Quote:
Originally Posted by 12Ounce
Thanks for the feedback. One forgets about valve springs. Of course, a compression test would have indicated something wrong with that cylinder ... but compression tests can be difficult. I have forced myself to do them ... nearly always beneficial. Running a compression test and recording the results ... when the engine is running OK, gives a good "base line" for later maintenance inspections. I have traced valve seat problems this way on other engines.
|
This problem appeared to be more to do with the PCM or other electrical issue though verses a mechanical problem. here is a list of all the symptoms it had that I remember.
Sometime when starting it took like 10 seconds for it to finally start.
At times felt like a older car with the distributor a few teeth off and dragged the starter down.
Spark plug wires arced everywhere
Plug wires had like 1/16th inch streaks of light down the middle of them almost the whole length.
Of course the odd noises it made.
Position of throttle seemed to make the miss less noticeable.
After PCM was cleared of DTC's maybe 15 seconds after startup P0302 would immediately come up however the other misses detected only came after driving or beyond idle conditions.
A listed of work done to fix problem prior to valve spring discovery
Fuel filter
spark plugs (autolite AP 105)
spark plug wires
coil pack
new fuel injectors
remove rust on coil pack mount
crank position sensor
fuel pressure check
disconnect EGR
plug all vacuum line ports
valve cover update
it already had the runner control plastic clips done & bolt upgrade
none of the above work made the van run any better
The original coil pack was re-installed (ford one) back on the van prior to starting after valve spring replacement. #2 spark plug was heavily fouled and replaced with another new one.
If you have a miss in one of these 3.8's run a vacuum test first. Seems to be a common problem with these "beehive" springs breaking.