Rob Edwards

How many O2 sensor bungs in your pre-cat downpipes, Randy? Just the factory one?

Randy V

Just one.

I actually just had a new O2 sensor (from 928sRus) installed in preparation for the Sharktuner session.

This replacement was done after I experienced the cutout issue, so not a contributing factor.

AO

I've had cutout issue before both on the GT and the 85. And both times it had to do with not getting the harness grounded to the block. On the Euro... I just plain forgot to attach it. On the GT, I attached it, but didn't tighten the bolt enough such that it worked itself loose and caused the engine to cutout.

If you had any work done that involved the intake or the harness, I would remove the airbox and start looking at how the harness is routed and make sure the 2 bolts at the back of the intake are secured abd are properly grounding the harness. Without these, the engine will not run. If it's loose, it may run, then cutout unexpectedly - at least that was my experience.

Good luck brother!

Mrmerlin

had an owner out in Denver with a GT,
and it too had the cut out issue , ,
many things tried ,
finally re seating the loose ground screws at the back of the V fixed it

AO

Data point #2!

Randy V

Replaced the ignition switch this weekend.

Still experienced engine cut out while driving this morning.

Battery contacts are tight.

At least i was able to replace instrument cluster lights and get the voltage gauge working while I was in there.

I guess I'll swap relays next.

Kevin in Atlanta

I had a similar issue with the 87. Turned out to be a loose connection where the CPS connects to the engine harness. Took the car dying a the cost of a tow to find it.

Randy V

Yep, time to pull the air box and have a look under there as well.

Any directions on where the CPS connector is located?

the flyin' scotsman

the CPS is triggered by the flywheel.....taking the MAF off you can see it then trace the wiring to its connector. the ground wires should be visible in the same location.

SeanR

Randy, here's a picture of the grounds and the CPS connector. CPS is the black connector in the middle.

Randy V

Thanks, guys.

I don't suppose you have a wider shot that shows these relative to the rest of the engine bay, Sean?

Will get in there later today.

Bilal928S4

If I am not mistaken, the black insulated cylinder is the fuel cooler at the fire wall on the driver side.
Hope that helps.

69gaugeman

When I put the GT engine back in I had a no start condition. I forgot the two ground points as mentioned. Instantly started up after tightening them up.

It is in the center at the back under the airbox. Even you, Randy, will see it instantly.

Randy V

The cut out condition occurs after about 30 minutes of driving, leading me to think it may be a relay getting hot and experiencing increased resistance?

The car starts right back up and runs for awhile until it occurs again.

Randy V

I've decided to approach this methodically starting with relays (after replacing the ignition switch last weekend). I wanted to take a look at the ground points but was unsuccessful in getting the MAF out. Should have paid attention to Bill Ball when he swapped my MAFs at SF this year. I couldn't get a wobble drive socket onto the clamp bolt.

I pulled the Ignition Relay XII and replaced it with another good -53 relay. This relay looks suspect as one side of the cover is smooshed in from some previous unknown side force.

Did not experience any cut-out during the drive this morning.