oldblue

so, thank you guys for the info on how to adjust the tps sensor, it had an open circuit off idle and needed to be adjusted. however, when i jump the te1 and e1 terminals to set my base timing, the check engine light flashes like it should but the timing does not change nor does the idle. i read that the idle rpm must be 800 +/- 50 rpm. i used an engine tachometer and my idle is currently 575-610 rpm, way too low. help point me in the right direction please. is there a test or adjustment for the idle circuit? what controls the idle? is there and iac valve or is it one of the vacuum elements on the side of the throttle body? thanks again, i really want to get this truck running right. also, the truck still has a miss at idle, and at lower rpms seems to lack power, hopefully this is why

Jay351

I have a similar issue. When I jump the connectors my idle will not drop. Turns out there is a bad wire from the TPS to the ECU. I used a test wire and bypassed the bad wire, and it fixed the problem.

Check the wiring

Also, adjust the idle with the big screw.

jpmountainboy

so your tps was adjusted but then you figured out the wire was bad??

for the test, which wire did you bypass and how did you connect it into the ecu??

my idle never dropped either, but I always thought that it didnt always have too.

oldblue

anyone have a link to a toyota service manual test of the idle circuit? the link for the tps was very helpful!!

oldblue

anyone?

Jay351

Yes, I adjusted my TPS on the bench, so its dead on. I then tested the resistance of the wires from the ECU to the TPS. When I got to The VCC wire I noticed a resistence value of over 4.50. So I scraped a little insulation off the wire about 1" before each end of the wire and attached a good wire.

After I did this, I started the truck back up, and jumped the TE1 and E1 connector, my idle dropped accordingly.

I removed the test wire and put shrink wrap around the exposed wire.

I will have to remove the upper intake to expose the wiring harness.
I have yet to make it that far yet. I have just delt with the rich mix and wandering idle..... I will have at it once it gets nice outside
Just gonna pull the wire and replace most of it.


Look at the top of the page in this secton. There should be a sticky with FSM's there. Scroll down and look at the 1993 toyota FSM. It will work for you.

oldblue

any other advice? the idle does not change nor does the timing position when i jump the terminals. also, low rpm power seems way down, but when the truck hits around 3k rpm, it feels like a turbo kicks in and power is good????