Help me! My car runs like garbage...

Bigfatts

Registered User
Been doing some work on my '94 auto and now that I'm done it runs like crap. Before I had a bad miss and it would stall occasionally while idling, it's run like that since I've had it. Now, it idles like garbage and stalls randomly when not under acceleration- sometimes while sitting still idling, sometimes while rolling up to a stop. Still misses occasionally, but not as bad as before, just idles rough with occasional surges. I start it up, idle goes to about 1200 for a second or two then dips to just under 500 before settling at 6/700. Runs for a minute or two then just shuts off. No stutter, no surge, just shuts off. It has no problems starting back up after it stalls, it is just doing it a lot and at inconvenient times. So here's what I've done to it:

- battery/alternator ( done just before I bought it)
-plugs/wires (a couple months ago)
- all aluminum radiator/ new t-stat (last week)
*and here's where the real problems started
- crank/cam sensors (this afternoon)
- fixed several broken vac lines

So my real problems started this afternoon. After we got the new sensors in we noticed some vac lines that needed replacing. The line from the pass side pcv valve that runs down the front pass side of the car was completely broken and disconnected. The other line coming from the pcv that looks like it should have run behind the engine was missing so the T had an uncapped end. We couldn't trace where it should have gone to on the other side so capped it for now. A few of the lines for the emissions stuff were broken so we replaced them. Couldn't get the plastic lines at the parts store so used appropriately sized rubber hose.

When we got it all back together and started it up is when it started running like crap. We had the battery disconnected the whole time we were working on it so the computer was reset. My brother seems to think that since the vac leaks we fixed had likely been there a long time and were substantial that it may take a little while for the computer to relearn what's going on. I drove it a little but not very far (under 10 miles) and the problems persist. Sometimes when I'm slowing down to a stop or to go around a corner it will lose power, the rpm dips below 500 and then it stalls. It's not throwing the engine light as of yet. Didn't have time to pull codes but I will tomorrow.

Sorry for such a long post but I need help. Driving it to work tomorrow will be an adventure. Does anyone have any ideas?
 
The line from the pass side pcv valve that runs down the front pass side of the car was completely broken and disconnected. The other line coming from the pcv that looks like it should have run behind the engine was missing so the T had an uncapped end. We couldn't trace where it should have gone to on the other side so capped it for now.

I bet the other end is uncapped, and therefore leaking vacuum like, well, like a 1/2" hole vacuum leak :D

RwP
 
That's true, we have to do some more digging on that one, I'm sure someone here might be able to tell me where to look. But it was uncapped on both sides before and didn't run as bad as it does now so I don't think that's a major issue.
 
What is the vacuum gauge at when its idling at 6-700rpm? I would clean the IAC valve and the MAF, or maybe try diconnecting the MAF and see what happens at idle.
 
Vac reads around 15 or so when idling. We tested the IAC (unplugged it while the car was idling) and it broke up and stalled, so I don't think that's it. Didn't do the MAF though. I'll give that link a look, thanx.
 
Sound to me like you didn't Hook up the vac lines correctly for the PVC. The Passenger side runs into a tube that connects to back part of the intake plenum. That Tube has a tee in it and the other end attatches to the front left valve cover vent. It is not a PVC valve from the factory.

Also always a good Idea to check all vacuum lines and electrical prior to throwing parts at it. Even if it is throwing codes. I have another link that also may help. Next Post.
 
Hm, well I'm sure we got the one we connected right. I can't see it going on the other part of the plug. But we did just cap the one that sounds like it should go to the back of the plenum. Didn't see any lines that were loose or unaccounted for, but it could be missing altogether. Can you give me a more specific location for where it would go on the plenum? It's very tight quarters back there and almost 0 visibility without taking the cowl and wiper motor out of the way, and that's a ~~~~.

Anyways, I don't see that as being the main problem here. It was just open in both spots before.
 
Here is a vaccum diagram with some addititions. The green line is at least partially a plastic tube. For sure where it runs onder the SC snout.
 

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Intake Plenum Pics

Also 2 pic's of the back side of Magnum Powers intake plenum. Do you see the L fitting on the back. It goes there. Stock will look slightly different but about the same place.
 

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Thanx guys! I'll get that taken care of this afternoon. This morning I had a hard time keeping it running. The idle while in drive has settled to just over 500 and the vac is just over 10, so somethin' ain't right.
 
While I'm definitely going to check out all the vac lines again, the more I think about it the more I think it might be the new cam sensor. A couple times while starting the car I've noticed the shift up light flicker. Then driving to work this morning I noticed the tach seemed to be off quite a bit. It said I was doin 2600 rpm at 65 and it's never that high in OD. Plus the whole shebang seems like it could be a timing issue. So after I check out the vac stuff, if therels no change I'm going to put the old cam sensor back in and see what happens. Thoughts?
 
While I'm definitely going to check out all the vac lines again, the more I think about it the more I think it might be the new cam sensor. A couple times while starting the car I've noticed the shift up light flicker. Then driving to work this morning I noticed the tach seemed to be off quite a bit. It said I was doin 2600 rpm at 65 and it's never that high in OD. Plus the whole shebang seems like it could be a timing issue. So after I check out the vac stuff, if therels no change I'm going to put the old cam sensor back in and see what happens. Thoughts?

How do you know you were in OD and the car hadn't shifted into 3rd?
 
Well it doesn't make a whole lot of sense that I would still be in 3rd when I'm in cruise control. I'll pay closer attention on the way home. At the time it just struck me as "huh, that's odd." But it was 4am...
 
Update: SUCCESS!!

Ok, got it home and let it cool off before hunting down the vac lines. Got the PCV lines sorted out and double checked all the others I could find and they seemed to be good. Started it up and not much improvement. So I swapped the new cam sensor out with the old one and started it back up. Now it runs like butter. So the new Cam sensor was a dud. I tell you what, since I've had the car it has never run so smoothly and gone so long without stalling. We let it run for about 15 minutes, normally it would have stalled at least once in that time just sitting still. It did just fine.

So it turns out my old cam sensor is just fine for now and the car is running like a champ. I guess I get to take that new sensor back and get my $40 back. Thanx to all the guys who gave me tips and especially to gr8ghost for the pics and diagrams.
 
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