22re stumble on accelerating

skyhighZJ

skyhighZJ

Gov retirement < needs to live
Joined
May 31, 2012
Location
Aberdeen, NC.
1989 Toyota pickup
22RE 5 spd 4wd
Issue: when accelerating the truck is stumbling like a lack of power unless you put the pedal in the floorboard then it accelerated just fine with all the 87.9 horse-pressures it can muster. Idle is smooth and flawless. Maintains speed on flat road. As soon as you give it pedal it will start to hiccup and buck like it’s starving for fuel but max throttle and it smooths right our so I don’t think fuel is an issue.
Has new plugs, wires, cap, rotor.
New timing set, water pump, oil pump.
Replaced the manifold and exhaust cause it had a cracked manifold and the O2 sensor was froze into the mid pipe.
Startup and idle are perfect and smooth.
Revs up without load perfectly.
It’s an ‘89 so not like I can just plug it in. No CEL either.
Pretty lost cause it was running fine.
I did fill up with a bottle of Heet and premium today. No change after about 60 miles. Thinking TPS ???
 
Ever get a check engine light? I'd lean towards TPS, mine did the same thing years ago and was a headache to track down.
 
grapehead said:
Ever get a check engine light? I'd lean towards TPS, mine did the same thing years ago and was a headache to track down.
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I got a check engine light on the way home last night. The connector for the new O2 sensor had not clicked all the way. Plugged it in left the battery disconnected then reconnected everything and light went out this morning on my way to work. Did not fix the stumble problem. I did find that if I’m only using a slight amount of pedal it doesn’t act up but it just doesn’t accelerate fast with such a light pedal input. In other words, pulling out into traffic is MAX pedal or it stumbles. (I hope that made sense).
 
I'm with the others on the vacuum lines. I'd get a vacuum gauge and read it while you rev up and down.
A related possibility is a small crack in the intake hose after the AFM.

Basically it sounds like you are not able to maintain constant pressure during quick swings in the volume of air flow.
 
So. New TPS. No change.
I have checked/replaced every damn vacuum line under the hood (1 by 1 so I didn’t mix up the spaghetti)
CEL is on full time now.
Crossed the connectors in the diag port and it’s reading for O2 sensor (which is brand new) guess I’m buying another one??
 
Sounds like a “lean miss” where it leans out on acceleration tip in until the AFM can catch up.

Tips and Tricks (yeah, celiacs had this too)

Adjusting the AFM - YotaTech Forums

86-95 Trucks & 4Runners - Adjusting the AFM - I've read posts of members doing this and wanted to share this info from DowneyOffroad and ask how those of you have done this handle Warning #4 on this adjustment procedure. MASS AIR SENSOR MODIFICATION* * Tampering not legal, should only be...
www.yotatech.com

some videos on YT that show how to do it as well. Not hard, use sensor safe sealer to seal things back up.

mark the wheel before you move anything so you can go back to stock if needed.

I did this in my ‘85 when I had it. Helped a lot, also had issues with stock coil breaking up so ended up using and ACCEL Super Stock coil, never had another issue. Miss the truck, it’s been gone 15years now.
 
Question. Can the wrong O2 sensor band cause the stumbling issue? I think after looking at the sensor I bought it is for a different Toyota application and it won’t say if it’s narrow or wide band. After further review I’m learning that the ‘89 is supposed to be narrow band only.
 
So this is exactly why I converted my junk to propane. Yeah it sucks because it’s $800 but my shiz runs aweeesome now. It’s impossible to get all those sensors working in conjunction like they did 30+ yrs ago.
 
DannyH said:
So this is exactly why I converted my junk to propane. Yeah it sucks because it’s $800 but my shiz runs aweeesome now. It’s impossible to get all those sensors working in conjunction like they did 30+ yrs ago.
Click to expand...
Just makes me frustrated cause it was a sewing machine and then it wasn’t.
 
I would assume that it's a narrow band sensor.

Also, I've been wanting to say this the entire time I've seen this thread open....

I guess the old 'Yota needs some more squirrel powers :D The one that's in there might be getting tired!
 
Croatan_Kid said:
I would assume that it's a narrow band sensor.

Also, I've been wanting to say this the entire time I've seen this thread open....

I guess the old 'Yota needs some more squirrel powers :D The one that's in there might be getting tired!
Click to expand...
Oh I know the squirrels are tired but I’ll just keeping tossing the acorns till they die.
Question if you might know. For OBD1 it uses narrow band (this application) if the O2 sensor is the wrong one ( either wide band or wrong element or XYZ…) it would cause fueling issues correct? Basically the O2 sensor is sending the wrong signal, the ECU can’t compute and therefore doesn’t communicate with MAF/TPS and messes with the fuel?
 
Sounds right to me.
 
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