unstable idle

Jan-78FJ40 · 07-08-09, 08:56 AM

81 SR5, 22r, California truck: The idle fluctuates anywhere between 1200 and 700 rpm. However, it does not go up and down, but returns to any of these rpms when going off the gas. when I stop at red lights, once it stops at 1200, then at 700, then at 1000....
any guess what this is?
The truck passed smog without any problem 2 months ago.

thanks,
Jan

WristPin · 07-08-09, 08:03 PM

sounds like somthin a 22RE does. you sure it hasnt been injected???

Family 40's · 07-08-09, 08:54 PM

I second that my truck does some weird things with idle too. Its not anything new it happened with my old 22re and now my newer 22re too. Just something I began to live with.

Mike C · 07-08-09, 10:32 PM

Sounds like a sticky throttle, and or weak return spring. When you stop to park, pop the hood and see if you can return the throttle to closed on the carb.

WristPin · 07-09-09, 02:45 AM

Quote:

Originally Posted by Mike C

Sounds like a sticky throttle, and or weak return spring. When you stop to park, pop the hood and see if you can return the throttle to closed on the carb.

very possible

WristPin · 07-09-09, 02:46 AM

Quote:

Originally Posted by Family 40's

I second that my truck does some weird things with idle too. Its not anything new it happened with my old 22re and now my newer 22re too. Just something I began to live with.

its a very simple fix.

set the idle lower by turning the big slotted screw on the throttle body

Mike C · 07-09-09, 06:51 AM

My 22re was missing the return spring between the dash pot and throttle body. That caused a similar problem in mine. After testing a few springs, and cutting them shorter I found one thats worked for a month now. I still have a strange low idle on warm start up issue which I need to look into, but I have been putting it off.

Side note with the 22re and a fluctuating idle. Turning down the idle speed screw will not fix a idle that fluctuates. The problem is else where, could be a number of things. I would start by checking for vacuum leaks, and adjust the TPS. It could be the throttle return spring as well like I mentioned, or the dash pot needs to be turned down a bit. I had to go through mine and make a lot of little adjustments before it ran right. Now once its warmed up, it idles great

Jan-78FJ40 · 07-09-09, 08:50 AM

Quote:

Originally Posted by WristPin

sounds like somthin a 22RE does. you sure it hasnt been injected???

Yes, clearly a carbed engine.

The fix was so simple it is embarrassing. The return springs were sticky, and cleaning and lubing them solved the problem.

Thanks,
cheers,
Jan

WristPin · 07-09-09, 09:32 AM

Quote:

Originally Posted by Mike C

My 22re was missing the return spring between the dash pot and throttle body. That caused a similar problem in mine. After testing a few springs, and cutting them shorter I found one thats worked for a month now. I still have a strange low idle on warm start up issue which I need to look into, but I have been putting it off.

Side note with the 22re and a fluctuating idle. Turning down the idle speed screw will not fix a idle that fluctuates. The problem is else where, could be a number of things. I would start by checking for vacuum leaks, and adjust the TPS. It could be the throttle return spring as well like I mentioned, or the dash pot needs to be turned down a bit. I had to go through mine and make a lot of little adjustments before it ran right. Now once its warmed up, it idles great

no, very common adjusting idle speed fixes this.
more problems on top of your statment may be true.

no rookie needs to be messin with the tps. setting the speed first is best

Mike C · 07-09-09, 10:01 AM

Quote:

Originally Posted by Jan-78FJ40

Yes, clearly a carbed engine.

The fix was so simple it is embarrassing. The return springs were sticky, and cleaning and lubing them solved the problem.

Thanks,
cheers,
Jan

Good to hear it was something simple and its fixed now

Quote:

Originally Posted by WristPin

no, very common adjusting idle speed fixes this.
more problems on top of your statment may be true.

no rookie needs to be messin with the tps. setting the speed first is best

Just posted what worked for me, I am still fairly new to the 22re

I agree though, best to start with the simple adjustments first and go from there. My poor engine was neglected by the PO, and it took a few weeks of trouble shooting to get it running how I wanted it.

Family 40's · 07-09-09, 02:44 PM

Wow, I have never thought of that I am going to clean and lube them today!

alteredraptor · 07-24-09, 03:58 PM

similar problem on my 87 22re... timing and idle speed adjustments fixed my problem