DUMPING FUEL, WONT UPSHIFT, PCM ISSUE?

  • Tiny
  • BlackOmega
  • 1993 Lincoln Town Car
  • 206,500 miles

Driving down the freeway @ 70MPH. Car bucks (split second loss of power), wont accelerate unless at really high RPM. Pull off freeway, dumping fuel (LOTS of black smoke out the tailpipe). Car seems to accelerate normally until 35MPH, wont upshift. Once at ~35MPH sounds like the car is missing.
Connected Innova OBD I scanner under the hood, can't pull any codes. Can read stored (memory) codes however.
PCM dead?
PS: Stored codes were EGR, and O2 codes.
PPS: I'm a mechanic that was injured at work. Have been out of work since May '11. Have no access to schematics. This is my only transportation for me and my three small children (5, 3 and 2). Please help!

Friday, January 6th, 2012 AT 8:06 PM

5 Answers

  • Tiny
  • cadieman
  • Member

Remove the o2 sensors and drive to check for a clogged exhaust system.

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Friday, January 6th, 2012 AT 8:17 PM
  • Tiny
  • BlackOmega
  • Member

Thanks for the speedy reply!
Exhaust is fine. Plenty of flow. Cat appears to be functioning normally. No sulfur smell, got hot when fuel started dumping (not glowing red hot). Car has power. Accelerates ok to 35MPH.

What would cause it to all of the sudden no want to upshift? (I.E. First to second gear, second to third, third to OD)
Has the AOD-E trans, I'm assuming powertrain control module, since all of the things that occurred happened at the same time.

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Friday, January 6th, 2012 AT 8:30 PM
  • Tiny
  • cadieman
  • Member

Than the problem is the o2 or the egr causing this codition of dumping fuel. Check the shift modulater vacuum if ok I would replace the shift modulater on the trans. For shifting problem

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Saturday, January 7th, 2012 AT 1:13 AM
  • Tiny
  • BlackOmega
  • Member

Thanks again for the reply cadieman.
The AOD-E trans that's in my car is fully electronically controlled. There is no vacuum modulator on this trans.
The diaphragm in the EGR has a pinhole in it so it doesn't open. That's what threw the EGR code (insufficient flow).
The O2 code is an old stored code. Last time I was able to actually pull a CURRENT code from the PCM was a few months ago and the O2's were fine then.
Still unable to pull a code from the scanner.
A friend is going to try to get me a schematic tomorrow so I can check for continuity to the PCM.

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Saturday, January 7th, 2012 AT 4:25 AM
  • Tiny
  • chelsiesuber
  • Member

My car seems as if its burning to much gas like flooding itself. So far I replaced the PCV valve, plugs an wires along with coil packs, fuel pump an filter, removed throttle an cleaned channel which was badly clogged, removed Cadillac coverters, new egr an vacuum lines, fflushed radiator, an cleaned out every line I seen. Still black smoke an gas tank sounds as if its grinding something now a clicking like orspark sounding noise kumn from somwhere under the hood

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Saturday, October 26th, 2013 AT 2:11 PM

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