HDi 2.0 8V wont start when cold - FIXED - NOT - YES

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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by Peter.N. »

I do get it right some times. :-D Pleased it worked for you.

Peter
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

:evil: :evil:

it didn't work....

car is now as bad as it has been.. warm starts are impossible as well as cold..
it bumps ok..

I took starter apart last weekend.. to replace the bushes, but there was nothing wrong with it really..

I took the latest pressure reg out as well, and there was a bit of swarf in the tube..
so.. I have a theory.. bearing in mind the reg is the only thing that makes the car start properly, albeit for a few days or a week..
maybe I am getting metal constantly into the reg, and its clogging up.. leading to starting problems.. from the lift pump as Peter suggested..

how are they bypassing the fuel filter..

ideas welcome :twisted:
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by Peter.N. »

Oh dear, it worked OK with mine but I had changed the lift pump as well. I can't understand how this rubbish is getting past the filter either, I thought it would remove particles smaller than you could see - unless of course the swarf is damaging the filter and forcing its way through. I fitted a second hand pump from the scrap yard and its been fine so far.

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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

Thanks Peter. . I changed my inj pump also. . As part of trying to fix this problem. .. along with battery.. glow plugs..filter.. grr

will change lift pump and report back. .
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by BX »

Just a little clarification. I originally suggested removing the filter but that was on a different thread. A clogged filter on the pressure regulator causes the engine to stop usually but not always either when being revved hard or when the accelerator is lifted as the car descends a hill.
Contamination of the valve in a reg without a filter can cause the no start problem as can a faulty regulator or several other problems.
Running with a regulator that has no filter cannot affect the injectors. Fuel that passes through the regulator is returned to the tank and must come through the filter to get back to the high pressure pump. If there is a continuous build up of contaminant then there is the possibility that the main fuel filter is not correctly fitted. Some of the earlier Bosch ones were difficult to get right. A little bit of displacement meant that the fuel could bypass the filter. If all is well with the filter then perhaps the contamination is being generated within the HP pump.
If changing the regulator seems to bring about a temporary fix then possibly there is a problem with the electrical supply to the regulator such as a bad connection or a wire broken inside its insulation. Another common problem on common rail systems is excessive leak off from one or more injectors. This often results in a failure to start on the key but will start easily when bump started.
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

thanks BX.. interesting..

this is the 2nd fuel filter.. fitted fine as far as I know..
second injection pump...
neither changes have fixed or made any difference to the problem..
can you elaborate on why leak off could cause bad starting?
I may plug the lexia back in sometime, to see if that can shed any light..

I must admit, for some reason I just assumed the reg was before the injectors, but from what you say it is after them, in the system.. interesting..


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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by BX »

If there is excessive leak off from injectors then the high pressure diesel is being allowed bleed off back to the tank. This usually shows up when the engine is being cranked to start. At these low speeds (200rpm vs 800rpm idle) the pump cannot pump enough to overcome the leak off and get sufficient pressure for injection to occur. Contamination on the valve of the pressure regulator causes the exact same problem. To check the injectors the leak off pipe from each injector is taken to a graduated container (seperate one for each injector). The engine is then cranked over and the flow from the injectors is compared. There is usually one major offender. I have never found a leak off problem from injectors on the hdi engine but as i always point out PSA cars are basically the same as most others so I would expect the same problems to occur. Im sure that someone has put a lead off test on Youtube by now. Simpler to look at than explain.
Just found one
https://www.youtube.com/watch?v=W58q42wYCM4
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

thanks :)

will get onto it asap.,...
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

hmm.. did a basic leak off check last night.. attached about 7 x 30cm pipes to the outlets (and blanked 3 of them off) and held them up..got the engine turned over and running..

1 3 and 4 weren't showing much..
2 was..quickly filled the 30cm or so pipe..

will fit an Injector for #2 and see what happens..

Out of interest, where is the log in the lexia? I can't find mine although have perused it before..

thanks all
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by BX »

Hopefully this will solve your problem. As regards the regulator being either before or after the injectors, neither is the case. It is in parallel with the injectors. The high pressure pump is a fixed displacement pump. The quantity of fuel pumped is directly proportional to the rpm. However one of its 3 pistons can be deactivated to save on power, to reduce the load on the timing belt and to reduce heating of the fuel. The deactivation is controlled by the ECU and effected by the electric unit on top of the pump. The high pressure fuel can go 3 ways. Into the cylinder via the injectors, leak off through the injectors and back to the tank or via the pressure regulator and back to the tank. So the following can result in insufficient pressure to start the engine. 1: lack of supply due to a faulty low pressure pump or other fault on the low pressure circuit. Low pressure circuit faults usually cause the engine to remain stopped. 2: a worn or faulty high pressure pump. 3: a leaky pressure regulator. 4. One or more injectors with excessive leak off.
Later high pressure pumps often have an internal lift pump and do not need the in tank pump. They also often have a metering valve and control the high pressure by controlling the amount of fuel entering the high pressure section. This is more energy efficient than early common rail pumps which can consume up to 4.5KW.
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by jgra1 »

big thanks to BX, and everyone else with suggestions.. feel I understand a bit more about HDi's now.. just a bit..

fitted spare injector last night, took all of 3 minutes :)

car started on the button today, quicker than it has ever to be honest.. 10 months.. 2 cans of easy start..

:twisted: :twisted:

if the car proves to be reliable again, I may even treat it to an interior drivers door handle! :-D

will post pre and post injector parameters soon. (I haven't seen the new readings yet)

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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by CitroJim »

That's good news John... Excellent :-D

Fingers crossed it was that injector [-o<
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by BX »

Hopefully that's the end of your problem.
All common rail diesels are very similar and give similar problems. I think that the number of hours running is often more important than mileage hence some low mileage vehicles giving problems whilst other owners get interstellar mileage without a problem from identical vehicles. This is very noticeable in vans which are fitted with ancillary equipment. Notable examples would be ice cream vans, vans where the engine is run for long periods for refrigeration, vans with powered access equipment etc. Many worksite vans run for hours keeping hazard lights and rotating beacon flashing. All the while the in tank pump (if fitted) runs the whole time while the high pressure pump is:- under high pressure as are the injectors. Likewise a car that never gets out of the city and spends its days in stop start traffic. Many of the newer Cr diesels use a metering valve which controls the amount of fuel entering the pump and thus regulates the pressure either by itself or in conjunction with a pressure regulator. In this case the pump does much less pumping, consumes less power from the engine and doesn't heat the fuel as much. Many of these have an internal vane pump similar to the one in the Lucas dp or the Bosch ve injector pumps and so do not need the electric low pressure pump. Normally these models have a priming pump under the bonnet.
Having appeared first about 16 years ago the 8 valve 2.0 HDI is well proven but getting rather old fashioned technology wise.
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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by Peter.N. »

I have two 8 valve Hdi's, one in a 406 which has done 226,000 miles and a C5 that's just coming up to 200k, they are both mostly original including the clutch and DMF - and of course the turbo's. 8-)

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Re: HDi 2.0 8V wont start when cold - FIXED - NOT - YES

Post by taffy »

well done glad u got it in the end!!:)
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