dirtydiesel Posted March 4, 2007 Share Posted March 4, 2007 Its a bit of a long story so bear with me I have a 1995 300tdi in my '71 rangie that untill recently was as reliable as the setting sun. Over the last 2 weeks it has developed a funny pulsing type of vibration under light throttle loads and deceleration. I checked all the obvious but couldn't find anything amiss Then yesterday the exhaust note also developed a pulsing/thuding noise. acompanied by a loss in power. The best way to describe it is that it sounded like a cross between subaru exhaust note and the thuding of a feild marshall tractor At first i suspected the exhaust manfold to head gasket had gone, i changed it and it made no difference. With the inlet and exhaust manfold off the engine and it runnng you can still very clearly hear the noise which eliminates turbo faults or inlet manifold faults. The noise is there wether engine is hot or cold The crankcase doesn't "breath" at all. No contamination in the oil or water. The engine idles fine with no missfires You cannot "feel" the noise through the engne you can only hear it. The noise seems to be coming from the n/s/r of th engne block undernieth the exhaust manfold. It is definately not coming from the bottom end or the injection pump side of the engine. recheaked the tappets and this altered nothing. So i began to suspect either a valve problem or a head gasket gone allowing combustion pressure to escape. so i removed the cylinder head and found... Nothing. head gasket is as new with no evidance of being blown. All the valves and their seats are in A1 condition. when i removed the head the coolent leaked into the bores and stayed there it did not leak away leading me to suspect the rings are fine. I've checked the timng it is spot on. All the valves are opening in the correct order I've dti'd the tappets and the cam lobes are all lifting to within 0.025 mm of each other. I have cleaned and cheaked everything very thoughly and i just cannot find a fault. Any suggestions please? Other than fit a petrol that is Quote Link to comment Share on other sites More sharing options...
imspanners Posted March 4, 2007 Share Posted March 4, 2007 Valve springs all ok? Cambelt tension ok? Too much slack could cause a resonance on over-run. If those are ok, Try removing the brake vacuum pump. Quote Link to comment Share on other sites More sharing options...
will_warne Posted March 4, 2007 Share Posted March 4, 2007 Holed valve maybe? It also sounds worryingly like a problem my co driver had with his Tdi Golf - front main bearing went allowing the crank to move about and timing belt skip. Quote Link to comment Share on other sites More sharing options...
NoHummer-Ed Posted March 4, 2007 Share Posted March 4, 2007 My 300 did something fairly similar (amongst it's many other badnesses) and it turned out to be dirt in one of the injectors. They are almost impossible to test properly (for reasons which you are probably not interested in) outside the engine, but they are easy to strip down, clean & put back together. Alternatively, swap one injector at a time with one from another engine. If you have to be buying four it is a big bank-ache but one is OK. It made mine sound like really bad bubbly. Ed Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted March 4, 2007 Author Share Posted March 4, 2007 Valve springs all ok?Cambelt tension ok? Too much slack could cause a resonance on over-run. If those are ok, Try removing the brake vacuum pump. valve springs mint, cambelt tension fine, could be the vacumn pump but the noise is from the opposite side of the engine. Holed valve maybe? It also sounds worryingly like a problem my co driver had with his Tdi Golf - front main bearing went allowing the crank to move about and timing belt skip. valves are all fine, as i've said above. My 300 did something fairly similar (amongst it's many other badnesses) and it turned out to be dirt in one of the injectors.They are almost impossible to test properly (for reasons which you are probably not interested in) outside the engine, but they are easy to strip down, clean & put back together. Alternatively, swap one injector at a time with one from another engine. If you have to be buying four it is a big bank-ache but one is OK. It made mine sound like really bad bubbly. Ed A faulty injector is about the only thng left, i've 4 new ones on the shelf so it's no hardshp to swap them in, if the noise is still there after the head goes back on. Quote Link to comment Share on other sites More sharing options...
istruggle2gate11 Posted March 4, 2007 Share Posted March 4, 2007 [hi-jack mode] Other than fit a petrol that is mmmmmmmmm, ammunition [/hi-jack mode] (Ps good look with the repair) Quote Link to comment Share on other sites More sharing options...
white90 Posted March 4, 2007 Share Posted March 4, 2007 Dan My TDi quietened down a whole lot when I fitted new injectors. so you may be into something, have you a compression tester? Quote Link to comment Share on other sites More sharing options...
perv Posted March 5, 2007 Share Posted March 5, 2007 Could be injector fault or fuel injection pump internal timing possibly pressure fault also. Can only be checked by bench testing though.. Regards Ash Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted March 6, 2007 Share Posted March 6, 2007 When i rebult the engine on my 90, i had to replace 3 of the copper washers that seal the bottom of the injectors. one of them leaked just enough to allow exhaust gas out, but no diesel leaked out, so it made a kind of "pfft pfft pfft" sound. Quote Link to comment Share on other sites More sharing options...
saley Posted March 6, 2007 Share Posted March 6, 2007 Hi Dan , sounds like my 300tdi tipper, injectors it is Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted March 6, 2007 Share Posted March 6, 2007 It just has to be said Dan .......................... Rip it out an fit a decent V8 .................... Ian Quote Link to comment Share on other sites More sharing options...
GBMUD Posted March 6, 2007 Share Posted March 6, 2007 Rip it out an fit a decent V8 .................... Agreed. A diesel one. Chris Quote Link to comment Share on other sites More sharing options...
istruggle2gate11 Posted March 6, 2007 Share Posted March 6, 2007 It just has to be said Dan ..........................Rip it out an fit a decent V8 .................... Ian Oh, I know something you dont! Can I tell em Dan, can I? promise Ill be good! Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted March 6, 2007 Share Posted March 6, 2007 Rog, I wouldn't surprise me to find that Dan was considering a 5.7 Hemi ................or maybe a Bob Marley ............ but that's 2 pots short of a full house Ian Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted March 6, 2007 Author Share Posted March 6, 2007 Oh, I know something you dont!Can I tell em Dan, can I? promise Ill be good! Go on then! Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted March 8, 2007 Author Share Posted March 8, 2007 Well i've changed the head gasket and fitted new injectors and it runs fine. tick over is a little lower than before so the injectors must be injecting less fuel. But i am almost certain the old ones were not at fault as i've tried them in another engine and they were fine. So i'm going to put it down to head gasket failure. Quote Link to comment Share on other sites More sharing options...
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