Rough Idle on Xantia 1.9TD.

JamesQB · Post by **JamesQB** » 04 May 2010, 00:41

MikeT wrote: which I suspect you can set the TPS to if you know the spec.

Thanks for that info Mike. Therein lies the problem, as the haynes manual only states that you need a lexia to set it up, so I assumed the lexia did the clever stuff and showed you when the TPS was correctly set up or something... or that there was a reset carried out via the lexia with throttle not touched, to let the ECU know that's the resting position of the TPS and to take that as the minimum and everything upwards is movement. Calibrate it, basically.

MikeT · Post by **MikeT** » 04 May 2010, 14:56

Hi James,

As you say, the fast idle is default. It requires mechanical intervention to be de-activated and is irrelevant when the engine speed exceeds it (obviously).

The TPS, (or more correctly the load lever position sensor) has no bearing on the idle directly. If you want to check it yourself, you should see a reading of ~0.9V at rest and 4.5V at full swing.

Xaccers · Post by **Xaccers** » 04 May 2010, 15:12

JamesQB wrote:Will a Lexia 3 give information on whether or not that lift sensor is working? And does it allow for setting the TPS position correctly?

I ask as my parents' 98 Xantia 1.9TD has similar trouble and is stuck on fast idle despite new solenoid. For some reason ECU isn't activating solenoid to cut the fast idle. Idles at just over 1000rpm and has that deep rattling noise someone else mentioned.

I had the same thing with Cassy until Saturday when I finally got time to look at it.
Moved the airbox and it's first large pipe out the way so I could get to the electrovalves at the back of the engine bay.
Placed a finger on each and reved the engine, feeling for which one went click.
Made sure that was connected to the fast idle cable, and connected the vaccum pump directly to the top of it as I don't use the EGR.
Revs dropped to 800-850 and she sound much smoother.

Post by **KennyW** » 04 May 2010, 16:05

Hi All,

I've viewing the postings with interest.

To use my multimeter what terminal numbers are we testing and what are we testing for?

1. Engine coolant temp sensor green connector at rear of thermostat housing.
Is it volts,amps or ohms?
2.Idling electrovalve
3.EGR electrovalve
4.Injector needle lift sensor

Is it volts,amps or ohms and working ficures.

Kenny

MikeT · Post by **MikeT** » 04 May 2010, 17:13

Hi Kenny,

1. Set to 20K ohms scale, measuring the two pins of the sensor. Something like 6K stone cold, falling as temp rises.
2. Supplied with 12v +ve and -ve, is either on (can be heard/felt to click as Xac advises) or off. Expect it to be off when engine is cold and come on once up to temperature (though they've never worked in both my Xantia's and the high idle when warm is usually an accurate sign of failure).
3. Don't care. It's the work of the devil and should be disconnected IMHO. But same principle as #2, it's eitther activated or not dependant on engine load I think.
4. Not entirely sure but I suspect it outputs millivolts (0-0.9), varying with injection lift.

Post by **KennyW** » 04 May 2010, 20:54

Cheers Mike,

Will check this week and get back to the forum with figures.

Kenny

Post by **KennyW** » 17 May 2010, 16:58

Hi All,

Slight delay in checking but here I go.

Needle lift sensor I got 137 ohms which is a bit higher than 90 -100 ohms but this was a cold engine. I presume engine has to be at running temp.

Again, I checked the resistance across pins 1 & 2 I hope that was correct but more importantly does the engine have to be running

Kenny.

MikeT · Post by **MikeT** » 17 May 2010, 17:17

Hi Kenny,

AFAIK, the needle lift sensor outputs millivolts when the engine is running. It show as 0.9v to 1.0v on my lexia for instance. What I don't know is what the proper spec should be but 130ohms sounds like it's not broken at least.

Post by **KennyW** » 17 May 2010, 17:34

Hi Mike,

I think my problem is No 3 Injector where the needle lift mechanism is located and probably faulty.

I am thinking of changing it for one from the scrappie, tempted to remove part of the wiring loom but it looks to be more trouble than it is worth.

Kenny

Post by **CitroJim** » 17 May 2010, 17:34

It should be fine as long as it has continuity in the hundreds of ohms..

Yes, low output, hence the screened cable.

MikeT · Post by **MikeT** » 17 May 2010, 17:58

Thanks for confirming that Jim.

Kenny, you know you can test individual injectors by releasing the fuel pressure and seeing if the problem disappears. What makes you suspect it's #3? It works on the same principle as the others, the only difference is the lift-sensor, an odd-on device that merely measures movement, it does no actuating.

Post by **CitroJim** » 17 May 2010, 18:40

MikeT wrote: an odd-on device

It's an odd device all right Mike...

Kenny, is there anyone near you with a Lexia? That would nail the issue once and for all as the NL Sensor can then be fully operationally tested.

Post by **KennyW** » 17 May 2010, 19:07

Hi Jim,

I think the nearest member is David Hallworth in Glasgow with a lexia, he has kindly suggested to contact him if it requires testing.

Kenny