Well, it finally happened, my car left me stranded at 5:50 this morning while on my way to PT.

Here's the symptoms, let the rescue operation begin!

1. Began hesitating during mid-range acceleration about two weeks ago. Hesitating as in felt like it was going dead and then reviving itself. I could not duplicate the condition consistently, but it seems like it happened more often when the engine had not been running more than ten minutes.

2. I discovered an extra computer spliced into my LH-Head (see below). We have narrowed it down to a couple possibilities, both of which relate to it taking a signal from the O2 sensor and conditioning it/responding to it to make the car pass US emissions. Since this is a Euro S, it stands to reason that it was installed during federalisation, and most likely in Germany.

3. The computer was discovered due to an incessant clicking sound. The suspect is the relay that is glued to the outside, though I have not confirmed that.

4. The car currently cranks but will not start. Luckily it loped almost all the way into a parking spot well off the road. It died twice on final rollout and was revived until the third time. Tried repeatedly to crank in five minute intervals. NO luck.

I suspect the fuel pump relay is the culprit since it started several times before finally quitting. Anyone know the jumper sequence for testing this theory on an Early LH-Jet Euro S? Is it different than the 85 US LH-Jet?

Lastly, the fuel pump is silent when the key is turned to the run position, unlike my 81 which hums like a bird. It has always been like this, is this normal?

 

Here's the computer

 

Tim a search of the forum will find the pump diagnosis procedure. I usually turn the key on, and off again, and see if I can hear the fuel pump at the back. If not, I suspect the fuekl pump relay. Second procedure for me is to take horn relay and replace it into the fuel pump relay socket.

 

So I should be able to hear the fuel pump? It usually humms away when the car is running, but not before.

 

Yes Tim. Turn the key, crank once, listen ....

 

The fuel pump only runs momentarily when the key is turned on - just enough to establish fuel pressure in the fuel line. After that, the pump WILL NOT RUN until the engine starts.

The easiest way to test the fuel pump is to remove the fuel pump relay and jumper relay socket positions 30 (should always have battery voltage) and 87. If the pump runs with the jumper in place, then the relay is bad or the relay "turn on" signal isn't being provided. Do not keep the fuel pump jumper in place other than for testing.

If the pump doesn't run with the jumper in place, you need to check the wiring path from 87 to the pump motor, and from the pump motor ground connection to the chassis ground. If there is voltage to the pump, and the ground connection is good, then the fuel pump is bad.

 

My fuel pumps all run when I turn the key to start, and they continue to run until I turn my cars off. If I turn the key on, they all come on for a few seconds as you say and turn off. If I crank, they all run as long as I crank, and for a second or so after I stopped cranking (if the cars don't start).

Is that not normal?

 

Only if the engine cranks fast enough. I've never heard the pump when cranking, but that could be due to the cranking noise. Lets just say the pump should never run with the key on if the engine is not cranking.

 

Well Rich mine will definitely all continue to run for a second or so after I have stipped cranking.

 

Assume this is your '85, eh Tim?

Also check the fuel pump fuse!

When you engage the ignition (kust 'bump' the starter) breifly and let the key return to position 2, you should hear the hum of the fuel pump for 1-2 seconds from the right rear of the car.

 

After some cursing at the fuse panel, I swapped the relay from the HVAC blower (couldn't ge the horn relay out) and she sprang to life again. Is there a tool that can be used to better remove/replace these darn things? Did they ever make a relay that wasn't about to fall apart if you pulled too hard on it?

The fuel pump relay is indeed bad. I appreciate all the help, and Rich I know you told us to have spares, I'll listen better next time.

Does anyone besides the big 3 stock these relays?

 

Tim, here's what I do (and by now I have a hoge stockpile of fuel pump relays). Invite some buds over, and while they bbq your steak for you and while you enjoy the Hefe Weizen that they brought, go through their fuse panel and remove their horn and ac relays. Heck they never use their horns here in Seattle, and ac ... well you know about that here too

 

Stipped or stopped ... whichever ...