Pug 306 - Lumpy idling when started + trip counter resetting

Our Peugeot 306 1.4l petrol, 1998 version has just started (as in today) idling quite lumpy once started - such that you feel it's going to stall (or at least, can imagine that it might).

It's just passed 120,000, so is getting longer in the tooth. Had it's MOT done last October and passed emmisions fine. Engine wise it's been okay. Slight oil leakage from the head gasket area (front left side) pretty much the entire time we've had it (6 years) - but not enough to cause us to have to top up much between oil changes, some tapping from the cam shaft (again, pretty much the whole time). No issues though with the running of the engine, starts immediately first time every time. Coolant has been okay-ish. No noticable mayo - but the coolant has always looked a bit rusty between changes, and is probably due for a change.

Plugs were changed last year, and we do about 10,000 miles per year. Oil change done about 6k miles ago. Earth strap replaced a year or so ago when it failed (causing weird electrical issues) - but haven't checked this time.

One other thing, which I wonder may be related, is that recently (last couple of weeks) the trip counter has been resetting on its own. I reset it each time I fill the tank and so noticed when, after half a tank of fuel has been used, it's suddenly reading only a couple of miles.

Just now, when the car was very lumpy, it seemed that whenever we pulled away from a junction, particuarly when changing up gears, it seemed to reset - we saw this happen a few times. Since then though, we've done about 15 miles without it resetting, even though we've had to stop the engine for a bit, and when re-started it was lumpy again. Might be a red-herring - but might be helpful. I'm wondering if it's an electrical problem (coil pack?) causing the trip counter to reset - which may also affect the ignition - but I've got no real idea of *why* it might cause it! Just a wild hypothesis.

There's no engine lights or anything else showing.

Any suggestions?

Thanks

David

Reply to
David Hearn
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On Tue, 19 Feb 2008 15:09:00 +0000, I waved a wand and this message magically appears in front of David Hearn:

Might be a worn camshaft?

Reply to
Alex Buell

When was the plugs last replaced? could be a plug playing aroundthey do now and again.check your coil pack is on a good earth as that does not help if it is not earthed ,

Reply to
Chris

This is a single pointer n'est pas? If so, its waaaay past having the injector cleaned / replaced.

Otherwise check the stepper motor and linkage for dryness / stiffness.

Tim.

Reply to
Tim..

They were replaced last year, I think around the same time as the oil was done, so maybe 6,000 miles ago?

D
Reply to
David Hearn

I've no idea whether it's single or multi point. The symptoms appear immediately after starting the engine, even when warm. After driving a couple of miles I don't notice any stuttering in the idling. I tried it at some lights yesterday after driving for a bit, immediately after restarting it was lumpy again.

I also noticed yesterday that it has started idling quite fast on occasions - not all the time and went for a bit after stopping and restarting the engine (but got the stuttering/lumpyness again). No idea of the actual RPM as my rev counter has no dial (the speedo motor died a while back and I swapped motors to get a working speedo - cheaper than £400 for a new instrument cluster from Peugeot).

Where's the stepper motor, and how would I check it? ;)

D
Reply to
David Hearn

I think it might be a bit worn as I've adjusted the valve clearances before to try and solve the tapping I've heard from that area at certain RPMs - but made no difference.

The stuttering/lumpyness actually seems to go after a few miles driving

- but immediately returns when you stop and restart the engine, even it was fine before (eg. stopped and restarted at some lights).

Is it worth purchasing an OBD reader of some sort to see if anything is wrong, or would it only show a fault code if the engine light is on?

D
Reply to
David Hearn

They sell them at this place:

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but I don't think your

98 model is covered. You can get fault codes without the engine light coming on.

You might want to try this:

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My recommendation is to disconnect and clean the battery terminals. Plus leaving the battery off for 5 mins plus will also reset the ECU. Then start up and take the vehicle for a good run. Might be solved as simply as that.

Reply to
daddyfreddy

Highly likely to be the Idle control valve/stepper motor sticking. I read of these only having 50k miles life. (my 405 ICV is playing up at

88k miles) Look for an electrically controlled valve with hoses in and out effectively bypassing the throttle butterfly. Sometimes these can be cleaned with carb cleaner and last a little longer. New ones (for my 405) are about £50 from GSF and double that from Pug. Not all ICVs are true stepper motors. Mine is a DC motor with two windings (three terminals) which by varying the current in the two coils can turn the armature though 90 degrees, enough to operate a valve between fully closed and fully open.

hth

Bob

Reply to
Bob Minchin

Well, I think I've found the stepper motor! After searching on eBay I came up with a similar picture, but not identical. See and/or . I think the part number is 1920 6W "Regulator MOT" in the parts CD.

The difference is that the black part of the shaft on my one is about twice the length.

The silver tip will rotate/move back and forth a tiny, tiny amount (more like play than intentional rotation as it's so tiny). The black bit on the shaft is a spring loaded collar over the inner shaft which connects to the silver tip. This black collar rotates fine, although with a little friction - more akin to the friction due to the end of the spring than anything else.

Other that that, nothing appears to move. Cannot rotate the tip, and cannot work out how the collar could drive anything.

My only conclusion is that this actually moves in and out, rather than rotates. Hence the lack of rotation of the tip, and a spring loaded collar around the shaft. Unfortunatately, this probably means its worm driven, and thus cannot be moved manually (I certainly couldn't!) - so difficult to be able to check whether it's working right.

What would happen if I just wired it back into the car, but didn't mount it? Should I then expect it to move? What about the fact that there's a big hole where it used to be? I don't want to spend quite a bit of money on it if this one is perfectly fine if this one could be tested somehow.

Thanks

David

Reply to
David Hearn

Your ICV is completely different from mine which is shown here and it works differently.

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Find something about the same size as the actuator and use that to control the engine speed manually. If the stepper is working properly, then you should see it smoothly move from one extreme to the other depending of whether the idle speed that your are controlling manually is above or below the set speed. Make sure the engine is not cold when you do thus and that the aircon is off and that the throttle is fully closed. I.e. you must be simulating tickover conditions. Bob

Reply to
Bob Minchin

Thanks for the advice - incidentally, any idea whether it's worth getting one from eBay? This one has the exact part number of the one I've removed: . At £25 (or maybe a lower offer) + delivery it's probably under 1/2 the price they seem to be at Euro Car Parts (not found exact one there, but looking at prices of stepper motors for same engine fitted to other cars), and apparently Peugeot would be about £110.

So - would you trust getting a part like this from eBay? Or is it better to pay the £60+ from a factors, or £100+ from the dealer? ;)

Thanks

D
Reply to
David Hearn

Well what you got to loose. go for it .

Reply to
Chris

Vendor says it BN and offers 12 months warranty. Feedback is good. I searched and found the vendor has accepted £20 for this item in the past so you should get it delivered for £25 or a bit less if you want to take the risk of losing it! I would take the risk but it up to you. First of all find out if you need one!!

Bob

Reply to
Bob Minchin

Well, I tried this - and as I turned the ignition on (not to start) I could see it move forward. As I started it, it moved out a bit further. As I turned it off, it moved out a bit further! As I tried to re-fit it, I noticed that it was now too long to fit into the hole! I thought I would screw it in as much as I could, and then hope that it might go backwards, and then I could tighten it. As I tried to do this, it all came apart!

As I expected, the centre shaft was threaded with a threaded rotor to the motor, driving it forwards and backwards (linear actuator?) and it had driven itself off the thread. Impossible to screw back in, you have to turn the motor to draw it back in. In the end I got it in as far as I could, then held it against the engine block whilst the car was started a couple of times, ignition turned on and off and eventually it drew itself back into the motor.

I did the screws up and started it - started first time and ran smoothly for a minute or two. Couple of small jumps up and down in the idle speed, but constant at those speeds for a while. Just need to take it for a test drive now.

The stepper motor shaft and tip was very heavily coated in oily gunk. Couldn't see how it would cause a problem, but I did clean it well, and when it came apart, I cleaned the thread of the centre shaft. Where it fits inside, I couldn't work out what it pushed (couldn't feel anything of any resistance when prodding in there) but what I did put in there came out with a slight oily gunky coating (rather than just clean oil). I stuffed a bit of kitchen towel in there to try cleaning it a bit.

Maybe I do need a new stepper motor - I don't know. Maybe it was just really dirty - have to see if the problem returns - or whether it's really fixed at all after a drive. Does make me wonder though, why it's so dirty in there though. It should only be oil, air and fuel going through there I'm guessing.

Thanks

D
Reply to
David Hearn

Well, didn't sort it (still stalling, hard to start without foot on accelerator). Long story short, it's now in a independent Peugeot specialist garage who tried re-initialising the new stepper motor (may not have done it properly myself) but didn't completely solve it.

Put diagnostics on it and said that it's giving 2 errors. Stepper motor (which is hopefully now historic) and MAP sensor. He's going to try replacing that to see whether it solves it.

Any idea whether it sounds right, and the sort of cost for the part?

Thanks

David

Reply to
David Hearn

They just called back with the price - just under £65 for the MAP sensor (I think inc VAT), and total cost of about £100 (again I think inc VAT) once the labour, testing etc is included.

Just checked GSF - don't know whether it's the right one, but they list (N92538) 306 MAP sensor as £46.50 (£54 inc), so not too bad.

Sound right? I hope it solves it!

Thanks

D
Reply to
David Hearn

Its taken time but at least you got it done and it will be running full speed ,so watch out for those speed cameras,and enjoy the sunny weather whats left of it,

Reply to
Chris

Well, full speed when it's not stalling at junctions.... ;)

The MAP sensor didn't fix it, and the stepper motor fault code keeps coming back, even though it's got a new one fitted.

The coolant temp reading was, I think -5 after starting the car, and -41 during the garage's test drive. It also said (on the fault code reader thing) whilst sitting in the garage it was doing 120kph with an RPM of 0.

The garaged suggested replacing the (green connector) coolant sensor as it's reasonably cheap, but if that doesn't fix it then it's probably a main dealer job to diagnose and it may be a "chase the sensor" situation. It also has a Sagem coil pack and Sagem ECU... so considering weird readings and the trip counter randomly resetting, it could possibly be an ECU fault.

He advised at 120,000 miles, financially it's probably not worth sorting the ECU (if that's the problem) or chasing the sensor problem (other than the coolant sensor). Particularly considering it has about £280 of brake/driveshaft work due (much fairer estimate than Peugeot's £680), it's due for a cam belt change, front tyres are getting near to needing replacement in the coming 6-9 months I think, slight external oil leak from around the head gasket area, needs a coolant change (deep rusty colour)... and the tax runs out at end of April.

I'm thinking that if the coolant sensor doesn't fix the problem, then it may be time for a new (well, replacement) car. :(

D
Reply to
David Hearn

It's not the code for the stepper motor being at the end of travel? In which case you're back to looking for air leaks.

Reply to
Duncan Wood

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