Rough *Idle* - Only While in Gear - 1988 FJ62 (1 Viewer)

[mjulaw]

here's the basic info. please ask for more details, but if giving advice or asking questions, talk to me like i'm 5 years old. i can do basic stuff, but i'm not a gearhead. this problem is not an emergency, i've had 'buck' since 2004. it's a hobby, maybe one day my DD.

i searched on here for a similar problem, but didn't locate one. feel free to include a link if i missed it.

- 60k engine bought from a member here (he was swapping out for a diesel)
- had engine installed by a shade tree dumbass around 2018
- not long after, auto transmission* went out
- it sat forever, two mechanics retired, another guy let it sit for years
- fast forward, bought auto trans from a member here
- trans recently installed. been driving a few times a week since december 20
- my transmission guy told me that it needs a kickdown cable. i have one ordered for him to install.

so when i'm in gear, say at a red light, the idle is pretty rough. if i throw it in neutral, or park, it smooths out.

am i correct in thinking that it's not the *idle* at all? in other words, is this a transmission issue, since it only happens in gear? it also shudders and shakes around 30-40 mph (not really sure since speedo cable is also on my to do list)

best case scenario is that the new kickdown cable is the problem and will solve everything.

if it's not a transmission issue, any basic suggestions? like a said, this is a very low mileage engine. i haven't even put 100 miles on it since buying it 6 or 7 years ago. i have done a few basic things to it since december 20:

- put sea foam in the gas tank. only 93 or non-ethanol since then.
- new battery, cleaned corrosion on alternator plug
- oil looked good, added some zddp. plan to change oil soon anyway with rotella 15-40.
- pulled spark plugs, checked the gaps. they all looked good, none were oily etc. didn't replace.
- installed new ngk plug wires.
- installed new toyota distributor cap

even if i don't drive it, i will usually crank it 3-4 times a week and let it run 10-15 minutes. it has smoothed out a bit since i got it home.

that said, what are some other basic things i can do to continue improving performance before taking it to a professional for a tune-up? for example, it's possible that the shade tree dumbass didn't get all the vacuum lines hooked up correctly years ago. replacing the entire exhaust system is also on my to do list.

thanks in advance!

*yes, i know everyone prefers a manual shift. i had an '85 for a few years, but when i'm driving around town and also sending work texts and emails, i didn't have a third hand to hold the steering wheel. i'm not a rock crawler, i drive this because it's the coolest vehicle on the road.

 

[Godwin]

Check the rubber air cleaner hoses between the canister and throttle body, especially the accordion hose. You may have a cracked hose that's causing a vacuum leak. Stopped and in neutral the engine is just sitting there, but in gear it may be torquing over just enough to open up a crack in the hose.

 

[mjulaw]

Check the rubber air cleaner hoses between the canister and throttle body, especially the accordion hose. You may have a cracked hose that's causing a vacuum leak. Stopped and in neutral the engine is just sitting there, but in gear it may be torquing over just enough to open up a crack in the hose.

thanks for the suggestion, will do. yesterday when i replaced the distributor cap, i removed part of the accordion hose. i did notice a little oil inside it. do you think would that be from the same issue, or something different like a valve cover gasket?

 

[RevISK]

I had what sounds exactly like this problem when I first took custody of Paul. First thing you should do is pull the code(s). I'm betting you'll get a 51.
Next you get to go down the vacuum leak, TPS, fuel delivery and on rabbit holes.

Desmogged?

 

[mjulaw]

I had what sounds exactly like this problem when I first took custody of Paul. First thing you should do is pull the code(s). I'm betting you'll get a 51.
Next you get to go down the vacuum leak, TPS, fuel delivery and on rabbit holes.

Desmogged?

i said '5 year old' and there you go with 'TPS'... will definitely pull the codes. thanks!

 

[RevISK]

i said '5 year old' and there you go with 'TPS'... will definitely pull the codes. thanks!

Hey little buddy, you get to learn about the throttle position sensor!
Do you have the ultimate Land Cruiser story book, the FSM?

 

[RevISK]

https://forum.ih8mud.com/resources/fj62-chassis-and-body-repair-manual-aug84-jan90-36262e.254/

 

[mjulaw]

Hey little buddy, you get to learn about the throttle position sensor!
Do you have the ultimate Land Cruiser story book, the FSM?

i have the haynes. i will check out the TPS. can't help but laugh thinking about where i've heard that before...

 

[mjulaw]

and i don't find the haynes manual very helpful so i should probably upgrade.

 

[Godwin]

and i don't find the haynes manual very helpful so i should probably upgrade.

Cold weather rolling through AL, burn the Haynes for warmth.

If you can't get the issues sorted out I recommend to take it to OTM @Bama4door in Leeds.

 

[mjulaw]

Cold weather rolling through AL, burn the Haynes for warmth.

If you can't get the issues sorted out I recommend to take it to OTM @Bama4door in Leeds.

yea, great folks there. that's where i picked up this transmission, a customer was doing a manual swap. once i get above my pay grade, i'm gonna let them get it across the finish line.

 

[mjulaw]

https://forum.ih8mud.com/resources/fj62-chassis-and-body-repair-manual-aug84-jan90-36262e.254/

i scanned through this. do you happen to have a link to the 3F engine manual? i looked through all 7 pages of the 'resources' on this site but didn't see one. thanks

 

[RevISK]

TPS test and adjustment is in the manual I linked.
3FE covers the 80 series as well and starts to veer off in several directions.

I’ll see if I can find it in the googles.
On my phone in an Irish pub

 

[toy_tek]

First and foremost would be to confirm your timing and valves are adjusted correctly. You can run circles troubleshooting a lot of other items and never solve the issue if those are not correct.

 

[RevISK]

Google is my red Slingerland.
Post in thread 'TPS testing question...'
TPS testing question... - https://forum.ih8mud.com/threads/tps-testing-question.926081/post-10346064

 

[RevISK]

First and foremost would be to confirm your timing and valves are adjusted correctly. You can run circles troubleshooting a lot of other items and never solve the issue if those are not correct.

True.
That’s why I told him to read the codes.
However, I had this same problem and between vacuum leaks and out of adjustment TPS I was able to solve.

Guessing valves and timing may be another subject for another day.

Let’s get an FSM in play.

 

[mjulaw]

TPS test and adjustment is in the manual I linked.
3FE covers the 80 series as well and starts to veer off in several directions.

I’ll see if I can find it in the googles.
On my phone in an Irish pub

found it, never mind.

 

[Kleatus]

The Cruiser Cult website has a lot of Factory manuals. The "new model features" book for I think 1988 has a lot of good 3FE info. The intake boot is a good easy place to start, along with any other potential vacuum leaks. Your idle control solonoid should also be checked and cleaned out. You also need to make sure your EGR isn't sticking partially open, you can have a condition where it will idle OK but at no throttle with some load (stopped in gear) the mixture goes lean enough to cause stumbling, but when you open the throttle that small leak of intert gas into the engine is "buried" in the larger volume of air and fuel and it becomes a non-issue.

 

[mjulaw]

The Cruiser Cult website has a lot of Factory manuals. The "new model features" book for I think 1988 has a lot of good 3FE info. The intake boot is a good easy place to start, along with any other potential vacuum leaks. Your idle control solonoid should also be checked and cleaned out. You also need to make sure your EGR isn't sticking partially open, you can have a condition where it will idle OK but at no throttle with some load (stopped in gear) the mixture goes lean enough to cause stumbling, but when you open the throttle that small leak of intert gas into the engine is "buried" in the larger volume of air and fuel and it becomes a non-issue.

great info, much appreciated!

 

[cruisermatt]

sounds like air main intake hose. pretty typical.