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Shogun sport 2.5 low speed misfire.


 
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win
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PostPosted: Wed May 11, 2016 20:58    Post subject: Shogun sport 2.5 low speed misfire. Reply with quote

Hello everyone I hope you guys and help me out with my issue. I have a shogun sport 2.5 2006. Here is the story. Last year after it was in for a service  it developed a intermittent misfire,the garage fitted 2 different fuel filters and no different. Long story short I got nowhere with the garage and it was left like that. The misfire/hunting was very intermittent and only at low speed 20to40mph and 1000 to 2500rpm. It then went away over the winter and has only came back now although more frequent. It seems to be less in the morning  but gets worse the more the car is driven.Aftervits stood outside work all day it is worse on the way home. When I accelerate it is hardly noticeable but drop down to crawl through traffic and its kangarooing but only for a few seconds. No eml on at any time.
So on reading through the forums on here this is what I have done so far. Changed fuel filter for a dealer one, ran a pipe from a can of diesel direct to the pump and drove it, cleaned the egr valve, adjusted the turbo as suggested on here,checked all working plugs in engine bay,checked vacuum pipes and all seem to be sucking. All this has made no difference. I think it definitely gets worse due to temperature as it went away in the winter and it gets worse as it warms up.
Any help would be great as I'm demented with it. If I can avoid going to the dealer it would be great.
Thanks in advance
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PostPosted: Wed May 11, 2016 20:58    Post subject: Google Ads keep the POCUK free to join!


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Simon_W
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PostPosted: Thu May 12, 2016 1:01    Post subject: Reply with quote

When you rigged up a temporary fuel supply did you by-pass the fuel filter or run the fuel through it? (I know that you wrote 'direct to the pump', but just wanted to be sure)

The description of your issue sounds to me like it's air getting into the fuel system.  When the engine is doing higher revs it's better able to purge the air out of the fuel pump.

If you can't fix the problem yourself, it may be cheaper and more effective to go to a specialist diesel shop than to a dealer.
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win
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Age: 50
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PostPosted: Thu May 12, 2016 6:37    Post subject: Reply with quote

Hi Simon thanks for your reply. Yes I bypassed the filter. I wanted to eliminate the fuel system right from the tank and the lift pump as like you say I did think it could be air. I used clear hose on both the return and supply and put the can in the passenger foot well.The supply did not look like any air or disruption but the return was full of small bubbles,there is no fuel leaks from the pump to the injectors so I presume it's not that. It starts on the button and no smoke or anything and no lack of power apart from when it hunts. Could it be temperature related? Or maybe an injector fault? I have spoken to a few specialist who most just say it's the pump however I'm not convinced as the fault went away all winter. Aghhhhhh
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Simon_W
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PostPosted: Thu May 12, 2016 7:24    Post subject: Reply with quote

Sounds to me like you've been very thorough.

If there are small air bubbles in the return line, there's air getting in somewhere.  I'm not familiar with the 2.5 engine, but on the 2.8 the fuel return line is teed and under certain circumstances the return fuel is fed back into the pump via a solenoid valve which is meant to advance the ignition timing.  So this could account for air getting back into the system.

The most likely place for air ingress is the leak-off rail, which sits on top of the injectors. If this was my truck, I'd remove it and make sure everything is in order.  It would probably be worth you fitting a new set of washers as a precaution. When I got my Challenger, the nuts had been overtightened and the washers mashed into the injectors.

Diesel is more viscous in cold weather, which might explain why you weren't getting this problem in the winter.

Don't forget that air ingress won't show up as a diesel leak - it's air getting in not fuel leaking out.  

It would also be worth checking that all the injector pipe nuts are properly tightened. A flare nut spanner is a good investment if you haven't got one already.

Good luck!  Smile
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win
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Age: 50
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PostPosted: Thu May 12, 2016 7:49    Post subject: Reply with quote

Simon
That makes sense. I never thought of that. The return is teed on the back of the pump but it looks like a banjo fitting. The bubbles were there at idle but got lessvas the engine reved. I will take a look at this tonight after work. Thank you again for your input. I will let you know how I get on Smile
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win
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Age: 50
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PostPosted: Thu May 12, 2016 20:03    Post subject: Reply with quote

So pulled the rail to bits and cleaned all faces (did not replace washers as did not have any and they did look ok) took for a drive. could still feel slight hunting,after 5 or so miles got worse again so exactly the same. more so in 2nd and 3rd gear low speed in traffic. losing the will to live now. Is there any point in having diagnostic as the eml has never come on?

Cheers
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Simon_W
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PostPosted: Thu May 12, 2016 20:47    Post subject: Reply with quote

win wrote:
So pulled the rail to bits and cleaned all faces (did not replace washers as did not have any and they did look ok) took for a drive. could still feel slight hunting,after 5 or so miles got worse again so exactly the same. more so in 2nd and 3rd gear low speed in traffic. losing the will to live now. Is there any point in having diagnostic as the eml has never come on?

Cheers


I wouldn't have thought so, if the light isn't coming on.

What about the small diameter hose from the leak off rail? Is that sound and tightly sealed at the ends?  It would only cost a few pennies to replace it, and it may be worth it.
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win
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Age: 50
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Location: newcastle upon tyne

PostPosted: Thu May 12, 2016 21:32    Post subject: Reply with quote

hi simon. no it was quite loose I could move it. when I put it back together I tightend the clips but now you mention it it is the braided kind so I guess the rubber inside could be perished. could it be that simple I wonder? I eill neef to get some fuel hose that size and repace it. I will get to the bottom of this!! Smile
thanks again Smile
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Simon_W
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PostPosted: Thu May 12, 2016 22:18    Post subject: Reply with quote

I hope I'm not wrong with my diagnosis of air in the system. But if I am right, it's just a matter of working through the possibilities and eliminating them.

I know from experience how frustrating it can be. A good feeling when it's fixed though.  Smile
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win
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Age: 50
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PostPosted: Mon May 16, 2016 15:26    Post subject: Reply with quote

Well my head is done in now! Think I may have to bite the bullet and send it off to a diesel specialist Sad
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