I've got an 86 244 that I'm trying to resurrect after sitting for 9 years...

I've got a whole new fuel system, including tank, pumps, and sender.

The problem is that I can't get the ECU to mamke the fuel pump relay work. I do have spark, since the car starts and runs on carb cleaner into the intake manifold.

Can someone offfer some suggestions as to what to look for electrically? Or post a link to a flowsheet/diagram as to what makes the FPR work?

Thanks-

Kerry
Austin, TX

Got it up and running...

to reiterate:

whole new fuel system to the main pump. Still not running. Plenty of pressure at the fuel rail, but no return to the tank from the FPR.

rather than try to figure out what was wrong with the fuel delivery, I shotgunned it and replaced the whole fuel rail (with injectors and FPR)

this got the car running!

Now to finish cleaning it up and get it on CL ASAP!

I pretty much had the same thing with an 86 that hadn't run in three years. I had a noid light etc., and finally traced it pin 17 or 19 on the ecu. Replaced with a known working ecu and shazaam! It started. This was after hours of checking and rechecking.

This could have been due to the rotten wiring any 86 has if the engine harness is original. When it shorted out in my 84 it took out the transistor in the ECU. This mess was all hiding underneath the vinyl sheathing.


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Art Benstein near Baltimore

Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat and drink beer all day.

I did try another 544 ecu with no success... I will try to hunt down a noid light to see if I have injector pulse.

I will also take a look at the wiring harness. I think it's ok, but will double check.

I'm afraid that all the injectors will be clogged after sitting for 9 years. The tank was in especially fould condition, and only after taking it off did I see that it had actually rusted through in a few places. This doesn't lead me to believe anything good about the injectors.

The whole thing is on hold for a few more days until I can free up some time. Work and a 10 month old don't leave many extra minutes to work on fun stuff like Volvos!

Here's a similar system. In addition to sensing spark, which arrives as a signal on a gray wire from the ignition computer, joined to the fuel harness under the intake manifold, the LH2.2 fuel computer needs power from the red wire and 25A fuse by the battery, and ignition-switched power to turn on the system part of the dual relay (E) named the "main relay" we call the FI relay (instead of the fuel pump relay, which is internal to it).

After making sure power is OK, pull the cover off of the FI relay and be sure the system half is operating, and that manually pushing the other clapper down starts the fuel pumps running.


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Art Benstein near Baltimore

Mahatma Gandhi, as you know, walked barefoot most of the time, which produced an impressive set of calluses on his feet. He also ate very little, which made him rather frail and with his odd diet, he suffered from bad breath. This made him what? (Oh, man this is so bad, it's good) A super callused fragile mystic hexed by halitosis.

Thanks Art!

I will peruse the green book diagram and sese what I can see...

I did resolve the Main relay/FPR issue... It was a bad 25A fuse. Fuse wasn't broken, but not passing current. Replaced it, and both relays close as they are supposed to.

However, it still won't run. Still no fuel. I'm getting fuel to the rail, but I don't have a running car.

So... Either the fuel injector aren't firing (and I don't have a noid light) or the fuel pressure regulator is bad (I don't have any fuel in the return line) A friend suggested the FPR, and said that there should be fuel going back to the tank. Obviously there isn't. Also don't have 12v at hte FI's with the key in pII, but I don't know if that is supposed to be with the car cranking...

Any other ideas?

OK, there won't be 12V to the injectors until you are turning on the fuel pumps, because in this instance, the "fuel pump relay" is also the "idle valve, oxygen heater, injector supply, and fuel pump relay" as you can see from the drawing. And you won't be turning on the fuel pumps until there is spark.

If nothing is being returned to the tank, it sounds like the pumps are not developing pressure. How do you know both pumps are running?

The blade fuse "not passing current" is usually not the fuse -- because that is pretty obviously one piece of metal -- but that fuse holder, socket and then the wire connections to the battery are many pieces of metal, easily disturbed by the action of replacing the fuse. Make sure that circuit is passing current under load, i.e. hold down the fuel pump relay clapper and hear the pump running or measure the voltage there. Remove fuse 4 to isolate the tank pump if you can't distinguish the sounds.
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Art Benstein near Baltimore

Did you hear about the Buddhist who refused Novocaine during the root canal? He wanted to transcend dental medication.

OK. There is definitely spark, both because the car runs on carb cleaner, and the relay is closing.

The both pumps are running, both by ear and feel. I can hear and feel the main pump run by jumpering fuses 4 and 6. Same with the in-tank pump. I can hear it running at the filler neck.

I measured voltage at the main pump as 11.9v. I realize there is some voltage drop, battery violtage is a bit low also...

That's good. 11.9 is OK. In fact that's very good for a car that is cranking.

And now you think there's still nothing coming out of the fuel pressure regulator?

I would run the pumps using a jumper from 4-6 and double check that return line by squeezing it quickly. Then move on to find out why the injectors aren't opening, if that is the case. I could never do it, but I read folks can use a screwdriver to hear those injectors over the cranking noise. I assume you've checked a plug and it is dry, not soaked.
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Art Benstein near Baltimore

A three-legged dog walks into a saloon in the Old West. He slides up to the bar and announces: "I'm looking for the man who shot my paw."