Right, im getting really bemused by my cossie. I have posted various running and missing issue with the car, but i have stumbled across this..

I recently finished my project, and the engine, has had every sensor replaced since i rebuilt it other than the TPS. Now i am having running issues, it idles mint, the C0 is at 2.5% the fuel pressure is spot on the and plugs are fine. When gently applying throttle it splutters and misfires, making driving it / pulling away difficult.

After reading posts about TPS sensors, i have gone out and tested mine with a multi meter. The results are puzzling. Its a 1988 2WD with L6 ecu, but im getting a voltage reading at closed throttle of 0.1V and 4.6V at WOT I was under the impression that the 2WD L6 was supposed to be the other way round?? HELP..... PLEASE

The engine came out of a running car, albeit now running well. so the TPS came with the engine !

 

See if the volts jumps around when opening slowly. Mine was also spluttering and jumping around when the tps was shot. Replaced and it went like a dream

 

The 2wd should be around 5V at idle, and 0.5V at WOT.
Maybe it has a 4wd tps ?, this would be around 0.6V idle, and 4.5V at WOT, if not have the outer wires in the tps plug been reversed as when fitting a 4wd ecu/tps to a 2wd loom.
At the moment your ecu will be going fully rich as soon as you touch the throttle, and progressively leaner as it's pushed further.
tabetha

 

Also,

when coming down from WOT which read 4.6v i can bring it down smoothly to 0.6 and then it drops straight to 0.1 nothing between 0.1 and 0.6v smooth through the rest of the range.

My issue is, should it not be the other way round on a 2wd L6, ie 4.6v and decrease upto WOT.

 

As said it sounds like you have PF09 TPS (4x4) this is done when people fit L8 ECU's, as they read the reverse of 2WD, the same readings as you are getting now, if you have L6 then you need the PF01 TPS.

Martin

 

The TPS is red, arent these the PF01's and the PF09's are black. Also, are the L6 and L8 looms different and how can you tell.

The reason i ask, the car used to be a track car (i bought it as a rolling shell and bought an enginre from another 2wd). Im starting to wonder about the loom. Maybe the TPS is a PF01 but the looms different.

 

Yes the looms are different, sounds like you have the correct TPS by the colouring which you correctly state, one difference with the wiring is the TPS, this is why you have to swap the outer two wires, I believe the 4x4 loom has a connector so you can seperate the ECU side from the car side so is easy to remove, whereas 2WD is a complete loom.

4x4 loom also has extra wiring for things like knock sensor/air con etc.

Martin

 

the old pf09's were also red

 

right, the TPS is definately a PF01 but the plug is wired for PF09 so I assumed it was a 4x4 loom. However, its a one piece loom and also pins 21 and 22 are not present on mine which are for the AC and knock sensor on the 4x4 suggesting it is a L6 loom. So im left with the fact im running an L6 ecu on an L6 loom with an L6 PF01 TPS but the TPS connector is wired wrong and voltages are reading the wrong way??

So am i right in thinking, i either need a PF09 or switch the outer wires on the plug to accept the PF01?

my brains frazzled and needs assistance

 

just swop the outer wires round job jobbed

 

Thats what i thought. how do the pins on the plug release?

 

not sure i just unpeeled the loom tape then cut and soldered the wires

 

Right, I have swapped the two wires around and its now reading the correct way. However, at idle the voltage is reading 0 volts, i need to apply a tiny bit of throttle pedal to get it to read 4.6v and then it decreases nicely to around 0.35v at WOT. Does this mean I have to adjust the TPS physically to get it to read 4.6v without depressing the pedal??

So close yet so far

 

The PF01 isn't a straight forward potentiometer it has a switch built in and is open circuit at idle, hence why you need to open the throttle a bit to see voltage, this signifies to the ECU the driver has taken control via the throttle.

Assuming the throttle cable isn't streteched etc, you can adjust the TPS but there awkward to remove, you have to remove the T/B to do so.

Martin

 

Thanks. Just bolted it all back together, and it seems spot on. Think the car must have been running an L8-P8 ecu at some point.

Just got to sort my leaking thermostat housing then I will wait and see whats gonna go wrong next

 

As said can get red 4wd tps, the 2wd is a straightforward linear pot, it has NO switch at idle unlike the PF09 4wd one, which has a dedicated idle position.
It does NOT always show up when they have a flat spot on the tps, this generally occurs just above idle as most used area, and can play havoc, I had a murmur that was there all the time on the L6 ecu, couldn't detect a flat/missing spot anywhere, it wasn't until I switched ecu's that the slight murmur became a serious issue.
With the new ecu not wanting to pump fuel in like the L6 did, the miss was so bad it couldn't even be driven through on the rollers with ZERO load, of course a brand new Ł25 pot and 2 minutes on the laptop had it all lined up with the new one, the part I used was a common as much universal tps that can be got anywhere, Ł25 brand new on the spot with no cossie tax!!
tabetha

 

Are you sure it's the PF09 that has a switch, I thought it was the PF01, although I could of got confused?

Martin

 

Its is the PF01 that is switched.

 

Thought so, as I say above then.

Martin