[dogboy2]

O.K., I'm beginning to think that holy water wouldn't be such a bad idea about now. I've tried using The Force and the Jedi Mind Tricks aren't working either. For the life of me and a local Cruiser specialist, we cannot get a handle on this one:

• Jim C. carb rebuild 6 months ago - truck runs GREAT after install
• currently won't pass Oregon emissions so: tune up to spec (see post Emissions puzzler - HELP PLEASE - Jim C.? Mark W.? Gurus?)
• Truck is totally GUTLESS when warm with timing set to spec, 7º BTDC on the ball not line, and runs horribly when cold, stuttering, choking out, missing, popping, and stalling
• When timing is advanced 6º to 13º BTDC as per Mark W's suggestion, the truck actually runs pretty well with more power, easy cold start and run, etc...
• Idle speed has been adjusted in both timing conditions to 650 RPM.

HERE'S THE MYSTERY AND THE POSSESSION PART:
• As throttle steadily advances engine RPM's from zero, the engine struggles a bit and is a little rough (I know, it's a 2F, but it WAS running smoothly) until the RPM's hit about 1800. At that point, the motor completely cuts out. Without changing throttle position and holding it in place where it cut out, the RPM's drop instantly to almost 0, the engine catches itself, revs back up to 1800, and then repeats the cycle on a regular/consistent interval until throttle position changes.
• If the throttle is opened beyond this position just as it starts to die and RPM's reach about 2000, then the engine runs O.K., not great but decent
• Plugs are fouled with carbon despite being new 1/2 tank of fuel ago.

NEW DISCOVERIES:
• Heat riser door is not opening when motor is warm so engine is not receiving full charge of cool air when running - ?HIC valve bad?
• Coil is producing spark

Sorry for the novel of a post but I am stumped. Any great ideas from the Cruiser Collective? I'm fairly confident that this is directly related to my emissions issues and why it has failed 5 times now.

's on me to the Guru who correctly identifies and gives detailed instruction on how to solve the problem,

Thanks in advance,
-dogboy- '87 FJ60

[Live to Ski]

Side question: How do you know the heat riser door isn't opening?

Also, that trouble area of 1800 rpm sounds like the cut-off solenoid (not sure of the nomenclature, it's the solenoid on the upper carberator). Just a waguess!

[dogboy2]

Originally Posted by Live to Ski

Side question: How do you know the heat riser door isn't opening?

With engine warm and running, when the controlling vacuum line is removed you can audibly hear/feel the heat riser door snap open. It should stay open when warm but is remaining closed after warm up.

-db-

[TyWebb]

I've got a very similar problem with my truck too. The engine runs pretty smooth when warmed up, but if I rev the engine up to 1800 rpm it cuts out and stumbles back to about 1000 before repeating the cycle. If I give the engine a bunch of throttle it will go past the magic 1800 point and continue to smoothly rev up.

I have gone through a bunch of stuff in the FSM's with no luck. I have replaced all of the vacuum lines and checked the routing, and it all looks good.

I too think there is something going on with the fuel deceleration system, but haven't been able to figure anything out yet.


Hopefully someone can help us out.....

[GLTHFJ60]

Check the fuel cut-off switch, aka the green plastic part on the carb. Testing goes like this...put the ignition to the "on" position, but with the engine off. Follow the wire that exits from the green plastic thing down to a plug which is in the middle of the wire. It is a big green plug that just sits in the wire. Unplug it. When you plug it back together, you should hear an audible click from that green device on the carb. If it clicks, then you're good. If not, then replace it and your problem should be fixed.

[roscoFJ73]

A bad fuel solenoid wouldnt even let it start.
Sometimes the wire on top can be loose and cause problems. It could be sensitve to the vibration around 1800 rpm

[NocalFJ60]

If you hook up a vacuum guage to the intake manifold, what is the vacuum at idle & at 1800 when it stalls? Watch the guage as you rev it. Maybe something is opening the manifold to a leak or around that rpm something just starts to leak and then seals again as you go higher.

Also you can hook your multimeter up to the fuel cutoff solenoid and monitor it and see if it is moving by watching the voltage. Hook one lead in the back of the connector and the other to ground. The fuel solenoid has to be opening for it to idle but maybe it is closing at the wrong time or flaky.

[lowtideride]

nother vote for the fuel cut off switch...My rig had a bad ground and it stumbled all over the place... Could not for the life of me figure it out. It will take 2 seconds to ground out the FCS and see if its the problem.....just run a ground wire from the connector to the negative terminal

[MDH33]

Have you already tried disconnecting the EGR?

How about disconnecting the tachometer from the Ignitor?? My 60 had a stumble/hesitation at a specific RPM and it was a faulty tach causing the ignitor to cut out momentarily.

Both of these are easy checks to help rule out causes, worth a try.

[Live to Ski]

Ah, I thought you were talking about the heat flapper valve in the exhaust manifold.

[dogboy2]

The fuel cut off solenoid huh? O.K., I'll poke around with that one and report back.

Thanks for the replys - you guys ROCK!
-dogboy- '87 FJ60

[euclid]

I know this may sound dumb, but are your sure you throttle linkage is hooked up correctly? Is the 2nd barrel opening?

[dogboy2]

Originally Posted by euclid

I know this may sound dumb, but are your sure you throttle linkage is hooked up correctly? Is the 2nd barrel opening?

Not dumb by any means, and yes on both accounts.

-db-

[chitown40]

Originally Posted by roscoFJ73

A bad fuel solenoid wouldnt even let it start.
Sometimes the wire on top can be loose and cause problems. It could be sensitve to the vibration around 1800 rpm

This is not entirely true. Not trying to discredit anyone, but the truck will start and run normally if you keep it above 1000-1200 rpm (off the idle circuit). Now the fuel cut solenoid will also get turned on during other conditions such as during deceleration, but honestly it doesn't sound like your problem. Basically the truck will not idle with it disconnected but you can still keep it running by keeping the rpms up.

Did your problem come on suddenly, or has the truck progressively run worse over time? From what you described above, it sounds like the problem is in the carburator. There are tons of little passageways which can easily clog up with any foregin material and are often difficult to clear out.

Were you able to get a vacuum reading off the manifold? With the engine choked will it run better or worse? I know you said that your heat flapper was inoperative, but did you also check the heat riser in the exhaust manifold? With that stuck in the closed (cold) position it can make the truck gutless at higher speeds and rpms mimicking a blocked up exhaust. Also if it has been inopertive for some time it can cause a crack to form in the intake manifold which will cause very poor running -- not exactly as you described but generally poor. Check the metal coil on the exhaust manifold as the truck warms up and see if it contricts and opens the flapper. But most definitely get some vacuum readings and let us know.

[87CRUSR]

My truck was sputtering as it reved by the majic 1800....
but after repairing the several exhaust leaks and replacing all the vaccuum hoses...all working well!

[hammer1]

fuel cut off..
only mine was not a grounding issue, but down where the wire went into the harness, atop the fire-wall side of the wheel well. Seems a plastic clamp that held the harness long cracked away, and the harness was rubbing ( for god knows how long) untill the wires inside actually wore away to bare, and the wheel well metal was rubbed bare. . And it was the hot wire for the solenoid that rotted through. The rubbing was shorting out the solenoid, then wasnt....then was...then wasnt....
unwrapped the harness, fixed all the damaged wires, and i was good to go.
BTW..took me two years until I figured it out!

[lowtideride]

Originally Posted by hammer1

fuel cut off..
only mine was not a grounding issue, but down where the wire went into the harness, atop the fire-wall side of the wheel well. Seems a plastic clamp that held the harness long cracked away, and the harness was rubbing ( for god knows how long) untill the wires inside actually wore away to bare, and the wheel well metal was rubbed bare. . And it was the hot wire for the solenoid that rotted through. The rubbing was shorting out the solenoid, then wasnt....then was...then wasnt....
unwrapped the harness, fixed all the damaged wires, and i was good to go.
BTW..took me two years until I figured it out!

took me about that long as well to figure it out. Had the same symptoms as well, worse in the rain it seemed.

[dogboy2]

Originally Posted by 87CRUSR

My truck was sputtering as it reved by the majic 1800....
but after repairing the several exhaust leaks and replacing all the vaccuum hoses...all working well!

Definitely haven't ruled this out. Have replaced about 40% of vacuum lines with new silicone, McMaster-Carr hose. Could be vacuum issue with one of the original, as of yet, untouched lines. Will finish replacing the remaining originals and test. Vacuum problem seems highly plausible.

Intake/Exhaust manifold and gasket are new OEM, Toyota installed, about 3K miles ago.

Loose wire doesn't fit with the consistent and constant nature of the problem but will still investigate. It seems to be directly relative to throttle position and engine RPM and occurs on an unchanging, cyclical, regular interval unless I change the throttle position.

Hard to say whether it is a new problem or one that I inherited with the rig. Each successive repair or part replacement to the engine has resulted in an improved running condition. Seemingly there have been several issues masking each other that have been resolved in turn, and now I'm getting down to the last of it. OR......another part has failed in the interim and created this issue suddenly. Hard for me to say exactly....

Thanks for the continued input everybody - I appreciate it
I'm (we're) going to nail this thing yet,
-dogboy- '87 FJ60

[burnsmancuisen]

I recently had a sorta similar problem on mine, it was Idling very rough and evened out about 1800-2000 rpm. But heavly bogged down with ANY load. I replaced most of the electrical, distibuter cap and wires/plugs suspecting that, and check the vacuum stuff (on a fully desmogged 83, I think) when that did not cure the problem I decided to drive it til it was to operating temperature to see is that made a difference, it did, helped, for a short time. I got it home and took off the filter assembly to see if anything sputtered and backfired as I reved it manually. I saw substantial backfire/sputter from the carb. OK now what, then the really bad, white smoke/antifreeze cloud of death burning smell started spouting. Sadly enough a compression check was my Next Idea. I haven't had the chance to tear down and see what the exact problem is, but I know it is bad. I am not sure it this really pertains to your situation, but I thought I may add my bad judgement to save someone else.

[shade]

hi
i just bought a 1989 fj62 GXL 4.0l 6 cyl with duel fuel (petrol +lpg) and manual transmission.
i know very little about cars.
HOWEVER
it has a throttle (other than the choke) and it is pulled three notches out. when i close it, the engine dies, then takes a couple of turns to re-ignite.
i think the previous owner didn't know what it was and drove like that for thousands of k's.
nice to know i'm not alone...