94 leg dies immediately

[tinyturbo10]

Hey guys,
I just finished swapping my engine and transmission for a 92 ss into a 94 twag. Had a few issues and figured most of them out, but I'm still having an issue on start up.

I got the wagon running, but it would immediately die unless I was on the throttle. Eventually I could get it to stay on after it warmed up with me being slightly on the throttle, but it would idle very low around 100-200 rpms and would fluctuate up and down quite a bit. That lasted for a day or so then I tried to turn the car on again and it would die immediately if I wasn't on the throttle again.

I've done quite a bit of research on these cars and have some experience with them so obviously the first thing I checked were my vac lines. I couldn't find any leaks or anything, but put hose clamps on every vac line I could find. Tried to turn the car on again and no change at all.

My next guess was my iacv. I know it was bad on the ss so I figured maybe that was the problem. I took the whole intake manifold off in order to clean and replace the iacv (and clean the rest of the engine off as it was full of oil and what not.) took the iacv apart and it was completely black. I ended up finding another one to replace it, so I cleaned that one as well and put it on and put the manifold back on.

Started the car again and it died immediately like it did before. I've searched all over for possible causes and can't find anything. I unplugged the MAF too and tried again and nothing. I don't know what else could cause it to die immediately and need help figuring it out! Any help would be greatly appreciated.

[mike-tracy]

Can you reset the computer and see what codes come back if any?

[tinyturbo10]

The car won't stay on lo g enough to read codes

[mike-tracy]

Right, , however after you reset the codes initially, you can check for new stored and active codes with the car in "ACC" mode.

[tinyturbo10]

Oh man I feel dumb haha yeah I have codes
11 - crank angle sensor
49 - air flow sensor

[mike-tracy]

Timing is off or crank sensor is bad.

[rallyak]

49-maf would cause it not to run and die after start up.

[tinyturbo10]

I tried it with the maf unplugged and the same thing happened

[mike-tracy]

I think they are two separate problems, both contributing to the same result.

[Legacy777]

You need to follow the diagnostic procedures in the factory service manual to test the MAF sensor & wiring as well as the crank sensor & wiring. You can d/l the manuals from me (info in the stuff you need to know forum)

[tinyturbo10]

I reread the codes and the only ones that cane back were the o2 sensor and inhibitor switch. The Inhibitor switch is from the 5spd swap. I think the other codes were stored codes and weren't actually still a problem. I talked to the guy who had the car before me I guess he was having the same problem with it so I figured it was probably something that was on the car before I had it. I had a td04 and tmic sitting around so I figured I'd put it on and redo all my vac lines just in case it was a vac leak and nothing changed. Then I talked to some other tleg friend's of mine and they thought it might be the wire harness so I swapped that and a New ecu in and the same thing is still happening. I'm going to change the fuel filter next because I'm sure it needs it if nothing else but I'm lost after that. Any ideas and help would be greatly appreciated I need to get this thing running again.

[turbo970]

check the timing and compression i had a similar issue and my motor was bad. ask josh i waited 6 months to drive my subie

[Legacy777]

Can you provide some details as to what you did for your 5spd swap? Did you pull out the TCU and adjust the wiring/pins accordingly?

[tinyturbo10]

I followed your thread on the 5spd swap. It's like the 3 or 4th one I've done and I've never had any issues with the other swaps. I pulled the tcu out. The pedals wouldn't go in with it still in. Cut the pin on the ecu. Connected the wires on the engine side. I haven't done the reverse lights I don't have all the wiring for that yet. I can take some pictures later but those things should all be done properly.

[Legacy777]

Code 51 is also the neutral switch for the MT cars. So maybe that's the code you're reading. Did you wire up the neutral sensor in the trans?

[tinyturbo10]

I'd did a compression test today and cylinder 4 had 0. I'll do a leak down test tomorrow and go from there. But I didn't wire up the neutral switch yet I have to get a New plug and wiring for that next time I'm at the junkyard

[tinyturbo10]

I did the leak down test and couldn't find anything so I retried the comp test and all the cylinders were between 110 and 120 even cylinder 4. I guess it was just a bad reading the other day.

[RoughDiamond]

Cold (I imagine) and WOT? Seems still to be pretty low.. Could have also been a stuck HLA or two.

IIRC, the IAC is "adjustable" and needs to be sort of "tuned" to the motor. You said it was a junkyard replacement too, right?

How does it run off-idle? Decently? Rich? Rough? If it's just an idle problem, I'd stick to the IAC and the appropriate hoses (you DID reconnect the air feed hose, yes?). If not, then I'd look at big picture stuff (compression, timing, massive vac leak)

[tinyturbo10]

The iacv was on the intake manifold I swapped. I cleaned the iacv before I put the New intake manifold on as well.. Yes, all of the hose are connected and properly routed. I've checked all my vac lines to make sure there's no leak anywhere several times and haven't found one. I replaced a bunch of hoses as well when I did my td04 swap just to make sure they weren't ripped or anything like that. The timing belt is still lined up properly too.

[Legacy777]

IIRC, the IAC is "adjustable" and needs to be sort of "tuned" to the motor. You said it was a junkyard replacement too, right?

The IAC valve is not really adjustable. It is factory calibrated, and any adjustment you do after the fact is either to compensate for another problem or for the IAC valve wearing. But in either scenario I wouldn't necessarily recommend adjusting the valve. If the valve is wearing and you had access to see the ECU data to make sure the IAC valve values are within spec, you could try adjusting it slightly, but without seeing the ECU data, I wouldn't recommend doing this.

[rallyak]

I still put money on the MAF, do you have a spare that you can try?

[tinyturbo10]

That's what my guess was too but I've tried 3 different ones and got the same result with all of them. And I've tried it with the maf unplugged too.

[rallyak]

I really sounds like the MAF isn't getting the proper vacuum signal, like a vacuum leak.

Things I would do:

Unplug every vacuum line and cap both ends.
This includes brake booster, IAC,and PCV it will run with all of these pluged. If it starts and stays running then it one of those that has the leak.

PVC is unlikely but possible if check valve is gone.
Brake booster could have a ruptured diaphragm and has a internal leak.
IAC could be stuck wide open or a bad gasket, but I believe it would idle high if that was the issue.

One other thing I've seen is a cracked intake, but usually creates a lean cylinder.
I'm sure you checked all hoses and vacuum lines but sometimes it staring at you in plain sight.