Help! - 2F Running Rough

[FJ60Cam]

I need some help tracking down the problem with my truck. It is an FJ60, but I figured y'all are better troubleshooters in here!

I went on a 3 day trail ride over the New Year's weekend. We went through some pretty deep water the first day - enough to ingest a little and cause a some sputtering. Once that burned off, the truck ran great as usual for the remainder of our time on the trails for the next two days. We did see quite a bit of creek crossings throughout the trip.

On the way home, after some highway driving, I noticed the truck running rough at lower RPMs, but seemed to run fine at speed. I continued the trip home, but the problem seemed to get worse as I went.

With the engine running, I've pulled the plug wires with the engine running to track down the problem cylinders. #3 and #4 don't cause a RPM drop when unplugged.I have replaced the plugs, wires, dizzy cap and rotor with known good parts, and still have the problem. If I hook up an external spark plug, I get a spark from each wire. The spark looks pretty weak, but I have nothing to base that off of.

When I pulled the coil wire off the cap, there was a considerable amount of corrosion on that one connection - so much that I can't see any metal. Could that have toasted the coil / igniter ? Besides some fouled plugs, that is the only visible problem I can find.

Where do I start?

 

[grant5127]

Where do I start?

A complete and thorough tune.....

that coil wire corrosion just didn't happen......

preventative maintenance is insurance against a bad weekend run.........

 

[CruisinMT]

x2 tune it up

 

[FJ60Cam]

I wasn't clear enough in the first post - I put a new dist. cap, rotor, wires, plugs in with no change in performance. The timing is the same, valves have been adjusted recently.

It went from running great to running like poo after 30 min. of highway driving.

 

[3doghouse]

...With the engine running, I've pulled the plug wires with the engine running to track down the problem cylinders. #3 and #4 don't cause a RPM drop when unplugged.I have replaced the plugs, wires, dizzy cap and rotor with known good parts, and still have the problem. If I hook up an external spark plug, I get a spark from each wire. The spark looks pretty weak, but I have nothing to base that off of.

When I pulled the coil wire off the cap, there was a considerable amount of corrosion on that one connection - so much that I can't see any metal. Could that have toasted the coil / igniter ? Besides some fouled plugs, that is the only visible problem I can find...

You might want to adjust your valves, and then check compression before you spend any more money replacing parts.

Order of operation is an important part of that suggestion.


EDIT: Just to be extra clear, unless recent means since the problem started, re-adjust valves.

 

[FJ60Cam]

I guess I was just hoping that the coil wire corrosion was an indication of the problem, but it seems not to be...

I will check the valve clearances and then the compression and go from there.

Has anyone ever had a sudden change in valve clearances without some sort of major failure or damage? Adjuster nut backed off or something along those lines?

 

[Pin_Head]

Your description of how it runs is a little too vague to make a detailed guess, but if it runs rough at idle, this is often due to a manifold vacuum leak.

If #3 and 4 cylinders seem dead, do a compression test.

What speeds does it run rough and is it better or worse under load? That kind of information might help more than the details of your adventure.

 

[FJ60Cam]

It's consistently rough at all RPMs and loads.

Should I go straight to a compression test?

 

[Mr. Toad]

I'd try to find a vacuum leak first. Look real hard at the middle runner of the intake manifold because that's what supplies #3 & #4.

 

[Pin_Head]

It's consistently rough at all RPMs and loads.

Should I go straight to a compression test?

That would be consistent with a couple of dead cylinders, but that would show up more as a lack of power in general, rather than running rough. Running rough would be something like a random misfire, which is inconsistent with consistently running rough under all conditions.

 

[bajaphile]

Don't know if anyone mentioned it, but, try replacing your fuel filter? Are they simple "inline" filters like 40's? Probably not. But, my gas tank some how got crud in it, and gummed up the filter, and caused the engine to run very poor.

 

[FJ60Cam]

I did a compression test first exactly how the FSM prescribes... not good. I will pull the valve cover and run it to see if I can find anything from above.

#1-180
#2-180
#3-20
#4-20
#5-170
#6-175

 

[Bryan062087]

That does not sound good Cameron, hopefully its not anything serious.

If you want any help or need an extra pair of hands let me know. I'd be happy to come over if you are working on it tomorrow.

Let me know.

 

[cruiserbrett]

time for a HG replacement.

 

[bsmith123]

hg?

Hopefully it is just the gasket or a human mistake adjusting the valves

let us know what you find

 

[flash02]

HG, or maybe it just needs a valve job. I just adjusted my valves yesterday, it is not too hard. I just found all the closed valves and checked/adjusted then turned it over to get the rest....I need one of those nifty remote starter switches, which would keep me form turning the key. I hope everything turns out good, hopefully nothing to serious.

Good Luck!

 

[FJ60Cam]

I haven't had a chance to check the valves yet... but the HG theory is starting to make more sense.

It went from running great to poorly in a rather short period of time, and it's affecting two adjacent cylinders. HG seems more likely than the valves in two cylinders suddenly losing adjustment.