Doctor Diesel

Old Smoker

Web02I have a 2003 Peugeot 307 D Turbo with the eight-valve 2.0-litre HDi 110 engine that has covered 97,000 miles with relatively few problems, apart from the dual-mass flywheel failing at 48,000 miles. It has been mainly dealer serviced from new, and I have a good relationship with my local dealer. However, over recent years, it has become somewhat troublesome to start after being parked for a few hours, more so in the last year. It takes quite a bit of turning over to bring the engine to life and, when it does start, it starts with a cloud from the exhaust and slightly rough idle for a few seconds. Once started, the car runs fine for the most part – except every once in a while, if I haven’t let it settle for a minute or two, when I find it losing acceleration until I pull over and increase the revs, after which normal performance is restored until it is parked up again for a few hours. Initially, I thought that it could be the fuel filter housing, as I know that they can be prone to hairline cracks, so I replaced it with a new Siemens housing from Peugeot. This didn’t work, so next I had the injectors removed, tested, and overhauled at a local specialist, but that didn’t improve matters either. They suggested that the starter motor was a bit slow to turn over, and that this could be preventing the fuel rail from building up pressure. So I replaced the starter motor and, for a while, there was a significant improvement to the starting. Now, however, a few months later, the problem starting has worsened again. It has been back to the dealer and they have checked for leaks in the fuel system, and also the pre-heat system, and they have found nothing, and are reluctant to do much more as the repair cost could be more than the car is worth. I have parked the car facing downhill to see if it makes any difference, but it doesn’t. (Is that based on some feng shui theory? Doc.) I am reluctant to sell it, as I like the car, and, in all other respects, it still goes well and is in good condition. Would you have any suggestions on what could be causing this problem? Yours frustratedly,
Huw Davies

They don’t make ‘em like that any more, do they Huw! A fine car, and I can well understand your reluctance to sell it. Apart from which, some purchaser or dealer will then inherit the annoying problem!
But I can think of a few other things that you haven’t tried yet:
1 Parking it uphill.
2 Beating it hard with a stick, Basil Fawlty style.
3 Speaking to it nicely, before you turn the key.

Seriously though, you haven’t told me what sort of motoring you do, but I would hope that you have tried giving the car a good hard run, maybe with a fuel additive in the tank, to see if the engine is just generally congested. But the key thing you haven’t told me is whether the “cloud from the exhaust” is white, blue, or black. I would imagine that the air is blue though, but is the smoke? Black smoke typically means incomplete combustion, in the form of too much fuel or too little air, or incorrect combustion conditions like injection timing, badly worn injectors, or poor cylinder compression. White smoke means completely unburned diesel fuel coming through, or can also mean water intrusion, maybe through a cracked cylinder head, or low cylinder compression. Blue smoke usually comes from burnt oil, from valve guide wear or poor cylinder compression, and oil leakage past the pistons and rings.
Now that’s a fair selection and, if you want to continue your DIY investigations, I think you should check a number of items that I would have expected the garage to have done, but guided by my comments on the colour of the smoke. Firstly, have you replaced the air filter and checked for any obstructions or kinks in the air pipes? The fact that the car apparently runs well once hot, apart from those odd loss of power situations when warming up, does suggest that this is strictly a start-up problem though, and poor cylinder compression could be possible at your fairly high mileage. You should probably get this checked by a garage before anything else now, and it could be either bore and piston wear (which you might have noticed from oil usage) or valve leakage. You haven’t mentioned the MAF sensor, which again hopefully the garage has checked out, by way of checking the signal voltage in cold start-up conditions.
You don’t say whether the starting problems are ambient temperature related, and you say that the garage checked the pre-heater system anyway, meaning presumably that the pre-heater plugs were working properly, and for the correct period of time. You could check yourself by turning the key to activate the pre-heater plugs, but without starting, and see if doing this two or three times before turning over the starter helps at all – the pre-heater light on the dash (if you have one) may only stay on for about five seconds, or in fact may not show at all at higher temperatures, although the plugs may be operating in the background as part of emissions controls. I presume that your battery is in good shape to generate enough cranking speed to get the required injection pressure?
Of course the killer might be injection pump wear, as pump replacement could be very costly, and I guess this can only be checked at a Peugeot garage or, better still, at a diesel specialist – usually well experienced in such problems on hard-working light commercials.
I hope this gives you some ideas Huw, and would much appreciate you keeping me posted. Best regards,
Doc Diesel

Huw replied:

The exhaust smoke is generally white, with a hint of grey, and if you give it a rev to help it on its way, it does result in a patch of soot on the ground behind the car. I tried parking uphill and also activating the pre-heat a few times, and it makes no difference. The air filter is a K&N panel filter and gets inspected every service, and if necessary cleaned. The driving I do is mainly to work and back, once or twice a week on the motorway, just over 50 miles each way, with trips to the shops each weekend. The battery was replaced a couple of years ago, but I’ll get it checked, and thinking about it, when I had the car remapped, the technician did mention that it wasn’t responding as well as other 307s he had remapped and did wonder if the mass air flow sensor might be to blame, although the engine management light isn’t on. I will try these two items next as the costs my dealer had warned me about was in fact possible loss of compression, or a fuel pump problem.

You didn’t mention before the engine had been remapped! Did you tell your garage? This usually involves raising the fuel injection pressure. If your tuning man said that the engine did not respond as well as other 307s, then he might have pushed the pressure up more than usual to get a good result. Who knows how this might have left you, but it certainly might be a factor in your problems. A proper professional job would adjust the pressure proportionately, leaving starting conditions unchanged, and it’s far from impossible that it is set too high for good cold starting. If you do feel, as it seems, a bit of a DIY man, you could try cleaning the MAF unit, with electrical contact cleaner. There’s not enough space to go into details here, but you can probably find instructions for an HDi 110 online somewhere. MAFs don’t often throw up warning lights or fault codes if they are just dirty, from oil and other deposits on the heated wire filament of mesh. See how you go on and keep me updated.
Doc Diesel

One Response

  1. I’ve had a long history of remapping, chipping and mechanically tuning Pugs, mainly 406s but also 306s, 307s and 407s. The only time I ran into a problem was with my, guess what, 307 1.6 HDi 110. It went like stink after being remapped (no DPF removal) but I did keep getting the engine light on because it was a poor quality remap done on the cheap. I currently own a 307 Feline (2.0 177bhp) which is about to be remapped; in the past, this car has just cut out on its own, I’ve had to pull over, it wouldn’t restart for a minute then spontaneously went back to normal. It’s done it twice but the last instance was a year ago. I think it may have been the fuel filter. Also 307s do tend to have head gasket problems. To be honest though, I’d say this sounds like a dodgy map. Pugs respond really well to tuning but are sensitive to poor quality work.

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