2.1 12v (XUD11BTE) Throttle Problems

[tenwierdufos]

Hi, i know its never a good thing to come new to a forum when you have a problem but ive run out of options!

Thanks for any help in advance.

I have a 1997 406 Executive 2.1 12v TDI and it has developed a perculior fault, and before you say it, it is not the throttle position sensor.

Basically yesterday it started to (at random but still drivable) idle at about 1000 rpm (only when the fault was occouring) and give very jerky throttle control and sometimes accellerating on its own without my control.

Now, today i tried to go to work, got about 20 minutes down the road at 70mph (a50 dual carriageway) and suddenly the car just opened full throttle, without my controll, had to turn the ignition off to stop it, but the engine did cut out when i turned the key so its not running on oil either.

Came off a sliproad, slowed down to a roundabout at the bottom, engine cut out and wouldnt start. Eventually managed to get it off the roundabout into a layby. and it was behaving itself completely for the RAC breakdown guy, untill he was about to give up where it started revving its nuts off at full throttle again. Big plume of unburnt derv shot out the back also. (not smoke to clear that one)


Now when i start the car, sometimes it will idle, sometimes it will sit there blipping the throttle like there is someone sat in the car blipping it.

Completely stumped as to what might be causing this.

Love the car, hate this problem.

Thanks XD

[steve_earwig]

Lordy! I wouldn't know where to start. I had some idle problems with a duff needle lift sensor but nothing quite so dramatic. Clutching at straws here, the engine revs are controlled by the ecu, with a nod to what you're doing to the throttle pot. Could be this has disintegrated or maybe some issues with the connector to the ecu, which sometimes pick up condensation and corrode.

[tenwierdufos]

Dont think its the throttle pot, when the symptoms are there it will do it regardless of if its even plugged in

i.e. if its idling correctly, it will continue to when you unplug it, and als if its revving itself like a boy racer at the lights it will continue when you unplug it.

same goes for the needle lift sensor

all connections i can find including between the pump and ecu and the ecu plug itself have been cleaned up, wasnt any corrosion there either

thinking mabye a duff pump or ecu so kind worried

[mark21TD]

I had a problem with my 2.1, it was reving up and dowm by it's self (but not quite like yours).
In the end it was either the a coolent senser (the one at the r/h end of the engine with a green conector) or the pump it's self.
I never got to find out which one as when I replaced the sensor it made no differance but after changing the pump it was fine,
I later found out that I should have disconected the battory for a couple of hours to reset the ECU after changeing the sensor,
So it may have been the when I changed the pump (and disconected the battory) Thats when the ECU reset it's self.

So for the cost of a coolent sensor I'd try that.

Or you could just swap the pump for a Bosch one viewtopic.php?f=1&t=7281

[poddack]

If there is air in the fuel line it will sometimes rev it's knackers off to clear it, look for bubbles.

[poddack]

I notice you have acone air filter on it, did it make any difference?

[tenwierdufos]

There was air at one point but that was sorted a while ago.

And as for the cone, when i bought the car it didnt have an airbox at all so that was the cheapest solution at the time to get it on the road, havnt found a reason to need to change it yet though.

Makes its sound very nice, turbo wistles quite loudley, doubt it makes any difference to the performance though.



Running out of ideas to what it could be causing this fault though, taken the battery out to charge it as got pretty low just from sitting there for a few days, think mabye thats on the way out

Hopefully having the battery out to charge it will give the ecu a nice reset anyway see if it makes any difference i doubt it will though.

[tenwierdufos]

Well, ive had to give up with this now, my knowledge of cars has been exhausted and i cant find any problems with it


So its been booked into a garage for tommorow.

I will tell you what the fault thats causing this is when i find out so that others can benefit at least .

[tenwierdufos]

a video of what it does on idle lol

http://www.youtube.com/watch?v=iR_rfkSmG-g

[mjb]

WOW that's vicious revving!

Getting it attached to a diagnostics setup with live sensor values is probably the best course of action. I imagine the correct course of troubleshooting should be pretty obvious when it misbehaves.

[tenwierdufos]

its official

i need a new fuel injector pump.

so im looking out for a bosch pump off a 1.9td

this will allow me to fiddle with the fueling to tune it up too

[jbh325i]

its official

i need a new fuel injector pump.

so im looking out for a bosch pump off a 1.9td

this will allow me to fiddle with the fueling to tune it up too

let me know what your cheapest quote is on a Bosch pump as I've had the chance of a complete car with the Bosch pump on it

[tenwierdufos]

its official

i need a new fuel injector pump.

so im looking out for a bosch pump off a 1.9td

this will allow me to fiddle with the fueling to tune it up too

let me know what your cheapest quote is on a Bosch pump as I've had the chance of a complete car with the Bosch pump on it

thanks, i need a pump off an older car than the 406 though, going to go to a scrap yard with a 405 on it today and will see how much they want to rip me off

[tenwierdufos]

Found a pump etc!

Have been round looms scrapyard in derby today scouting for parts, and spotted an L reg Citroen Xantia with a big sticker on the back saying somthing along the lines of 'police seized vehicle' 'no insurance'

haha





so i stole the fuel pump, injector pipes and injectors off it


40 pounds! bargain...

[omega]

good luck fitting it