Robrt32

even though i do not have a CEL on... I'm still working on the hesitation problem.. I have it 80% fixed but still have some hesitation.. seems the longer the truck runs the better it does .Like 10 miles or so down the road AFTER a 5 minute warm up before leaving the yard.. The list of things i have done.. New plugs, wires, distributor cap, rotary button, fuel filter, coil.. Throttle body took off and cleaned..I pulled the codes and have, 24,31,41 and 42..... Is there any one thing that could tie all these together? where and how do i trace this down.. I'm not the sharpest knife when comes to tracing stuff like this , so dumb it down for me, best ya can....

Team420

did u check the wires goin to ur o2 sensor? They sometimes "rub" the exhaust and melt the insulation grounding them or breaking entirely. would be the 1st place I would start.
Then if that does not help go to
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

and start running some tests.

abecedarian

if you're not getting the CEL light, those codes are not current.
the 24 and 31 could occur if you had the AFM unplugged with the engine running
the 41 and 42 could occur if you had the TPS unplugged with the engine running (42 is tied to 41 for some reason, along with the A/C switch)
clear your codes- pull the EFI fuse in the fuse block above the drivers side kick panel or disconnect the battery (either one) for a few minutes. then drive it a while and see how it goes.
if it's running better after warming up, it could be a failing coolant temperature sensor or possibly a plugged idle-air valve. also, the cold start switch or injector may not be triggering causing you to be a bit lean when cold.

js9924

x2 on clearing the stored codes and the rest abe said

Also I would check the wires they can get hot and become brittle or break completely like team420 said

Get a meter and test for continuity to ground. Best $20 I ever spent

Robrt32

I will clear the codes tomorrow.. I certainly haven't and i have had all the stuff mentioned pulled at 1 time or another in the last week.....

Robrt32

Ok, I pulled the fuse and the neg. battery cable.. I'm gonna leave it unhooked 30 - 40 minutes to be sure.. Should i put the paper clip back in after i hook every thing back up, to be sure the codes cleared?

Robrt32

Ok, I got no answer to that one , tell me this... after being unhooked, I put the clip back in.. now when i turn the key on to check for codes, It blinks continuously , no pauses.. Does that mean there cleared?

Workhorse

yup continuous blink means no codes (FSM)

Robrt32

Ok , Here is where I'm at now.. All codes are gone after running it except for the code 42.. If i understand correctly code 42 says,

VEHICLE SPEED SENCOR SIGNAL CIRCUIT--NO SPD.SIGNAL FOR SEVERAL LOCATIONS

WHILE VEHICLE IS OPERATED UNDER HEAVY LOAD{TPS/MAP/AIR FLOW INPUTS}

SPEED CENCOR/CIRCUIT

ECU

my Speedo does not work, so would that cause that code?? I'm lost.. between trying to work on the farm and trying to figure this out, I think I'm going crazy.. The hesitation or stuttering doesn't stay the same either.. at times i can get almost half throttle before it does it, other times i can barely get up enough speed to shift to 2nd gear....

4Crawler

iTrader: (3)

Depending on the speedo you have, the VSS is either on the back of the speedometer or if you have an electronic speedo, it is screwed into the transmission. Probably be a good idea to find out why the speedo doesn't work and try fixing that first, may solve the code 42.

js9924

i had that come up after rebuilding my motor it turned out the clip to the speedo sensor on the back of the tranny was loose and dirty I blasted it with some quick dry contact cleaner and re seated it and it went away.

Otherwise you need to replace the speedo sensor im not sure about your vehicle, or mine because I havent been in the tranny, but alot of times they are plastic and can break easily after a while. They are fairly cheap and install pretty easily.

Make sure it isnt the wiring before you go buying unnecessary parts. Keep us posted.

Robrt32

So will the speedo sencor cause the hesitation i have? I don't know a whole lot about this electrical stuff but that seems like it would have no affect on my problems.. I don't need the speedo .. I just need the motor to run right.. Its hard for me to go spend a 100 dollars on something if its not gonna make the motor run right.. I'm guessing its a 100 may be more

edit... I cleaned all the connections on the speedo last year when it quit working.. had no effect..

4Crawler

iTrader: (3)

No idea, but there is a code that references that part and it does not work. Maybe grab a VSS at a junk yard. A Factory Service Manual would likely have testing procedures to help isolate the problem as well.

thook

On automatic transmissions, the speed sensor input is on the same circuit as TPS and AFM circuit. Electronically controlled transmissions are operated partly by the ECU which relies on input from all three sensors to control proper shifting. This may account for what you see in the code description. They don't always distinguish between manual and automatic vehicles.

The VSS had gone out on my wife's '92 4rnr and caused the vehicle to drop out of high gears under load intermittently....plus, the speedo, odo, and trip meters wouldn't always work. I don't know exactly how VSS function in manual trans. equipped vehicles.....other than speedo operation.....but, even on the 4rnr it didn't cause hesitation.

So, I'd check the TPS and AFM. 4crawler's page covers the TPS testing and AFM. If the TPS passes the intial static positions, make sure to also run a throttle angle movement test on the TPS....specifically on the VTA and E2 terminals. Again, covered on 4crawler's page:

"One final test, not listed in the FSM, would be to run the TPS shaft from idle to WOT and watch the VTA-E2 resistance and make sure it increases monotonically, no drop outs or dead spots. If you observe abrupt resistance changes, the TPS could have a burned area on one of the current tracks."

Also, if the AFM passes intial static tests, run the same type of "sweep" test on the AFM:
https://www.yotatech.com/forums/f116...esting-146662/

If these two components pass on all accounts, you can test at the ECU to see if signals are getting through the wiring properly.

If that all passes, I'd look more deeply into how the VSS functions on your vehicle. I can do some research myself since I've been curious about it for a while now, but see what you turn up first with the other tests.

Then, there's the ECU.... (j/k.....though, it's always a possibility)

Robrt32

I have a update.... I messed with it this morning in between working on the combine.. I read a long thread on here this morning about how people had advanced the timing and it helped hesitation.. I decided to give it a try.. I marked it good so i could always go back to where i started.. I went the wrong way the first time and made the problem worse.. I went the other way and i would say my hesitation is 95% gone.. I can still feel just a little bit.. I can live with that if need be.. I'm standing in front of the truck by the air filter box and I'm turning it towards me.. Am i advancing or retarding the timing?I will buy a timing light this weekend when i get to town.. I'm not gonna fool with it anymore until i get a light on it..It feels like it has more power than it ever has.. I should have bought a timing light a long time ago , I WILL now

just a 22re

with the engine running and you paper clip her for the timing does the motor drop a few r's??? and does the cel blink?

Robrt32

I have been working all weekend and still haven't had time to buy a timing light.. She still runs good.. Still a slight hesitation but WAY better than it was.. I think i will be off next weekend and can fine tune it