Last couple of days, the Mondeo has started "chugging" at idle when the engine is hot. It got particularly bad tonight after enduring a 6 mile jam on the way home.
The idle speed is an indicated 900 RPM as it always has been, but it's possible to feel a "jiggling" sensation through the car when ticking over. If I lift the bonnet, the engine is visibly rocking back and forth on its mounts at a frequency of perhaps 4-5 times a second, and the exhaust note is "chugging" in time with these engine movements. If I pick the engine up off idle with the accelerator, it smooths out and seems fine. I've just been out to the car now it's cooled, turned the key, and its fired up with a completely smooth idle again (well, by Endura-DE standards). Certainly, the idle has always been completely even, and standing behind the car, the exhaust note has always been perfectly even.
The car is starting normally, not smoky, still doing mid 40's MPG, and seems to drive just as before. Any ideas?
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
Tweaked subject line, to avoid going down a TDCi blind alley ! - PU
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Hello.
Could it be a loose or perished engine mount.
Does this occur without any electrical load.
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(iam not a mechanic)
Martin Winters
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Hi Martin,
Electrical load makes no difference, and it's definitely only happening after the car has been running for more than an hour or so.
You're onto something with the engine mount suggestion. I just had a look under and there's a big crack in the rubber of the rear mount. It's mounted about 1" from the exhaust downpipe which would explain why it's heat related. My guess is that the heat soak from the exhaust is softening the rubber even further.
It's been a little jerky on/off throttle and changing gear recently, so hopefully it's all part of the same problem. A genuine Ford replacement mount is £30 so that's reasonable at least.
Will keep you posted. Cheers for the reply.
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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New rear engine mount (roll restrictor) fitted today. Old one was completely shot - the rubber had three big cracks in it, and had separated from the metal around about 180 degrees of its circumference.
Engine certainly transmits less vibration into the cabin under acceleration now, but I guess Monday morning rush hour will be the real test of the chugging problem.
Thanks for the advice!!
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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Nope, still chugging at idle when the engine gets hot.
The new engine mount has massively improved the symptoms, but the problem is still there. The engine is definitely not idling right when hot. The rev counter is steady, but the engine is rocking slightly and there is a chugging note to the engine. If the idle is picked up even a fraction on the throttle, it smooths out and runs fine.
Performance still the same, economy still good, starting is fine, and no odd behaviour when driving. If the engine is left to cool for half an hour, the problem has gone when it restarts.
Any suggestions?
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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DP,
How are the valves adjusted on these engines?
I had a few problems with the 1.8 diesels from the early 90's with valve clearances being tight when cold, and becoming tighter to the point of holding the valves open when the engine was hot. The clearances weren't often checked and adjusted properly.
If the valve clearances are adjustable, at least it's a cheap and easy thing to check.
Number_Cruncher
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Yes they are shims. I must confess I've never checked the clearances, and I have nothing to say they've ever been done. It would make sense as the problem is definitely temperature related.
Thanks for the pointer. I'll have a peek at the weekend.
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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OK, the specs for the inlet valve clearances are between 0.3mm and 0.4mm, and the exhaust valves 0.45mm - 0.55mm
Didn't use the car yesterday, so took the opportunity yesterday evening to check the clearances on a stone cold engine. Here's what I have:
Inlets: *Cyl1: 0.3mm*, Cyl2: 0.35mm, Cyl3: 0.32mm, *Cyl4: 0.29mm*
Exhausts: Cyl1: 0.48mm, *Cyl2: 0.45mm*, Cyl3: 0.51mm, Cyl4: 0.46mm
No4 inlet needs urgent attention, but should I do something with No1 at the same time (right on the limit)?
Again, no2 exhaust is right on the limit. Does this need doing now, or are they okay anywhere within these specs?
I tried to remove the shim on no4 inlet to work out what I'd need to buy, but I am struggling to depress the tappets to remove the shims without the proper tool. Tried the screwdriver method in the manual, but couldn't find a way of doing it without partially covering the shim as well (and therefore making it impossible to remove). Also felt like I was running a real risk of damaging the follower.
Can anyone suggest a good way without buying an expensive tool that I'm probably only ever going to use once?
Cheers
DP
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Those clearances don't sound likely to be causing your problems-next step sounds like set of serviced injectors.
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You could try some of that injector cleaner stuff first - a lot cheaper, if it works...
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>>Those clearances don't sound likely to be causing your problems...
Yes, I agree, although the inlets are beginning to close up a bit, I don't think this would cause the poor running.
Like jc2 suggests, the problem will most probably lie in the fuel system.
Number_Cruncher
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>>No4 inlet needs urgent attention, but should I do something with No1 at the same time (right on the limit)?>>
I wouldn't worry about that, just check again in a 1000 miles and if it has gone to 0.25 ish then do it, chances are it will be the same or a fraction greater. Just starting the engine, letting it cool and remeasuring could give a different reading.
I would say they a damn good for a 120k + engine that has never had the clearnces done.
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Thanks everyone for the responses. :-)
OK, I'm quite happy to leave them if they're not likely to be causing problems. No point disturbing them for the heck of it. Any recommendations on injector cleaner brands? Worth a try first I think. Will recheck the clearances in a thousand miles or so - takes all of 2 minutes to take the rocker cover off, and can even check no4 without taking the baffle plate off (not that it's difficult)
Cheddar - I'm not sure if they have ever been done, but certainly I've got nothing to say they have. I think it's a 100k service item anyway, and I bought it with 97k on it, so it's probably unlikely. Lovely clean top end though. No scoring or marks on the cam lobes, no sludge or carp and lots of oil everywhere. That said, the car has only done maybe four short journeys since I had it, which helps.
Cheers again all.
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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What sort of pump / govenor system is fitted?
I notice that above, you say that only a very slight throttle opening is required to smooth the running. This suggests that the fuel is bubble free, and the injectors can't be that bad - does the engine smoke under load?
If the linkage between the govenor and the device which meters the fuel has worn and there's some slack, you would get exactly this type of behaviour - you might be stuck with it! You've probably heard it happen in older bus and truck engines where the hunting at tick over is quite slow but also quite pronounced.
Number_Cruncher
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Hi Number_cruncher,
It's the Lucas / CAV system (with the through bolt type fuel filter and black primer button on top of the housing).
The engine's not particularly smoky. The odd puff under hard acceleration, but not what I would call excessive. No smoke whatsoever at idle. As I said, it really does seem to drive okay - it's just hot idle that's showing any sign of problem. Economy and starting both still fine too.
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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Can post photos of the pump (or anything else on the engine) if it helps identify it.
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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>>Can post photos of the pump...
The reason I asked was to see if the governor was mechanical or hydraulic as opposed to being electronic.
I think the longer bodied Lucas CAV pumps are fitted with mechanical governor, (although I could be completely wrong), and there's quite a linkage between the rotating weights and the valve which controls the metering pressure, and hence fuel flow. Any slack in this linkage, and the engine will hunt when it's relying on the govenor to control tickover.
Before getting too close to condemning the pump, is there any electronics controlling this engine?
Number_Cruncher
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