Mrmerlin

also get your IR gun and shoot the relays after a while of operation any that are hotter than the rest have bad connections and should be investigated

PHIL928

Had a similar deal with Gisherton's GTS turned out to be a crumbled connector at the CPS. It get's pretty hot in there, it really takes its toll on those connectors.

Rob Edwards

Randy-

FWIW, the clamp on your MAF elbow/lower MAF body connection is clocked a bit strangely, normally they're clocked so the bolt is pointing towards 9 o'clock (as viewed from the front of the car) and you can get at it from the passenger side. Yours was clocked at about 4:30 or so, so that it could be turned from above with a long screwdriver between legs 7 and 8 on the intake manifold. Bill and I commented about it at the time, IIRC he left it in that orientation.

Randy V

Good idea! should have done that before I swapped out the first one.

Yeah, exactly my problem. I tried a loooong screwdriver between the manifold legs but couldn't get the correct approach to get it straight on to the bolt head. Looks like I'll have to try it again if you guys were able to get it.

Then reclock it to the correct orientation upon reinstallation!

Bill Ball

Yes, it was actually pretty conveniently located, accessible from the driver side, as Rob notes. Usually the clamp is accessed from the passenger side and requires removal of the fuel rail cover to get a shot at it from under the fuel rail. Always a pain. In your case, once I spotted it, it was very easy to get to. One thing that can happen after you loosen it, is that when you go to tighten it, the clamp will slip and the screw head will disappear from view. So, I try to get something on the clamp band so it does not move when I tighten it, and I only loosen it just enough that I can get the MAF out, leaving it a bit snug on the boot, which also prevents it from slipping and disappearing. I think yours moved a little downward when I was tightening it, but I managed to get it snug with the screwdriver. It may now be at a little bit of an more obtuse angle, but should still be accessible and you can re-position it up a little after you get the MAF off.

So, the CPS connector is on the front of throttle cable bracket under the MAF and fuel crossover pipes.

Tony

ya know..i never thought of that. Good idea.

Bill51sdr

Randy,

Had your exact symptoms on my '86.5 and it was the LH relay.

Really surprised Jim Bailey hasn't been in here yet preaching "relay, relay relay... "

Randy V

Had replaced the Ignition relay and the problem seemed to go away - until yesterday when I needed a tow home.

Will try the LH relay now.

Any thoughts on fuel pump failing?

The engine runs normally then will completely die. I can continue coasting at freeway speed, put it in neutral and the engine starts and runs again for a few minutes, then it dies again.

the flyin' scotsman

Randy.........my fuel pump failed on the s4 while on the highway and it was as if the ignition had been switched off. Car was towed home where of course it started as if nothing was ever wrong. As I had previously replaced all the 53 relays and much other work I deducd eith er the FP or LH but wasnt getting the relay chatter so a new pump, 'S' pipe and filter and she was as good as new.

the GTS will also have the intank filter which should be changed or converted so theres no future concern.

Randy V

It's looking like the fuel pump based on various tests performed so far.

Randy V

Spoke too soon - no loss of fuel pressure when the engine dies - so not the fuel pump.

Mrmerlin

use the IR gun check the relays check the battery connections and the grounds at the rear of the V

the flyin' scotsman

how do you know that? didn't you remove the FP guage?

When the S4 pump failed it would start repeatedly but I never trusted it again until I swapped the pump out. Should also explain when it failed on the hwy it was after hitting a small bump on the road at speed; +160km/hr

I wouldn't waste time with the relays other than to replace all of them (the 53s) with new.

Good luck.

Randy V

Done, done and done.


Installed a temporary gauge on the fuel rail.

Randy V

Still no luck.

Looking at the ECU for possible cracks in the circuit board traces or bad solder joints.

My mechanic calls it a DME (Digital Motor Electronics) - he insists that is the correct terminology.