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Coolant temp sensor. |
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Nikolaj |
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Joined: Aug 29 2019
Member No: #4047
Location: Roskilde |
My 2,7 starts to "cough" just as it reach normal operating temp on the dash display, it's like when I turn off the choker on my old Jaguar a moment to soon. After a few minutes it slowly gets back to normal. Temp on the display are spot on, and stays there, but I guess that the engine management has it's own temp sensor, that may be a bit off!? When I bought the car a few months ago in Germany, day temp was 30-40 deg. so this issue didn't reveal itself, until I got back to Denmark, and the day temp dropped to 20 deg. and below. Any thoughts? No error codes from Diabox. |
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C6Dave |
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Member No: #1
Location: Northumberland |
Yes there is a separate 'coolant' temp sensor but if you have Diagbox it would be worth monitoring the engine readings before swapping out the sensor as it could be something else.... | ||
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cruiserphil |
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Member No: #38
Location: Celbridge |
Hello Nikolaj, As per C6Dave, live monitoring of the data with Diagbox might help. Faults may not be logged if the"fault" is not present for a set minimum time. Regards, Phil C. |
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Nikolaj |
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Joined: Aug 29 2019
Member No: #4047
Location: Roskilde |
You're right, had the Diabox on today, (still finding my way around the menues) and temp says 88 deg. idle after driving home, so I guess thats OK. It also caught me, I forgot to tighten a clamp for the tube to butterfly house, so low turbo presure. I found a mesurement for "correction of injectors", I was looking for injector presure, (don't know if its something you can mesure with Diabox) but the value for the 6 injectors are quite spread out from 87 to 127, and when I check that some weeks ago, it was "only" 88 to 115. How close do these values have to be for the 6 injectors, and at what level? I do have a "sound", at light acceleration, it seems to dissaper under medium to hard acceleration, and that could very well be the injector on 127, a diesel like sound, if that injector is very poor in the low range, and more up to the game under medium to hard acceleration. 2 weeks ago I did a Bell Add "One Shot" treatment, in order to clean the injectors and system, but now it's like it switch betwen smooth and uneven running at lower speeds. Thank you for your patience with us newbies, with only a couple of months C6 ownership under our belt. |
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C6Dave |
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Member No: #1
Location: Northumberland |
Well the tech doc - Click Here - does say that using additives to clean the injectors etc. is 'forbidden' but everyone does it anyway A dirty fuel filter can cause all sorts of issues and with winter coming it won't be long before diesel is sold with anti waxing agents which compound the problem. Where you are will dictate when those additives start appearing (and the refineries, sellers etc. don't really publish it) As for measuring the injector pressures I can't find anything to say what they should be but on piezoelectric injectors there isn't a 'single' spray but several very fast ones from what I have read on a Jag forum using the same engine: The solenoid-controlled injector does three "squirts" per power stroke, the first small "pilot" squirt just B4 top dead to heat up the combustion chamber even more than the natural compression-ignition principle. This speeds up the main burning when the main squirt comes slightly later, enabling the DIRECT injection system AND reasonable revs AND a better fuel economy than the older indirect systems with lossy swirl chambers in cylinder head. The third squirt after main-burn is to deal with NOX emissions Piezoelectric injectors as fitted to your diesel Jag. are quite different, although they achieve the same objective in a better way. Instead of solenoids with their inertia, there is a stack of piezoelectric elements like a stack of very small coins inside each injector. A voltage of about 400 volt is applied across the stack, controlled by the ECU, and the stack gets ever so slightly longer. This change is applied to an hydraulic amplifier (like a jack in reverse) which opens a valve allowing fuel to squirt. The force this can apply is truly enormous. This is all contained in the body of the injector. This system has virtually NO inertia, and is therefore extremely fast, so much so that there can be FIVE squirts per power stroke, resulting in even better fuel efficiency and even less combustion noise. The piezoelectric elements are well proved and tested, they have been around a long time in other common applications. If that is the case, then it would explain the differing readings you have seen via Diagbox? |
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Nikolaj |
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Joined: Aug 29 2019
Member No: #4047
Location: Roskilde |
Fuel filter is next on my list, I like to change fluids and filters, when I get a "new" car, even that the previous owner and servicing Citroen garage, say it's been changed. Glowplugs was changed 2 years ago thay said, (I don't remember if the word "all" was included in the sentense) but it turned out that the 3 rear plugs was changed, and maybe they tried to start on the 3 plugs in front, 1 was broken, and the last 2 stuck, so thats another small project. I tried to listen for a more noisy injector, but with no luck, so I might buy a test kit to measure the amount of returned fuel from the injectors, to get a rough indication, if one of the injectors are way off. (very simple/cheap tool from ebay) |
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C6Dave |
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Member No: #1
Location: Northumberland |
Fuel filter is next on my list, I like to change fluids and filters, when I get a "new" car, even that the previous owner and servicing Citroen garage, say it's been changed. My car had a service last December at 123,000 miles with all the filters changed, I bought it in August with 126,000 miles on the speedo and after a trip to France I now have 128,600 miles on the speedo so I had the engine oil and filter changed whilst a new radiator and water inlet tank were fitted plus I reset the 'service schedule' to 'Arduous Conditions' i.e. 12,500 miles or annually given the car is not going to be used more than 5,000 miles per year (and I will try and avoid 'short' trips in it anyway) |
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Nikolaj |
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Joined: Aug 29 2019
Member No: #4047
Location: Roskilde |
Okay, problem solved, it turned out to be the injectors after all, well 2 of them to be more precise without haveing them tested. The give away was when I as a desperate meassure, blocked the EGR returnpipes with 2 coins, (quarters should be an exact fit in the pipe connection at the throttle body) then I could see smoke at the lightest tuch of the accelerator. I started with the front row, since 5 and 6 was already changed, number 4 was in the spotlight, and shure enough, the symptoms almost went away, so I knew I was on the right track. After changing the back row, I can't tell when operating temp are reached, without looking at the dash, and the "sound" has gone to, so after pulling my hair for 3 months, I'm beginning to think this could be a good relationship.. I'll do another post with injector symptoms and some pics, if I can get them out of my b.... Iphone. |
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