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        General >> Problems >> Idle problems
        
(Message started by: Spannerdemon on Jan 22^nd, 2007, 7:56am)

Title: Idle problems
Post by Spannerdemon on Jan 22^nd, 2007, 7:56am

I'm still having idle problems on my 1996 12v 2.9.

Have replaced the IACV, and this has made a slight difference in that the engine now keeps running rather than cutting out occasionally, but I am still getting problems with fast idling (around 2000rpm), when I select N at traffic lights.

Car runs fine, with no other problems, but what I would like is a picture of the Throttle Position Sensor, and any info on TPS resetting or adjustment, if anyone can help here.

Butterfly spindles are clean, cable is free, and I am starting to run out of reasons for this problem. I've disconnected and re-connected the battery to re-set the ECU, but without much difference. I read somewhere about a pipe which has a coiled covering around it which may be damaged (is this on the 12v?), but don't want to poke around without knowing what I'm doing.
I also have a very slight (and I mean VERY slight) petrol smell occasionally, which may be connected.

Any ideas?.............Thanks. Can't check till later, but I'll be back. ;)

Title: Re: Idle problems
Post by tintin on Jan 22^nd, 2007, 11:47am

Hi,

Mine has a high idle (about 1500rpm), which drops after 10 seconds to normal again. Sometimes jumps back up too, but usually instigated by a rev. I am suspecting vacuum hoses incorrectly re-attached after work on engine, or an air leak somewhere.

I think the TPS is reset with a battery disconnection, so i dont think it would be that.

Hope this helps,

Title: Re: Idle problems
Post by Simmo on Jan 22^nd, 2007, 12:25pm

S/D, have a look at the first two items on THIS page (http://search.atomz.com/search/?sp-q=TPS&sp-a=sp100172f5) and see if they help. ;)

Title: Re: Idle problems
Post by Spannerdemon on Jan 22^nd, 2007, 2:49pm

Thanks for this guys. I'm planning on sorting this out on Wednesday when I have some time off, so any further info will be useful.

Many thanks. :)

Title: Re: Idle problems
Post by gary1 on Jan 22^nd, 2007, 4:20pm

Hi
Not sure if this helps but i had the same problem on my 2.3. I cleaned the IACV and it made no difference so i then chaged it and it made no difference.I then thought it might be cheep petrol so i started to buy it from a bp garage and the problem went awy. 2 months later put some supermarket fuel in her and the problem came back. Started to use bp petrol and the problem went away again.
Gary

Title: Re: Idle problems
Post by TiberiuS on Jan 22^nd, 2007, 5:42pm

SD, from my recent experience with 3000rpm cold idle attempting to carrying me down the road at 40mph, I come to the conclusion that the TPS is very sensitive. If you can get at the TPS you can try rotating it a bit and see if this cures the problem...does the car start and idle ok until you give it some throttle and then latch up to 2000rpm?

Regards, Bruce.

Title: Re: Idle problems
Post by Spannerdemon on Jan 22^nd, 2007, 11:51pm

come back to you soon. have burnt my hand quite badly at work. just got back from a&e.

thanks s/d. :(

Title: Re: Idle problems
Post by Spannerdemon on Jan 23^rd, 2007, 1:03pm

Quote:

If you can get at the TPS you can try rotating it a bit

Bruce, can you elaborate on this, as I'm not sure what you mean here. As far as I can see, my TPS is held on by a couple of bolts, so 'revolving' isn't really possible......or maybe I'm missing something.

Please keep those ideas coming, because I need to get to the bottom of this. It's driving me mad. >:(

Sorry about the delay in replying. Tipped very hot cooking oil over my hand at work last night and needed A&E, Morphine and all the rest. Bit messy!! Really hurts like hell if I'm honest. :o

Title: Re: Idle problems
Post by TiberiuS on Jan 23^rd, 2007, 1:58pm

SD, just had a racing idle on my X300, spent all weekend rebuilding the throttle body trying to sort it. Most TPS are similar, on the AJ16 it's held in beneath the throttle by 2 bolts. In the service manual it says to rotate it and calibrate it with a voltmeter (no idea how to do this) but as you say there's not much 'give' in it. Might be worth undoing the bolts a tad and trying to move it around a fraction or undoing the throttle butterfly stop screw (if you have one ::)) a bit, just to see if it will idle then. On mine it would idle fine but then latch up to 2500rpm if I revved it (remember the old auto chokes?), trying to adjust the TPS has cured mine for the moment.

Take it easy, bloody painful thing to happen...had a few injuries in my job now :o

Regards, Bruce :)

Title: Re: Idle problems
Post by Spannerdemon on Jan 23^rd, 2007, 2:00pm

Cheers Bruce. I'll have a go at this probably on Thursday now, as I'm a wee bit sore today!!

Teach me to be more careful!! ;)

Title: Re: Idle problems
Post by Dave on Jan 23^rd, 2007, 2:09pm

Ouch! Sounds very nasty, take it easy mate :)

Title: Re: Idle problems
Post by TiberiuS on Jan 23^rd, 2007, 4:36pm

A few of us have been having idle trouble on the XJ. Just got an email back with this by an ex-Jaguar technician:

“The TPS signal is critical to entering the idle speed control. It is the main signal by which the ECU determines that the throttle is closed and therefore the engine is meant to be idling at a fixed speed. If the signal from the TPS is too high, the ECU will not trying to control the idle speed. I assumes that the operator is holding the throttle partially open and will not attempt to set the idle speed..

The idle control stepper motor goes to a std position based on the transmission’s selection of drive or neutral and coolant temp. This position is intended to give a slightly high idle speed, the ECU then fine tunes the position to get the idle speed to the correct value.

If the ECU doesn’t think the throttle is actually shut (i.e. the driver is holding the throttle slightly open with the accelerator pedal) it will not try to control the engine speed be modifying the stepper position.”

I know it's Jaguar again but both cars are similar in many ways, may help someone :)

Regards, Bruce.

Title: Re: Idle problems
Post by Spannerdemon on Jan 24^th, 2007, 11:42am

HERE (http://fordfuelinjection.com/index.php?p=30)

Found this too which may be very useful to others, and certainly has helped me to understand this aspect of idle more thoroughly. :)

There are also a large number of TUNING downloads on this site.

Title: Re: Idle problems
Post by Spannerdemon on Jan 25^th, 2007, 9:33pm

Thanks Dave. Recovering, and VERY VERY lucky to get away with some large 2nd degree burns over quite a lot of my left hand. About half a pint of almost smoking olive oil....... :o

You're right Bruce. I've managed to have a VERY close look today at the Throttle Position Sensor. I told my missus that it's occupational therapy....she wasn't impressed.... }{ }{. Well, got to do my chores haven't I ;D ;D

Anyway, as a nurse, I said she needed some practice in changing the dressings...........OUCH!! >:( >:( Even less amused. }{ }{

It's held on by two very small thin 7mm bolts (GOD you wouldn't want to drop THEM into the engine compartment).., and there's a plate which prevents the bolts from turning. Just a simple anti tamper (yeah right ;D ) bend over flap on each side.

By flattening out the plate, and slackening off the screws, the TPS can then be rotated 'very' slightly (not much in it), but there IS a definite adjustment area to either the left or right. I've turned it fully anti-clockwise for now, and tightened it down again. Also cleaned the throttle butterfly spindles, chambers and all round that area on both inlets. There was quite a bit of muck in there. I also slackened off the idle screw so that there was no pressure on it whatsoever.
It's now 'just' touching the cable lever assembly.

Then cleaned and checked the TPS plug, and disconnected the battery for a couple of minutes to re-set the systems. I'll let you know how I progress, but it MAY just be a starting point. I'm also going to try and source a new TPS for a reasonable amount, so I'm on with that now.

Haven't had any time to take it out today, but I'll update tomorrow. I'll rotate it the other way if there's no improvement. Got my spanners with me. ;)

Title: Re: Idle problems
Post by Dave on Jan 25^th, 2007, 10:47pm

:o I say again, ouch! As you say, could have been worse I guess, glad it wasn't :)

Re the TPS, have you had a gander at this page, makes interesting reading:

http://www.fordscorpio.co.uk/obd2scan9.htm

Title: Re: Idle problems
Post by Spannerdemon on Jan 25^th, 2007, 11:21pm

Yeah. I've seen this. Trouble is, my 12v 2.9 can't run the OBD2 diagnostic stuff. I gather that none of the 12 valve models are compatible with it, which is a bit of a bummer.

I've actually just put a new post up to seee if anyone can help me to get to grips with this.

thanks anyway. Any advice is always welcome. :)