I had posted a few weeks ago about my car not starting, well the problem has evolved. The car started yesterday and worked OK (not perfect it would be touchy with the gas). I drove about 40 miles on the freeway then all of a sudden fuel delivery stopped. I would try to press the gas but nothing happens. Pulled over stopped the engine. Tried to restart to no avail. Had it towed. I tried swapping out the extra DME relay I had in the dash but it didn't help. I also swapped the fuel pump fuse in the front trunk as I had one handy in the dash as well, nothing. Next stop fuel pump relay? Anyone think they can pinpoint this one accurately?

 

Hi,

Its always helpful to have sufficient information to get the "big picture" and that includes how many miles are on the car,....

Two things come to mind in no particular order:

1) Fuel pump

2) Ignition switch

The DME relay provides power to the pump as well as the ECU so you should see if you have spark or not. If not, I'd be looking at the ignition switch (assuming that your spare DME relay was OK).

You will need a fuel pressure guage to see if the rails have the correct operating pressures or not.

 

Steve,

1987 Carrera cab with 130K on the ODO. New ignition wires, distributor cap, rotor, alternator, dme rebuild, dme relay new, and I do have spark. What happened was one day I went to a friends house, we went to lunch in his car, when I came back my car wouldnt start, even with starter fluid. Towed it back to my place, didnt drive it for a couple of weeks. Then yesterday it started up, I drove it on the freeway for about 40 miles and then the gas pedal just stopped working, I pumped it, it worked again for a second, then cut off again and the car cruised to a stop. Wont start again. I bet if I let it sit for a while it would start up again but it just revs up and slams back down to 0rpm and crashes.

 

Much better, thank you!!

The first thing I'd be checking is the fuel pump & ignition switch. After that, its time to go through all the engine sensors and their connectors/wiring.

If someone ever ran the car out of gas, that really shortens the life of the fuel pump as gasoline is what cools and lubricates it.

 

Why ignore the fuel pump relay? I really don't think it's the ignition switch because a few times the car starts like a charm and drives fine for a while. Is a fuel pump difficult to swap out? Do I test it by just using a stethoscope and listening to it while the key is is in the ignition? What should I hear?

 

Steve's diagnosis is absolutely correct, but try this as your next step. Whack the skid plate (protection plate) immediately under the fuel pump - use a hefty mallet - then try to start/drive the car. Sometimes a sudden vibration/impact will revive a fuel pump for a short period of time (we started, "diagnosed" many no-start tow-ins at the shop using this method). Be careful to not dent the steel plate!

 

Make sure the spring clips holding the fuse in place and really STRONGLY SPRINGY, grip the fuse FIRMLY. Look for indication of overheating of the spring clips and surrounding phenolic mount.

 

Sorry about that guys, I wasn't going to post that and it sorta slipped out. I hit delete as quick as I could but some of you may have seen it. I'll shut up now.

 

What about some sediment in the tank itself? Maybe its cloggin the pick up, or fuel filter or the pump and once the car sits long enough it stops blocking.. but under pressure it blocks up?

When the car wouldn't start,but the key was turned on, could you hear the fuel pump run at all (or is the Motronic car different than a CIS car in this regard?

 

FYI: Motronic car fuel pumps don't run w/ignition, neither do CIS SCs/late 2.7s/Turbos... I'd have to check my books for the '73.5/'74/'75 cars on that one (too many years have passed)!

 

I dont know if something is caught, that would REALLY suck. My fuel filter is new so I don't think thats causing the problem. I haven't listened to the pump yet, tonight. Pete are you sure they dont run? I have seen a P-car mechanic listen to mine before while it was in the ignition....

 

Oshin, you have gotten some killer advice in this thread. If I may suggest, just follow Steve and Pete's advice. Get a fuel pump gauge, and have someone check your fuel pressure. You might want to buy the Bentley service manual.

 

I have the bentley manual and I am in the process of checking these things, I know I'm getting good advice =P

 

Diagnosis: Fuel Pump....new one is on its way, thanks guys.

 

Oshin, the fuel pump on a 84-89 Carrera does not activate/come on until the switch is in the start postion and the starter is turning on. It does not come on with just power to it. Probably the same with the CIS on SC's, but that's a guess sinvce I'm not familiar with CIS systems.