Outer Limits 4x4 Board

I just bought a car and the diesel is quite old, it seems strong, it idles a little high (1000rpm) and has a tendecncy to blow smoke between gear changes and when he is coasting like down a big hill!!

any ideas for a good cheap solution? Is the motor okay?

So many variables dude, what sort of diesel animal are we talking about?

Like Troy said what kind of truck. At a glance though sounds like an injector problem as a cheap solution to fix any hiccups it may have is to increase the revs so that fuel is being constantly pushed into the engine, When you change gears the engine idles and you see the black smoke. My Nissan had that problem and I was able to fix it by the cleaning of the injectors and tightening some of the clamps. Only other thing it might be is the fuel pump is on its way out, a bit tired ou could say.

7/88 HJ75 Series, 2H 4.0L diesel.

It blows white smoke between gears and when backing off, particularly, coasting, like down a big hill.... Or just slowing down.....

I would like to get it so it did not do this....

White smoke definitely, not black, it idles alright until it warms up, then it idles at 1000rpm.....

Okies, I found this on http://www.freeautoadvice.com/diesel/smoke.html

The first category is blue-white smoke:

Blue-white smoke may be noticed at engine start-up whether the engine is at normal operating temperature or not. Blue-white smoke can be observed at all ambient temperatures and should not last longer than a minute or two after the vehicle has been driven. Blue-white smoke can return when ambient temperature is below 10 degrees C (50 degrees F), and after the engine is warmed up due to extended idling. This is due to combustion chambers cooling own during periods of extended idling time. Heavy blue-white smoke may also occur if the engine is operated at full throttle with the transmission in neutral or park. If you see continuous Blue-white smoke while driving, then you probably have air being sucked into the fuel system.

The second category is white smoke:

White smoke and blue-white smoke share some of the same characteristics. White smoke is fuel not being burned. Extreme white smoke can be caused by the combustion chambers cooling down. One cause of this could be incorrect injection pump timing. Coolant getting into the combustion chamber can cause white smoke also. Possible causes are blown head gaskets, cracked heads cavitation, etc.

Hope it helps!!!

DOH'ETH can i run some injector cleaner through it and hope like hell?

The high idle could suggest that its the pump right? (Hopefully) this means a pump tune up could fix it...no?

would injector cleaner fix it temporarily?

can always try and see if it does

hi BJ my 60 series is doin the same thing ,i to cramers diesel service to find out about it ,he said it could be over fuelin and leekin injectors . about $100 to check pump timing and set it , injectors recoed are about $40 each , new$ 85 each. he said that should fix it .

I was told that with a diesel that the pump has to be calibrated(Timed) to the engine, not as simple as other fuels, ie petrol where if it stuffs up you just replace it with whatever is around. But if you can time it to the engine you should be right, should be easy though I have not had a chance to do it on mine as yet.

Okay, lots of things to check.

Here are some things you can check without special tools:
Bubbles in the coolant when the engine is running will identify a cracked head/gasket.

Change the supply line to the injector pump from the fuel filter to clear fuel line to identify air bubbles in the fuel supply.

Where the pump is mounted to the motor, there will be timing marks on the case of the pump and where the pump mounts on the motor. These marks are for the factory timing settings, the motor will handle a slight advance in the injection timing over standard factory setting. Ensure the timing is not retarded. Adjustment is easy, just undo the bolts and rotate the pump (you will find resistance from the injection pipes going to the injectors - coming out the top as is it an inline pump not a rotary)

Does the motor run excessively hot? Athough it doesn't sound like an overfuelling issue, as you say the smoke is more whitish than sooty black.

When the motor is running, pull the breather hose off the top of the rocker cover - is there excessive blowby, and what colour is the vapour? With blowby comes oil burning, and soot buildup in the oil. Carbon soot is abrasive, and then of course creates premature wear in the motor.

Regularly check the oil level for any drop in oil levels.

Some special tools required:
Compression test - ensure eveness between cylinders. This will give you an indication on the overall condition of the motor itself.





I would do the injectors, they are a 100,000km item anyway, unless you know when they were done. It's hard to check the pump without removing the pump from the motor and hooking up to the machine. Unfortunately the pump is the heart and soul of any diesel motor, and there is no short cut to diagnose properly.

Don't waste any money on injector cleaner, could make it worse by giving you more problems, like dragging water through your water trap/fuel filter and running the fuel/water emulsion through the pump, creating wear as the metal surfaces contact with no lubrication from the fuel.

Does sound like a blowby issue, with excessive oil being drawn into the combustion chamber during decel.

I'm thinking valve guides or shitty valve seats/ valve springs..

At idle no smoke when cold ----Oils thick

at idles idles up when warm----oils thinner

mechanical advance unit in the pump may be starting to fail/worn

engine could be running to rich as well..

my thoughts

the first thing i would do is to pull the injectors and take them in to a diesel specialist, they should be able to test them for nothing, by what you have said they are leaking and probably have a bad spray pattern, when you pull them out if they are wet on the end they are definatly leaking and while they are out grab someones diesel compression tester and see what your compression is like.

by the way is the fuel economy very bad??? injectors leaking and dribbleing unburnt fuel = white smoke. after i had the injectors on my truck done the idle dropped considerably.

2H are easy to time just get an old injector pipe and put a u shape in it just after the nut and then after the u shape cut the pipe on a 45 degree angle, fit to no.1cyl on the pump rotate engine to timing marks on balancer (just past tdc no1cyl) loosen pump bolts, operate lift pump and rotate injector pump until flow from cut pipe is just a drip hanging from the end of the cut pipe.

Most of the diesel compression testers will go into the glowplug holes in the head, not the injector holes. You will need a dedicated diesel compression tester as most petrol engine testers will blow due to the higher pressures reached in testing a diesel engines' compression.

The GQ was having blue-white smoke issues like you describe, was running rough and hotter than normal. It ended up being a dose of bad fuel that worked thru the system after a couple of tanks.

I now only ever buy deisel from reputable suppliers.

Who knows, im gunna put some good diesel in it, it came with half a tank and used most ofthat in 100kilometres, so its not real efficient, but it is running cool, it has a brand new radiator.