vibrating

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timh1970

New Member
Posts
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Hi, I have a P38 Diesel Auto which seems to me as if it vibrates a little too much when idling. I don't have anything to compare it with as I have never had one before but it feels a bit like one of those massage chairs or like the exhaust was catching the frame somewhere (It isn't).

I hooked up my nanocom to it and it is reporting that the timing is out of range but there's plenty of power and the car seems to run normally. (it does have one of those power upgrades fitted and I have researched that those can cause this particular fault so am not really concerned as long as it is not this that is causing the vibrating.)

So far I have changed the cooling fan, tensioner, serpentine belts, pulled the plug on injector no.4 and checked the mountings. The harmonic balancer appears to be fine from a quick visual inspection but I have to admit that I am not entirely sure what to look for. It's an auto so there's no dual mass flywheel so now I am stood here scratching my arse.

Any ideas would be much appreciated.
 
Now on the stuff I work on if the timing is out (I guess we're talking pump timing here) it wouldn't cause the engine to vibrate, it would just run rough. Is it really just a case of re-timing the pump?
 
Hello,

I've got a P38 diesel too and had the same problem. I fixed mine by replacing gearbox mounts (easy) And check your CAT heat shield it's below your drivers seat (uk) mine was lose and flapping about making any vibration sound far worse than it was with these things changed it's fine and no vibrations!

Hope it helps you.
 
timh1970 said:
Now on the stuff I work on if the timing is out (I guess we're talking pump timing here) it wouldn't cause the engine to vibrate, it would just run rough. Is it really just a case of re-timing the pump?
Click to expand...

That depends on the amount the timing is out and the state of the mountings.
 
The timing thing is an intermittent fault according to the nanocom so I am guessing it is some sort of electronic advance/retard functionality within the pump rather than the the mechanical pump timing. I have only worked on all mechanical pumps; mainly on trucks, so I know nothing about ones with electronics in. Is there a sensor somewhere that advances/retards the pump timing?
 
timh1970 said:
Hi, I have a P38 Diesel Auto which seems to me as if it vibrates a little too much when idling. I don't have anything to compare it with as I have never had one before but it feels a bit like one of those massage chairs or like the exhaust was catching the frame somewhere (It isn't).

I hooked up my nanocom to it and it is reporting that the timing is out of range but there's plenty of power and the car seems to run normally. (it does have one of those power upgrades fitted and I have researched that those can cause this particular fault so am not really concerned as long as it is not this that is causing the vibrating.)

So far I have changed the cooling fan, tensioner, serpentine belts, pulled the plug on injector no.4 and checked the mountings. The harmonic balancer appears to be fine from a quick visual inspection but I have to admit that I am not entirely sure what to look for. It's an auto so there's no dual mass flywheel so now I am stood here scratching my arse.

Any ideas would be much appreciated.
Click to expand...

Personally I would wash my hands.:)
 
timh1970 said:
The timing thing is an intermittent fault according to the nanocom so I am guessing it is some sort of electronic advance/retard functionality within the pump rather than the the mechanical pump timing. I have only worked on all mechanical pumps; mainly on trucks, so I know nothing about ones with electronics in. Is there a sensor somewhere that advances/retards the pump timing?
Click to expand...

Yes there is a solenoid that does that.
 
timh1970 said:
What sensor does it get the raw timing data from?
Click to expand...

Start of injection is measured by the number four injector and compared to the CPS reading the timing solenoid is modulated to adjust timing for various needs. If the problem is intermittent that would suggest that timing solenoid is faulty. The amount of modulation that needs to be applied gives an indication of static timing state.
 
wammers said:
Start of injection is measured by the number four injector and compared to the CPS reading the timing solenoid is modulated to adjust timing for various needs. If the problem is intermittent that would suggest that timing solenoid is faulty. The amount of modulation that needs to be applied gives an indication of static timing state.
Click to expand...

That makes sense
 
Just had it up to Colne and he reckons it might be the damper. He said it was a reconditioned pump and because it started well both hot and cold he reckoned that the timing was probably OK.

Just put the new damper on after a fight with the crank bolt (only to realise that I did not even need to touch it) and it seems a bit better (none of the auxiliary stuff or the fan is on at the moment so cannot be certain); going to change the mountings as they are fairly cheap and I hope that will cure it. (also going to change the front crank oil seal as they are only 6 quid and I don't want to have to pull it off again in six months if I can help it)

PS. If you ever need to get that bolt out then get a second hand aircon pulley and weld a fairly hefty piece of flat bar to the front of it at one side of it (Pick a side; any side; it's a circle) so that you can still get a big ol' wrench on the nut afterwards. Put it back on with as many of the bolts that you can get back in it, so the bar hits the ground on the offside (if you have cut the bar too short as I did then use a concrete block as a spacer). Once you have done that get the biggest wrench that you have got, put it on the bolt, stand at front of the offside wing, and heave (I think somebody put threadlock on mine as 100nm and 150degrees should not be that tight).
 
timh1970 said:
Just had it up to Colne and he reckons it might be the damper. He said it was a reconditioned pump and because it started well both hot and cold he reckoned that the timing was probably OK.

Just put the new damper on after a fight with the crank bolt (only to realise that I did not even need to touch it) and it seems a bit better (none of the auxiliary stuff or the fan is on at the moment so cannot be certain); going to change the mountings as they are fairly cheap and I hope that will cure it. (also going to change the front crank oil seal as they are only 6 quid and I don't want to have to pull it off again in six months if I can help it)

PS. If you ever need to get that bolt out then get a second hand aircon pulley and weld a fairly hefty piece of flat bar to the front of it at one side of it (Pick a side; any side; it's a circle) so that you can still get a big ol' wrench on the nut afterwards. Put it back on with as many of the bolts that you can get back in it, so the bar hits the ground on the offside (if you have cut the bar too short as I did then use a concrete block as a spacer). Once you have done that get the biggest wrench that you have got, put it on the bolt, stand at front of the offside wing, and heave (I think somebody put threadlock on mine as 100nm and 150degrees should not be that tight).
Click to expand...

100 nm and 150 degrees is bloody tight hope you torqued it up correctly or you may lose the oil pump.
 
timh1970 said:
That's what it said in rave 100nm followed by 60degrees then a further 60degrees then a final 30 degrees.
Click to expand...

Pity you didn't read the bit in RAVE about replacing the damper before you started. Yep two flats then half a flat for those without an angle gauge. :);)
 
My timing out of range thing is an intermittent fault so it comes and goes on the Nanocom

At idle without the car moving modulation is 11.90 give or take a bit. Give the car a little gas and it drops to 4.67. It stays at 4.67 until around just under 2K (Note I am going off the rev counter because the revs are on a different screen on the Nanocom). Over 2K revs and it jumps up, first to 18 and then on to about 30.

The highest it gets when driving is 65, but you have to be going up the M65's steeper bits at 80mph for it to get that high. Average is around 40 to 50 ish under a reasonable load, but drop to around 1500 and hold it without much load and it will drop back to 4.67.

My (slightly) educated guess is that 4.67 is as low as it will go and that it should never really get that low. My next educated guess is that there is some form of potentiometer type device on the solenoid sends feedback to the ecu about it's position. My final educated guess is that this "device" is £@(&ed.

Would this make sense?
 
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