Won't Idle (1 Viewer)

[msummer]

I've got a late '83 FJ60 that I desmogged around 6 months ago. JimC did the carb and dizzy work and I used the diagrams to hook everything up. I've since taken it on several road trips across a few states and the truck ran like new. I averaged 17.5 mpg on my last trip (hit 19 on the highway).

I just yanked out the tranny/t-case to rebuild them (they are leaking like crazy from everywhere) so the truck has been sitting in the garage for a month at least. I went out to crank it yesterday for the first time since I parked it and it won't idle.

Cranks perfect (couple gas pedal stomps and crank) and revs great. Seems to run perfect still, except it will not idle. I got it to run at 750 rpm by playing with the choke. The idle solenoid is working correctly. I need to check the vacuum numbers, but my thought is that gas has dried in the idle ciruit plugging the little hole around the throttle plate.

Give me some ideas before I take apart an apparently working carb. Is there a way to clean that circuit without taking it apart? I forgot to mention fuel is in the middle of the sight glass.

 

[freebornred]

my guess would of been the idle so lenoid on the carb, then mayby a vacume leak some where. how is your fuel filter ?

 

[FJ40Jim]

You can clean out the float bowl by removing the drain plugs and then hosing carb cleaner in through the vent tube (brass pipes at the top of the carb throat).

The idle circuit can be cleaned somewhat by removing the idle mixture needle and hosing carb cleaner and compressed air in the hole. More thorough idle circuit cleaning can be acheived by removing the idle solenoid and shooting carb cleaner and air in that hole.

HTH.

 

[msummer]

Thanks Jim, I'll give that a try tomorrow and see what happens.

The filter is fairly new as well and looking good.

 

[msummer]

Results

I took the solenoid out and blasted it with carb cleaner, followed by lots o compressed air. I had a cloud of vapors spewing out of the throttle body during the air cleaning. I assume that was carb cleaner coming out the little hole in question, or entrained fuel, not sure. No change in the idle condition.

I drained the carb bowl and cleaned as directed. Reassembled with no change in the idle condition.

I noticed the boot on the accelerator pump is blown. Any issues there?

Finally I did some vacuum tests. Looks like I'm getting 15-16 inches @ 900 rpm. That was the lowest rpm I could get the engine to run smoothly (done by messing with the choke). The engine died instantly when I unplugged the brake booster vac line to hook up my gauge (engine running @ 900 still). I assume that means I don't have a large vac leak, or unplugging something else shouldn't affect it much.

Anyway, I thought the vac numbers were low, so I started spritzing carb cleaner around and noticed the engine rev a little when I shot around the carb base and possibly the manifolds.

My next plan is to remove the carb and heat shield, check gaskets and retorque everything. Somebody stop me with an easier suggestion. Thanks guys.

 

[CruisinTiger]

Look at your fuel pump. Your truck will start but will die after if the pump is bad. You mentioned gas gad dried. I'm thinking that it dried and "dry rotted" the rubber seal in the pump. Easy to take off and seperate and check. Hope that's your problem, I had the same problem and I was glad to find that as an esay fix. Good luck

 

[msummer]

The fuel pump is pretty new, less than a year old. Besides, I've got gas in the carb bowl. It will crank and run all day, just as long as I keep it at 800 rpms or higher. It's wierd because I haven't touched the engine bay and it worked perfect when I parked it to drop the tranny (still waiting on parts for that job). Keep the ideas coming though.

 

[brett76]

does it sound like the idle is at nine hundred. maybe your tachs off. just a dumb suggestion

 

[msummer]

The tach may be off a little, but I don't think thats it. As I said, everything was perfect when parked and I didn't do anything under the hood. That's why I'm trying to find something that changed while it was sitting, like dried gas varnish.

 

[beaufort-fj60]

can gas turn to "varnish" in one month? how dirty is the air filter?

 

[FJ40Jim]

I noticed the boot on the accelerator pump is blown. Any issues there?

No issue w/ the idle problem. AP and idle are totally separate circuits.

Finally I did some vacuum tests. Looks like I'm getting 15-16 inches @ 900 rpm. That was the lowest rpm I could get the engine to run smoothly (done by messing with the choke). The engine died instantly when I unplugged the brake booster vac line to hook up my gauge (engine running @ 900 still). I assume that means I don't have a large vac leak, or unplugging something else shouldn't affect it much.

I think the vac reading is slightly low because the engine is running poorly. the engine is running poorly because there is a chunk of dirt in the idle circuit of the carb.

Anyway, I thought the vac numbers were low, so I started spritzing carb cleaner around and noticed the engine rev a little when I shot around the carb base and possibly the manifolds.

If the manifold/carb nuts are all tight, then that was the carb sucking in carb cleaner around the throttle shafts. Normal, especially for an engine that is starving for fuel.

My next plan is to remove the carb and heat shield, check gaskets and retorque everything. Somebody stop me with an easier suggestion.

When it is trying to idle, can the idle be smoothed out and maintained by spritzing carb cleaner right in the top of the carb? If yes, then the engine is definitely fuel starved. Then try spraying carb cleaner on the manifold gasket. If no change there, then the problem (F.O.D.) is likely inside the carb.

 

[msummer]

I'll play with the carb cleaner some more tonight and post the results. Thanks again for all the replies.

 

[msummer]

Issue Resolved

All is well with the cruiser again. I finished the tranny/transfer rebuild and found alot of PO problems. It looks like he reused all the old gaskets and just RTV'd the snot out of everything. I allso found a couple of spun bearing housings and a crack in the case on the transfer drain plug hole. Everything has been repaired/replaced/welded/etc and stuffed back in along with a new clutch and rear main seal.

Now, back to the issues I was having. I kinda forgot to support the engine when I removed the tranny. The engine sagged and the throttle linkage was stabbing the carb. The end result was a bent bracket and a need to adjust the idle speed screw. When I was playing with it before I was turning the fast idle speed screw (forgot there were two). Everything is retuned and running great.

Seems like it's always what you fix that leads to the next repair, hehe.

 

[2mbb]

I just finished putting my transmission and transfer in after a reseal, and accelerator linkage bracket was bent, too. I couldn't get the truck to start. I've had the transmission out a few times before, but never had this problem. The FSM doesn't say that the engine needs to be supported. Next time the transmission comes out, I'll either support the rear of the engine or disconnect the accelerator linkage.

 

[msummer]

So I 'm not the only one