Hi guys,

Looking for a bit of advice/guidance if possible.

I have a 1991 JDM Mitsi GTO TT which at present is a non-starter. I have had it for around 2 years now though it developed the non-starting issue 4 months ago, so roughly 20months into my ownership.

I took it out for the first drive of the day and less than a mile down the road, while braking and taking a left corner, it suddenly just cut out. It would turn over but not restart. I tried this for a few minutes but nothing changed, it would just keep turning over and over.

Fortunately, I have a mechanic friend whose garage was a bout 1-1.5 miles away so the GTO was taken to him. He's a very busy guy and so has only spent moments working on it and so 4 months later I'm fed up not having it and want to fix it myself - which is what I would have done in the first place had I known it would take him this long to essentially do not much with it.

What he did find out is that there was no ignition pulse. He suspected that perhaps the alarm/immobilisor was affecting it and so he called in an alarms specialist. He did some testing and declared that the alarm is fine and working as it should.

From my own research I have found that it seems very likely to be one of three things: 1) ECU - leaky capacitors, 2) Crank sensor, 2) Auto Shut Down relays.

I visited the garage a week ago hoping it would be an ECU fault so decided to remove the ECU myself. To my dismay it had a sticker on it and some 'void if removed' stickers. Obviously the ECU has had some work on it before. I cut through the 'void' stickers and opened the ECU to find that it looked absolutely pristine inside, so, unlikely to be the ECU?

Is it possible that it is either, or both, of numbers 2 & 3?

Would a failed crank sensor result in the engine just dieing and not restarting and there being no ignition pulse?

Likewise, could a failed ASD relay cause exactly as above?

The more I read about the ASD system the more it sounds like this is what happened. One moment the GTO was running fine and the next it completely shut down and will not restart.

So, onto my real questions.

Where is the ASD relay and how do I test if this has failed? I've heard of buying a replacement relay - what are the requirements?

If I can source an ASD relay at a reasonable price I'll just buy one and swap it out. Likewise, I have a supplier of a Crank Sensor so can buy one of these and replace this.

Would replacing both of this allow the GTO to just start and run as it used to or would the underlying problem still be there? Maybe the ASD system detected something and has shut down as it should - how can I find this out?


Two other things to be aware of:

At some point during my ownership I would find the engine cutting out under fairly heavy braking. Some days it happened a lot and sometimes it would be fine for weeks - very intermittent issue. Theory on this is that there may have been a slight split in a vaccuum line causing a stall under heavy braking and only when the split was 'open'. Could this be related to the engine cutting out and never restarting?

The lesser thing is that the stater motor seemed a bit 'sticky' recently. I noticed it taking a split second longer to start turning over until one day, after 48hours of no movement, the engine wouldn't turn over. I jumped out and pushed the GTO slightly and it fired up fine. Since being in the garage the starter seems fine as they had it turning over while testing with no sticky starter issue.

I'm going to visit the garage again and remove both the ASD relay and crank sensor and consider replacements if it is likely swapping both of this will solve the problem, assuming the ECU is working fine (but it looks fine, no leaks and has definitely had some sort of work on it before).

Where is the ASD relay and what is the generic model number? I've read up on standard Bosch replacements?

Any advice is appreciated. I want the GTO back for the summer and have definitely missed it the last 4 months.

Thanks in advance,
Cammy