Aftermarket TPS

Hi guys,

I have a 1999 4.6 Thor V8 on which I replaced the original BOSCH TPS with a £25 variant from JGS 4x4 when hunting down a problems I had which is now finally fixed, it wasn’t the TPS at fault. However, now the car seems to judder and almost loose power momentarily while accelerating. When the TPS is disconnected it doesn’t do this. I noticed on live data when idling the Throttle angle will erratically jump about and do strange things. It will read 0% and then spoke to 72% and then drop to 27% so on and so on. Is this down to the aftermarket cheap TPS I replaced the original with. Annoyingly I didn’t keep the old one so I can hook that one back on and see if it still does it. I have reset adaptions and it still does it with the TPS plugged in.

It also revs up high on start up and sits at around 2,500 revs until I rev it and it drops back down. Could that also be linked with this or is that more likely to be a sticking IAC valve??

If the tps value is jumping about, i would say that's the issue

kermit_rr said:

If the tps value is jumping about, i would say that's the issue

Click to expand...

I thought it may be. Any idea where I could get a new genuine one from. Been looking and see them sat at around £250-£400. Is that about right?

Never tried to buy one have you checked scrap yards, ebay etc for a used one?

kermit_rr said:

Never tried to buy one have you checked scrap yards, ebay etc for a used one?

Click to expand...

There’s some used ones that look to be in good condition in the exterior and for about 50£. Might try one of them

kermit_rr said:

If the tps value is jumping about, i would say that's the issue

Click to expand...

As above, the change in value should be smooooth

Very likely a faulty TPS.
Try a 'wiggle test' of all of its the wiring you can get at & see if anything happens.
Plenty on ebay etc for various prices. Can't say I'm a fan of cheap aftermarket stuff though.
You could raise the issue with the suppliers of your TPS but many won't accept returns of electrical items that have been fitted.

Josh Wiggill said:

I thought it may be. Any idea where I could get a new genuine one from. Been looking and see them sat at around £250-£400. Is that about right?

Click to expand...

Rimmer Bros for genuine.

If you want cheap then eBay scrapper one. Classic Rides North Wales or someone might remember what Charles's pseudonym is. Cn4x4?

Grrrrrr said:

Rimmer Bros for genuine.

If you want cheap then eBay scrapper one. Classic Rides North Wales or someone might remember what Charles's pseudonym is. Cn4x4?

Click to expand...

Not sure if the the same chap you are on about but I did order the outer handle for mine from a chap on eBay called cn4x4sss so I assume that’s that’s the one you are on about.

Khemitude said:

Not sure if the the same chap you are on about but I did order the outer handle for mine from a chap on eBay called cn4x4sss so I assume that’s that’s the one you are on about.

Click to expand...

That's charles he's the bloke who supplied/fitted the engine for me

I would check it with a multi-meter before assuming it's the cause of erratic readings. Definitely clean the IACV & throttle body inside as well.

kermit_rr said:

That's charles he's the bloke who supplied/fitted the engine for me

Click to expand...

Ah right okay, I’m actually texting him now to see if he has any of those clips for the inner door handle.

pwood999 said:

I would check it with a multi-meter before assuming it's the cause of erratic readings. Definitely clean the IACV & throttle body inside as well.

Click to expand...

If you do then as already said by datatek the swing of the readings must be smooooth without any sticking or sudden jumps.