Throttle Position Sensor

[mark]

My TPS has gone bad - giving off intermittent low voltage readings, and the car runs so rich that I can't get it out of my driveway if I can even get it started. Does anyone know if an Isuzu TPS will work? The picture from the Isuzu parts book shows a circular TPS with the electrical wires coming out of a round opening, while the Lotus TPS is rectangular, with the electric hook-up coming off the end. No surprise - Lotus wants $385 for a new one, while the Isuzu part is about $80.

Also - any other GM part number or car that might have same TPS?

[GeoffSmith]

There's a lot of information in the TPS cross reference thread Mark.

Geoff

[mark]

thanks - good stuff - i'll get in touch with Ekapol who lives up the road and see if he got the Beck Arnley to work.

[Ekapol]

Please let me know if you want to try my spare TPS sensor. I could let you borrow mine. It will take a day or so, sending through our mail system to your address in the bay area.

Just give me a shout or IM me.

Yes, they are way~ overpriced from Lotus.

[ratman]

Ekapol! It's time to make a test with your/mine new TPS .... let me know!!

[Ekapol]

Ekapol! It's time to make a test with your/mine new TPS .... let me know!!

Yep, my TPS is with Mark now. Perhaps he could do a quick test. Most updated news was that he just needed a re-soldering job.

[mark]

right, solder did the trick on the old one. I'm headed out of town this week so if you send me your address, or Ratmans, i can pop it in the mail before leaving.

[garymb]

Ekapol! It's time to make a test with your/mine new TPS .... let me know!!

Yep, my TPS is with Mark now. Perhaps he could do a quick test. Most updated news was that he just needed a re-soldering job.

I'm looking for a TPS as I think mine is on the way out (occasional low voltage error codes). Lot's of people seem to have found possible replacements but I cant find anyone who has successfully fitted one. Ekapol have you tried yours yet?

[Ekapol]

Mark: How did it go? I haven't heard from you ever since last time I let you borrow my spare one.

Did you have a chance to try it out?

On my green baby, I found out the hard way that my TPS wires broke on the inside. That was about half a year after I soldered the wires back together.

The soldering joints looked fine but the wires were all brittle. They cracked and finally broke off.

It actually costed me few head gasket jobs When TPS signal wasn't there, in my case, with 3 bar MAP and high flow fuel injectors, the car went into running extremely lean in some conditions.

Make sure you cut off the broken/dried end of the wires before soldering them back.

[rip]

Another example of TPS low voltage from Dave Eds' red Elan.

Can anyone please determine whether the TPS is actually on its way out or could it just be a poor connection?

[Dave Eds]

GST have run Tech 1 on my daily this morning and confirm my TPS is f**ked. Has any one got a spare for sale, new or used please?

[GeoffSmith]

Sorry Dave, saw this at work but can't run ES, then forgot about it when I got home.

You've got quite a few dropouts towards 0V which is either the TPS or it could be the connections between the TPS and ECU. Your zero position isn't zero either, so either the TPS needs adjusting or it's shagged (technical electronic term, invented long before the Welsh discovered sheep).

[dapinky]

I'm no expert on these things (luckily I send Geoff any scans i need looking at!), and i don't know if they are connected , but.......

At about 400 seconds into the run, the TPS voltage shoots up to a peak, this corresponds with a bit of engine knock - well, a hell of a lot, actually - a count of 54 all at that time.

I ain't got a clue if a faulty TPS can cause this, or not.

When i was getting a low TPS voltage flag on the red one it was a duff earth connector from TPS to coil base plate - but this should give a low MAT reading as well......

[dapinky]

Your zero position isn't zero either, so either the TPS needs adjusting or it's shagged

Geoff,

Further to my last post, i know you are the guru on these things, and I am a mere grease monkey......

However, perhaps another alternative is that at zero movement, it should still be 0.4V, as per any other scan I've seen. (or do you mean the bits where it does drop towards zero but doesnt quite get there?).

I'm not trying to be picky, but i don't understand what you're getting at - and I'm sure Mr Spud wants the correct information, as (I'm sure he'll agree) he and I know about the square root of SFA about the magical workings of an electronic management system. (give me points, plugs and condenser and I'm happy).

[paulwatkins]

There should be a value of 0.4V with the throttle closed and around 4.0V when wide open.

However, the ECU has the ability to auto-zero the TPS voltage if it is below 0.66V. ie any voltage below 0.66V, the ECU determines 0% throttle.

according to the ECU manual

[Dave Eds]

With the car running and Tech 1 connected, Gerald played with all the connections to the TPS while the Tech 1 guage danced all over the place. Other symptoms are idling at 500 revs or 2000 revs in traffic, and stalling for the hell of it. Accelerating is no problem, but let the foot off the gas and it feels like an old fashioned points problem. His diagnosis is a shagged TPS , and at £190 + VAT my chances of going to the IOM are shagged with it. I'm hoping for one or two miracles.

[paulwatkins]

Dave,

can't you 'borrow' the throttle sensor off your good car just to get you to IoM?

Its only a couple of screws and an electrical connector, 10mins on ElanScan and you're done!

[GeoffSmith]

Good advice Paul.

Dave, if you connect up ElanScan and change the "acquisition period" and "update period" to 10 and press F1, the TPS voltage should be stable; if its not (e.g. when you waggle the leads) you should be able to see the reading fluctuate at ~100 times per second. I'd be tempted to do it as-is so you are sure you can monitor it then swap the TPS to see if you can cure it; if it's still doing it, then it's likely to be the connections. Give me a buzz if you need to.

[dapinky]

Spud,

You have PM!

(please don't phone me - I'm just off to a Memorial Parade and it will be embarassing if me 'phone goes off! - any problems, 'phone Geoff!!!! )

[Dave Eds]

Geoff and Dave you both have PMs.

I will take Dave up on his offer of a temporary solution and Geoff on his!