Strange K Series

[evotell]

1.4SS K Series done just 600 km. Started this morning as always without issue, noticed within 50 yards that idle was very high almost like throttle was stuck flicked the throttle and it went back to slow idle speed. So the issue doesn't make any difference whether the car is hot or cold. Sometimes maybe 3 out of 10 time when changing gear instead of the idle dropping it rises. I have also noticed that when it starts the rev counter doesn't work and then all of a sudden works fine.

 

I'm going to take it to a friends tomorrow and plug a scan tool in and see what it says. Apart from the rev counter causing issues when its starts you would think it is symptomatic of frayed throttle cable, but it isn't. Except for the revs rising occasionally when changing gear the car runs fine. doesn't miss, hesitate and idles smooth.

 

Any suggestions.

 

[elan_fan]

Has it got a plastic throttle body, if so its not unknow for them to stick the butterfly open a bit causing these sorts of syptoms

[TomB]

Dodgy Throttle Position Sensor? If it is, there are two types depending on the age of the car. One about £80-90 and tricky to get hold of is for the older EU2 engine, one much easier and cheaper is for the later cars.

[evotell]

Quoting elan_fan: 

Has it got a plastic throttle body, if so its not unknow for them to stick the butterfly open a bit causing these sorts of syptoms

 

I'm hearing this, but how would this cause the engine to rev itself up? and how can that cause the rev counter to not initially work?

 

Thanks for your input

[revilla]

Terry,

 

If the throttle is stuck open even a little bit, when you dip the clutch to change gear all the load will go off the engine and it will rev up. It only takes a little bit of throttle to get the revs up quite high at idle when the engine is not having to drive anything.

 

The other thing worth having a good look at might be the IACV.

 

I suspect the rev counter issue is unrelated. For how long does the rev counter not work on startup?

 

Andrew.

 

Edited by - revilla on 12 May 2014 14:26:27

[evotell]

Somebody has mentioned on another post a TPS reset. press the throttle peddle down with ign on 20 times. Rev counter kicks in after about 2 seconds after its started. It seems strange because both issues appeared to start at the same time.

 

Edited by - evotell on 12 May 2014 14:34:40

[revilla]

Worth a try, if the ECU doesn't have a good closed throttle reference it can cause problems but I wouldn't expect to be so intermittent ... but 20 times is a bit excessive unless you like leg exercise!

 

From Mark Stacey at Z&F Tuning (who is an ex MG Rover development engineer and worked on the development of MEMS3 mapping) ...

 

"I should have mentioned that a new ecu sometimes needs a closed throttle reference - which involves 5 pumps open/closed on the throttle just with ignition on before firing up, to set the closed voltage for correct idle control."

 

So ignition on (don't start the engine), pump the throttle smoothly to fully open and back to fully closed five times, then switch off. The ECU sees this and says "aha, TPS voltage swinging from low to high five times in a row, I'll make a note of that low voltage as being what the TPS reads when the throttle is closed."

[evotell]

Did the tps reset and it appears to be running fine, however the rev counter is still slow to get going when started. Got a friend to plug his scan tool in and got the followi

PO 141

PO 195

PO 443

PO 501

 

Edited by - evotell on 12 May 2014 17:55:36

[revilla]

P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

 

Refers to the post-cat oxygen sensor. Your car doesn't have one. The Rover that the ECU came from did. The ECU doesn't know you don't have one, so it thinks it's failed. ACTION: Normal. Ignore it.

 

P0195 Engine Oil Temperature Sensor Malfunction

 

Your engine, being non-VVC, won't have an engine oil temperature sensor. ACTION: As for P0141.

 

P0443 Evaporative Emission Control System Purge Control Valve Circuit Malfunction

 

Your car probably doesn't have an evaporative emission control system. That is a charcoal canister and associated gear to purge it. UK models don't, although I believe those produced for the USA did. On the assumption that you don't have one, ACTION: As for P0141.

 

P0501 Vehicle Speed Sensor Range/Performance

 

Your car won't have a vehicle speed sensor connected to the ECU. My car doesn't normally bother to complain about it, maybe yours has picked up some crosstalk on the floating disconnected pins and thought it was a bad signal rather than no signal at all. ACTION: As for P0141.

 

So nothing there to worry about. Certainly nothing relating to your throttle problems. Hope the throttle reset has settled it down, if not just try slackening off the air filter clamp :)

 

Edited to say I just fired mine up while watching the rev counter. There is a short delay before it jumps up to read correctly, but more like half a second than your two seconds.

 

Edited by - revilla on 12 May 2014 21:30:46

[evotell]

Thanks guys, all seems to working well, except the slow to start rev counter, any suggestions?

[richy]

Quoting evotell: 

Thanks guys, all seems to working well, except the slow to start rev counter, any suggestions?

 

Drive it? 😬

[evotell]

Quoting richy: 

Quoting evotell: 

Thanks guys, all seems to working well, except the slow to start rev counter, any suggestions?

 

Drive it? 😬

 

😬