Truck will not stay running

CLINT2DUNN

MEMBER
1998 FORD F-150
4.6L
V8
4WD
MANUAL
202,000 MILES

Cold revved my truck the other day and heard a loud bang, checked for holes in the block and even pulled the plugs and noticed the passenger side plugs were wet with fuel so I cleaned them up and put it all back together. Fired it up and it stuttered for about 2 minutes before turning it self off I felt of the manifold and the driver side was hot while the passenger was stone cold on every cylinder. Truck was running like a top until this.

5 Replies

JACOBANDNICKOLAS

MECHANIC
108,300 POSTS

Hi,

Don't continue running it this way until we determine what happened. If you are dumping fuel because one side of the engine isn't working, it will damage the catalytic converter.

It sounds like the ignition coil for that bank is bad. The first thing I need you to do is check to see if there is spark to the plugs on the passenger side. Here is a link that shows how it's done:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If there is no spark, switch the coils and see if you get spark then. There should be a coil pack on each side. Switch them and see if the spark returns to the bad side and is lost to the other. If it does, replace the coil.

If you look below, it shows how to replace the coil. Make sure not to mix up the spark plug wires. They must be reinstalled exactly in the same positions.

Let me know what you find.

Take care,

Joe

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Monday, July 5th, 2021 AT 9:09 PM

CLINT2DUNN

MEMBER
8 POSTS

Okay, so I double checked both coil packs and the wiring just to make sure, the truck was only $500.00 so it isn't the best but after I investigated some more I notice the driver side Down stream O2 sensor has been blown clean out leaving the threads behind there is no exhaust just the four catalytic converters with about 4 feet of pipe from where it was cut by previous owner, I also got mad at it and hard revved a few times which brought 7 of the 8 cylinders to life. Also This is not coil on plug. The truck will not run unless I give it gas at about half throttle as well.

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Tuesday, July 6th, 2021 AT 5:31 PM

JACOBANDNICKOLAS

MECHANIC
108,300 POSTS

Hi,

The idea that it blew out a sensor makes me question if there is too much back pressure due to a plugged converter. Also, that is certainly what you likely heard.

Were you able to check for spark to the plugs on the side that the exhaust didn't get hot (passenger side)?

Let's try something. Remove the oxygen sensors before the catalytic converters and start it to see if it seems any better. If there is a blockage, the removal of the sensors will provide a bit more flow and you should be able to notice it.

Also, take a look through this link. It discusses the most common symptoms with a plugged converter.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

Let me know.

Joe

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Tuesday, July 6th, 2021 AT 10:10 PM

CLINT2DUNN

MEMBER
8 POSTS

So I tried the suggested removal of O2 sensors even disconnect both still the same extreme hesitation at a throttle jab and extreme backfiring. The truck does not have a tachometer, but I suspect it to reach about 2,000 before shutting off. Could I have possibly jumped timing?

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Saturday, July 10th, 2021 AT 8:19 PM

JACOBANDNICKOLAS

MECHANIC
108,300 POSTS

It is possible, especially with 200,000 on it. Could you record it cranking and running and upload it for me to hear? I can usually tell if it is a timing issue.

Since it is backfiring, the timing could be an issue, a burnt valve, excessive fuel pressure, and so on. First, take a look through this link that discusses how to fix a backfire:

https://www.2carpros.com/articles/engine-backfires-while-running

Now, since one side of the engine stayed cool and the other got hot, you may be right with the timing. The easiest thing to do at this point is a compression test. If cam timing is off on one side of the engine, it could be causing the symptoms. A compression test will help identify if that is the issue simply because compression will be much lower if the valves are not opening and closing at the correct time.

Here is a link that shows how to test compression. You will need a compression gauge. If you don't have one, most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know what you find or if you have other questions.

Take care,

Joe