Hesitating and Lurching

[BlueCruiser84]

Allright,
I just got this 84 fj60 and i love it, but it has this problem. I drove it about 90 miles home when i bought it and it ran great. When i got home it was kinda hesitating around 1500 rpms. About a week later it was really bad, it would lurch and buck when i would give it gas to start moving and idle erratically. I took it to the toyota dealership and they said it was the carburetor so they did some work but it didnt help. I brought it home and it was almost worse then it had been. After reding some posts on here i went out and plugged the EGR and it ran 100 times better but still not 100 percent. It still has a hesitation/dead spot between 1500-2000 RPMs. When i checked the vaccum on the distributor diaphragm there was none on either of them, and we are not sure where those vaccum lines lead to. Any help would be much appreciated. Thanks

 

[Cruisergreg]

Get the factory emissions manual and verify the vacuum routing. Everyone I know with a later 2F has had the vacuum lines misrouted when they bought it.

 

[lowtideride]

also check the fuel cut off selenoid ( man i kill that word everytime i try to spell it)

 

[Landpimp]

yeah get the emmsion manual, start tracing the hoses. If your 60 demoged? stuff missing under hood?

but the inner(most important one) of the vac ports on the dizzy goes thru a temp sensor in the t-stat housing then off to the carb(can't tell ya off hand which port but it sould be on the decal in the engine bay)

 

[60wag]

A failing fuel pump can make for some jerky operation.

 

[BlueCruiser84]

I got the emissions manual, but i haven't traced all the lines. I unplugged the EGR because it was giving me trouble and the charcoal canister isnt working i dont think.

How would i go about testing the fuel cut solenoid becasue i've heard that that can be causing trouble but i am new to all this landcruiser business and all these vaccum lines are crazy.

Also i forgot to mention that i have just recently experienced a dramatic loss of power (once i could go 75 now i can barelly do 60), so any help on that would be great.

Thanks

 

[Gordo]

Sounds like a fuel feed problem

My guesses in order of troubleshooting:

-Fuel filter clogged: replace it, it's cheap and a regular maint/replacement item anyway.
-Check for fuel pump leaks (bad fuel pumps normally result from ruptured diaphram, shine some light on the bottom of the pump while the engine is running and look for a fine mist coming out of the bottom weep hole)
-If it only occurs after you have been running for a while (after 1/2 hour or so) I would suspect a fuel tank venting problem and temporarily disconnect the vent line from the charcoal canister.
-If the vehicle sat for over a year without running with fuel in it: varnished fuel in float bowl
(no sure way to tell other than rebuilding the carb, the varnish flakes off into the jets causing fluctuating fuel flow)

Not sure how it could be the decel/fuel cut selenoid but should be an easy troubleshoot by disconnecting the wire from the vacuum/electric switch.

Good luck, Gordo

 

[lowtideride]

My guesses in order of troubleshooting:



Not sure how it could be the decel/fuel cut selenoid but should be an easy troubleshoot by disconnecting the wire from the vacuum/electric switch.

Good luck, Gordo

It will slowly get worse and worse over time. Took me about a year to find out what it was and by then my truck would just shut off almost. Cahil had the same prob with his rig and it was at the early phase of the missing and stumbling....grounded out the fuel cut off and the prob was fixed.

 

[crawlin60]

Blue Cruiser has the same bugmine has had, and my search of the mud archive didn’t yield a clean cut answer, maybe you fellas can point the way on this one too. My 60 has been bucking since last summer (‘03) and it comes and goes. Using the keyword “bucking” in the search function points to EGR modulator, EGR possibly and then the kitchen sink.



In this truck the bucking happens between 1000-2000 rpms and light throttle (as when cruising thru the neighborhood streets at ~/<35mph) the truck will announce that another bucking bit is coming by stumbling while accelerating from a stop sign (rpms/power drops suddenly, with gas pedal depressed for approaching upshift). Then it will seem to recover, to repeat the same stumble/recovery in rapid repetition, making the truck’s nose rise and dive, like going over a speedbump. I end up either flooring it and going faster, or engaging the clutch to dampen the bucking, letting off the gas. Just as quick, the condition disappears. What I think it’s not is fuel related. Carb has been rebuilt by me (granted, I’m not in the same league as Jim C., but I’ve rebuilt a dozen others over the years, including this one twice since owning it. Pump seems ok, for volume and pressure. Filter replaced with oem, tank is a LongRange 150L, also year old. Sight glass looks a tad high over center dot.

Passed emissions (was 3 percent CO with dead cat and no good air pump, 0 with new cat, same air pump, HCs were 200/300 before cat, 20/50 after).

Truck runs otherwise good, starts with choke and 3-4 pumps in the morning, gets 11mpg and does 75 on the flat.



Back to the bucking and EGR. Who can tell me what the procedure for checking the EGR modulator is, and which one is it. EGR has new gaskets, pipes are tight (full smog intact) but how do I check the EGR is operative? I’m open to more ideas too (‘cept desmogging it to solve this) I have the 2F and 60 series FSM, who has a link to the relevant pages in the emissions FSM, a pic/scan maybe?

 

[BlueCruiser84]

Mine was doing that really bad bucking and i unhooked the EGR and that cured that. Now it only has minor hesitation and a big loss of power.

 

[87CRUSR]

I had a similar head jolting problem on my rig a couple years back. Damn whiplash! Turned out 2 of the plug wires were shot and the carb needed to get rebuilt all at the same time. Ran smoothly after that and no probs since.

 

[CMD82]

Blue Cruiser has the same bugmine has had, and my search of the mud archive didn’t yield a clean cut answer, maybe you fellas can point the way on this one too. My 60 has been bucking since last summer (‘03) and it comes and goes. Using the keyword “bucking” in the search function points to EGR modulator, EGR possibly and then the kitchen sink.



In this truck the bucking happens between 1000-2000 rpms and light throttle (as when cruising thru the neighborhood streets at ~/<35mph) the truck will announce that another bucking bit is coming by stumbling while accelerating from a stop sign (rpms/power drops suddenly, with gas pedal depressed for approaching upshift). Then it will seem to recover, to repeat the same stumble/recovery in rapid repetition, making the truck’s nose rise and dive, like going over a speedbump. I end up either flooring it and going faster, or engaging the clutch to dampen the bucking, letting off the gas. Just as quick, the condition disappears. What I think it’s not is fuel related. Carb has been rebuilt by me (granted, I’m not in the same league as Jim C., but I’ve rebuilt a dozen others over the years, including this one twice since owning it. Pump seems ok, for volume and pressure. Filter replaced with oem, tank is a LongRange 150L, also year old. Sight glass looks a tad high over center dot.

Passed emissions (was 3 percent CO with dead cat and no good air pump, 0 with new cat, same air pump, HCs were 200/300 before cat, 20/50 after).

Truck runs otherwise good, starts with choke and 3-4 pumps in the morning, gets 11mpg and does 75 on the flat.



Back to the bucking and EGR. Who can tell me what the procedure for checking the EGR modulator is, and which one is it. EGR has new gaskets, pipes are tight (full smog intact) but how do I check the EGR is operative? I’m open to more ideas too (‘cept desmogging it to solve this) I have the 2F and 60 series FSM, who has a link to the relevant pages in the emissions FSM, a pic/scan maybe?

Mine seems to have a similar problem after it sits hot for ~30 minutes or more.
When I start it in the morning cold it runs like a champ. If I go to the store for a while ~30 min to 1 hour, it is very hard to start. When I get it started it idles kinda low and bucks and skips when a light throttle is applied, but if I gunn it, it runs strong.???? After a mile or so it is fine again.
I don't know if it is a EGR, CAT, or Carb problem. But I am open to suggestions.
Thanks,
Chris

 

[polarweasel]

Chris, it sounds like your carb fan doesn't work...

On another note, how do you test the charcoal canister? I might want to test mine and see how close to replacement time it is.

Alex

 

[CMD82]

Alex,

My carb fan runs everytime that I shut her down, without fail. I'm wondering if it is cat related. When I start it up some small ceramic-like peices shoot out of the exhaust. I guess that my cat is shot. I've noticed it a few times mostly when I start it cold, but it may be present from a hot start as well. ?????
The bucking and skipping is the wierdest thing. It is very prnounced for a short time, only when it has been shut down when hot. And only if it sits for greater than 30 minutes but less than 2-3 hours. Once I get down the road a mile or so it smooths out and drives fine. While its bucking and skipping there seems to be a huge power loss.
Maybe its an EGR problem. Does anyone have a write up on how to test that thing to make sure that it is operating correctly.

Thanks,
Chris

 

[dogboy2]

this is a common problem with the '60's series.....mine suffers from this as well. the only recourse (which I will embark upon this week) is to get a hold of the Toyota Emissions manual and as tedious as it is, go through the emissions system piece by piece.

as you've guessed, it could be a combination of problems and fixes: fuel delivery related and emissions related.

hit SOR for the manual -- it's like $18.00 or something close to that, find some time, and dig in.

-dogboy- '87 FJ60

 

[BlueCruiser84]

Hey thanks for the tips everyone.

 

[Tennessee80]

Bumping this thread…. My ‘85 fj60 has had a desmog, headers, Weber 38. It’s runs pretty good on the road. I took it on a trail for the first time yesterday, and in low range and 4wd I was getting a bucking and not smooth pedal response in 1st and 2nd, even 3rd really. Made it hard to wheel because of the lurching. I could really only get it to crawl smoothly if I feathered the skinny pedal.

Could I have issues like the guys above that are only really enhanced when I am in low range?

Thoughts?

 

[OSS]

Low range driving on the flats requires very low throttle angle. If the engine is bucking when crawling in Low, it’s being starved of fuel.
Carburetor.

 

[Tennessee80]

Low range driving on the flats requires very low throttle angle. If the engine is bucking when crawling in Low, it’s being starved of fuel.
Carburetor.

So I need my Weber to be adjusted then. Makes sense that it needs more fuel. Mixture screw then, and lean idle adjustment?

 

[kirvesmies]

So I need my Weber to be adjusted then. Makes sense that it needs more fuel. Mixture screw then, and lean idle adjustment?

well, some in here would adamantly tell you to swap back to a stock 'yota carb i've got buddies who run webers n are happy with them, mind you, not on tractor motors