TBI probems; clearing codes and stalling

[tcarlson78]

greetings,

After 5+ years of faithful service My FJ40 is running poorly, It will start fine but once warmed up it stumbles at idle and will die sitting at an intersection unless RPMs are added. However, when driving it does fine at speed 10-65mph. I get two hard codes 22 and 43. I tested the TPS and it gets 5v from the ECM but I could not get a good reading when trying to see volts from idle to WOT. I replaced the TPS which is not adjustable.

I replaced the knock sensor from a manual to automatic. I zeroed the codes (disconnected neg cable for a couple min) and then tested again. Same codes. I looked at other issues and replaced the PCV. Zeroed the codes and tested again. Same codes but idle went from 1200 to around 800. small victory

I want to get the engine running smooth but want to clear the codes first. So here are my ??s
1. what is the resistance for the knock sensor and how do I test that. THe wires are clear of the spark plug wires and exhaust.
2. The TPS is the 3 pin round type, Is there a trick to testing the resistance from idle to WOT. When installing is there a trick to ensure the TPS and throtle are both at "zero" as I just removed and replaced the TPS
3. I have ALDL setup to help me solve this and future problems, is there a more indepth reference to read to explain what all the numbers mean and how to use them to solve my problems. I am finding the ALDL web site not much help for me to understand all the numbers
4. Once I clear the codes how suspect is the idle air control sensor regarding the bad idle?

The engine is a 5.7 350 out of a 93 1500 truck with about 130K miles on it (WAG)

Thanks in advance.

 

[lone gunman]

i dont know much about the TBI set ups, i am a TPI guy but have a link that might help. New Page 3 they have a decent TBI section. the genaral TBI section has a wiring schematic and info on clearing codes etc. i hope it helps!

 

[cruiserbrett]

you have to set zero throttle TPS voltage to .54 volts or something like that. That is the adjustment.

There is also a procedure to reset the IAC, but it should do it automatically.

Also, there are lots of variables in the ECM tuning that differ from auto to manual programming regarding idle. Has the computer been reprogrammed?

 

[LandCruiserPhil]

Check and clean your IAC. The plunger in the IAC can come unscrewed.

 

[Elbert]

is 22 TPS and 43 the knock sensor

http://www.northidahooffroaders.com/fuel-injection/TBIcodes.pdf

I know these codes are for a 5.0, but in that year range 5.0 and 5.7 have same controls.

you need a GM shop manaual, check out the link...it has some troubleshooting diagrams.

What do you mean when you say you replaced the knock sensor from manual to automatic? Did you install the right knock sensor that applies to your engine?

TPS in my experince is just a bolt on for the most part....knock sensor is easy to replace...you just unscrew it and then screw the other one in, rather fast to avoid loss of coolant.

I had a knock sensor fail on my 92K1500 and the truck ran lick crap.... swapped out and good as new.

 

[tcarlson78]

Thank you all for the help I am studying the links you sent me. I am thinking there is a short in the TPS connector. Need to test it again.

Elbert: The old knock sensor had a black connector on it for a Manual trans. The new sensor has a white top for an Automatic. The only reason I know the difference is that when I bought it on-line I had to run out and check what I had and realized it was a manual rather than the auto. Perhaps that is why the code is set. I hope this is correct as I don't really want another coolant shower.