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Sat Sep 06, 2014 5:41 pm

I tried using the search but had no luck finding answers to my problem with my 84/1.9 automatic daily driver.

So my story starts out with me and my 3 year old daughter driving home from the grocery store and slowing down for a stop light my van stalls. I tried to restart with no success and had a heavy fuel smell so assuming I lost spark I had it towed home. After a quick check I found I have excellent spark. I threw in a new set of spark plugs and tried firing it up with no luck and in doing so noticed fuel poring out of my exhaust. I then pulled the fuel pump relay and cranked it over at which time it did fire up and ran for a minute till it burned of the excess fuel. So I stuck the relay back in and it flooded out to the point off fuel pouring out of the tailpipe after a minute of cranking. Once I had an assistant again I pulled the injectors out and had her crank it over and found all four injectors were spraying full force (not pulsing) the entire time. I then disconnected the electrical connections, tried it again and as one would expect they didn't spray.

After that extremely long boring description my question is- does this sound like a bad ECU?

Thank you ahead of time for any advice you can give me.

Sat Sep 06, 2014 6:41 pm

Gangestad wrote: After that extremely long boring description my question is- does this sound like a bad ECU?

That would be my guess.

Sun Sep 07, 2014 5:44 am

My choice too, only 1 I ever had fail does this.

Sun Sep 07, 2014 5:35 pm

I'm glad to here I'm not the only one with bad luck. Now for the fun part- tracking a good used one down.

Sun Sep 07, 2014 11:20 pm

Since you say that all four of the injectors were at full flow, there is one possibility other than the ECU. It has been a long time since I played with mine, but it is possible that power is available to the injectors and the ground is the switched lead. I am not certain, but something to check. If so, it might point to a shorted wire.

I did have a time where I had a failed injector that stuck open and flooded the crap out of the motor. but that is obviously not your problem.

Good luck
Bo

Mon Sep 08, 2014 7:57 am

I did check all the wiring before my post as well, I just thought my description was getting a little long so I left that out. That was my original hope though.

Mon Sep 08, 2014 8:35 am

If one injector shorts internally, it will spray all 4 continuously. Unplug one injector at a time and retest the engine. It will run rough on 3 cylinders, but should not flood once you find the shorted injector.

Mon Sep 08, 2014 6:23 pm

No luck with unplugging the injectors one at a time so I got a brand new used ECU coming from a fellow samba member in the classifieds. Keeping my fingers crossed it takes care of it. If not there could be an engine conversion in the near future.

Tue Sep 09, 2014 8:47 am

<< If not there could be an engine conversion in the near future.>>

This is pretty interestiing---

Every time your engine won't start--replace it?
Diamond Jim--I'm in the wrong neighborhood-- :roll:

Tue Sep 09, 2014 8:57 am

fuel pressure regulator

Tue Sep 09, 2014 9:41 am

Wellington wrote: fuel pressure regulator

If you pull the vacumn hose of the fuel pressure regulator, there should be no fuel there. Worth a look. If the diaphragm fails, fuel will be sucked into the intake plenum through the vacuum hose.

Also, not sure, but did the 84 have a 5th injector or cold start valve? If so, they can fail to close and leak fuel into the plenum.

Tue Sep 09, 2014 2:07 pm

The fuel pressure regulator is good and no fuel sitting in plenum, it is definitely flooding from the injectors staying open constant.

T.K.- more just an excuse to justify to the wife finally installing the subaru motor I've had sitting in the garage for the last couple years. I did the same thing to her years ago with a small hole in a muffler turning into a brand new header and performance exhaust on another toy.

Wed Sep 10, 2014 6:59 am

Do you believe the ECU is holding the injectors on continuously? A noid light or a simple test light across one of the connectors will tell you if the injectors are actually pulsing. If they are pulsing the ECU is working. That is not to say that something is telling the ECU to spray more fuel than needed. If the current ECU is pulsing the injectors, I would be looking at inputs first. A restricted fuel return would also cause the engine to run very rich. Have you tested the fuel pressure?

Wed Sep 10, 2014 7:21 am

Do the above before throwing any more parts at it. I have always found on digijet engines that its best to verify all wiring is reading properly before going to parts. Troubleshoot it first!

Wed Sep 10, 2014 9:53 am

All other wiring is good, fuel pump is good and injectors are not pulsing. I remember reading in motor magazine years ago that "the problem is never the computer", but I have replaced a lot of Computers on GM products over the years at the shop I worked at.

Now I'm just impatiently waiting for my replacement ECU. Ups tracking is showing anywhere between Friday and Monday, and the way things seem to ship into ohio I'm expecting it Tuesday.

Wed Sep 10, 2014 10:03 am

That sucks, cause I would have loaned you my spare to verify for postage cost. Hope the new ecu gets you goin

Wed Sep 10, 2014 10:31 am

I appreciate that. I didn't pay much for the used one though.

Wed Sep 10, 2014 12:02 pm

Quote: All other wiring is good, fuel pump is good and injectors are not pulsing.

So you are saying that the injector circuit is on full time? How are you testing that? ECU's go bad, but I don't recall one failing the way you are trying to describe. Hope that solves it for you. Good luck.

Wed Sep 10, 2014 2:17 pm

First I had pulled the injectors out and had the wife crank the van over and there was constant spray but I did later confirm with a noid light. Any Japanese or domestic vehicles I've worked on have typically cut the injectors out, not locked them on full blast.

rsxsr- I don't mean to sound like I'm shutting you down at every turn. I appreciate you double checking me. This makes me feel more confident with my diagnosis. I agree it seems weird for it to fail this way, that's why I posted this question, to make sure I'm not crazy.

Okay I am a little crazy but at least I might be barking up the right tree.

Thu Sep 11, 2014 7:07 am

No worries, you are there, I am sitting at a desk working from my memory. The ECU sounds like a logical test at this point, but maybe one more test. What happens with the ECU disconnected? It sounds more like crossed wiring to me somewhere.