TPS

[dickie]

Hi folks.

I decided to take the ITB Eunos to work today cos its Friday.

While I was on the main road I got a missfire and the Lambda gauge went fully rich I thought Oh Dear"

I pulled into a layby switched off and had a think.

Re started and it was all back to normal !!

Got to work OK but stayed in the slow lane, Just in case !!

After work I started up and set up the laptop ! full rich again, on looking at the ecu it was showing TPS at 100 percent at tickover.

I switched of the engine then switched the ignition back on and had a wiggle of the TPS wire and a look at the action of the TPS

After a couple of fiddles and checking the TPS calibration Which was showing full throttle ! things then went back to normal and the TPS went back to ready correctly so i drove it home with no problems.

I think that I need to buy a new TPS if I can't trust the factory original It from 1994 so done quite well.

I am glad I had the laptop which instantly showed the TPS was not changing with pedal inputs.

I have a spare Mk2.5 TPS so I might see if that can be fitted.

[Zed.]

May 20, 2022 20:06:42 GMT dickie said:

Oh Dear

Rich.

[atlex]

ITBs / Alpha N are really really sensitive to a good TPS signal and calibration.

My white car that just wouldn't idle because the TPS signal just wasn't quite calibrated right - it always thought it was at 1% or 2% tps when actually it was closed. Recalibration completely changed that. I had to rework that area of the VE tables too. Obviously.

I can imagine if your car thinks it's at 100% tps and the RPM isn't increasing, it's going to be in big trouble style, at least it isn't a lean condition.

Guess that's a safety factor, if the TPS fails, it fails to thinking it's WOT. It's the engineer's best safety choice.

the K series ECU I had (standard) worked almost flawlessly in the standard intake setup with the TPS disconnected. It used a clean MAP signal for 99% of the load. On some cars the TPS is used to help with acceleration enrichment/tip in rather than much else. on the K series standard EP3 ECU it could 'fake that' by detecting a sudden increase in RPM but it still wasn't as good as having an actual TPS plugged in....

[dickie]

Hi folks,
The Mk2.5 TPS has a different plug !!
Luckily I also had a spare Mk1 TPS on the pre ITB manifold so thats fitted to see if the problem is cured, If not I will be buying a new one.
Its the first time I have had this problem.
I have had three Mk1 Eunos all with no problems over the last twelve years so I have been lucky.

[dickie]

I have just ordered a new aftermarket TPS just to be on the safe side.

[dickie]

I Went for a long drive yesterday with the other TPS fitted.
Car is running much better now.
I suspect that I need to re tabulate the tuning tables the give more definition at the low end of TPS the table goes 0 to 3 percent
I will try and work out if I can add more lines, If not I will move things around at the low end and widen out the 50 percent upwards part of the table.

Running an ME221 Gen2

[Zed.]

May 23, 2022 17:37:16 GMT dickie said:

I will try and work out if I can add more lines, If not I will move things around at the low end and widen out the 50 percent upwards part of the table.

where (in the rev range) do / will you spend the most time??

then concentrate here

Rich.

[dickie]

Hi Rich,
Mostly under 25 percent around town and cruising at 70 MPH
But 100 percent @ 7500 rpm in the lower gears ( Full Noise )
Engine quite happy doing 70 MPH in third for a couple of miles on the way home today.