2H - strange buzzing then difficult fuel shut off

[daem0n]

So it was extra cold here this morning and I ran into a strange issue with my truck that hopefully someone can help me figure out. It was hard to start the truck so I needed to give it extra throttle and it finally started.

It made a strange buzzing sound and rattled the hood a bit (I could only tell from the ice that was bouncing around near the windshield). It subsided after a minute or two. After the truck warmed up I was driving it and every so often the buzzing would happen (only about 3-4 times during 20 mins). During the buzzing, the spedometer would jump around a bit and go maybe 20 km/h faster, then back down to normal (even though the truck didn't surge and the rpms stayed the same).

Now when I went to shut the vehicle off it kept spinning the engine (barely - maybe like 100rpm stutering or something) for about a minute (with the key out of the ignition).

It's never done either of these things before so I'm thinking it's all related. Does anyone have any ideas of what to check or what the issue might be?

Thanks for any help!
-Joe

 

[Jan-78FJ40]

So it was extra cold here this morning and I ran into a strange issue with my truck that hopefully someone can help me figure out. It was hard to start the truck so I needed to give it extra throttle and it finally started.

It made a strange buzzing sound and rattled the hood a bit (I could only tell from the ice that was bouncing around near the windshield). It subsided after a minute or two. After the truck warmed up I was driving it and every so often the buzzing would happen (only about 3-4 times during 20 mins). During the buzzing, the spedometer would jump around a bit and go maybe 20 km/h faster, then back down to normal (even though the truck didn't surge and the rpms stayed the same).

Now when I went to shut the vehicle off it kept spinning the engine (barely - maybe like 100rpm stutering or something) for about a minute (with the key out of the ignition).

It's never done either of these things before so I'm thinking it's all related. Does anyone have any ideas of what to check or what the issue might be?

Thanks for any help!
-Joe

My understanding of the 2H would suggest that there are 2 things going on. They are independent on one level, but connected on another.
The truck not shutting off is a problem with the edic, where you don't get complete fuel shut off.
The speedo jumping is a problem with the electrics, as there is no mechanical connection between drive train and the speedo (unless you mean the tach).

I think the connection is an electrical problem. You likely do not get enough juice at the cold weather to operate everything correctly. Check the batteries for good charge, the alternator for function and all the grounds.

cheers,
Jan

 

[Tapage]

NO electronic speedo in HJ60 ( at least not down here ... )

 

[Jan-78FJ40]

NO electronic speedo in HJ60 ( at least not down here ... )

And Tapage is of course right, sorry!
Speedo is mechanical from the transfer case, tach has an electronic pickup at the flywheel.
cheers,
J

 

[Chang-kuao-lo]

i have a '89 taco 1 ton that would do tha same thing with the speedo. the drive cable was on its' way out.

 

[daem0n]

Thanks a lot for the replies - some good places to start. The alternator was just rebuilt but one battery is on its way out...and the ground cables could definitely use some work - those will be my next major steps. I'll check out the drive cable also since I suspect that sounds like an issue. What is the drive cable connected to?...I'll look for it in the FSM

 

[87 HJ60]

Your spedometer cable may not be seated to the spedometer. They sometimes work loose over time. You can tell when the connection is good as the cable doesn't seat into the spedometer and you hear a funny noise coming from behind the gauge cluster.
If this is the case with your Land Cruiser you can re-connect the spedo cable pretty easy. Undo the six phillips head screws holding the gauge cluster, tilt the steering wheel all the way down and remove the gauge cluster out slightly. With your left hand you should be able to reach the end of the cable and pop it back onto the rear of the spedometer. There is a little fitting that clicks once everything is in place but it usually doesn't hold too well. You just have to make sure the cable is pushed good onto the spedo. Reinstall the six screws and put the steering wheel back into position and you're good to go.
As for the engine running after you turn off the key you can check your EDIC. There's a procedure for checking it in the 2H Repair Manual on page ST-21&22.

 

[Ben-jammin]

Joe,

wouldn't worry about the speedo jumping - they tend to bounce a bit with the mechanical type, especially in the cold. I think the bounce is probably caused by torsional vibration in the cable. I would be suprised if related to the buzzing.

Either your EDIC motor or relay is giving you some grief. Pages ST-21 & ST-22 of the 2H, 12H-T FSM give you diagnostic for checking EDIC system. Most likely the cold is stiffening up the linkage from EDIC motor to fuel pump and the fuel pump is not fully turning off. If you don't have 2H FSM I can pdf the pages to you.

Cheers

 

[BJSnooper]

Joe,

wouldn't worry about the speedo jumping - they tend to bounce a bit with the mechanical type, especially in the cold. I think the bounce is probably caused by torsional vibration in the cable. I would be suprised if related to the buzzing.
Cheers

I had an old VW Rabbit, which when cold, the speedo would bounce around and "squeal" a little. Not sure if its the same thing, but it did make a little noise and only when it was sub -20C.

 

[BJSnooper]

woops, double post

 

[RisingSunLCS]

My truck has had the exact same sound you describe - the speedo cable problem and the delayed shut off. Only, when the weather is really cold that happens. If you encountered this during the cold snap we had over the weekend (JAN 21-23) as I did. I attribute it just to the cold with cold/stiff linkage for the delayed shut off.

I had an older 95 Tacoma that made a crazy buzzing and erratic speedometer thing a couple times. I was told I just needed a new speedo cable. Purchased one from toyota, installed it......problem solved.