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Topic: misfiring badly at 50 mph (Read 7333 times) |
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Mike H
Senior Member
Renault Clio
  
Posts: 2594
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Re: misfiring badly at 50 mph
« Reply #80 on: Oct 8th, 2011, 7:56pm » |
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on Oct 8th, 2011, 7:05pm, Tompion wrote:
You could try recording the outputs of sensors ... with the misfire occurring to see if any readings are fluctuating |
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Good thinking Batman 
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Mike H
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: misfiring badly at 50 mph
« Reply #81 on: Oct 13th, 2011, 3:17pm » |
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How are we getting on with this?
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Mike H
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pedropedro
Full Member
Posts: 677
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Re: misfiring badly at 50 mph
« Reply #82 on: Oct 14th, 2011, 6:17pm » |
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found split hose on one of the egr connections....not sure if it sorted but got the impression seemed better on the short run i took it on, but have had to go away on business...back in 2 weeks so will be able to investigate then
would make sense if the dumping of exhaust gasses into the inlet wasn't doing its thing correctly
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Cosray
Full Member
8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: misfiring badly at 50 mph
« Reply #83 on: Oct 14th, 2011, 6:30pm » |
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Hi John - which hose pls?
Was it on of the two hoses/tubes running off the Diff Sensor towards the two pipes from the venturi behind the engine?
Curious,
Ray
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pedropedro
Full Member
Posts: 677
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Re: misfiring badly at 50 mph
« Reply #84 on: Oct 14th, 2011, 7:03pm » |
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Hi Ray
yes the x2 rubber hoses from the transducer go into the heat shield and at that point connect onto x2 metal tubes going to the venturi...i went to pull the top one off and it fell off in my hand....it had been rubbing on the lower connector and had split underneath..separated the pipework refitted and got impression problem had gone ,,,but just short test drive ...will test thoroughly in 2 weeks time
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Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
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Re: misfiring badly at 50 mph
« Reply #85 on: Oct 14th, 2011, 7:48pm » |
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You may do better to replace them, although mine looked OK they just kept splitting again. I used some high pressure petrol hose.
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ABS multiplug wheel sensor pins MK IV or MK 20
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pedropedro
Full Member
Posts: 677
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Re: misfiring badly at 50 mph
« Reply #86 on: Oct 14th, 2011, 8:36pm » |
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good idea...will do that when I am back..tks for tip
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: misfiring badly at 50 mph
« Reply #87 on: Oct 15th, 2011, 10:09am » |
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Ah-ha!! It's all making sense .. 
Air leak in EGR hosing, so EGR valve won't work properly.
Because EGR won't work as it's supposed to, strange driving behaviour.
Stop EGR being used by pulling MAF plug, car appears to behave more normally.
I also note "engine has died couple of times" I guess it could if hose leak has opened inlet manifold to atmosphere, as ultimately that's where the vacuum comes from.
Tip for the future then as pedropedro has proved ~ cursory looks at vacuum hoses not good enough, need to take off for a more thorough butchers. This could have been solved in 10 minutes if only you knew what you were looking for. 
Yep I agree treat yourself so some new hose pipe. Local motor factors should have something, just need the diameter.
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Mike H
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Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
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Re: misfiring badly at 50 mph
« Reply #88 on: Oct 15th, 2011, 10:41am » |
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I minor leak on the exhaust side may allow air to enter the exhaust causing the oxygen sensor to richen the mix.
With a leak there when the EGR is commanded open the DPFE may receive false information causing the EGR to open more or less than it should.
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ABS multiplug wheel sensor pins MK IV or MK 20
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Cosray
Full Member
8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: misfiring badly at 50 mph
« Reply #89 on: Oct 15th, 2011, 9:25pm » |
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Hi all - just for kicks I tried to replicate Jonh's car's behaviour and mine of some years ago.
I pulled one each of the EGR Differentail Pressure Sensor's hoses. The open one could be felt huffin' and puffin'. I am not sure which EGR Diff tube it was, the lower one near the exhaust or the upper one over the venturi. Both huffed and puffed equally.
No bad signs though on all speeds.
Put the hoses back on, pulled the connector of the EGR Diff sensor slightly loose and that made the engine hesitate at light throttle and around 100 kmh, especially on Cruise Control I could feel the control unit try to cope with the unusual sitaution.
Perhaps on a 24v it's different?
I should have taken off the MAF's connector for test; will do later this week.
HTH
Ray
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: misfiring badly at 50 mph
« Reply #90 on: Oct 16th, 2011, 11:57am » |
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Top research
So could still be dodgy wiring / connector problem
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Mike H
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