Help! Whats happening here.....?

[Sunroof]

1973.5T - CIS

Installed rebuilt fuel pump about four years ago....................

Now that the weather is warmer here, I am going back to that hard start issue after a long run. Its like this, turn the key, listen to the fuel fill the injectors, ignition, a slight sputter, off we go.....................

The car suddenly stopped on me in traffic today and I could not restart! Hand throttle up, pedal down, nothing..................strong engine turn over but no ignition.

I replaced the fuel pump relay, checked the points, rotor and cap, vac. lines, listened to the CD unit and heard the fuel pump sputter! No odor of flooding...

An hour later, when the car COOLS DOWN, it starts right up, only to die again after a few minutes............we waited this time for the tow truck.

Just whats going on? Can a fuel pump overhead and fail once hot? Is this characteristic of a failing coil or CDI unit? A myriad of possibilities.

Any ideas? suggestions? My gut tells me the fuel pump.................

Thanks

Bob
73.5T/CIS...........................fuel pump mounted in rear left wheel well.

[SP2]

Something about the solenoid in the starter not functioning when hot. It has happened to me on my 69.

[ossiblue]

When a car dies suddenly after a bit of driving can be a PITA to diagnose because you usually have to wait for failure to test the suspected components--in this case, ignition and fuel. Here's some hints from what you've posted:

"The car suddenly stopped on me in traffic today and I could not restart! Hand throttle up, pedal down, nothing..................strong engine turn over but no ignition." I assume by "ignition," you mean the car wouldn't fire up but turns over well so that likely eliminates the battery/electrical connections.

"...listened to the CD unit and heard the fuel pump sputter! No odor of flooding..." Did you hear a whine from the CD? The word sputter doesn't sound good, if you mean what I think. The pump should have a constant humming/buzzing sound. You would not smell gas unless you were cranking the engine over as the injector don't open unless there is vacuum in the plenum or you lift the pressure plate. Simply turning on the ignition switch to run the fuel pump simply recirculates the gas back into the tank.

Testing for spark is easy, but you won't know until the car fails again if that's the cause, and fuel pump failure would require a dead car also to confirm. However, before you jump in, let us know about the sound of the fuel pump when the car failed--could you could hear it running and what did it sound like. Also, let us know if you heard the whine of the CD unit.

If you can get the car to "die" again, a simple test for spark should be done, IMO, as that is easy to do. If you have spark with the "no run" condition, try this simple test next: Remove the air cleaner, turn on the ignition, and gently lift the pressure plate in the intake plenum. You should hear the injectors squeal, indicating they are shooting out gas. If you don't hear it, your pump is the likely suspect.

[Sunroof]

Thanks LJ.

I did remove the air filter and turned the key on (no starter run) and lifted the plate. NO SOUND of the injectors filling up. That certainly is the key. Its hard to hear the CD with the pump being mounted close by in the wheel well. With my hand I felt the vibration of the CD however. I can feel flow or pressure through the hose coming from the fuel filter to the fuel distributor. I was thinking that the fuel distributor might have failed as well or could be the problem.

I rechecked my records and I bought the rebuilt pump (****** Auto) back in March 2003! My car though is not a daily driver.

With so many components in line (pump, accumulator, distributor, etc), it is a PITA to test them all until I have a failure like today!

Can anyone advise as to why a fuel pump would fail when hot!!!!! Or how do you test the fuel distributor without removing it?

Thanks

Bob



The biggest question is what is going on with the pump when it works fine cold, but fails when hot. Something obviously shuts down. The pump hums but it seemed to be more intermittent when trying a hot start and failure.

[don gilbert]

i drive around with my cis gages all the time, you might try that to verify press. drop. Sounds like a pump going bad. You could cut open your filter to check for debris from a rusty tank. (i went through 2 pumps real quick because of a bad tank) If that turns out to be the prob. FUEL PUMP KING in cali had a new Bosch pump for 150.00. and I now intal a clear plastic pre pump filter. Give me peace of mind on trips. Good luck.

[ossiblue]

Bob,

You should get a set of fuel gauges and test your system in the failure mode. Test for your system pressure and report the results--should be about 5 bar, tested at a point between the fuel distributor and the wur. If it isn't, try connecting your gauges at a point before the fuel distributor. If the pressure is still low, your filter or pump may be the problem.

If you don't have test gauges, you might try this next: (Caution! Use care and have a fire extinguisher handy!) Disconnect the fuel line that enters the fuel filter from the pump (or, disconnect the line from the pump and add a short piece of hose.) Put the end of the line into a container and have an assistant turn on the key. Does fuel flow rapidly from the line? If so, reconnect and repeat with the line from the fuel accumulator to the fuel distributor. If no flow there, it's probably your filter.

If you don't get flow from the pump (first test), it could be the pump or a restriction in the line from the tank. You may wish to check the filter in the tank by draining the fuel down and removing the bolt in the center of the tank bottom. There is a nylon screen filter that is very fragile. If it is clogged, replace it. You should also be able to tell if there is a problem with rust in the tank.

Let us know what you find.

[Sunroof]

Thanks for the responses.
My fuel tank was restored last year and the screen filter replaced. All the fuel lines were replaced as well as the accumulator, WUR and injectors. From everything I have read, its the pump. If it runs fine til hot, the fuel distributor and electronics are obviously okay.

They no longer make a Bosch, sl all that is available is the rebuilt Pierberg and Bosch units. Our host sells a new Pierberg (OEM) unit..................thats the ticket.

thanks

Bob

[don gilbert]

If you call 'the fuel pump king" with the #'s on your old pump, he will cross ref. it to a newer updated replacement Bosch pump. That is unless you just want to spend 260.00 on one.

[ossiblue]

This might be a good time to consider relocating the pump to the front cross member--less heat and a bit easier on the pump to "push" the fuel rather than "pull" all the way from the rear.

[HarryD]

Originally Posted by Sunroof

1973.5T - CIS

Installed rebuilt fuel pump about four years ago....................

Now that the weather is warmer here, I am going back to that hard start issue after a long run. Its like this, turn the key, listen to the fuel fill the injectors, ignition, a slight sputter, off we go.....................

The car suddenly stopped on me in traffic today and I could not restart! Hand throttle up, pedal down, nothing..................strong engine turn over but no ignition.

I replaced the fuel pump relay, checked the points, rotor and cap, vac. lines, listened to the CD unit and heard the fuel pump sputter! No odor of flooding...

An hour later, when the car COOLS DOWN, it starts right up, only to die again after a few minutes............we waited this time for the tow truck.

Just whats going on? Can a fuel pump overhead and fail once hot? Is this characteristic of a failing coil or CDI unit? A myriad of possibilities.

Any ideas? suggestions? My gut tells me the fuel pump.................

Thanks

Bob
73.5T/CIS...........................fuel pump mounted in rear left wheel well.

Bob,

From your post, it is hard to tel what the issue is.

You first need to determine if you have a fuel delivery or ignition issue.

The next time the car dies, pull one of the spark plug wires, attach it to a spare spark plug, gound the other side and crank the engine. See if you get a spark. If so, you have a fuel problem; if no spark, you have an ignition problem. If you have an ignition problem, find some ice and put it on the CDI Unit. See if it starts to work, if so, then you have a heat related failure ofhte CDI and you will need to get it repaired or replaced.

If it is a fuel problem, you may have a failing fuel pump, a plugged fuel screen in your tank or lord knows what.

But first isolate if it is ignition or fuel.

BTW, your car does not have fuel relay if it is stock.