View Full Version : Truck running rough and not driveable - help

02-18-2007, 01:20 AM
Driving home tonight. Truck has sat for about a week or two, ran fine a month ago when I was driving it everyday, and has run fine since even though it's been more or less sitting, but it's been started and run for a few minutes every weekend for the past couple of weeks. Fuel was basically empty.

Tonight I filled it up to about 3/4 and was driving up to Golden (~50 minutes). Running on the interstate at about 60-70 that whole time, running great, making great power, smooth, then I got onto I-70 West from I-25 north. I had gone through just under a 1/4 tank of the new gas (85 octance, which it has run for 2 years with no problem). There is a small hill there, and I immediately noticed a lack of power, but it wasn't just the hill, there was something not running right with the engine, it was immediately dogging down to 50 on just a slight incline. Once I got on the flat I couldn't get it to pull above 60mph and then it started hesitating like the brakes were sticking intermittently or something. Then on a corner the engine quit for a split second (my Lockright made the truck lurch pretty suddenly) and then starting running again, but getting rougher. So I was getting close to Wadsworth and it was running pretty rough with no power, so I shut the engine off and coasted to a stop. Tried to get it started again, didn't want to start so I waited for a minute and then it started again, but I have to keep it revved up to keep it running and it runs really rough. Made it to Treeroot's house, and made some diagnostics.

This is what I've checked - 10/76 FJ40 with stock engine etc.:
-No oil leaks anywhere (oil pressure is good)
-All vacuum hoses that had previously been hooked up are still hooked up (checked multiple times)
-All wiring at the carb (I think) that used to be there (though not complete I don't think, the truck ran fine with/without it) is/was still there, as far as I could tell. Don't know what most of it does or would do if it was hooked up...
-Dizzy looked fine on inside (electronic '78)
-Glass bowl showed good level of fuel in carb even while running (not starved before it reaches the carb)
-Primary barrel has plenty of fuel being squirted into it (not fine mist, kinda "droplety," but that shouldn't make the truck run rough should it?)
-Secondary barrel doesn't look like it's ever been used, but I don't think that has anything to do with this. That's a separate issue.
-Plug wires all tight. Pulled them one by one with the engine running, the only ones that made any difference to the way the engine ran (engine speed slowed down) were #3 and #4 (made engine drop in rpm). Unplugging 1,2,5 and 6 (one at a time) didn't change the way the engine ran at all. What? :confused:
-All plug wires arcing to plugs, so the plugs are getting voltage and should be firing.

Yeah so don't know what else to check. Thoughts on what might be wrong?
-Something jammed in a jet in the carb, or fuel not being misted causing problems.
-Bad fuel? Should I get fuel additive and see if that helps?
-It happened pretty suddenly, but I couldn't find anything that changed. So either electrical or fuel related I think. But what changed?:confused:

This is my only vehicle until my red truck gets a new timing chain tensioner, so the sooner I can get this fixed the better.

02-18-2007, 01:43 AM
I'm a lousy mechanic but I don't see any mention of checking the fuel filter?

Maybe just coincidence but with a near empty tank and then fill maybe some gunk on the bottom of the tank got stirred up and migrated to the fuel pick up and is blocking fuel to the engine?

Like I said though, I'm a pretty lousy mechanic especially when it comes to diagnosing problems.

One more thought...How is your battery? On my 40 I was getting some 'surging' in 4th gear like the engine wanted to die and wouldn't put out full power. Dinked with the carb and all sorts of stuff but couldn't figure it out. Later (I don't drive it much) I replaced the battery 'cuz it was dead and I've haven't noticed the surging or lack of power since....

Oh, and if you get in a bind and need a vehicle for a few days, my 40 could certainly benefit being driven :)

02-18-2007, 02:03 AM
Thanks Jeff! I might have to take you up on your offer if I don't get this figured out! Anyway I don't think it's fuel filter because the glass bowl shows plenty of fuel, even when running, and fuel comes out into the carb pretty good. I think I'm going to pull/maybe replace it tomorrow anyway, but not sure it's causing the problem.

Having a hard time understanding why the battery would have anything to do with this? Engine runs off alternator once it gets started...I guess I can pull the battery and see if anything changes...and maybe put a battery from a friend of mine in there...truck is still at Treeroot's house and if anybody wants to go mess with it you're welcome...I have the keys though.

02-18-2007, 08:16 AM
i would guess bad fuel. put a couple of things of gas alcohol in there and run it a bit. it will take a little while for it to work. i don't think you've got points, but check for that also.

02-18-2007, 08:23 AM
yeah, fully electronic ignition so no points.

Uncle Ben
02-18-2007, 09:59 AM
It sounds like either bad gas or overly rich. How much black soot in in the tail pipe? :confused:

02-18-2007, 11:42 AM
There's not too much...but there was unburnt fuel coming out I did notice when I came up to a stop sign driving it home from Mike's. Couldn't go above 40, still running really rough...I'm thinking maybe now it's related to vacuum advance? :confused:

-I noticed the PCV was very erratic...but I just recently cleaned it out and it was fine.
-Still need to check the fuel filter...but if I can see fuel in the glass then that should be fine right?
-I put HEET into the gas tank and have run if for about 20 minutes since then; it's been in the tank almost an hour now, no change.
-It was spitting fuel back up the carb last night when it was about ready to die, then today it actually backfired and I saw exhaust coming out of the carb once. I have the valve cover off to check the valve springs, but now I'm thinking it has to do with vacuum advance or something on the fully electronic dizzy? I don't know how to check timing or vacuum or anything, any tips?

02-18-2007, 11:45 AM
I would drain the tank and refill. There is nothing like bad gas to make you think it's something else. I've had it a couple times and it is truely a PITA.

02-18-2007, 11:58 AM
Okay, valve on the firewall side of cylinder 5 has like 1/8" or 5/32" of play (engine is warm). Is that bad? Others are tight, a couple have a small amount of play. Even if this isn't related, I'm assuming it's bad?

02-18-2007, 12:25 PM
So if cylinder is not at TDC then I guess valve clearances don't really mean much right? Either way, the intake valves (I think) on 5 and 6 have a lot of play.

02-18-2007, 01:11 PM
Having a hard time understanding why the battery would have anything to do with this? Engine runs off alternator once it gets started...I guess I can pull the battery and see if anything changes...and maybe put a battery from a friend of mine in there...truck is still at Treeroot's house and if anybody wants to go mess with it you're welcome...I have the keys though.

:confused: Doesn't make sense to me either but it seemed to do the trick for me. Then again, at all other times it was running fine so who knows. You didn't happen to notice a fuel tanker at the gas station while you were there did you? I've read where that really stirs up the 'crap' in the gas station tanks and can lead to quite a bit of water that can take awhile to settle back down to the botton. Happened to me once with a Subaru although the gas stationed denied any liability (near empty tank, filled up, car died couple miles away from the station, Subaru drained tank and said it was like 1/3 water :eek:)


02-18-2007, 02:29 PM
Check out the rod side of the lifters...the picture isn't great but that third one from the back (intake on #5) is almost able to slip off the top of the push rod. :eek: maybe?

02-18-2007, 03:25 PM
PR looks fine.. those 2 valves look a little loose even from a pic but you need to follow the adjustment procedure or do it running to get the proper spec.

My money would still be on water in the gas...

02-18-2007, 03:34 PM
:rolleyes: Check this out. Plugs 1, 5, and 6 (attached) have been impacted. Plugs 3 and 4 were a brown-red-burnt orange color, and 2 was that color but more nasty. Looks like I'm parking the 40 for a while :(

02-18-2007, 07:55 PM
What Matt didn't mention is the intake valves on #5 and #6 cylinders won't return to a fully seated position. This assumes that all intake valves and retainer components are nearly the same dimensionally. When measuring the distance from the retainer to the the head casting on all fully closed intake valves and comparing to the same measurements taken on #5 and #6, there is a difference of approximately 0.15". This is approximately the same gap between the rocker arm and tappet (or rocker arm and pushrod seat) seen in the photos. What could be holding those two valves open? I'm not sure of the head configuration but how about loose valve seats? I've seen this on a small engine, don't know if the head has replaceable valve seats.

02-18-2007, 08:04 PM
Some more pics of plugs 2, 3 and 4. Anybody ever seen red/burnt orange/brown spark plugs?

02-18-2007, 08:19 PM
whoa Matt, that doesn't look good. :eek:

What kind of work had you done to it prior to noticing the plugs being impacted?

02-18-2007, 08:27 PM
The only thing that keeps the valves out of the pistons are the springs. The valves can't hit a spark plug, only the piston can. Something came apart inside and smashed the spark plugs. If your valve springs broke or wore out, the valves could hit the piston and then the piston chunks might have been able to hit the spark plugs. To have it happen on one cylinder sure. For it to happen on multiple cylinders....that is just nuts.

If you have a bad brake booster, the last few cylinders run lean and the pistons blow apart.

02-18-2007, 08:36 PM
Hm...the brake booster idea might have some warrant to it. Anybody wanna come gawk at it sometime this week? :D Let me know

02-18-2007, 08:46 PM
that red looks pretty normal to me. My old plugs all have a hint of red if they aren't soaked in oil.

02-18-2007, 09:11 PM
Plug #4 looks normal. The valve springs are good, nothing broken or collapsed. That was my initial thought from Matt's description of blow-back thru the carb. The entire valve train looks good except for the failure to seat as previously discussed.

02-18-2007, 09:23 PM
I know the valves can't hit a plug, but if the heads use replaceable valve seats and a seat came loose, banged around head area as the valve cycled and fuel air charge is pumped thru the cylinder, the question is; could a loose valve seat reach the plug to inflict the damage as seen on #5 and #6? Kind of like the valve seat doing the hula hoop around the valve stem as the valve cycles.

It's all probably interesting discussion until the head comes off.......

02-18-2007, 09:26 PM
Wow. Great pictures, Matt. The backfire out the carb is because that valve doesn't seat. Valve doesn't seat because there is a piece of something big in it. The "something" banged around a while and damaged the plug before it got stuck. The gap on that rocker is because the valve won't seat.

The red on the plug is OK. That's just addatives. probably from running the HEET for 20 minutes.

Now how you got mechanical damage in 3 cylinders at once: I don't get it. I guess it is possible that when the valve got stuck open chunks from the bad cylinder got pushed back up into the manifold and sucked down another jug.

No matter what, you're pullin' the head on this one. With that much damage, I think you'll find some beat up piston heads as well as the head damage. Sorry. It may very well be time for a different engine.

02-18-2007, 11:23 PM
put new plugs in... adjust the valves and see how it runs :D

02-19-2007, 06:26 AM
The intake valve on #5 is either bent or has something caught in it. I'm with Steve on this - pull the head. It could be a chunk of a broken spark plug or something that got sucked in through the intake manifold. I vagely remember a Mud thread about some bolt in the carb coming loose and ending up in a cylinder. This might be similar.

02-19-2007, 12:12 PM
If your pistons aren't shot, you'll only be down for a week if you pull the head. If you simply replace the plugs, you may get it to run again and do further, much more severe damage.

02-19-2007, 01:03 PM
I have an empty trailer behind the dmax today. Let me know if you wanted to move the Cruiser to your dad's place today. I have extra F parts laying around. Some of them will cross over to the 2F engine.

02-19-2007, 02:06 PM
Yeah, definitely not starting it again until I take the head off and see what's going on.

Thanks Root, not today but soon I might be giving you a call :thumb:

Anybody wanna come gawk at it while it's still up here? I guess the mystery is no longer as much of a mystery now that I pulled the plugs at Zepp's suggestion...

02-19-2007, 02:42 PM
I found the thread on mud and I think Grant is right on this one. Your cam probably slipped.

02-19-2007, 11:17 PM
I have never had a 2F apart so I can't speak from direct experience on this one, but I have had a bunch of old school Honda motorcycle engines apart. Many have long cam chains and jumping a tooth isn't unheard of. When they do, the valves contact each other or a valve and a piston contact, causing some disintegration/breakage. Likely cause of your plug damage. I would get the head off and take a look to see what's in there jamming in the valves. :(

Oleg has a rebuilt 2F for sale :)

02-20-2007, 12:29 AM
Check out my thread (http://forum.ih8mud.com/showthread.php?t=138196) on MUD for some thoughts down near the bottom of the first page and Jim C's comment on page 2. I'm learning a lot of new things about the 2F engine, and I'm sure once I pull the head I'm going to learn a lot more.

02-21-2007, 12:57 AM
Sorry, nothing really new. Is this spark plug length (from the washer to the end of the threads) right? It's about 0.675 on plug #4.

03-03-2007, 10:44 PM
Got the head off tonight with my dad, I forgot my cable to connect my camera to my computer, but I'll post pictures Sunday. Imagine those hose clamps that have the springy wire and the bolt with the 10mm hex/philips head that compress it, and imagine that the bolt is stuck into cylinder number 5's intake and keeping the valve open while the spring is stuck into cylinder number 6's intake and keeping the valve open. The cylinders appear to be okay, but the piston faces are pretty banged up. Valves appear to be okay, but who knows about the seating surfaces. We were able to compress the springs and get the pieces out, but I have no clue how that got in there. I had the carb/intake out during the summer a year and a half ago, but we cleaned out the intake and made sure it was clear. I *might* have had the carb off since then, but definitely don't remember anything falling in there, and I know I was pretty careful. I don't think there is any way this thing could have fit down the throat of the carb. Also, since I last had the carb off I've done Chinaman's, Triple Bypass, driven to Buena Vista/Leadville, did the Ghost Town Run, driven to Westcliffe/up the road to the Crestone Peak and Needle, and driven to work a LOT this summer, not to mention a bunch of other smaller trips here and there. I guess I coudn't be happier about the location of where it decided to let go, but still it's weird.

So the question is: what would YOU do?

03-04-2007, 07:33 AM
I'd check for any damage to the cylinder walls. If the cyls look good and the dings in the face of the pistons are minimal, I'd call the block good and leave it alone. As for the head... the valves and seats might look ok but if they leak, its going to run poorly. You might consider taking the head to a shop for a full valve job. New valve stem seals, springs and even surfacing the head shouldn't be much more than 250$.

03-04-2007, 07:45 AM
so how did one clamp get into multiple cylinders?

03-04-2007, 08:29 AM
You show me how a hose clamp can get into my intake manifold, and I'll show you a hose clamp getting into 3 cylinders...


03-04-2007, 08:46 AM
squirrels did it...insert photochop squirrel holding hose clamp. (I had to remove photoshop from my work PC.

03-04-2007, 09:34 AM
Or maybe kitties did it..."I'm in ur engine, sprinkling hose clamps down ur intake..."


03-04-2007, 09:55 PM
-Valves 5 and 6. yummy.
-Cylinder #4 on left and #5 on right.
-Cylinder #5 on left and #6 on right.
-Cylinder #1
-Here's the parts. The bolt was in #5 and the curly part in the first picture was only part of the spring. The nut and the part that broke off the spring are gone, probably one of those somehow ended up in #1. We looked down the intake ports when we had the manifold off and before we put it back together, I wasn't missing any hose clamps...it was probably something I just overlooked though...sigh :(

Okay to get a valve job and get new plugs and put it back together? Are the piston faces something to worry about? The cylinder walls look good and polished.

03-04-2007, 11:38 PM
Oh man... wow. sorry, Matt.

03-05-2007, 06:20 AM
The peened surface on the pistons looks pretty odd but shouldn't hurt. Is the notch in the piston face in cyl #1 pointed towards the rear of the engine? I think its in backwards. It might not matter much but I think there's a reason the notches are all supposed to be facing toward the front.

edit: Wait a minute, that's not cyl #1, that's another shot of #6.

03-05-2007, 09:10 AM
The backfire out the carb is because that valve doesn't seat. Valve doesn't seat because there is a piece of something big in it. The "something" banged around a while and damaged the plug before it got stuck. The gap on that rocker is because the valve won't seat....I think you'll find some beat up piston heads as well as the head damage.

Pretty darn good guess, eh? It is all because of your great pictures!
Why in 3 holes? Well, there are 3 parts to those clamps. There should be a flat piece with some holes in it in your muffler.
The times I have seen piston heads and like that, we junked the engine. Too much money for the head work, pistons, and machine work on the block.

On the other hand, it might run fine with just head work. My fear is that latent damage to the piston heads is going to cause an oil burning problem in the near future. If you have to pull the block for machine work anyway, just drop in a different engine.

03-05-2007, 01:26 PM
all the notches face the front.

03-05-2007, 01:57 PM
WOW, that's interesting. That had to have fallen in relatively recently...

I'd be kinda worried about the pitting on the #1 cyl walls. So.. those pistons have a hammerite finish now? Really that's not ideal because the combustion process will not be as smooth. I doubt you'd have an issue with burning oil from them. I'd try and wire wheel them and clean them up some. This is still a tractor motor so I still think you have life in it. I'd button it back up and see how she goes DTR.

03-05-2007, 03:13 PM
Wow Matt-

I have been there and done this... my #4 cylinder let go at the main bearing on the highway, talk about a bang!

If I were you, I would check out:

1. Any locals with a running 2f laying around. Could be the fastest way to get you up and running, but in my mind every engine that isn't in a vehicle isn't in a vehicle for a reason... just be careful if you buy one.

2. I would look at getting the head totally reworked, I had a performance race shop do a complete head rebuild and angle valve job for 180 bucks but that was in Iowa were everything is cheaper. I would bet that this gets you up and running again, a new head gasket and valve job will get you up and running again.

3. I would pull the pan, and check each piston for any play at the crank, if you smacked a piston hard enough it could have damaged the bearing on that cylinder, if they check out okay I would run it with a rebuilt head.

4. Sell everything you own and drop a Ramjet 350 in...

Sorry bud, there are no easy fixes here, that is a real bummer, but fix it right and you won't regret it.


Uncle Ben
03-05-2007, 04:50 PM
I doubt there would be any rod bearing damage but really check piston height closely on all cylinders as rod damage is possible. Another possible area of concern would be the piston deck itself as cast pistons will crack rather than bend. You should be able to assess from underneith with the oil pan off. If the cylinder walls are not damaged and the piston height is OK I would do as suggested and clean up the tops of the pistons with a rotory scotch brite pad freshen the head and drive it.

03-05-2007, 11:04 PM
Make sure you use a Toyota head gasket. It's a bummer pulling the head to redo a head gasket only a year after you had the head off the first time. Don't ask me how I know. :(

03-06-2007, 09:29 AM
Matt, that's rotten news.

You could always pick up Olegs rebuilt 2F (http://www.risingsun4x4club.org/forum2/showthread.php?t=3094).

Not a bad deal for a rebuilt engine. You could drop it in over a weekend and be back up and running. Use your old engine as a parts donor.

Hope you can get it running soon.

04-08-2007, 12:37 AM
Yay! Got it running tonight! Valve/head job at Gunn Automotive, good guys and know stuff like the oil galley plug that pops out, so they replaced it etc...Head gasket (OEM Toyota) from a forklift supplier (forgot which one just now?), oil pan gasket from Shark Bait, cleaned it all up and threw it back together! My valves were in somewhat poor shape, so after we adjusted the valves tonight the rocker assembly was running noticeably smoother and quieter! No surprises, but got by pretty cheap considering what could have happened.

Figured the culprit hose clamp came off of the EGR tube that feeds the carb...it runs right next to the carb and there's a rubber hose that attaches to it. When I had the carb off this past summer to replace my brake booster I'm pretty sure that's when it fell in, now that I think about it I remember not being able to find it but brushing it off as not important...:rolleyes:

Anyway thanks guys for the help, and I'm actually kinda glad I got the chance to do this, I learned a ton!

04-08-2007, 08:30 AM
Cool. Glad to hear its back together and running.

04-08-2007, 12:59 PM
good job, I hope it's ready for another 100 thousand miles. :thumb:

04-08-2007, 09:41 PM
Great Job Subz!


04-08-2007, 10:45 PM
Nice job. Glad it all turned out ok.

04-08-2007, 11:08 PM
Great job, Matt! man that's got to be an awesome feeling..

04-09-2007, 10:02 AM
Great Job Matt! The Subzali is ready for summer wheelin :)

08-14-2009, 01:48 PM
Well coming up on 2 1/2 years later and things are still on the good side over here. Don't know how many miles I've put on it, not too many really, somewhere between 5,000 and 10,000 I would have to guess.

-Head gasket from the forklift supplier is holding strong (it's an OEM gasket (with OEM part number), just not from Toyota Automotive).
-Engine is holding strong. It doesn't burn an appreciable amount of oil (every once in a while I might have to put some in, but it's a small amount and it's random). It could probably pull hills and such better, but considering it's an unbalanced engine with a little over 200,000 miles on it, it's been through all that junk above, and only has a little over 100 psi compression, I think it does pretty darn well.

I do end up with oil in the air cleaner housing though. From what I gather that is a sign of blowby and excessive crankcase pressure, which ends up with a lot of oil vapor condensing in the air cleaner. So someday the engine will need to some work. But in the mean time I've gone to CM '07, Ouray '07, CM '08, GTR '08, GTR '09, and a lot of other trail runs and driving in the winter time and it's been great!

I keep reading threads by Trollhole and others on MUD though...:drool:

11-06-2012, 08:12 PM
Following the link you sent me Matt, I look forward to reading your adventure!

11-06-2012, 08:45 PM
Check out my thread (http://forum.ih8mud.com/showthread.php?t=138196) on MUD for some thoughts down near the bottom of the first page and Jim C's comment on page 2. I'm learning a lot of new things about the 2F engine, and I'm sure once I pull the head I'm going to learn a lot more.

I don't like how threads in MUD close automatically now...

11-07-2012, 09:15 AM
You can ask Woody to re-open them if you want to past back to them.

11-07-2012, 02:57 PM
You can ask Woody to re-open them if you want to past back to them.

Yes, I have done so for a few, just adds another layer to trying look up relevant material.
What is harm in leaving them open?
Just not a very customer-centric approach.

11-07-2012, 03:01 PM
somewhere I read that it's so that troll-bots can't look up old thread titles and resurrect them from the dead...not sure why that's a problem.

11-07-2012, 09:14 PM
somewhere I read that it's so that troll-bots can't look up old thread titles and resurrect them from the dead...not sure why that's a problem.