ok this is my latest problem towards getting this truck back to normal. i have the timing belt water pump changed and it is running now however the check engiine light is now on and it is missing little under all conditions. i know you re going to tell me i have one tooth off on my timing belt. but i have removed and refitted this and still have this problem.... the problem i have to get past is the OBDII computer at the local auto zone wont turn on the 3 different prople tell me it should have 12 or at least 11 volts to run this. it will not turn on.. the key is in the forward position and the check enging light is on.. there are only a few wires going to this plug which one is 12 v which one is neg and data. i think im going to have to break down and buy a haynes manual again. but wont have the money till friday..

How is the voltage in the rest of the truck? Maybe you've got an electrical problem somewhere (loose ground?). If you've got low voltage, your ECU won't be happy and your engine isn't going to run right...

i had a serious voltage problem with my truck as well, it's a long shot but check and make sure you have a ground wire going from the battery to the body of the truck that leads to the driver side fender support. If this is missing youll get no more than 10V during idle.

no replaced all connections around battery and all grounds seem to be ok. 12 volts at the battery. lights dont even dim a idle. battery to fender is ok. ground wire to intake manifold tight, 12.2v with exgine off and lights on 14.1v with engine running at 1000 rpm in park are there any other grounds that i should look for.

So you don't have 12V going to any of the wires to the plug or is the voltage low?

it looks like there are only a few wires in this ODBII plug and i have no voltge on any of the plugs. which of the plugs will have voltage. which wire will be 12v which will be 0v and so on. im buying the haynes manual tonite so i can see which wire goes where but it wont be until get of work at midnight. there is a diagnosis plug on the engine is this for a different type of hookup. maybe at the dealership only...

According to the diagram for a 97T with A/T there are 2 data links. Data link 1 is located on the drivers side of the engine and is fed from the battery, through the EFI 15A fuse in the block under the hood,then throught the EFI relay (which is turned on by the ign key)to a white wire with a red stripe on the data connector. The brown wire is ground and the violet/white goes to the ECU.

Data Link 3 is located in the lower center part of the dash and is powered by the EFI fuse through the 7.5 A OBD2 fuse in the left kick panel to a violet wire to that connector. Brown and white/black go to ground. White goes to the ECU. So far I have not had to screw with these so I can't give you anything else. Hope this helps.

thanks i just got the haynes manual and will look for the circuits you describe. tomorrow if it is not to cold . ill have to check all my fuses again i already had one badone that looked good. thanks again