89 2.3 low idle

[bryanb]

have an '89 Ranger with 223K on it, and maybe 100K less on the motor. Its new to me, and I've posted before on this topic, and some suggested that the Idle Air Bypass is involved. I haven't had time to take it off and check it out yet, but certainly will.

I went to pick it up after inheriting it, and drove it back home, over 1000 miles. It seemed to run fine the night before leaving, but on the way back I noticed that it started idling funny. Down to 500, on the tachometer, and a real bad chug-chug-chug-chug feeling, like its about to die. my old 2.3 Turbo Thunderbird seemed to idle around 900, if I remember right.

I did get some computer codes. 13, 52, and 74. I did the codes procedure from memory, from when i used to do it on my old Turbo Coupe, so I might have missed a couple steps, and that would explain the 52, and 74?

The 13 makes some sense though, if we implicate that sensor/ switch. Especially with the below link.
http://www.thorssell.net/hbook/2digit.html

If did run though this procedure last night:
http://www.cadvision.com/blanchas/Ranger/idelspeed.html

It ended up idling pretty much the same, at around 500-550 rpm, and that real bad chug-chug-chug-chug feeling, almost like its missing on one cylinder. I ended up just moving the idle set screw to around 950-1000 to keep it smooth. After the drive to work this morning, the computer 'learned' again, and its idling at the same old 500-550 again.


It does have brand new spark plugs, and wires on it.
I check the vacuum and it seems fine, at around 18" mercury. if I pull on of the lines on the vacuum tree, it immediately speeds up the idle.

 

[skyy_4life]

My 1994 2.3t Is Also Doing This Atm.
Idles Around 500-600 But Now When Mines Cold
It Just Dies While Idling. Please Let Me Know If
You Find Out Your Problem.

 

[bryanb]

i've definitely decided to pull off, and check out the Idle Air Bypass, on the rear of the intake. If you have some miles on your engine, I'd do the same. I've read that it gets gummed up with dirt/ oil etc, and doesn't actuate correctly.

 

[bryanb]

Well, I pulled off my throttle body, and then pulled the Idle air bypass valve off of that. I removed all the sensors, and what ever plastic I could.

It was a little coated with that black carbon film, but I didn't think it was extra ordinary for a 20 year old truck.

Then sprayed it out with Brake cleaner. It seemed to clean out the gunk, and it'll evaporate clean, and quickly. I was careful to not harm the paper gaskets when I pulled them off with a nice sharp putty knife.

I noticed that when I did that rain dance to make the computer re-learn the idle speed, that the idle screw was almost turned all the way out. And the butterfly inside looked like it was closing ALL the way, so I turned it back in a turn and a half or so. I unplugged the battery, to reset it as well, while I tightened all the bolts up, and plugged back in the IAB, and the TPS.

I started it, and then ran it at 2500 rpm for a few seconds, maybe 20-30. Then let it idle by itself.

Seems to idle at around 950 now, in park, about 750 in D. So its better. But still has a more of a shake than I think it needs, but its no where like it was before; like a one cylinder diesel.