ok so as I have said it's not running right
I just did head gasket and all seemed good
then thismorn it's all messed up
will there be codes even if cel is not on

it seems that it is running way rich at idle pipe is black smoke
if you slowly advance throttle it seems to clear up and rev not bad but this is in driveway so no load

could this be

TPS
MAF

I'm trying to figure out so I can get to work
any help is good

 

Ok got codes
24
25
31
Just trying for info on them

 

http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf

here is the info on the codes. it is on page 7 of this link.

24 intake air temp sensor
25 air fuel ratio lean malfunction
31 volume air flow meter signal

 

oops... here is the full link.. it will be your new best friend

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

 

ok so I did bench test of afm it apears to ohm ok but truck runs like crap

it runs very very rich black out the pipe

if you guys think its afm I think there is a scrap yard with a runner about 1/2 hr from here
but any thing else i should pick up
the truck has a new tps
new flamethower injectors

what makes them run rich

 

code 25 would suggest the o2 sensor. if the afm tested ok than I wouldn't replace it. . if the o2 is sending the wrong signal the ecu will send more fuel at the truck than it needs. is the tps adjusted correctly??

clear the codes and run the truck again to see if any codes come back.

 

the tps was adjust corectly on the bench last week when I didthe head gasket

 

just did cold test on O2 sensor spec 5-7 result 7.5

is it really that close to say it's toast

 

Well the code was suggesting that the o2 sensor is bad and now its test showed it out of spec. So i would change it. O2 sensor is the biggest single input to determine air fuel rato. Which is your main problem. Change the sensor and reset the ECU. That should solve a lot of your issues. Good luck

 

Codes 24 and 31 would indicate nothing other than a failing AFM though, in my opinion. I've had O2 sensors go bad (throw codes) but I usually got 21, 25 or 26. I don't think a bad O2 sensor would correct a Intake Air Temp code, those are two separate circuits.

I would check your wiring from the AFM all the way to the ECU, looking for any cracks, pinches, or any abnormalties, making sure you didn't pinch or damage and wires along the AFM harness when you were working on it. Also make sure the AFM has that metal clip still on the connector, if that's missing it could wiggle loose and throw codes at you.

 

^^^^ good posting ^^^

 

Any clues to why it won't start at all

 

Well the AFM has to be working to allow the fuel pump to work. But you said you tested the AFM and it passed right? There are about 5 different patterns to check with the voltmeter across the 7 pins on the AFM. Better double check it

 

try pinching off the fuel line for the cold start injector see if that makes a difference

 

got it I found the issue
it was bad ground at back of motor on pass side
but the afm that I bought works better than my old one

 

Nice when you find the gremlins, GJ.

 

lol always something simple. I'd be lying if i said i've never stumped myself leaving a ground loose