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theboomboom
01-10-2010, 03:21 PM
Yesterday I was doing some work on the truck, and have had an issue with the truck idling since then.

The previous owner had a bicycle gear shift installed as a hand throttle. The cable itself ran from the shifter to the original throttle cable where it was clamped on. The shifter had broken somewhere along the line, and it was never removed until yesterday. The truck ran fine with this setup.

After removing it, then driving all day, I believe that it was also acting as tension on the throttle cable itself. Now the truck will not idle when warm. Once the choke opens fully, it seems like the engine just isn't getting enough fuel and it dies. There is a lot of slop in the cable especially where it attaches to the carb, does anybody know of an adjustment to tighten the cable?

I checked the choke, played with the idle screw, but based on the symptoms I'm almost certain this is what my problem is.

RicardoJM
01-10-2010, 06:21 PM
I looked at this a bit this afternoon and am not clear on how to adjust the slack out of the accelerator cable, or if there is more room for adjustment. It's been a couple of hours, so I may get the description a bit off, the accelerator cable housing comes out of the fire wall.

Following the cable housing it there is a threaded section with two 12mm nuts that appear to be what is used to adjust the tension by locking the threaded section in the appropriate position of the bracket on the manifold cover. In this case, the nuts are adjusted all the way to the end, but there is still considerable slack in the throttle cable.

If anyone with a 22R could post of some photos of their accelerator cables with the air cleaner removed, it might help us see what we are missing/overlooking.

After cutting off the hand throttle cable it seems clear that it (hand throttle cable) was not allowing the throttle to fully close - so I expect we will may need to revisit the idle settings on the carb. But first, we need to get the cable tightened.

jacdaw
01-10-2010, 07:15 PM
sorry I didn't see this thread right away. I'm available tomorrow for comparison in person.

theboomboom
01-10-2010, 09:02 PM
Thanks for the offer John, but unfortunately I have to work tomorrow. What's the furthest south you make it on a regular basis? Lafayette is a pretty far drive for me, but if you'll be closer to denver that would work better for me.

jacdaw
01-10-2010, 09:23 PM
Silly boy, I'm a diehard non-recovered Bay Area commuter. Right before I moved here, my commute was 75 miles one way. Driving to The Springs is not too far. And now I'm a pensioner with cabin fever most days. PLEASE, give me a reason to get out of the house that is more fun than medical appointments!:cheers:
I regularly drive to Golden, Lakewood, Thornton, Commerce City and Broomfield for deep fried tacos. I hate being recognized as a regular at a fast food joint, so I gots to mix it up. When Jack in the Box opens a store in Boulder County, it'll be the death of me...:blah::blah::blah::blah::blah::blah:

MDH33
01-10-2010, 10:36 PM
Please don't smear me as the previous owner of this rig. It was actually the the previous previous owner who connected the bicycle cable hand throttle (which worked awesome!) ;)

leiniesred
01-11-2010, 08:25 AM
It should idle without the throttle cable connected at all.

Next up, the adjustment is probably a barrel adjuster right before the carb. 2 10mm nuts on either side of the throttle cable bracket which is bolted to the valve cover.

theboomboom
01-12-2010, 12:40 PM
12mm to be exact Rudy ;)

I've adjusted it all the way and there is still considerable slack in the cable. I called groove and found out the date range for this specific cable is Aug 1981-Jul 1983. They could have ordered one and it would have taken a couple days. I elected to see what napa had and when I gave them my year it sounded like their computers were telling them it would either be 26 or 28 inches long. My suspicion is that someone installed the longer one when they should have used the shorter one. The part is on order an should be here this afternoon.

jacdaw
01-12-2010, 01:38 PM
Got your PM, sure I'll come down this afternoon...:thumb:

leiniesred
01-13-2010, 08:39 AM
Yeah, I saw that, Boom boom. Memory failure.

More from memory, we found that the throttle brackets on JKimmel's various engines were a little different. Sometimes, only 1 bolt would line up. This could put the exposed part of the cable at different lengths, eh? I have no idea what is "right" or "wrong," I only know there are differences in the bracketry too.

jacdaw
01-13-2010, 10:22 PM
The way Rick installed his new cable, he has full WOT and complete release with his pedal. Perfect fit and installation! We played with it for hours and it seems to me that it is a float/needle valve issue. It will idle no lower than 1,500 rpm. And it surges pretty bad. Ricardo agreed, and I see a rebuild in the near future. More fun educational projects...

RicardoJM
01-14-2010, 09:11 AM
For those of following along and update. The throtle cable was too loose and the new one is in. Rick and John confirmed the travel of the new cable goes full cycle with the pedal and is responsive. Also on Tuesday, we were were thinking it was a simple matter of adjusting the carb; the following was done and learned:


The slow idle screw is set so that the engine will run (@2000 rpm) when the gas pedal is released. When we adjusted this screw to lower the rpm - we found that at 1700 the engine starts to putter and will die when the gas pedal is released. When we adjusted this screw lower still, the engine dies.

The fast idle screw was backed off so that it does not affect anything right now. We did this so be sure that it was not affecting our slow idle screw adjustment. We'll revisit this screw setting after we figure out the slow idle screw.

The idle mixture screw was removed from the carb base so that we could do two things; inspect it for any damage and blow air through the passage. We then gently put the idle mixture screw back in. Once fully seated we backed it out 2.5 turns. We did these things to eliminate variables, upon completing these things we know; idle mixture screw is good, passage is clean and idle mixture screw position is at starting point specification. Next we adjusted the idle mixture screw - when everything is working adjusting the idle mixture screw will affect the RPM. In our adjustments, out and in there was no effect on idle rpm. When everything is working as it should, with the engine warm and running on the slow idle circuit; if you adjust this screw all the way in, it should kill the engine. We gently closed the idle mixture screw all the way in and it had no effect on the engine.


All indications are that our problem is with the choke portion of the carb not making the transition from fast idle to slow idle. At the end of Tuesday, we were leaning toward rebuilding the carb. Later that night, we decided to do some diagnostic checks that we did not do on Tuesday. On Wednesday afternoon, I did some diagnostic checks with the truck cold, TheBoomBoom had to work.


I checked to see the choke plate is fully closed when the engine is cold. It is:thumb:.

I checked to choke mechanism to see if it engages as it should. When the gas pedal is given a full pump (holding it to the floorboard for a full second) the fast idle/cam choke should be engaged and the choke plate will open to about 1/8". This is not working as it should. I did find that if I move the throttle manually in the engine bay, open the choke plate, release the throttle, then release the plate - it appears to engate the fast idle/camp and the plate stays open about 1/8". :(

I checked to see if the dis-engagment of the fast idle/cam choke works as it should. If you blip the gas pedal, it should close the choke plate fully. This works as it should. :thumb:

I checked to see if the choke adjustment works as it should. When rotated it should move the choke plate. Rotating the choke adjustment does not affect the position of the choke plate at all.

I checked the OHM reading of the red wire going to the choke. The specification is for a reading between 19-23 OHM at a temperature of 68 degrees. The temperature was in 50s and I forgot the OHM reading value and did not write it down. :o

I checked the idle solenoid; no click with the power on. Power and ground to the idle solenoid, power to the choke and power to a outer vent control valve all come out of the same green plug. This wiring has splices in it and black tape at the base, upon removing the tape, I found the one of the wires (for the idle solenoid) is not connected to the plug base:eek:. There was just a nub of wire on the connector base. This connector base plug will need to be replaced. I brought some nips and will stop by the junkyard on the way home to see if I can find a suitable replacement plug. I should have (but did not) check the idle solenoid for a click. :(

I checked to see if the choke plate opens fully when the truck is warmed up. The truck starts up and really takes some nursing for a few minutes
for it to get to where it will idle on its own. Once fully warmed up,the choke plate remains closed and is not getting to vertical. It is kind of cool to see what a difference in RPM it makes just to have more air being drawn in when I manually move the choke plate vertical. :(

So, as you read all of this - we have two known issues; air gap in an electrical circuit and choke plate will not open to vertical. We also still need to test the idle solenoid.

MDH33
01-14-2010, 09:22 AM
Aha! So, it sounds like the idle solenoid getting no power was the problem. I remember that plug being all taped up. The previous owner seems to have had a weber in it at some point and probably cut the harness. Is the bad wire on the carb side of the plug, or on the harness side? If it's on the carb side, I think I have another plug you'll be able to use from another carb. I did test the idle solenoid when I was working on that carb and it did work. Just needs power. ;)

My guess with the choke is that all of the fiddling you did trying to make it run with the solenoid blocking fuel to the idle circuit just has everything out of adjustment. You mentioned that the choke plate didn't "move" when you turned the choke adjustment. It shouldn't, The choke adjust only changes the tension on the bimetal spring which is probably why it's no longer opening all the way when warm. It's likely too tight now.

If you guys want to wait until Saturday, I can stop by after my class and help you get it re set.

:thumb:

RicardoJM
01-14-2010, 10:05 AM
Is the bad wire on the carb side of the plug, or on the harness side?

It is on the carb side. I'm going to look in the yard on my way home today to see if I can find a plug. If I strike out, we will take you up on your offer of another plug.

That is good to know about the plate not moving as the choke is adjusted. As I read through the information on the site, I had it in my mind that the plate should move. :o

jacdaw
01-14-2010, 01:42 PM
Good to hear about the broken wire. Would be great if that fixes the idle circuit!

MDH33
01-15-2010, 10:42 AM
Any luck with the plug, Ricardo? I'll be down in Denver tomorrow, so if you would like me stop by with that other carb and plug, let me know. :thumb:

leiniesred
01-15-2010, 10:51 AM
When Jkimmel and I were messing with his carb, we found a ball of goo (varish) up in a top area of the carb (carb top removed). This goo-ball would shut off a port to somewhere. I don't know if it was the idle fuel ckt or if it was the accelerator pump fuel ckt. but, it ran a lot better without the gooball. maybe a quick once-over with the can of carb cleaner and a piece of welding wire down some of the ports...

RicardoJM
01-15-2010, 12:58 PM
Any luck with the plug, Ricardo? I'll be down in Denver tomorrow, so if you would like me stop by with that other carb and plug, let me know. :thumb:

Yes - I found a suitable plug on a Tercel:thumb:. The position of the wires for the choke and air valve were reversed from what is spec, but I was able to get them swapped so the plug is the correct color wires in the correct slots.

We didn't splice it in last night, but will do so this afternoon and see where we are at.

When Jkimmel and I were messing with his carb, we found a ball of goo (varish) up in a top area of the carb (carb top removed). This goo-ball would shut off a port to somewhere. I don't know if it was the idle fuel ckt or if it was the accelerator pump fuel ckt. but, it ran a lot better without the gooball. maybe a quick once-over with the can of carb cleaner and a piece of welding wire down some of the ports...

We may look into that if we are still having problems after we get power to the fuel cut off solenoid.

RicardoJM
01-15-2010, 05:37 PM
Ok - picking up this thread with the sad faces from the post above...


I checked the OHM reading of the red wire going to the choke. It was 14, temp was in the mid 40s:thumb:
I checked the idle solenoid. When power is applied it clicks.:thumb:
I checked to see if the choke plate opens fully when the truck is warmed up. It does open fully.:thumb:
We spliced in the new connector. :thumb:

The truck is better:D. There is some carb tuning and engine timing that needs to be done. We are going to be reading up on that tonight.

RicardoJM
01-16-2010, 04:49 PM
Ahhhhh.:D

Got out there today and got everything tuned up and running smooth. Went through a couple of rounds of adjusting the slow speed idle and was not able to get it below 1400 - it was just like the idle cut off solenoid was not working. Of course we tested the solenoid a few times by connecting it to the battery and hearing the click and were stumped. After going through everything for about the 4th time, it occurred to us to check if there was power coming through the harness to the plug. Sure enough, now power, a quick check of the engine fuse found it be bad. Replaced the fuse and we were on our way.:doh:

High idle is set at 2600 rpm. Slow speed idle is set at 700 rpm. Timing is set at 8 BDTC. Rick took me on a run out to HRO and back and th mini-truck it is running great.:cheers:

jacdaw
01-16-2010, 04:51 PM
Very nice, guys. Wanna let some of your juju rub off on my truck?

corsair23
01-16-2010, 05:41 PM
:thumb:

Great work guys

leiniesred
01-17-2010, 09:17 AM
Nice job, guys! feels good, eh?

MDH33
01-17-2010, 10:17 AM
Glad you guys got it figured out. Now you'll know exactly what to do the next time. :thumb: