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

 

Might be a worn camshaft?

 

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 ,

 

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.

 

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

D

 

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

 

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

 

They sell them at this place: www.ecutools.com 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: http://www.peugeotdiesel.com/ECU_Faults.html

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.

 

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

 

Well, I think I've found the stepper motor! After searching on eBay I
came up with a similar picture, but not identical. See
<http://cgi.ebay.com/NEW-Peugeot-Idl...yZ10406QQssPageNameZWDVWQQrdZ1QQcmdZViewItem>
and/or <http://i7.ebayimg.com/01/i/000/a3/74/f16c_1.JPG>. 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

 

Your ICV is completely different from mine which is shown here and it
works differently.
http://i115.photobucket.com/albums/n313/9fingersphotos/IdleControlValve.jpg.

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

 

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:
<http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230225592876>. 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

 

Well what you got to loose. go for it .

 

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

 

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

 

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

 

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

 

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,

 

They tell me Autumn starts tomorrow ;o)

 

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