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Bad gas/dirty gas or what?

I have a 1991 Plymouth Grand Voyager and last week I bought about half a tank of gas at a station I used to go to regularly. Two days later the van started sputtering and stalling as though it were out of gas. I replaced the fuel filter and, after blowing backwards through it, found a large amount of rust/dirt had come out but the van still runs rough.

The gas station was very busy at the time and several pumps had covers on them indicating out of order or out of gas.

The only other info that might be useful: when I first got the van almost 2 years ago, I thought I needed a fuel pump due to similar conditions. Records from previous owner indicate the pump isn’t that old, but they also indicate gas from questionable storage sources. After dropping the tank and completely cleaning it out of all gas and starting fresh (twice) the problem went away until this weekend.

Sometimes it will run 5 minutes without a problem and sometimes I can’t go 30 seconds without it stalling and sputtering. Any help is greatly appreciated.

Forgot to add that codes indicated a problem with the auto shutdown relay but I’m not sure how to test it.

That was an important addition.  I would start with the relay because I doubt if it is related to the fuel in the tank, although I can't rule it out. 

If you have the exact error code (like P0123) that would be helpful.

I suspect someone more familiar with your car will be posting some information, possibly including  instruction on finding and checking that shutoff valve.

Joseph, it is a '91, an ODB-I system. It will not have ODB-II style codes, like P0123.

I’m assuming the OP is talking about the fuel cut-off inertia switch. This should be easy to check with a multimeter. Unless it is activated, the output voltage should be 12V, battery voltage with the engine off, and 13.5V, alternator voltage with the engine running. Also, if disconnected, you should read no resistance across both terminals on the relay. If you do not get these results, it is bad.

However, I doubt this is the case. If you found a mound of rust in the filter, enough to blow out, I think the inside of your tank has lost it’s anti-rust layer, which I believe is a galvanic coating. The tank is rusting from the inside out. A replacement tank would be the best alternative. Although, there are some products to coat the inside of the tank with a polymer coating to replace the galvanic coating. This is usually done with antique cars, where replacement tanks are scarce. Your van shouldn’t have that problem.

It’s error code 42.

And what shutoff valve are you talking about? I didn’t say anything about a shutoff valve.

Sorry, I was trying to understand the original question, and never heard of an ‘Auto shut-off relay’. I’m not too familiar with this van, so I was replying based on general knowledge.

After reviewing a wiring diagram for this van, it looks like they have an auto shut-off relay that cuts power to the fuel injectors when the PCM tells it to. Where on the van it is located, I do not know. It should be a typical-style relay with a red w- white stripe wire, dark blue wire, dark blue w- yellow stripe wire and a green w- orange stripe wire. Here’s the diagram.

Code 42 Link. Click It.

Already found that info, but thanks.

Sorry, wasn’t responding to you BustedKnuckles.

And from what I’ve found, the relay could just be worn out and adding to the problem.

I still think the gas isn’t helping matters.

I have found the relay on the van, on the inner fender by the battery. I just hate switching parts out without being able to verify if they’re bad and still have the same problems.

The tank isn’t rusting, it looked brand new 2 years ago. I think the rust is from gas I bought just prior to the problem starting, though it could be from the fuel line or the pump itself. When I dropped the tank previously for a similar problem, I thought I would find the screen clogged or something and everything looked clean. I just drained the last little bits of fuel to be sure there wasn’t any dirt to be sure the pump was actually dying. And the pump could finally be giving it up, just got a reprieve from what I did before.

Thanks to everyone that answered but it looks like it was a bad case of dirty gas. I disconnected the battery to clear the codes and then drove the van this morning as usual. Today it stalled a total of 4 times very early on and then drove normal the rest of the time. The timing was too perfect for it to be anything other than gas, and the stalling could have tripped the ASD relay code. The code hasn’t come back yet so I’m just going to keep an eye on things for the next several days.