Process of Elimination

[spazntwitch]

We took our dedicated 1997 Ford F250 to a mechanic to have him flush the water out of the motor and replace the CNG filter. (A friend of our mechanic, who works for Questar as a fleet mechanic, was the one who told him to flush the water to help with our cold starting issue.) The truck started and ran great for a whole two days. After that, the truck just won't run properly. We've replaced the spark plugs twice, swapped out the mass air flow sensor with a new one, and have beat our heads against the wall to no avail.

The truck will not go over 10-15MPH even with a full throttle and it has absolutely no power.

We have taken the truck to another mechanic who connected the OBD-II computer and cannot find any error codes. The truck was a powerhorse before this. Are we looking at a possible compuvalve issue? Does anyone have any other ideas?

[cnghal]

Re: Process of Elimination

Flush water out of the motor? Where was there water, and how did they flush it?
Did they flush the injectors using the coalescing filter?
A 1997 F250 dedicated would not have a compuvalve, only bifuels had compuvalves.
Late 90s Fords have a terribly lacking OBDII strategy so don't expect much.

[jblue]

Re: Process of Elimination

From the Ford Symptom Chart:

PRELIMINARY CHECKS

Perform the following preliminary checks:

• Vacuum lines (check for damage and proper routing)
• Intake air system (check for damaged tubes and dirty air cleaner element). Vehicle wiring (disconnected, corroded / damaged).
• Throttle linkage.
• Radiator (obstructed).
• Transmission (fluid check).

If the engine runs without any problems, my vote is for low transmission fluid or one that is failing.

Keep us posted.

[spazntwitch]

Re: Process of Elimination

Flush water out of the motor? Where was there water, and how did they flush it?
Did they flush the injectors using the coalescing filter?
A 1997 F250 dedicated would not have a compuvalve, only bifuels had compuvalves.
Late 90s Fords have a terribly lacking OBDII strategy so don't expect much.

Hi, I should have been more specific. The mechanic flushed the water condensation from the fuel rail, not the motor, which did improve startup significantly for two days. After that, the motor just lost power until we are now at the 15MPH limit on speed.

From the Ford Symptom Chart:

If the engine runs without any problems, my vote is for low transmission fluid or one that is failing.

Keep us posted.

The engine isn't running well anymore except at idle. Without putting the transmission in gear and when we press the throttle, it just dies down like it is getting too much fuel or something.

[jblue]

Re: Process of Elimination

The mechanic flushed the water condensation from the fuel rail, not the motor, which did improve startup significantly for two days.

One certainly cannot ignore that the symptoms abated after having the water condensation flushed from the fuel rail. Depending on your situation, is feasible to have it flushed again? If the symptoms go away, you would have a very plausible troubleshooting vector to pursue.

@cnghal: can the HPR leak coolant?

As an aside, keep in mind that *all* of the Ford driveablity symptom charts have the same preliminary checks starting with inspection of the vacuum lines, etc. Attached are some .pdf's of symptom chart #9 concerning Lack/Loss of Power.

FWIW.

[spazntwitch]

Re: Process of Elimination

Thanks, I'll get onto those documents when I'm not fixing computers.

[jblue]

Re: Process of Elimination

If you need additional troubleshooting charts, IM your email address and I will get ya what you need.

Thanks, I'll get onto those documents when I'm not fixing computers.

Get your ITIL and/or PMP cert and let someone else fix computers bro.

[spazntwitch]

Re: Process of Elimination

It's been a long while, but the cause of the issue was actually a plugged catalytic converter. I had sold the truck to a friend and the first thing he did was break out the converter and voila, it worked wonderfully.

[Curtis]

Re: Process of Elimination

Unburned fuel is a probable culprit for the demise of the cat.