Advice on niggly issues...

[Captain Jack]

Always happened - pretty much since owning. Remap/deFAP/deEGR was only recent.

You get the jolt when coming off and on the throttle pedal? How does EGR go in play here?

[Bailes1992]

Always happened - pretty much since owning. Remap/deFAP/deEGR was only recent.

You get the jolt when coming off and on the throttle pedal? How does EGR go in play here?

Also get it if I'm cruising at very low engine demand situations and I give the accelerator a press. One bit of live data I have you can see my TPS goes from 6% to 62% and the EGR opens.

[Captain Jack]

Hm, well, it does happen when cruising but only when I come on or off the pedal. If the wheels are already being propelled by the engine and I give it the bean then there are no jolts. Which is why I suspected the knackered dampening on the flywheel - no dampening would cause sudden jolts as the engine is engaged/disengaged.

[barbaren]

Hm, well, it does happen when cruising but only when I come on or off the pedal. If the wheels are already being propelled by the engine and I give it the bean then there are no jolts. Which is why I suspected the knackered dampening on the flywheel - no dampening would cause sudden jolts as the engine is engaged/disengaged.

automatic or manual?



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[Captain Jack]

Manual...

[barbaren]

Then try to disconnect the clutch control switch. See if that does'nt help. If it does your troubles are over.
Have been strugling with mine, it started like yours, then little by little it became worse, cutting out for just a split second when accelerating. Disconnected the the switch, and voila it stopped. Fitted a new one £9 on Ebay. No issues since.


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[Captain Jack]

Er... what does clutch switch have to do with anything? I don't have issues with the clutch. And which issue are you referring to?

[barbaren]

Just try it.


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[fattail95]

Er... what does clutch switch have to do with anything? I don't have issues with the clutch. And which issue are you referring to?

Certainly on the 406 amongst other models, the clutch switch is used to change the throttle response dependant on the clutch state, be it engadged or open. When the clutch is engaged (pedal up), the throttle comes on more smoothly -- albeit slower -- than when the clutch is open (pedal down). This is done particularly on the HDi's to prevent a jolty throttle response due to the high torque the engine is capable of low down in the rev range. If you drive with the clutch switch disconnected the engine will appear more jolty not less. If I were you I'd check the clutch switch behaviour in PP2000 and replace it if possible, might just cure your issue.

With regards to the turbo lag, I had the same symptoms you were describing on my '6. Turned out to be a MAF issue, even though it was replaced a few years prior with a genuine Siemens one. I hooked up PP2000 and fired up my log converter to get me a graph of the parameters. Here is my car after replacing the MAF sensor:



As you can see it follows a similar pattern to injected quantity, as it should. Before I replaced the MAF, the line was not following injected quantity during the lag periods, as the ECU was seeing the incorrect air flow and refusing to deliver fuel. Definitely give a new genuine MAF a go if I were you, if its the original it will certainly be past its best.

[Captain Jack]

Very interesting about the clutch switch - had no idea it affected response. How many are there? Asking as I have cruise control and it works OK, so surely the switch it at least open, though doesn't necessarily mean CC will switch off with pedal down. Will check with PP tomorrow to see if the switch is functioning.

Is there a way to test the MAF other than cleaning or disconnecting it? Don't really want to spend £80 on a new one if my current one isn't faulty.

[barbaren]

Very interesting about the clutch switch - had no idea it affected response. How many are there? Asking as I have cruise control and it works OK, so surely the switch it at least open, though doesn't necessarily mean CC will switch off with pedal down. Will check with PP tomorrow to see if the switch is functioning.

Is there a way to test the MAF other than cleaning or disconnecting it? Don't really want to spend £80 on a new one if my current one isn't faulty.

my cc also worked fine. Try to start the car in first without the clutch pressed, if it jumps forward the switch is bad. There is only one switch. Of course the cc will not work once you have disconnected the switch. It will also come up with a fault in pp 2000.
But it doesnt cost anything to try, and if it is faulty its only £9.


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[Welly]

Try to start the car in first without the clutch pressed, if it jumps forward the switch is bad

That describes how any car would behave, I'm confused

[barbaren]

Try to start the car in first without the clutch pressed, if it jumps forward the switch is bad

That describes how any car would behave, I'm confused

the clutch control switch will not let you start the car without the clutch pedal pressed.


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[Captain Jack]

My clutch switch seems fine. What isn't fine is the car (or rather PP2000) always says that I am in neutral, when I can be in any gear....

[steve_earwig]

Eh? Is that stationary or in motion? I think it calculates the gear by comparing the engine and vehicle speeds (via abs sensors), so it'll be clueless until it's moving.

I suspect you know this...