hdi 90 - hesitation at low revs and coming off clutch pedal

[eoin27]

Accelerator cable was slightly slack, though I then adjusted the pin too much and it became worse to drive, have put the pin where the cable is now just tight enough and drivable.

Completely off topic here. But I adjusted my accelerator cable last night as it was a liitle bit slack. Not like the HDi method, the cable itself had actually stretched past the last adjustment on the thingy. I had to put a load of elecrical tape around the end and stick the pin on then. RESULT! I thought it wasnt affecting acceleration but man was I wrong! Its really really responsive now. For the first time since I bought it last month Im getting some serious power response in the low rev band. Now I just need to get rid of that awful exhaust rattle and oil leak

edit: also realised that the cruise control switch is dodgy rather than the vaccum pump in the engine bay Must get to that at the weekend

[sirwiggum]

Seemed to run a bit better last night with the MAF disconnected.

I can only assume that the default setting of a disabled MAF is such that the ECU is overfuelling slightly?

Strange that the engine management light didn't come on though.

I'll wait on the new MAF arriving, fit and connect it and see how it gets on!

[FlySpeck]

yep overfuelling at idle mostly but a default airflow (mass actually) is assumed across the board, and the fuel injected accordingly, and thru filter clogging, or carbon build up etc the airflow will be less than factory spec now.

[sirwiggum]

yep overfuelling at idle mostly but a default airflow (mass actually) is assumed across the board, and the fuel injected accordingly, and thru filter clogging, or carbon build up etc the airflow will be less than factory spec now.

Both the air and fuel filters (whole housing) were replaced.

New MAF on. Feels bit better to drive.

However, the 1500-1800 rpm hesitation is still there.

Will need to drop off for a diagnostics.

Think the accel cable is slightly slack at the longest pin position, so might try Eoin's electrical tape trick, see if that feels a bit better for a less jerky gearchange.


This mornings drama was, after having to mount a kerb to turn into a side street because a disAstra decided to sit near enough in the middle of the road to turn out, the ABS light came on.
Googled ABS light, and the consensus seemed to be sensors etc, and a dealer reset of the ABS ECU, £££s.
Driving it for an appointment an hour ago, ABS light and ABS FAULT on the display came on at startup. Drove it down the road and the light went out. Road was not busy so tested emergency stop at 30 - braking straight and true, can feel the ABS on the pedal, no lockup. Never came back on.

I read on the board that if the ABS ECU feels a difference between wheels, it assumes a fault. Therefore it doesn't like mounting kerbs on morning drives.
This, or my 406 is magic and fixes itself

[eoin27]

I wouldnt worry about the ABS light if it went off straight away again. If you just hit a kerb, the sensor could have moved slightly and then corrected itself. If it stays on all the time then you need to worry.

disAstra

Ha, havent heard that one before. Ashtray seems to be the most common term for that terrible car.

Think the accel cable is slightly slack at the longest pin position, so might try Eoin's electrical tape trick, see if that feels a bit better for a less jerky gearchange.

If the cable is slack, then that most likely is your problem as that issue only affects low RPM driving. Interesting that it happened on a HDi. TBH, Im not happy with the tape trick as I feel there is a bit of play still. I heard another trick is to use a pen top and that will effectively lenghten the range of the adjuster and you can place the clip at the top of the pen-top. Complicated to explain. This should help.

[FlySpeck]

if its got a DBW (drive by wire) electronic throttle control like mine, the DBW/TPS sensor may have a bad bit on the carbon track inside, where the actuator sits at that particular revs, might be worth a swap from a scrapper....

[sirwiggum]

if its got a DBW (drive by wire) electronic throttle control like mine, the DBW/TPS sensor may have a bad bit on the carbon track inside, where the actuator sits at that particular revs, might be worth a swap from a scrapper....

Yea seems to be DBW, the cable comes up to the end of the throttle, a spring loaded movable end that doesn't seem to be connected physically to the air intake / a butterfly valve. On the other side of the spring loaded mechanism is that throttle potentiometer.

Had never thought about the throttle pot. Def. worth a try, strangely enough I remember it going on my old Xantia 1.8 16v.


Other thing is, last night I got round to tweaking the accelerator cable, felt a bit more willing. However, nearly every time she idled the engine management light came on with anti-pollution fault.


Then this morning she was reluctant to start without a fight. Re-adjusted cable to where it was and replugged the EGR just in case and eventually coaxed her into starting.
Once I made it in, parked up and restarted the engine without any problems.

Other thing I noticed while I had the engine cover off was that my new fuel filter housing (supplied by part number from reg/VIN from Peugeot dealer), which had 3 ends (I kept the cover on one end as I only have 2 lines which I guess are in and out), the cover of the unused end was loose and it was dripping a small bit of diesel. Will need a 2 port fuel filter housing.

[Welly]

If you've got a diesel leak then maybe that's a cause of the rough running (air in the fuel) ??

[eoin27]

Diesel leak? I'm guessing High pressure fuel pipes.

[Welly]

He said the fuel filter had a weep, the system primes itself but I wonder if bubbles can occur??

[sirwiggum]

Though it was running like this before I put the new fuel filter housing on, the old one was the 2 pipe one.

The Pug dealer gave me a 3 pipe one. I had it fitted and tried, the engine ran as normal and I didn't think anything of it.

Definitely going to search for the 2 pipe one though.

That is maybe what happened this morning, maybe if the pressure of the diesel loosened the cap on the unused 3rd pipe out of the fuel filter housing, and air may have gotten in.

Will report back with results!

[sirwiggum]

Looked up, dealer sold me a Siemens fuel filter housing with 3 pipes instead of the 2 pipe Bosch one. The particular dealer has a bad rep locally, I think I will try the one in the next town next time.

She is having trouble starting in the mornings now. Feels like fuel starvation, like that seen if you change a fuel filter on the old XUD engines but do not prime the system properly.

What I will do later is:
- Temporarily block the 3rd pipe with a big screw / bolt wrapped in PTFE.
- Order and wait on the Bosch fuel filter.


Strange that this is only happening now, about a month and a half after the fuel filter housing was replaced.
I can only guess that my tweaking to the accelerator cable caused the fuel pressure to loosen the cap on the unused 3rd pipe.

I shall report back.
This may or may not help the original issue, if the seal on the original housing and the loose cap on the 3rd pipe of the new housing are having the same effect.


Other than that the starting issue and hesitation issue may be symptoms of the fuel pump dying a death?

[FlySpeck]

possibly, if the lift pump is weak then you may need to try switching the ignition on for 3 secs at a time, then off, then on again etc 3 or 4 times and then see if it fires up, showing that eventually the injection pump gets fed enough to prime the rail, or use the rubber baloon hand pump and prime it manually and see if that helps, if not, its not the lift pump I think but if it does, it would point to pump or filter.

If the system doesnt remain pressurised overnight that would cause the problem too from air entering and allowing the feed lines to bleed off back into the tank.

[sirwiggum]

possibly, if the lift pump is weak then you may need to try switching the ignition on for 3 secs at a time, then off, then on again etc 3 or 4 times and then see if it fires up, showing that eventually the injection pump gets fed enough to prime the rail, or use the rubber baloon hand pump and prime it manually and see if that helps, if not, its not the lift pump I think but if it does, it would point to pump or filter.

If the system doesnt remain pressurised overnight that would cause the problem too from air entering and allowing the feed lines to bleed off back into the tank.

Priming with the bulb doesn't help a lot. Nor does turning the ignition on (I used 10 seconds), off, on a few times.

Just sheer turning, pumping accelerator and gnashing of teeth.

I am certain that air is entering from that 3rd pipe input, I can see it in the pipes. If, when it is running, I push the plastic cap tight, I can see the air bubbles in the fuel line dissapear.

Had a big bolt to fit it to block it temporarily at lunchtime, but it is awkward to get at with the radiator hose right beside it, so the bolt fell into the engine bay somewhere. Tried to clip the cap tightly. Will look in the shed when I get home later.

New one on order, proper Bosch 2 pipe version (none of this dealer nonsense!), recorded delivery, hopefully be with me either tomorrow or more than likely Monday.


(Yes, I know I should have looked at the one in it with 2 pipes, the one the dealer gave me with 3 pipes, and literally put 2 and 3 together. I assumed it was one of PSA Peugeot-Citroen-Talbots "lets change the shape" things, and as it worked at the time I didn't think anything of it...)

[FlySpeck]

sounds like you hit the nail on the head then mate, air entering via the 3rd pipe.