Hello,

I recently bought a 1990 Cutlass Supreme (36k original miles) in February. It initially started and ran beautifully for a month or two after replacing the battery. It still runs great cold, but recently it’s been having issues with either refusing to start or starting and then stalling when hot. Here is a list of what we’ve done to it:

-fuel lines
-fuel filter
-ignition coils
-spark plugs
-fuel injector cleaner
-tested fuel pressure (was low)
-fuel pressure regulator (check engine light came on)
-MAP sensor (check engine came off)
-cleaned throttle body
-ECT sensor

We were thinking it may be a fuel pump for a bit, but it primes fine and everyone I’ve talked to doubts a fuel pump would be such an intermittent issue.

Does anyone have any suggestions? Anything would be truly appreciated. Thank you much.

 

Does it have VATS/ pellet in the key? IIRC, that would interrupt the fuel pump... Put a fuel pressure gauge on it and see if it has pressure through crank. If the pellet is worn or the contacts corroded, or if the relay is stuck open, or...... could be lots of stuff. Check power to the fuel pump at the pump.

 

Is it still low ? If so I would fix that first.

 

What is "low"? 43psi is normal

 

The key and contacts look good. Relay is closed. I don’t have the equipment to check the power to the pump (the guy that helps me is out of town), but I can hear it pressurize without hesitation, so I assume it’s at least getting power.

thanks much for the suggestions

 

prior to the fpr it started at ~40, but then dropped to 32 in a minute or two. After the fpr it didn’t drop as fast, but just stayed in the 30’s.

 

I haven’t checked since after doing the fpr. I’ll go ahead and do that today.

 

Another easy check: the ground from the fuel sender to the body.....

 

VATS started in 86. If it fails to start because of VATS connectivity there should be a security light illuminated on the dash. Often times, if you give it an hour or so the car will then start normally.

My 96 Oldsmobile 98 has a VATS key and thankfully it hasn't been troublesome. You can bypass VATS by installing a resistor inline with the ignition key. I had a 93 Buick LeSabre I did this to. As I recall, I even replaced the ignition lock cylinder.

 

Is it most likely not the VATS system then? I’m not getting a security light or anything, and it seems like everything comes down to how hot the motor is.

At this point I’m thinking there’s some bad electrical connection that acts up when it gets hot. Or maybe a crankshaft position sensor

thank you much for your help

 

will take a look at this today. Would be in line with what I’m thinking about it being a bad electrical connection.