2.9l Fuel Fouling Number 3 Cylinder

[88 XLT Ranger]

Are you sure it is gasoline that is fouling #3?

Could it be water/coolant?

Ron

The three plugs I kept changing last night are still wet looking. All the other plugs are burning good nice clean looking. These that fouled out are dark wet looking and smell like fuel. This is why I was thinking of putting a real hot plug in number three to keep this crap burnt off. I was thinking MSD makes a powerful coil for the 2.9l "Master Blaster" maybe needs more powerful spark?

I think why the plugs are still wet sitting in the garage that Lucas the fuel injector cleaner and that water remover. I think they both has upper cylinder lubrication in them

 

[RonD]

Well if you are sure it is fuel, and injector and fuel rail are not leaking then I would test compression.
Compression is needed to heat up/vaporize the gasoline when it comes in.
Liquid gasoline won't ignite by a spark(yes Hollywood gets that wrong, lol)
Only gasoline vapor will ignite by spark.
Fuel injectors squirt liquid gasoline into intake, same as carb put liquid gasoline in intake.

This is also why engines needed to be "Choked" when cold, cold gasoline(50degF) will only be about 10% vapor after compression, you need 30% vapor in a cylinder to get it to fire.
A choke plate simply sucked in more fuel to get the 30% vapor, computer adds more fuel via the injectors to do that.

If compression is low then you don't even get that 10% to start off with so never get to 30% until engine/gas warms up a bit but by that time spark plug could be fuel fouled in that cylinder.
Generally you need at least 100psi compression to get gasoline heated up, should be 150+ psi compression normally

 

[88 XLT Ranger]

Well if you are sure it is fuel, and injector and fuel rail are not leaking then I would test compression.
Compression is needed to heat up/vaporize the gasoline when it comes in.
Liquid gasoline won't ignite by a spark(yes Hollywood gets that wrong, lol)
Only gasoline vapor will ignite by spark.
Fuel injectors squirt liquid gasoline into intake, same as carb put liquid gasoline in intake.

This is also why engines needed to be "Choked" when cold, cold gasoline(50degF) will only be about 10% vapor after compression, you need 30% vapor in a cylinder to get it to fire.
A choke plate simply sucked in more fuel to get the 30% vapor, computer adds more fuel via the injectors to do that.

If compression is low then you don't even get that 10% to start off with so never get to 30% until engine/gas warms up a bit but by that time spark plug could be fuel fouled in that cylinder.
Generally you need at least 100psi compression to get gasoline heated up, should be 150+ psi compression normally

Ron

I fired it up it seamed loaded up kinda blue/gray looking smoke out the tailpipe and popping its 32% out very cold. When I shut it off last night it was running great real smooth. I took it to town got on the highway popping I ran it up to 4K bogging than let it shift into high it picked up that cylinder. It ran perfect up the grade through town and back home. I think stepping the heat range up on number 3 plug might keep it from fouling out

I just need to find out what the hotter heat range is than Autolite AP 105 or in a Champion plug. I can smell a lot of fuel when starting it cold I do have to give it a little throttle to get it going

 

[Andy D]

I lost track. Have you replaced the cap, rotor, wires? If so what did you replace them with? Wouldn't be the first time ignition parts were bad out of the box. Some are just garbage. Also, wires are tender, After I ruined 3 wires on a jeep V8 , I started using di-electric boot grease. I revived the wires on a Willys 6 by working the grease into the dried out jackets so dew wouldn't ground the wires out.

Also what Ron D says. Time to rent a compression tester. It is a 29 yr old Ford. They were never intended to last this long. How is the oil pressure?
Another part of old cars is their dried out shrunken wire ends , fraying a strand at a time just beyond the strain relief. I had a flukey hesitation under load, bugged me, but was very intermittent. got worse on dirt roads. finally the jeep died completely. I was mystified when I raised the hood until I saw that 1 of the little wires to the coil had broken off. A quick jury rig . restored volts and awaaay we went.

 

[88 XLT Ranger]

I lost track. Have you replaced the cap, rotor, wires? If so what did you replace them with? Wouldn't be the first time ignition parts were bad out of the box. Some are just garbage. Also, wires are tender, After I ruined 3 wires on a jeep V8 , I started using di-electric boot grease. I revived the wires on a Willys 6 by working the grease into the dried out jackets so dew wouldn't ground the wires out.

Also what Ron D says. Time to rent a compression tester. It is a 29 yr old Ford. They were never intended to last this long. How is the oil pressure?
Another part of old cars is their dried out shrunken wire ends , fraying a strand at a time just beyond the strain relief. I had a flukey hesitation under load, bugged me, but was very intermittent. got worse on dirt roads. finally the jeep died completely. I was mystified when I raised the hood until I saw that 1 of the little wires to the coil had broken off. A quick jury rig . restored volts and awaaay we went.

Andy

I replaced the cap and rotor with BWD Borg Warnner Division from Oreilly Auto Parts. The plug wires are Mileage Plus from Napa Auto Parts as is the ignition coil. I was still having the same issues I messed up the number 3 plug wire removing it and replaced with a used SuperMax wire still same results. Now my question is if it runs popping as soon as I put a load to it the plug re-fires runs up a steep 6 mile grade and through town no issues and back home. If it where compression it wouldn't run like it did today. There is something going on as far as fuel and or ignition I feel. I am going to try a hot plug in that cylinder I might have to order one from Summit Racing as it looks thus far

I think the last number on an Autolite plug is heat range? I see Autolite has no heat range chart thus hard to figure out. If I raise the heat range in that plug it will stay hot longer thus burning away anything that might foul it out am I right? I am just grasping at straws in hope to nail this issue in the butt

 

[88 XLT Ranger]

Just a thought guy's

Is it possible to disconnect the FPR vacuum line plug the intake plenum and run it on the road? It cleared out and ran perfect up the 6 mile highway grade than around town and back home no popping. I did disconnect it last night ran it a bit in the driveway. Maybe the thing it leaking into the plenum I just don't notice it. As far as finding a hotter plug no luck thus far I wonder who sells Denso plugs? I need a 14 and 9

Denso 14 is one heat range hotter than Autolite AP 105's Denso 9 is two heat ranges higher. The way my luck has been going probably more waste of money

 

[Mark_88]

That might work for you, but my inclination is to fix the problem properly instead of throwing questionable fixes and parts at it.

What about just replacing the FPR? If the fuel is getting into (leaking down) #3 via the vacuum line then it is, essentially, getting past the diaphragm like a wonky FPR usually does.

 

[AndyB.]

I'd take a step back. Pull the number three plug, lay in on the exhaust manifold with spark plug wire connected to it. Have someone crank the engine and verify you're getting a spark.

Regarding spark plugs. I'd run Motorcraft AWSF42C or AWSF42P, and nothing else.

 

[88 XLT Ranger]

That might work for you, but my inclination is to fix the problem properly instead of throwing questionable fixes and parts at it.

What about just replacing the FPR? If the fuel is getting into (leaking down) #3 via the vacuum line then it is, essentially, getting past the diaphragm like a wonky FPR usually does.

Mark

The FPR might be ok I don't see no fuel in the vacuum line or a smell of fuel. Is there a way of testing this? like disconnect the vacuum line plug off the intake plenum test drive it. If it still pops than its not the issue the only one I can get is a BWD FPR at $52.99 there not cheap

 

[88 XLT Ranger]

I'd take a step back. Pull the number three plug, lay in on the exhaust manifold with spark plug wire connected to it. Have someone crank the engine and verify you're getting a spark.

Regarding spark plugs. I'd run Motorcraft AWSF42C or AWSF42P, and nothing else.

Andy

I was thinking on doing that but there is no one around to crank the engine. I am out in the Bonnies here in hillbilly land. Do you know anyone that has had issues with Autolite plugs? the only way to get Motorcraft plugs here is at a dealership

 

[Mark_88]

Mark

The FPR might be ok I don't see no fuel in the vacuum line or a smell of fuel. Is there a way of testing this? like disconnect the vacuum line plug off the intake plenum test drive it. If it still pops than its not the issue the only one I can get is a BWD FPR at $52.99 there not cheap

No, not cheap at all...I just went in search for a view of the engine and location of the FPR on them but couldn't see one that made sense or had a clear shot of it...and how it works on these engines (not the function works)...

Pulling the vacuum line off probably wouldn't fix the issue or even a good way to test..but I didn't find anyone else with the same issue either...so you're cutting new ground here...it seems.

 

[AndyB.]

You can get these plugs that will last you the rest of the truck's life.

https://www.ebay.com/itm/282297911345

I think the plug is wet because the cylinder isn't firing. You could probably pull the plug, rest it on a ground, start it, then check for spark. There are spark testers you can buy, but they won't help you diagnose a bad plug.

 

[88 XLT Ranger]

Guy's what do make of this

I fired it up ran great up the highway grade I took the off ramp stopped. As soon as I gave it throttle popping same old story. I pulled into the Auto store pulled number 3 plug dry as a bone just a little dry black carbon on the outer edge. I went in bought a Motorcraft fine wire plug they don't foul out at low RPM's they say. I put in fired it up popping I drove to the post office popping running like crap I shut it off. I started it back up running fine all the way home until I stopped to take the exit to my house than popping. I got home pulled number 3 plug clean burning perfect I put back in. I fired it up I hear a sharp tick tick a good misfire I gave it a quick throttle loud pop and running rough


The last thing I can think of that I haven't changed is the computer main brain issue. I hate to blow $150+ on one and the same issue again. There is no way to test the computer? when I pulled it inside looked perfect on the computer board

 

[Hagan]

Guy's what do make of this

I fired it up ran great up the highway grade I took the off ramp stopped. As soon as I gave it throttle popping same old story. I pulled into the Auto store pulled number 3 plug dry as a bone just a little dry black carbon on the outer edge. I went in bought a Motorcraft fine wire plug they don't foul out at low RPM's they say. I put in fired it up popping I drove to the post office popping running like crap I shut it off. I started it back up running fine all the way home until I stopped to take the exit to my house than popping. I got home pulled number 3 plug clean burning perfect I put back in. I fired it up I hear a sharp tick tick a good misfire I gave it a quick throttle loud pop and running rough

The last thing I can think of that I haven't changed is the computer main brain issue. I hate to blow $150+ on one and the same issue again. There is no way to test the computer? when I pulled it inside looked perfect on the computer board

Sounds like you have a random misfire issue. Believe it or not my brother had a bad distributor cap on his boat. It would run for a couple minutes then die. After it cooled down it would restart. He thought the clear fuel filter was getting clogged (you could see it wasnt clogged) and once he would change it it would cool down and run fine for another couple minutes. He swapped the old distributor cap on and it has run fine since.

Have you taken a compression test yet?

 

[pjtoledo]

exactly what do you mean by "popping"?

have you put a vacuum gauge on the intake?