Carl's Z

Ok, yesterday, the car hiccuped a couple of times heading over to Wildman's house. It got progressively worse during the day, with the engine dying now and then. This morning it was idling fine, after cleaning the AFM out and it's contacts. But then it got worse again, and would idle ok, until I shut the hood or the drivers door. So, now it idles real rough, almost dying, but if I tap on the ECU box, it will go back to normal and then right back to idling rough again. Anything else I can check on the ECU?? Any other thoughts???

Thanks

Carl

NismoPick

Check your ecu wiring harness?

Carl's Z

Well, I uplugged and replugged the large connector on the ECU itself with no results...

There is, though, a T shaped plug (two connectors, one vertical, one horizonal) that is coming from the ECU, and isn't connected. Can't seem to find anything that it connects to. Has a yellow wire with a red stipe, and then a black wire...

Carl's Z

Here's something weird, too. Now when I turn the key to ACC. the engine jolts a bit. Never did that before and could be unrelated...

NismoPick

That's part of the Datsun diagnostic tool... don't worry about it.


When the car is off, and you turn it acc, it jolts? Or when you shut the car off and turn it to acc?

Carl's Z

Well, it seems to be just once in awhile, but it's after I shut the car off, wait awhile, and then turn the key to acc..

Just went out, and the car started and idled fine, but then I jiggled an injector wire, and it started the rough idle business again. Guess I'll check all the injector connectors and see whats up there. Should'nt idle that bad with just one injector not getting a signal, though...

NismoPick

You'll deffinately notice a diff if one of the injectors isn't working... it will barely run if 2 aren't.

Carl's Z

Ok, just checked 3 injectors and redid one of the injectors wiring. I then noticed that when I put the key on "ON" (not acc.), the fan spun a bit. Could it be just a worn out belt on the alternator??? Should I just try to tighten it??

NismoPick

The only way your engine would be rotating at the on position, is if the starter is engaging.... is that happening?

Carl's Z

Can't hear it engaging at all. Plus when it does that, it's in the wrong direction. I just went out and the car started and idled fine again until I tapped the ECU, then it turned to **** again...

I don't think it's the engine, just the flex fan, which really could only be turned if the alt is doing it for some reason.

Carl's Z

Ok, here's the deal. I just went out a bit ago and started the car. I went around and barely touched the head temp sensor wires and the car died. So, I took off the connector and cleaned it. Back on and it seemed to have fixed the problem. Car ran for awhile, got warm, didn't bog down or anything. At least for awhile, then it started doing it again, but not as frequent. My sensor connector could use replacement, but could this be the sensor as well???

Carl's Z

Bump, cause I need some more ideas....

NismoPick

A couple things I'm seeing...
-Your car might just be possessed
-Your car might have A LOT of wiring probs (loose / dirty wires)

I'd start w/ cleaning all the connections & make sure they all seat tightly (might want to use a tiny flathead screwdriver to tighten the connection pins on the connectors). Also apply some di-electric grease to all connections including ecu connections.

z-hag

tis the only true and logical answer............

wreckedj30

possesed, maybe. But if you remember mine was doing the same, didn't want to run and had many problems....before the ecu swap..so i'd say its either the afm or ecu....my fix was a new z31 maf..

Carl's Z

Well, I started it this morning and took it around the block. Ran fine, so I went to park it, and as soon as I put it in neutral, it bogged for a second, went back to normal, bogged again, and then went and stayed normal. I'm going to swap the CHTS connector with the newer one I put on the cold start valve, since that isn't working anyways, and see what happens...

Carl's Z

Well, did the connector swap, but still periodically bogs down and up. If it bogs down, I can give it gas, and it will come back...

Stumped...

NismoPick

So can you get a spare ecu & swap them? How far is it to WildmaN's?

Carl's Z

Not far. Maybe I'll see if he can help me out...

Thing is, it won't start doing this until it's warmed up, and even then, it takes a little while.

RodMoyes

...Intake air temp sensor on AFM...

Check it.


Clean it.


Try it.







Rod.

Carl's Z

How to.....

I did clean the AFM pretty well. Noticed that the AFM damper doesn't move while it's bogging, though...

Carl's Z

Would the alt. belt being kinda loose have anything to do with it? I'm trying to think of things that would heat up and have an effect...

Water temp sensor
Alt. Belt
Head temp sensor
ect..

z-hag

all connections are clkean and tight and no cracked wiring or anything simple?????

Carl's Z

Kinda goin' through that stuff, but the car does run great until I've had it out for a few miles, then it starts. I've kinda figured it down to air intake somehow, but not sure. Got some "Haynes" tests to do tomorrow and will see whats up there. Keep ya posted...

Carl's Z

Found this in an old post from '04. What do you guys think???

"I had a problem close to this last fall. The car ran fine cold but went to hell after it was warmed up. My problem turned out to be the oil pressure switch. The oil warms up, starts to thin some and poof the pressure falls. My 83 zx n/a has the shut down feature. The oils pressure drops and the fuel pump shuts off. My gauge never showed no pressure (around 30 psi or so) new switch and great pressure. Never had the problem again. If I were you I would slap a new pressure switch in it, could be a simple solution for what seems like a big problem. Takes 2 mins. and about 20 bucks to do. Oh yeah a 14mm wrench too."

Let me know

Carl