cps

[socc924]

Ok, just wanted to be sure. Im still stumped, would a sound clip help figure this out at all? I dont even know what else to test

 

[jdub]

Ok, well a few more things. When I first went to start my car this morning all it would do is crank. So I went under the hood and played around with the wires going to the coil pack and the ones going to the cps. Sure enough it fired right up. I wish I did each individually to pinpoint the problem.

I just check it and there was a code 12. Then I cleared them and I dont get it anymore. Also... as a side note, its normal to get code 51 when you rev the motor while checking the codes at the same time, right?

That's normal for code 51. Code 12 is the CPS...I'll bet your wiring in the vicinity of the CPS is not in the best shape (brittle, bare spots). I had to re-wire mine...code 12 will cause stalling, roughness, no-start etc. It will also cause the ECU to enter fail safe mode. I'll bet you the CPS is the problem.

I also hooked the egr directly to vacuum and the car immediately stalled.

If your coolant was above 145 deg F the VSV normal condition is open. Connecting the EGR Vacuum Modulator directly to vacuum with the throttle plate closed will likely stall the engine. If you want to test the VSV, hook the vacuum line that runs from the hardline directly to the vacuum source...with a cold engine (coolant below 135 deg F). The VSV should be closed preventing vacuum from reaching the modulator...therefore, the EGR should stay closed.

Edit: Take a look at this schematic...it might make what I'm saying a little more clear.
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=EC&Page=16

 

[estrellainc]

sounds like my problem i had last month.
It was a dirty AFM.

pull out the electronic box, and clean it. including the contacts.
the car will hesitate when theres a discrepency between the TPS and the AFM.

also, have you check the vacuum with a guage? 21-24hgms right?

mine was at 18 due to a bad intercooler.

maybe wiggle the harness and see if the car stalls. you can surely find it!

 

[jdub]

If it were the AFM, the ECU would likely throw an AFM related code...he's throwing a code 12 which points to the G1 or G2 contacts (or wiring) for the CPS.

If you decide to clean the AFM, do not use any kind of spray cleaner on the sensor that protrudes into the housing. This is almost a sure fire way to kill your AFM electronics.

 

[socc924]

Thanks so much guys, I realy apreciate the help. I will do what ever I can when I get done with work and school today. Now, when you rewired the cps, did you just run wires from the ecu to the cps directly? Thanks again.

 

[jdub]

Thanks so much guys, I realy apreciate the help. I will do what ever I can when I get done with work and school today. Now, when you rewired the cps, did you just run wires from the ecu to the cps directly? Thanks again.

I had to change the wire on the CPS itself to the connector and the wires from the connector across the top of the motor to where the harness turns down behind the alternator. The heat from the motor takes a toll over the years on the wiring insulation.

When I rebuilt my motor, I got a new main harness from Toyota

 

[socc924]

At risk of jynxing (sp) myself I want to say that your the man jdub. Im almost possitive that the problem is the wiring to the cps because yesterday I moved around the harness that goes along the top of the valve covers and I could hear it idle smoothly sometimes. i am assuming that the problem is somewhere between the cps itself to the other side of the engine, where ever the harness goes. What do you suggest is the best way to rewire it, should I just go straight from the ecu to the cps, or just from the cps to across the top of the motor to whereever it goes in the harness?

 

[jdub]

The way I did it (before I replaced the harness) was get a CPS connector and wiring from across the top of the motor from a scrap harness...the wires were in much better shape than mine. Then I spliced right before where the harness ducks down between the intake manifold and head/block. You could also do splices on both sides...at the CPS connector and the same place as above.

The wiring at the top of the motor gets brittle from heat. Tubbie may have what you are looking for (CPS connector attached to good wires)...PM him.

You could also go straight to the ECU, along the passenger fender, through the firewall, to the ECU. If you do it this way...make damn sure of the wire pinout on the ECU before you cut. I would use a 4 strand 16-18GA wire with the correct colors to avoid confusion. The colors are blue, red, black, and yellow. Personally, I think the 1st method (at top) is better

 

[socc924]

Thanks again for the help. I will most likely replace up to the intake manifold rather then back to the ecu. I may even see about replacing the entire harness that goes across the valve covers cause all the wires are probably crappy. Only thing though is that would it be ok to just splice in some temporary wires from the cps to the wire harness untill I am able to get a harness from someone? I would probably be ok driving it the way it is for a little while but i would really like to get it fixed for saturday's englishtown meet.

 

[jdub]

You're welcome

Sure, you could do a tempory fix. All you should have to replace are the 4 CPS wires...loss of both G1 & G2 signals or the NE signal is one of the few things that will cause a no start or shut the motor down (code 34 is another...fuel cut).

 

[empera]

Video of car at idle. After rewiring the top portion of cps wires and exchanging a few parts. Problem still there.

http://home.comcast.net/~emp00/briansupra.wmv

Right click save as

 

[empera]

Problem Solved. We drove the car and it seems the ecu had to set after rewiring everything. Thanks Jdub for the help, along with everyone else.