Fuel Starvation, seems to be heat related... Options

[black73]

This has happened two times in the past couple of weeks...

The 914 runs great in the morning on the way to work, about 35 miles one way, mostly interstate, driving 70-80 mph. On the way home is a different story. Ater 25-30 miles it starts cutting out until it finally dies and I coast to the shoulder. The first time I had it towed home, thinking it was a bad electrical connection. Changed the relay board to a known good one and took off again this morning. Ran good this morning, but quit again about 5 miles from home. This time I crawled underneath and pulled the harnees off the fuel pump and ran two wires directly to the battery. The fuel pump worked and I was able to get it started. BUT it quit again about a mile from home. I disconnected my jumper to the fuel pump and sat there about 5 minutes, tried again and it started and I was able to get it home.
I'm thinking the fuel pump is dying a slow death, but I wanted to get some other opinions before I spring for a new one. It's been kinda hot here, temps in the mid 80's, but it ran fine last summer with temps in the 90's, making the same trip.

It'a a 73 1.7 djet , 3 hole pump I bought from AA about 2 years ago, mounted on the fire wall.

Sorry for the long post.

Any help would be very much appreciated.

[underthetire]

CHT sender? Mine was bad showing similar symptoms at one time.

[SLITS]

From numerous threads ... The fuel pump is cooled by the fuel that flows around it. If it is experiencing a slow death and getting hot, it may be that the volume of fuel is decreasing and leading to vapor lock (fuel boils in the pump and it won't pump air / bubbles / fumes).

I thought George had them made in China and their QC isn't all that great. Regardless, before you blow a chunk of change on a new pump, you need to check it out with a fuel pressure gauge and flow.

I assume that the drive to work is cooler (ambient temperature) than the drive home.

Another solution is to move the pump up front away from heat a la the '75 - '76 cars.

If the CHT goes bad, the car can do many things, one of which is not run at all. Check PBanders site for D-Jet diagnostics. Fortunately, it's relatively cheap but a pain in the ass to change.

Further, the FP relay on the relay board could just be old and oveheating, causing loss of contact until it cools.

From your description, the problem seems heat related but I am just guessing.

[dr914@autoatlanta.com]

It is possible that the fuel pump is overheating but more likely that maybe one of the lines is folding over on itself from the hot fuel. Try cleaning the strainer sock on the bottom of the tank, changing the filter, make sure that the lower fuel lines under the tank are routed smoothly, and that no hot air is blowing on the pump (like from an open heater control valve!!)

This has happened two times in the past couple of weeks...

The 914 runs great in the morning on the way to work, about 35 miles one way, mostly interstate, driving 70-80 mph. On the way home is a different story. Ater 25-30 miles it starts cutting out until it finally dies and I coast to the shoulder. The first time I had it towed home, thinking it was a bad electrical connection. Changed the relay board to a known good one and took off again this morning. Ran good this morning, but quit again about 5 miles from home. This time I crawled underneath and pulled the harnees off the fuel pump and ran two wires directly to the battery. The fuel pump worked and I was able to get it started. BUT it quit again about a mile from home. I disconnected my jumper to the fuel pump and sat there about 5 minutes, tried again and it started and I was able to get it home.
I'm thinking the fuel pump is dying a slow death, but I wanted to get some other opinions before I spring for a new one. It's been kinda hot here, temps in the mid 80's, but it ran fine last summer with temps in the 90's, making the same trip.

It'a a 73 1.7 djet , 3 hole pump I bought from AA about 2 years ago, mounted on the fire wall.

Sorry for the long post.

Any help would be very much appreciated.

[black73]

I'm pretty sure the pump is stopping when the car dies. Cant' hear it running when I turn the key. I guess my question is would anything besides a bad pump cause this? Like I said, it happened even when I had the pump direct wired to the battery.

[76-914]

I'm pretty sure the pump is stopping when the car dies. Cant' hear it running when I turn the key. I guess my question is would anything besides a bad pump cause this? Like I said, it happened even when I had the pump direct wired to the battery.

If the pump is crapping out it doesn't matter what you have it connected to. Slits is right. Check your fuel pressure. Lucky for me that I had a FP gage in the cockpit so when mine quit (a pm return trip, am trip went fine) I could see the pressure had dropped to <15psi. Otherwise, I would have "just bin guessing", cause it started right up the next day as if nothing ever happened. Too late; so I replaced her. And a quick plug for GPR, nice Bosch pump in 3 days. WOW

[black73]

I've been chasing gremlins since I got this pump. I wouldn't trust it if it did check out cold and I'm sure not going to take 30 mile trip on a hot day to check it hot.

So, I'm thinking of getting this one from Summit....http://www.summitracing.com/parts/SUM-G3138/?image=large

now where is that thread on eliminatung that third hose? (IMG:style_emoticons/default/idea.gif)

[black73]

Well, I did it. Installed the Summit pump, new fuel filter, pulled the gas tank to get to the sock and clean the crud out of the bottom. Put it all back together and went for a drive. Seems to be working quite well.
I omitted the sock, as it just seems to keep junk in the tank that the gas must pass thru to get to the fuel lines. I would rather change a filter than pull the tank.
Does this sound like a good idea or am I headed for disaster? (IMG:style_emoticons/default/dumbass.gif)