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Dodge Repair/Flex fuel bypass


QUESTION: Hi Roland, I have one more question for you regarding the 1994 Dodge Spirit Flex Fuel problem. Have been unable to resolve the problem I wrote you about some time ago (back in Septmeber) Thanks for your advice. Now, my son wants to know if we can bypass the Flex Fuel Sensor. I can't find parts for the car around here and I desperately need my car. Can we bypass the sensor?  Codes on car now are 12 27 64 55. On a mechanic's advice we also replaced the ASD relay. Starts better but does not help the problem of missing badly after the car warms up and is turned off. Then turned back on and the check engine light goes on. Help! I need to get this car going. Thanks Roland

ANSWER: Hi Rebecca,
As for the flex fuel sensor you could try to by-pass it by unplugging it at the fuel tank. It is located near the fuel filter/fuel inlet hose/fuel outlet hose area and has three wires (orange, black/red, and black/light blue). I suspect that the check engine light will still be 'on' by doing that but if it is at all responsible for the engine issues I doubt that would  make worse by disconnecting it based on the meanings of the 64 code. It is needed if methanol fuel is used, but as far as I can tell it would default to the pure gasoline setting if you disconnected it. So try that.
The 27 code is saying that there is a problem with the fuel injection electrical control circuit which could either be with the wiring harness or with one of the injectors not responding as it should to the signal that controls it. Each injector has 2 wires: a dark green/black which should show 12v when the engine is running, and then a separate colored wire for each of the injectors. You could inspect the wiring harness to the injectors for any signs of melting of the insulation. And if that shows nothing then I would suggest that when the engine malfunctions when hot that you remove the 4 spark plugs and check to see if any of them are "wet"  with unburned fuel which would then suggest that the injector for that cylinder is out of control and needs to be replaced. It is possible that a fault code reader that is sophisticated could tell you which of the injectors is the faulty one.
When you say the issue is when the car is warmed up do you mean the car starts running badly or does it not run badly until you have warmed it up, turned it off, and then start it again and then it runs badly?
Please read the PS (below) and respond to it.
Thanks for doing that,

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QUESTION: The scenario is like this, I jump in it to go to the store, I make it to the store with no problem, runs great. Come out from store, turn it on and about five minutes later the check engine light goes on and it starts missing so badly that it tries to stall. If I push on the gas, it bucks real bad, but sometimes it goes (chugging all the way) LOL  Seems like after it is warmed up, it starts missing. Thank you Roland, for your answers. You are the only one who hasn't thrown up their hands and said, junk it.  Rebecca

Try doing this. Disconnect the battery briefly before the next time you drive it. That will erase all the fault codes except 12. Then drive it, and when it acts up and the check engine light comes on, then do a fault code readout and tell me the resulting flash counts.
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Roland Finston


Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

I answer questions seven days a week and respond to you in about 30 minutes. "Maxed Out" means I am answering another question or briefly unavailable so try again later.

I have do-it-yourself experience (50+ years) and a library of 100 1982-2012 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.

I was voted "Top expert" from 2010-2015 here at AllExperts, and have answered 20,000+ questions.


Five decades as a 'do-it-yourselfer' on domestic and imported cars

Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)

Degrees in Physics/bruised knuckles.

Awards and Honors
"Top expert" of 2010, 2011, 2012, 2013, 2014, and 2015 here at Allexperts. Quickest "average response time" at Allexperts (currently no. 1).

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