any light on this or even give us something else that we haven't tried

 

Have you tried connecting a logger to the ECU, to see what the ECU is seeing?

 

We have had the laptop connected and logged it and it appears as though the ecu is seeing everything it is meant to

 

Is it seeing CAS pulses while cranking? All the temperatures look right?

 

[brisvr4]

I've had a look at this on my laptop Jeff. The Temp was tyhe first thing I looked for.
When it does start it seems to only want to run on 2 cyls. And those appear to be 2 & 3 /ubbthreads/images/graemlins/banghead.gif
We did hook up a timing light to it while cranking and there seems to be a weird spark pulse. It goes something like - - - ... - - - .. - - -
The lines are normal pulses and the dots are rapid?
As Craig said we put the ecu into my car and even with completely different settings ( I run 1450's and SD on Ecmlink) it started and idled on all four cylinders.
I'm thinking of calling in a priest for Craig next week to exorcise it!

 

Tim,

we have lost those 2 cylinders now, all it wants to do is crank and crank and crank. we have also had a timing light on every lead and they are firing correctly now. we are checking the CAS tonight with a known good one to see if that solves our problem, but really we are just clutching at straws now. I have changed the fuel just to be sure that it is fresh and good quality fuel in it. Troy seems convinced that if we put a haltech or aftermarket ecu into it then it will start and run no problems, i'm doubtful though and think it's alot of money to spend on an aftermarket system that may not change anything about what my car is doing - like you said, it ran your car on 4 cylinders.

it has got me stumped. maybe it is the wiring in behind the dash where the aircon units used to be. maybe the ecu requires something from there. or maybe one of the old alarms was wired in deeper than first thought, although I traced every wire with those back to where the originally went and reconnected everything to the factory location. /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif

 

Even if the new CAS doesn't fix the problem, I will still suspect a CAS issue with the wiring between the CAS and the ECU. I don't know what else would cause those symptoms. Have you gone over all the transistor and coilpack connectors?

 

Hi Jeff,

we changed the CAS and it made no difference, we have checked the wiring between the CAS and ECU and there is continuity along each wire and there are no short circuits going anywhere else. we have chacked the transistor and coilpack connectors and all the wiring for those and they are all going to the right spots on the ecu loom.