So you turn the car on, and when you turn the key back one click the engine stays on and it seems to change the idle slightly like a little electrical load on the engine. What is this meant to do if it has any function.

So just to clarify, car turns on. Key is in ACC position. Turn it back to ON position engine stays on. I remember many years back on one of my first FDs it done this and a light turned on at the dash but can't remember what, other FDs I've owned you do this and engine just turns off

 

You're saying that the car stays running after you've turned the key to off? My FD had some weird electrical issues with the front body harness and/or battery harness that would cause it to power on if it got wet (I'd have all accessory power turn on in the middle of a shift if it rained), and/or it would remain running even after I pulled the key out if it was damp enough outside.


A new harness (which is on the list for this rebuild) should fix that for me. If you're seeing something similar than I'd check the wiring.

 

Hold up.....the engine is NOT supposed to stay on when the key is in the ACC position. The RADIO and a few other electronics will stay on but the engine should NOT.

 

Yeah, that's why I'm thinking he's got a short somewhere in his body/battery harness. Mine was so bad I could remove the key completely and it would keep running.

 

I had a similar issue it was the harness due to previous owner had uninstalled the turbo timer incorrect. Plus it was a weird older unit. But it is freaky when that happens to you best of luck!

 

Isn't there a fan recall harness that does that?

 

Hi guys,

Thanks for the feedback. It's definitely a recent issue. I've also noticed an additional problem which maybe related.

The only electrical changes I done is relocate the firewall ground strap with a thicker gauge wire, bolted it from the old location of the ac pump bolt hole to the chassis. I've also installed a push button start in the cigarette lighter (yeh yeh I know prepare the flame, but it's more useful than a lighter I'll never use). Anyway I'm sure I wired it up correctly. But here's what I've recently discovered.....

Aside the engine not turning off when the key is switched back into the on position. My tps sensor on the pfc, both vta voltages read just under 5v which is really weird. Could this be all related?

I have also removed the throttle body and refit it with a different unit using the same tps. Did I install it incorrectly for the values to read this high? What a mess ay

 

Sounds like you're oh for two

The TPS is definitely not installed correctly, sounds like you didn't index it properly. The factory TB is a pretty nice unit and works well up to high hp levels, did you install another factory TB or one of the aftermarket ones?

 

Think I may have made a boob of it hehe. Yeah it's still the factory unit. I thought installation was pretty easy, is there any guides on how to index it properly?

 

http://www.rx7.org/Robinette/tps_adj.htm

http://haywire.nu/rx7/How%20To%20Che...20FD%20RX7.pdf

It's even easier if you have a Power FC.

 

Oh sorry I thought it meant I had to do something with the tps before I fit it onto the butterfly thing.

I know how to adjust it. My tps is sitting dead middle via the screws however the voltages on the pfc are both just under 5v so does this mean I've installed it wrong onto the butterfly?

 

TPS needs to be preloaded since it has an internal spring.

 

Thanks banzai so would it be a case of turning it then fitting it? I literally put it on with the plastic parts on the tps round part resting into the metal butterfly part on the throttle body

 

Start with the TPS at appx the 11 o'clock position and roll it back to appx 9 o'clock, then adjust the voltages to spec when the engine is warmed up.

 

Problem solved, didn't have the preload set on the tps. Thanks banzai by the way why does the engine need to be warm to do this? How much does the voltage change from the cold figures

 

Thermal wax fast idle holds the throttle open when cold.

 

As far as the pushbutton start you installed, I think this may be having an effect on the car running after the key is removed. I would go back over the wiring you did there.

I also have a pushbutton start in my cigarette lighter hole, but I wired it differently to the tutorial online. In my honest opinion the way they show you to wire it up in the online DIYs is not a very good way to do it and could lead to the issues you're having.

 

Ahha makes sense so I would assume voltage readings when warm would be lower than when cold.

Sa3r thanks I'll have a look. I'll disconnect the relay and ground and test if engine still stays on. Tbh I found the guide poor as the coloured wires they used were completely different in my car, maybe because it's a RHD.

Thanks for all the help gents. Shall post back when I find the issue

 

Readings are higher when cold, since the throttle plates are being held open.