I do not want to play

1994 DODGE CARAVAN
278,000 MILES • 3.8L • V6 • AWD • AUTOMATIC
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BBYLSMA
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Older van that sat for a few months. It had some rough running issues so I changed out the plugs and wires, TPS and the EGR assembly and it ran great for about 3 months.
Then the engine light came on but I could find nothing. Then the occasional stumble in acceleration and some slight surging.
Codes, 21 and 32. O2 sensor and EGR again.
Side note - I cannot get the !#$@ O2 sensor off and since I have broken one off before.am procrastinating some;-)
Now --- it starts right up but after a few minutes stumbles, misfires, quickly decreasing power until none.
If on the road I turn it off, wait awhile then start and limp home. Sometimes the gas smells very bad.
I changed the fuel filter because it sounds like it is not getting fuel, (and we all hope its something stupidly simple), NOT....
Checked fuel pressure and it SLOWLY rises to 38 psi when I start it and stays even after it is shut off.
Longer crank time now I assume because the pressure needs to rise and if I let it idle it will stall after approx. 3 minutes. Starts up again or have to wait a few minutes.

Help.
Nov 30, 2015 at 7:22 AM
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HMAC300
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  • 48,601 POSTS
should be 48 psi with vacuum line disconnected. gently squeeze return line to tank if pressure rises to specified then it may be a bad regulator but age of vehicle i'd go with pump or plugged strainer or both.
Dec 1, 2015 at 2:45 AM
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BYLSMA
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Hi and thanks for the reply.
Yeah I am thinking pump as well but I have changed out 2 previously on a Ford and a Chevy and it turned out to be something else so I am hesitant to jump into a $400.00 fuel pump.

I will let you know how your recommended test goes......well once it stops snowing....and warms up. Some of the vacuum line in this model are plastic and since it is below zero here they are very brittle.
Would a regulator gone bad produce the low and slow pressure like that?

I did look at it quickly and smell gas in the line but it was not wet like I have seen before.

thanks again.
Merry Christmas.
Brad
Dec 1, 2015 at 5:29 AM
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HMAC300
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  • 48,601 POSTS
no if it was leaking vacuum the pressure may be higher as it needs vacuum to keep a steady pressure
Dec 1, 2015 at 5:37 AM
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BYLSMA
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Yeah that's what i thought , but was hoping I was wrong.

Because this thing is acting like it has a restricted gas flow and the pressure rises slowly I am thinking that this old fuel pump may still have a future but that the, in tank strainer, is plugged.
Either or the line itself is partially plugged.
BUT...the fact that this happens after a bit of warm up time has me wondering.
The only other fuel pump symptom I have known is a dead pump that does nothing.
Can you think of any other component that changes after heat up that could cause rough running but also low and slow fuel pressure?

Thanks.
Brad
Dec 1, 2015 at 6:09 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
a fule pump drawing to many amps and not pumping required amount an d partially plugged fuel lines. I think 21 years out of a fuel pump is nothing to complain about or try not to fix.
Dec 1, 2015 at 6:58 AM
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BYLSMA
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Hi. I have been away at work so I haven't touch the van all week so I started it up as I past it and thought to see how long it would run and it ran great for 1/2 an hour.
The thing for me is though 21 years is a good run for a fuel pump I do not want to change it out only to find that is not the problem.
And now that it is not showing any symptoms I am back to testing, this time I will follow the wiring down with the DMM.

If it is the pump what do you want to bet that if I test drive it the pump does a full sudden death thing in me?
I think I will stay on the street I live on just in case.

Thanks for your help.
Dec 4, 2015 at 4:17 PM
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