TPS adjustment

[bitrootvz]

So the manuals say to adjust the TPS use a special test harness. What is it and do I make one or what.

[royster]

I was hoping someone with more knowledge would answer that (where are ya, Geezer ?!) because electronics is my weak point. I made a jumper wire for the task according to the manual, but never really understood the process, and got no results. To be honest, I just set the new TPS at a point where the old one had been marked. I adjusted it a few times afterwards, and it is running fine where it is.

What you might try is just adjusting it a quarter inch one way or the other and see if it affects anything. Hopefully Geezer or another experienced member will give some better advice.

[bitrootvz]

I stuck the plug back on, put a paper clip down inside the middle wire and adjusted it to .5v. I still have the 15 error code but everything checks out ok, I have not replaced the distributor but the truck runs fine when it finally starts so I have a hard time thinking its the distributor crank sensor. Wonder if you would get a code 15 if the cam gear was one tooth off on the timing belt?

[geezer101]

Eliminate what you haven't done to the truck, then look at what you have done. If you've pulled the distributor and it was running fine before doing so, go through and check the timing alignment marks. If it was out a tooth I doubt it would run with any sort of power (or at all). I am not big on MPI and they can be so temperamental to diagnose for a novice (greasy finger pointing in my general direction). I'd only be doing whatever 'the book' would say. I know they need to be tripped into diagnostic mode when making any adjustments to ignition timing but this is where my ign tuning experience comes in and I know how to dig up extra torque and HP.

[bitrootvz]

Once it starts I can drive it no problem, cruse down the freeway 65. I never pulled the distributor but the timing was off as far as the cam shaft. they had the timing mark pointing straight up. I just thought that the code 15 means either the TPS, ICS or the Crank position sensor. I have replaced the ICS and adjusted the TPS so the crank position sensor in the distributor is whats left. Just don't think it would run at all if this was bad. I'll just keep plugging at it til I figure it out. Thanks for the reply