Low power after engine rebuild

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kkjkeane

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Hi

I had an engine rebuild (1996 Disco 300Tdi) in late January 2007. When the car was handed back to me, I found it very sluggish, I had been told that it would take a while for the new rings to bed in, and that they had retarded the timing to stop me from driving the car too hard.

I put up with it for the 1st 1,000klm, and took it back for service, oil change etc and timing adjustment. Although there was some improvement, it still goes like a dog. Injectors were serviced (this was done in front of me in the workshop, is this normal) and injector pump replaced, all to no avail. Fuel filter has been replaced and lift pump checked.

It is a bit slow to start, cranks up to 10 times first thing in the morning (7 degrees in Sydney),it is parked on a level surface, starts ok later in day when engine is warm.

It is a struggle to drive up even the gentlest slope. Hills I used to cruise up in 5th gear at 110klm/h, are now a struggle in 3rd getting to about 70 klm/h. I can not drive faster than 100klm/h in 4th.

The rebuild was required after one of the pistons gauged a channel in the engine block. There was no power issue before the rebuild.

The engine has no oil leaks, blows no smoke, and sounds fine. If I floor the accelerato pedal in neutral, it seems to take longer than I would have expected to reach max revs.

I am taking the car back to the service station next Tuesday. Should I be asking for compression testing, turbo boost tests etc?

The mechanics never try to fob me off, are always prepared to spend time on it, and tell me to come back if I am not satisfied. They just dont seem to fix it!!!:(

Any suggestions would be greatly appreciated.

Ken
 
kkjkeane said:
Hi

I had an engine rebuild (1996 Disco 300Tdi) in late January 2007. When the car was handed back to me, I found it very sluggish, I had been told that it would take a while for the new rings to bed in, and that they had retarded the timing to stop me from driving the car too hard.

I put up with it for the 1st 1,000klm, and took it back for service, oil change etc and timing adjustment. Although there was some improvement, it still goes like a dog. Injectors were serviced (this was done in front of me in the workshop, is this normal) and injector pump replaced, all to no avail. Fuel filter has been replaced and lift pump checked.

It is a bit slow to start, cranks up to 10 times first thing in the morning (7 degrees in Sydney),it is parked on a level surface, starts ok later in day when engine is warm.

It is a struggle to drive up even the gentlest slope. Hills I used to cruise up in 5th gear at 110klm/h, are now a struggle in 3rd getting to about 70 klm/h. I can not drive faster than 100klm/h in 4th.

The rebuild was required after one of the pistons gauged a channel in the engine block. There was no power issue before the rebuild.

The engine has no oil leaks, blows no smoke, and sounds fine. If I floor the accelerato pedal in neutral, it seems to take longer than I would have expected to reach max revs.

I am taking the car back to the service station next Tuesday. Should I be asking for compression testing, turbo boost tests etc?

The mechanics never try to fob me off, are always prepared to spend time on it, and tell me to come back if I am not satisfied. They just dont seem to fix it!!!:(

Any suggestions would be greatly appreciated.

Ken
Click to expand...

Damned annoying when this happens! You've paid your brass and you should toughen up and get them to get it back to how it was before. Definately a compression test on all cylinders is crucial - this will immediately rule out things like leaky injector seating (injectors not tightened), overtight tappet adjustment. Proove your compression and these things can be ruled out for sure. Then, did they fit a new timing belt? OR was the old one refitted but in the wrong direction - this can cause poblems. If it was running ok before, then major parts like injector pump should have been ok, so why did they replace it? Anyway, they need to check timing again if compression is up to spec. Any leaks on the turbo? Is fuel filter seated properly and not sucking air - any bubbles in the spill back pipe, for example? My disco has 160K on the clock and starts immediatley from cold - I don't touch the throttle pedal, just turn the key. Churning away on the starter after a rebuild (providing you have a good battery that whips the engine over) isn't encouraging so you need to start asking the right questions! Good luck mate!
 
you dint want a comp test you need to have a leak down test done on it, this will show up any faults quicker and more efficently than a comp test will.
if yer piston had dug a gouge in the cylinder, did they rebuild that block or use a different one?

also i really dunt think a clutch fork problem is gonna affect the starting of yer engine unless its bent so much it is interfering with the turny round parts in which case you wint be changing gear too easily.


if its turning over slowly it might be that who ever did the rebuild has fooked up on the main or big end bearings and made them too tight. so the starter has to over come all that extra friction. i don't think there is an easy way to check this and it would mean takin the engine back out! But if every thing else that is checked from outside the engine is ok then i'd say it wur a strong possibility
 
Try checking that the diesel pump throttle arm is moving to its fullest extent when the pedal is on the floor. Miles 000 wrote 'My disco has 160K on the clock and starts immediatley from cold - I don't touch the throttle pedal, just turn the key' ......156k on my 1993 exactly the same, the engine does not even crank a full turn and fires so the throttle may not be the prob starting but may be the reason for low top speed.

regards
Dave
 
think Vital NOT to have a clog on the pedal when starting these engines, or the cold start doo-dah won't work.

My guess is the pump is mis-timed by one whole tooth on the belt, retarded.

So There,

CharlesY
 
Thanks for the input.

Before the rebuild, mine also started pretty much on the turn of the key. I never touch the accelorator until after it has started.

I did wonder if the max rev was not quite right, so will ask them to check it.

I decided to have a look at the fuel filter yesterday arvo, and found it to be a bit dirty, had some green resin in it. Anyway, I replaced it. There has been some improvement. Started after 4 cranks at 5 degrees. Seemed to go much better, but still no pulling over certain speeds that used to be fine. Turbo?

I did mention that the injectors had been serviced. This consisted of them being pulled from the engine, dismantled and cleaned with some spray, a piece of wire (Ithink) to clear the nossle, and then blown with compressed air.

I had a chat with a fellow who suggested that they should be sent away and soaked in some cleaning solution for about a day or so, and should always have the nossles replaced. Is a poor spray pattern from the injectors likely to cause or exacerbate my problem? Or would I be seeing a lot of smoke etc?



Ken
 
Had planned to have it checked independantly, but busy busy busy.....So will give these guys one last go, then it is independant assesment and possibly Dept. of Fair Trading, (NSW, Australia).

If they weren't so agreeable, I would have done this ages ago!

Did read a post about timing needing to be advanced a bit after timing belt change?

What about the injector nossles? Spray pattern, would I see smoke if this is not right?

Ken
 
Here's a good article from your neck of the woods on injectors and spray pattern.

Berrima Diesel Service - Tuning

Loss of power, yes; poor starting, yes; smoke - not mentioned but not necessarily so. Good point made was use of crappy diesel, same in my neck of the woods so I stick to Shell.

Will be interested how your problem pans out.
 
quote:

I decided to have a look at the fuel filter yesterday arvo, and found it to be a bit dirty, had some green resin in it. Anyway, I replaced it. There has been some improvement. Started after 4 cranks at 5 degrees. Seemed to go much better, but still no pulling over certain speeds that used to be fine. Turbo?

unquote

This symptom is typical of a diesel engine that has had the high speed governor setting made deliberately less than normal so you can't rev it too much for the first while after the rebuild.

They would probably have set it higher after a while, IF they got their hands on it again. If you didn't take the car back to them they would have the satisfaction of knowing you are suffering from low revs!

BASTARDS!

Take it back and TELL them to set ALL the settings properly.

Which failing it's a lawyer's letter job.

CharlesY
 
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