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Hi,

I am in the process of troubleshooting my fathers MK3 Mondeo (2001, 1.8L)

Some background on the car. It is heavily used. It now has 340tkm on the clock. It was converted to flexfuel at 300tkm using a injector piggyback box. It ran great for 1½ yers, but then the problems started. There is an issue on the low RPMs.

Between 1000-2000rpm, there is a hesitation when you stomp on the gas pedal. It seems to show itself more if you load the engine, by having it in a high gear. It feels like power is completly lost momentaarily, and then resumed. It can manifest itself 1-10 times between the 1000-2000rpm range. As soon as you overcome the 2000rpm, it goes perfect all the way to redline.

Thing's I've checked.

-Checked for codes. Only one P0171, seemed to be related to ethanol content. Adjusted settings on flexfuel box. Cleared and did not come back.

-Replaced fuel filter.

-Removed flexfuel converter box, running only straight gasoline now. No change.

-Replaced sparkplugs. Platinum iridium.

-Checked TPS, perfectly smooth signal 0-100%, no disturbances on it whatsoever.

-Checked coil. 0.8Ohm's on both coil ends.

I just wanted to share my story, and maybe get some insight from this forum. From what I've read, ignition coils and spark plug wires seem to degrade on this particular model. I just ordered a new coil, and will pick up a set of spark plug wires. I think they are original, with 340tkm on them, so a change might not be wasted money :). I will report back to this thread when I have them on the car. Any other input on what to check is appreciated.

/Dala
 

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Possibly ignition leads, but:

This symptom, misfire is usually caused by one of the three of the great ignition trinity: Spark plugs, leads, coil.

Be advised that it's actually best to simply change all three at the same time, since faulty parts may cause perfectly good parts to go bad.

I will give you an example: one of your leads is bad, but you see that the corresponding spark plug has a color change due to inperfect ignition conditions, or electric arcing. You change the spark plug. Problem remains. You change the leads. By this time, your leads are good, but the problem still remains since the good sparkplug went bad due to possible electric arcing from the previous lead. So you need to change plug again to actually get rid of the misfire.

Make sure you get correct leads and coil (best is genuine) since mondeos are really picky when it comes to ignition.

I had the same symptom and changed all three to NGK Iridium plugs, Bosch Coil and Bosch Leads (8mm).

Works perfectly. No missfire whatsoever for 2 years now. And actually my mpg went up considerably.
 
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P0171 = mixture too lean, not enough fuel or an air leak.

It nasic tests do not reveal a fault then you may need to remove the flexfuel

system. Blank off any holes left in the manifold etc and start from a

standard engine.

Does the problem persist after?
 

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Discussion Starter · #5 ·
:rocker: Hurray! :rocker:

The coil+plug wires did the trick! No more hesitation on low rpms at all. Thanks to this forum for pointing me towards the coils and wires going bad overtime.

Thanks again everyone!
 
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