# 1988 D21 won't start



## WFKeller (Sep 20, 2011)

I have a 1988 D21 with the Z24 4 cylinder, manual transmission. I got this pickup from my dad. He had issues with it, would just quit on him. I got it running and drove it all last summer then it started quitting on me. I got it going a couple of times and then it quit on me again and I parked it all winter. It started for me this summer and ran for a weekend then quit. It turns over but will not fire, no spark. I've checked the coils with a meter and they check ok. I pulled the fuel line off the filter and am not getting any fuel. When I check the ECU, I get no lights whatsoever. I turn the switch on on the ECU, turn the key on and no lights. Could I have a bad ECU? Will a bad ECU stop the fuel pump and spark?


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## livinlifes2short (Oct 2, 2011)

ok so I am having the same issue, but to be clear are you getting spark?? I pulled my wires and did the old school screw driver to ground and watched for spark. Let us know hopefully someone can help us out here.


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## WFKeller (Sep 20, 2011)

I've pulled the wires off both coils and had no spark either.


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## smj999smj (Jan 1, 2006)

It could be a bad ECM. I would remove it first and check for signs of corrosion in the harness connector and on the ECM circuitboard.


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## azaware (Aug 25, 2011)

It kind of sounds like a wire. If you can get it running, while running go around from the front to the back and try to move the wire harness around and see if you can make the eng stop. If you can get it to stop while moving the wires then check that spot you were moving. Check the connectors it could be one wire. Pull on each wire in the connector for a broken wire.


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## WFKeller (Sep 20, 2011)

So I went back out to it earlier in the week and checked some fuses, then I checked the connectors on the ECU and the wiring harness near the ECU, then I checked the fusible links off the battery. Everything looked ok, no major corrosion that I could see, all the wires looked good. I got in and it started! It ran all week just fine until I got home. I went out to leave again and it wouldn't start. I think I have a loose wire or something. I guess it's back out to the garage this weekend.


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## WFKeller (Sep 20, 2011)

Cleaned up the positive battery terminal. Cleaned the contacts on the fusible links. Started and drove about 2 miles. Went to leave and it will not start again. I've read where there is a blue relay on the passenger side that people have replaced quite a bit. What does this relay do? I've also read where there is a relay that controls the voltage to the ECU? Is there such a relay? If so, where is it located? Trying anything before I shell out the bucks for a new ECU.


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## Grug (Aug 20, 2009)

Yeah, hold off on the new ECU...gotta' be something else.

So does it quit while running or does it turn off normally and then fail to start?

Maybe a bad clutch interlock switch?


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## WFKeller (Sep 20, 2011)

It runs then I shut it off and it fails to start again. If it was the clutch switch wouldn't that cause it not to turn over? It turns over fine just won't start. It will not start again and everything I've tried in the past isn't working. Still no spark and no fuel flow and when I try to get the codes off the ECU there are no lights whatsoever, like it has no power. Still tempted to order a new ECU.


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## Grug (Aug 20, 2009)

Sorry, man. You're right (must've missed it in a previous post) that if it turns over...it's not the clutch switch.

Not too sure about the relay you mentioned earlier, but I think if the relay was bad, the engine wouldn't turn over.


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## jones.william.willia (12 mo ago)

WFKeller said:


> I have a 1988 D21 with the Z24 4 cylinder, manual transmission. I got this pickup from my dad. He had issues with it, would just quit on him. I got it running and drove it all last summer then it started quitting on me. I got it going a couple of times and then it quit on me again and I parked it all winter. It started for me this summer and ran for a weekend then quit. It turns over but will not fire, no spark. I've checked the coils with a meter and they check ok. I pulled the fuel line off the filter and am not getting any fuel. When I check the ECU, I get no lights whatsoever. I turn the switch on on the ECU, turn the key on and no lights. Could I have a bad ECU? Will a bad ECU stop the fuel pump and spark?


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## rogoman (Dec 16, 2004)

WFKeller said:


> Cleaned up the positive battery terminal. Cleaned the contacts on the fusible links. Started and drove about 2 miles. Went to leave and it will not start again. I've read where there is a blue relay on the passenger side that people have replaced quite a bit. What does this relay do? I've also read where there is a relay that controls the voltage to the ECU? Is there such a relay? If so, where is it located? Trying anything before I shell out the bucks for a new ECU.


By looking in the FSM, didn't see any such thing called a voltage control relay. According to the FSM, there are three major relays. Main relay, fuel pump relay, safety relay. Check those relays before condemning the ECU. The blue relay that everyone is referring to is probably the safety relay located in the passenger's compartment behind the right side-panel.


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