98 Intermittent P0305 - Lots of troubleshooting

[wiswind]

I saw the new fuel filter in the list.....and most other routine maintenance items.
The only thing that I would add is the Berryman's B-12 Chemtool in the gasoline tank.
From the reading that I have done......it does the most cleaning when it is not all used in a short time, like on a trip.
Having it in there to soak for a while is a good thing.
Even though you have had the injectors off.....there may be some stubborn deposit....or like I had once when I had serious misfires right after I had had the injectors off and clean them (when I replaced my lower intake manifold gasket)......something worked loose and lodged.....patience with the Berryman's was what solved it.

The flashing does indicate a condition that could cause damage to the catalytic converter, misfire being 1 big one.
However, the PCM does not know the cause of the misfire (would make your job a lot easier if it did).
If the cause is due to lack of spark, you have raw fuel going into the catalytic converter.....which is bad.
If the cause is due to lack of fuel to that cylinder, such as a dirty injector, then it is not so bad for the catalytic converter.


One other thing that can go bad.....though one would expect a code....is the Camshaft position sensor.
This is easy to change and not expensive.
You ONLY remove 2 small bolts and an electrical connection.
The actual pickup part of the unit, which is what you are changing, can become brittle and crack from all the heat cycles.
The camshaft position sensor is located on top of the syncro gear.....all that is left of the old time distributor.
You DO NOT want to mess with the sychro as that can be difficult to get back into the correct setting.....but changing the CPS does not require any messing with that part.

Rockauto has this part listed under "Ignition"....a Genuine Motorcraft CPS is $60.79 plus shipping.
You will want to check to see if you have the 2 pin or 3 pin connector.

Here is a picture of the CPS on my '96 3.8L.

[94LebConv3La604]

So far I've put in a can of seafoam and a can of B-12. I was considering the CKPS as well or possibly the TPS, but I can't seem to get a good probe on it for testing. This is our main vehicle, but a tank of gas usually lasts a few weeks as I mainly just take the wife to work, kids to work, a trip to the in-laws each weekend that is only 10 miles away...it's mostly short trips and I am still getting over 200 miles per tank. I was planning on putting another can of B-12 into the tank next fill. There definitely isn't lack of spark. I bought one of those crappy spark testers from autozone and made some modifications to it so that it actually works reliably and it has a strong blue spark. Admittedly I have not tried this with the car in gear...my wife doesn't like helping me work on the car and I don't trust my kids to have their foot on the brake.

Our engines are pretty much identical...even down to the broken alternator + boot.

[wiswind]

The 2 weeks is GREAT.
I used to think that using the cleaner when I went on a trip was good....but the 2 week soak is what I'm told is what will get the most out of it.
I would put ONLY the B-12 in......it is a solvent based cleaner, where as most are detergent based.
The B-12 is the ONLY cleaner that would work on my injector deposits.....and I tried a LOT of different ones.

[94LebConv3La604]

Yeah, I tried the Seafoam first, but it seemed to only make it worse. I will never use it again.

[wiswind]

The Throttle Position Sensor (TPS) should not cause a missing.
I once forgot to plug mine in....gave me a code and the thing that I really noticed is that I did not have that downshift when I romped on the accellerator.
However, the vehicle did not run rough at all.

My '96 was really prone to building up deposits inside that cap over the end of the fuel injectors.
Later years did not seem to have the same issue, but it was an issue that would come up about 1 time a year for me......very slight miss that most people would not notice.
It would take a couple years to get bad enough to light the CEL, but it would drive me crazy until then.
MANY parts were replaced and finally I figured it out.
Then when the problem came back very suddenly, my local mechanic handed me a can of the Berryman's B-12 Chemtoool and told me about it being a solvent based cleaner vs the detergent based.
I add a "maintenance dose" of Redline Complete Fuel System Cleaner because the fuels in my area are not the best in terms of additives.
The Redline gives a boost in detergency and also provides an upper cylinder lubricant.
I will be first to say that it is overkill, but I DO tend to keep my vehicles a long time.

On the Windstar, I STILL needed to run the Berryman's about 2 times a year.

This is a fuzzy picture, but you can see the cap on the left and the dirt deposits right on the outlet of the injector on the right.
The combination of oil from the PCV line and the EGR carbon........
Although I would NOT want to reduce the PCV flow as that is super critical.
I did add a catch can, don't know if it was of any help or not.



Here is a clear picture of the end of the injector after I sprayed the end off and you can clearly see the spray holes.
Again, the dirt was over the end....and also built up inside the cap.

[Searles Lewis]

Originally Posted by 12Ounce

Good that you did the compression test. Of course, the readings depend on the gauge ... and gauges vary ... but your numbers seem a bit low. Was the throttle plate blocked in the full open position when the test was made?

why do you say that? I ran a dry one-that means with the spark plugs out, right? My haynes book said anything over 101 psi was good, mine were all over that 120-130 psi.

It stopped the popping noise when it did that, too.

[12Ounce]

Originally Posted by Searles Lewis

...........I ran a dry one-that means with the spark plugs out, right? .......

It stopped the popping noise when it did that, too.

.
A dry compression test is just that ... no oil has been dropped into the cyl to "seal", possibly worn, rings. ( I will never again try a wet test ... too indefinite,and likely to damage the gauge.)
.
What stopped what popping noise?
.
I think I remember approx 175 psi when I tested my 3.8 .... but that may just be my gauge ... or bad memory.

[94LebConv3La604]

Haven't had much time to try any other troubleshooting as the damn deathstar blew the power steering return hose...it was pretty badly rusted and took the better half of a week to get replaced due to weather, replacement not being in stock, and an overall PITA of getting the old out and the new in. Good news is that it has been mostly sitting in the driveway with only a few test drives after replacing the power steering return hose and bleeding the air out of the system. I think I will take it for inspection before the misfire comes back so I have a bit more time to figure out what is going on.

Some additional info: my scanner picked up a pending code for failure to bleed up fuel tank pressure....I forget the code....P1450? Pretty sure it's not the FPS going wonky since I have on occasion heard a growling sound come from the fuel tank. It has a nearly brand new gas cap on it so I'm thinking vapor canister as the most likely culprit and if that isn't it, the lines to and from it. Would this contribute to the misfire situation?

Also had a pending code for TCC solenoid being stuck in the open position I believe....only pops up after a long drive, which is not often for me. If it pops up again I will make sure to take note of the exact code.

[94LebConv3La604]

Went through inspection today successfully. So far it has been driven 30 or so miles with no sign of misfire, but the guy at the inspection station managed to stall it out stutter stepping the gas pedal. I swapped the 1 and 5 wires at the coil pack before heading out so we'll see if the misfire switches cylinders once it starts to act up again. The van was sitting w/o being started for about a week and it didn't start misfiring for a few days the last time I allowed it to sit that long. We shall see.