Spits and sputters

[luigisho]

 

[reags8]

please drive it a few days and see if any codes reappear.

if no codes after a while, and the symptoms persist, I am starting to think its a pcm issue.

Can you expand on this comment ? "pcm issue" ??

 

[luigisho]

Computer. Try and eliminate MAF and plugs and wires first. Then you go deeper into possible spark and fuel areas. Don't jump around swinging at things. Eliminate the easier stuff first then go deeper if necessary.

 

[reags8]

Computer. Try and eliminate MAF and plugs and wires first. Then you go deeper into possible spark and fuel areas. Don't jump around swinging at things. Eliminate the easier stuff first then go deeper if necessary.

The car came with a larger MAF (tube) so I've switched back to stock; cleaned the MAF in that one; no difference; installed the MAF (not the larger tube) from the one that came with the car after cleaning that one as well....... what are the chances both are faulty ? so I've ruled out the MAF and installed new plugs ....
Wires next.

 

[SHOdded]

The wires hopefully will fix it, if voltage is the issue, as pointed out earlier in this thread. The coil pack rarely fails, so that can be saved for last. DIS & grounds would be next on the list if the wires don't work out.

 

[pjtoledo]

The car came with a larger MAF (tube) so I've switched back to stock; cleaned the MAF in that one; no difference; installed the MAF (not the larger tube) from the one that came with the car after cleaning that one as well....... what are the chances both are faulty ? so I've ruled out the MAF and installed new plugs ....
Wires next.

OK, since it had an aftermarket MAF is there by chance a tune chip attached to the PCM?

 

[reags8]

OK, since it had an aftermarket MAF is there by chance a tune chip attached to the PCM?

How do I check that?

 

[zoomlater]

The PCM is located behind the glove box, open the box and push the two sides together to lower it. If there is a chip on the PCM, you should be able to see it attached to the end of the PCM

Here's what the chip may look like

http://www.shosource.com/catalog/product_info.php?cPath=61_43_46&products_id=252

 

[reags8]

Ok here is a pic of the PCM (I didn't notice any chip?); Also I am starting to think someone has tried chasing this issue because the following extra hardware is in the trunk :
DIS
Stock MAF
PCM
Set of Plug wires
Coil pack

I'm not giving up .....

 

[zoomlater]

When my 92 started bucking while driving, it turned out to be the cam position sensor. It usually throws a code, but you can try and unplug to see how it runs after that. It may take a few tries to get the engine started.

 

[luigisho]

That plastic bracket holding the backside would likely be in the way if there was a chip in there. That PCM looks like a replacement from a salvage yard. I don't recall seeing that kind of colored marker writing on any new units. You may be correct that someone was chasing something. This may get complicated. You get this car on the cheap?

 

[rubydist]

luigisho is correct - that plastic bracket holding the rear of the pcm in place would have to be removed in order for a chip to fit in there, so no chip. also, it shows "X2J" is the pcm code.

are there any codes now?

 

[Dustin Chambliss]

My 91 does this bucking thing once in a while. Where is the cam position sensor located? I assumed it was the crank sensor.
Also, on a side note, check for any play on the crank shaft. If there is enough play, it will lose connectivity with the crank sensor, causing it to run shotty at different rpms.

 

[luigisho]

My 91 does this bucking thing once in a while. Where is the cam position sensor located?

Upper corner of the rear head passenger side just below the intake. Looks like this http://www.shosource.com/catalog/product_info.php?products_id=194

 

[reags8]

OK one last hint that might help you guys deduce the issue and no I have not gotten a chance to pull the MAF and run it nor have I gotten around to wires (hockey season just started) - When I get home from work 20 min highway 5-10 backroads .... under the hood smells like raw gas (with a little exhaust)... any ideas?

 

[SHOdded]

Could be unburnt fuel and a leak from one of the exhaust manifold/downpipe gaskets (hopefully no pinhole leaks in the parts). I was thinking canister purge solenoid till you mentioned exhaust smell. But worth a check anyway.

 

[reags8]

You sure it's the problem? Don't throw stuff at it until you have it narrowed down. Disconnect it and see how it runs. If it runs better with default computer values vs active sensor input then you know that is faulty. You can spray and clean all the contacts and filaments easily and cheaply to try and fix the problem or if the sensor is faulty and beyond cleaning to perform correctly then you replace. It may be something else. It may be combo of stuff. You are chasing ghosts by making assumptions and throwing money around. Be logical and methodical. Replacing one wire is not the same as fresh plugs and wires. Talking about MAF issues does not equal MAF is the or a problem. It is only likely based on available information from you.

I use Dan Barbush for used parts. He goes by SV&HODan on the forum.

Ran the car with the MAF unplugged and it ran exactly like it does with the MAF plugged in .... CEL immediately came on, ran the codes and got a 157.

 

[rubydist]

The unburned gas smell is likely from a crack in the hose from the charcoal canister to the throttle body. And, since such a crack would let unmetered air into the engine (when the purge valve is open) that can account for some craptastic behavior of the engine at times.

I recommend you take a careful look at all the vacuum lines under the hood, and replace all the rotten / cracked ones.

 

[reags8]

OK looked up where the canister should be (http://www.wikisho.com/wiki/Gasoline_smell_in/around_a_SHO) cause as you can see from the pics there isn't one post the valve sorry pic sucks.......

Can someone send me a pic of what the charcoal canister should look like when mounted on the wheel well ? I think I located it but nothing is obvious where this missing hose should connect .

 

[rubydist]

follow that vac hose that runs over the front side of the coil and tell us where it goes and what it connects to.

There should be a T down there that connects it to the charcoal canister (inside the driver's side frame rail) and to the vent line that runs back to the fuel tank (which runs along the bottom of the radiator).