This thing has had ongoing problems sense I got it. I'll start from the begining.

I bought this truck with a rod knock. The head is brand new Ported and polished with Cam. So I rebuilt the lower end. The first problems required me to put in a Mass air flow sensor. Second problem required TPS. Now all the check engine lights have gone off. Now when I start the truck it starts right up then dies. It will run about 20 seconds before it dies, then will start right back up.

If I jumper the wire in the diagnostic port to time it, it doesn't idle down like it used to. It acually acts as if it is already jumped.

Next is, do I have the TPS adjusted right? Used a feeler guage between the stop and hooked up my olm meter, When adjusting it how do I know when it is right?

Thanks for your help, Hope this all makes sense

 

Stupid Question....have you checked the timing???

Dan

 

Ya but, I cant get it to set around the right timing make and it still run. Seems like it has to be advanced to run.

 

Go to this site ,there is an online manual that will help set the TPS. Did you set the TPS when you installed it?
PM me if you need more help.

 

PM'ed ya

 

Ok. tonight I readjusted the TPS. It was set wrong. The truck had all the same symptoms. I did some calling around and talked to the guy that built the head. I have always thought that the rocker arms were noisy. He told me that with the cam that was in there the valves had to be adjusted tighter than Toyota specs. .06 and .10. Good thing I took it to the dealer and payed them to do a valve adjustment:mad3: . I adjusted the valves and changed back to my original MAFS. The engine turned over for awhile before it started but after it started it ran great. Took it for a drive, it had more power and was quieter than before.

So I think the MAFS is still bad. I can jumper wire the fuel pump to be on when the key is on and the truck will start right up.

What do you guys think?

 

Are you saying, then, that the truck is running fine other than having trouble getting it started?

 

Demasters, Glad ya got the TPS right. Are you getting any codes? If the MAFS is bad you should.

 

Last night I bought a used MAFM, From T.A.P., Installed it, ran great, Drove it to work today and the check engine light came back on.

Codes are,
24 Intake Air temprature signal
25 Air fuel ratio Lean
31 Air flow meter signal (vacume sensor signal)
41 Throttle position sensor signal

Now what the ˟˟˟˟˟˟ do I do? I'm ready to burn it. Wife wants me to sell it.

I noticed that if it is not warmed up and I get on it, it starts bucking until I back out of it.

 

First, don't buy from TAP. EVER. When they sell you a POS part and don't give a crap (even if it's wrong) - don't say I didn't warn you.

24/31 sure sound like AFM related... Did the part you put in look exactly right?
Have a FSM to run the diagnostic tests?

 

what is a FSM?

 

He's referring to a Field Service Manual. I sent the link for one to you.
Sounds like you got ripped on the part. the MAFS can cause all those codes to pop up.Remember if one sensor is sending wrong info. then others will adjust to try to compensate and also kick out codes.
Am I right: You had no codes before putting the used part on? If so, that is your problem.
Be patient , They can be a pain in the A** sometimes.

 

Test the AFM and TPS (should always be done before replacing those parts):
- http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

And if the sensors test out fine,make sure the signals are getting back to the ECU. A good sensor connected to bad wiring will look like a bad sensor to the ECU.

 

I havent tested the wires to the ECU yet. Do you know the wire colors or numbers at the ECU? The TPS is brand new from Toyota. I used your procedure to set it. The original AFM was tested and checked out good. Hell I have ran the test on two different AFM's and they both tested good, But when installed in the truck they performed different.

 

You can see the ECU connector pinout in the FSM. I show the earlier ECU pinout on my web page:
- http://www.4crawler.com/4x4/CheapTri...roubleshooting

 

Trace the ECM ground, and every ground. The wires are on the side of the intake plenum in plane site. There is another on the fender on the drivers side and another near the alternator. There should be a strap behind the head to the firewall. You should always do this first. This will solve a lot of problems in a mater of minutes on most cars. Don't forget the negitave cable. The MAF has a switch in it to start the fuel pump. Green and black wire's on the plug. The circuit opening/ fuel pump relay has a lead to the key start position to force the fuel pump on to prime it. Once it fires up the MAF takes over the relay and controls it. If it does not it will stall out again for fuel. This does not set a code.

As far as grounds go, it has geen my experiance that those wires dont get put back after an sloppy engine job. Neither do a lot of the vacuum hoses.

As far as the codes go, check the 5 volt v-ref if it is kicking out a LOT of codes at once. This is the low voltage power supply to most of the sensors coming out of the ECM.

Oh and I am new here. Hola. I also have a '94.

 

look on downey off road web site richen you mafs 3-5 teeth

 

im havin the same problem. i installed a new TPS and adjusted it to manufactures specs. It drove fine for about 30 min and then died. it would start just fine then die after 10 sec. i removed the upper plentum and cleaned the throttle body, but that didnt help. What should i try next?

 

Any stored codes in the ECU:
- http://www.4crawler.com/4x4/CheapTri...CheckConnector

Might try the fuel pump test jumper:
-http://www.4crawler.com/4x4/CheapTricks/index.shtml#FuelPump

If that helps, might test out the Air Flow Meter:
- http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

 

It turms out that the maf sensor flap was stuck closed. I reset the sensor and it ran just fine. Just have to adjust the timing and ill be good to go.