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Old 06-09-2011, 06:50 PM
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Rzeppa Rzeppa is offline
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Default FJ60 Intermittent Stall at Idle

I have an issue with my fully smogged 1987 FJ60 where it sometimes will idle just fine and other times will stall when pulling to a stop. We are only talking about full normal operating temperature. I have eliminated the EGR system as a potential cause by disconnecting the line between the vacuum modulator and the EGR valve and capping the line, so the EGR isn't coming on. I also verified that the idle cut solenoid is operating.

Backing up in the story a bit, she used to do fine until I had to do some work to get her through emissions testing. She failed the first try. So I changed out the air filter element, backed the static timing back to stock 7 from the 17 she was at, changed the main jet from 147 to 138, and dumped 4 bottles of Heet into the remaining 5 gallons of fuel, and then she passed with flying colors. She ran like crap though and stalled at idle a lot. After passing, I put the static timing back to the 17 that she was running good at and put the 147 jet back in, filled the tank back up to dilute the methanol. That made her run a lot better, but there is this intermittent stalling issue that is really making her a PITA for my wife to drive her.

It is almost as if the fuel (or timing?) is connected to a LSPV: when you come to an abrupt stop, as in traffic and press the clutch in, she will often stall. If you slow down really gently to your stop, no stall. The idle adjustment mixture screw is set at 3 turns. I tried other settings, both leaner and richer and neither seemed to make any difference. And besides - she used to work just fine before I messed with her to pass emissions. For now the brute force fix is setting the idle too high, around 1200-1400 RPM. Whenever she gets much below 1000 she wants to stall.

There are no obvious vacuum leaks, although I haven't done a thorough test for those. She runs great just driving around. If there is a vacuum leak, it would only be under the circumstance of coming to an abrupt stop and putting the clutch in. I figure there are about 3 or 4 other emissions subsystems which might cause this symptom other than EGR and idle fuel cut solenoid, so I am coming to the Rising Sun forum to see if anyone has any suggestions for where to look and what to test. I have good manuals but am kind of looking for a shortcut here.

Thanks and happy cruisin'!
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Old 06-09-2011, 06:59 PM
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subzali subzali is offline
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Brake booster leaking?

Junk in fuel bowl?

What's the fuel level in the float bowl when it stalls? I understand it's hard to see on an FJ60.
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Old 06-09-2011, 07:37 PM
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Is it possible that you ran such a rich mixture of methanol that it ate something up in the carb? I know thats why a lot of older rigs can't the stuff.
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Old 06-10-2011, 06:15 AM
SteveH SteveH is offline
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Can you temporarily (or permanently) mount a vacuum gauge in the truck so that you can watch the vacuum under the stalling condition? I wonder if something could be hanging up and causing low vacuum and a stall when you return to idle.
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Old 06-10-2011, 07:04 AM
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Bummer about the stalling issue. There are many potential causes, and it would be nice if fortune shines upon you and it is easily addressed. Along those lines, I would recommend you inspect the wiring that provides power to the Idle Cutoff Solenoid. TheBoomBoom had a bad splice in his Hilux which caused intermittent stalling behavior similar to what you have described. I would also recommend you conduct a thorough check for vacuum leaks. These two things may find an easy issue that once addressed fixes the problem.

If you don't find any of the above issues there, the next step would be to tuck into those manuals (and/or get side by side with "correct" 60) and make sure the components and connections for fuel and emissions is what it should be. Followed by conducting the FSM tests on the components. It is time consuming and laborious, but anything less and you could easily spend much more time as you work through issues and finally arrive at the same place. Compared to our early 40s the 60s have more things, but even on our 40s in these situations success is the result of checking each thing.

Presuming all that is done, next I would recommend getting into the carb. With the jet changes, it is possible that some debris (it doesn't take much) made its way into the fuel bowl and is floating around in there causing fuel delivery issues with the idle circuit.
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Old 06-10-2011, 10:25 AM
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Quote:
Originally Posted by subzali View Post
Brake booster leaking?
Good theory. Except she'll idle fine most of the time just sitting there with the brakes on. And, she can also stall when the brakes are not on, just the parking brake.

Quote:
Originally Posted by subzali View Post
Junk in fuel bowl?
I thought of that, especially since I had to access it (twice) to change out the jet. But, when you come to a stop, anything heavier than fuel in the fuel bowl would go forward, away from the jets.

Quote:
Originally Posted by subzali View Post
What's the fuel level in the float bowl when it stalls? I understand it's hard to see on an FJ60.
She starts right up instantly after stalling, so there is plenty in there.
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Old 06-10-2011, 10:29 AM
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Quote:
Originally Posted by Air Randy View Post
Is it possible that you ran such a rich mixture of methanol that it ate something up in the carb? I know thats why a lot of older rigs can't the stuff.
I was a little worried about that. Basically I went to the gas station across from the emission station, while the gauge was on "E", put in four 12 oz. bottles of Heet, went across the street, passed emissions, then immediately filled up with 15 gallons, so it means I had 8 gallons in there when I put the Heet in, and the full 23 gallons for most of that tank. I refilled again at about halfway down.

The stalling started as soon as I backed the timing to 7 and changed out the jet. It just didn't stop when I put the timing back and put the old jet back, however it did improve quite a bit.
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Old 06-10-2011, 10:31 AM
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Rzeppa Rzeppa is offline
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Quote:
Originally Posted by SteveH View Post
Can you temporarily (or permanently) mount a vacuum gauge in the truck so that you can watch the vacuum under the stalling condition? I wonder if something could be hanging up and causing low vacuum and a stall when you return to idle.
Yes, I can, and that is an outstanding idea. I have a portable gauge that when I use it in dynamic conditions driving around I just run the hose into the cab through the window.
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Old 06-10-2011, 12:14 PM
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Jeff, I had junk floating in my carb that would cause a stall when I was coming off the interstate or up to a stoplight and my rpm would drop to idle. Cleaned it out and it was good to go. It might still be worth a check.
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Old 06-10-2011, 12:51 PM
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BreckBJ44 BreckBJ44 is offline
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I vote junk in the carb... I had the same issue with an 81 40 and an 87 60.

I also second the fuel cut off solenoid. Both of the above rigs would have your exact issue when run on the highway and I would hit an exit ramp. I think it had something to do with heat and resistance in the weak wires to the shutoff. I rewired both and it went away.
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