I am getting about 17 MPG, i Have had the injectors done,good compression but i just checked my IP timing and it is about 7 Degrees BTDC (Checked several times), My question is can this cause low MPG and rough idle, also i see no black smoke.
Thanks

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1979 300D.

It is going to hurt to some extent of course. The fuel is being injected late at a lower compression point. Or to put it another way the burn interval tends to be on the backside of the ideal peak. Less ability to develop power for the engine will automatically mean more fuel for the same performance level. I would check the chain stretch as well before moving the pump. If it's okay then reset the pump. It certainly will not hurt and should be done hopefully giving you a good gain in fuel milage. I know you love your 17mpg so much your going to try it.

What method did you use to check the IP timing?

The rough idle might be something else other than the delayed injection pump timing after remembering that I did not comment on it. The best thing one can do when faced with an engine or performance that is substandard to the average example is a general tune up. By systematicaly doing it you tend to pick up faults along the way and many small things combined can lead to really poor performance. Or as in your case sub standard milage. My gut feeling is put your pump where it belongs after establishing your chain stretch is reasonable and correcting the cam timing with an offset key if required. It is very important to inspect your chain guides as well. Then do a compression check. Get your injectors checked and matched if you do not know their status. If compression check is good and cylinders are reasonably close . Compression tester is as cheap as 9.95 at hudsons I am told so there is no longer a reason not to have one if you cannot borrow one or have one already. Grab a digital meter that can read milli volts.. Read the output of all your glow plugs. If they are equal you should be good to go. If they are not then swap the glow plugs around to verify the plugs are not the factor. If the mixed voltage readings continue there is most likely a problem with the pump. Next a volume flow test to make sure pumps output per fuel element is simular. If volume test checks out you probably have a sequential pump timing problem or enough of an indication that the pump needs retimed to itself not in refference to the engine. Of course before any of this the first thing to always do on one of these engines is to set the valves. They are famous for all kinds of symptoms that are valve clearance related. If an engine makes all these tests and adjustments with reasonable equal compression it's going to hum like a pussycat. It's also all in the archives. Basically as soon as I hear rough idle in refference to these engines
I know it's time to do a total tuneup if I have no knowledge when it last had one. You of course can stop as soon as you have located the problem but for maximum performance and milage you should do it all. Your airfilter is reasonably clean by the way? it will cause reduced milage combined with excess smoking. I would expect that a rough idle may also be caused from too much air entering the fuel system as well. You have to keep an open mind. Most of the above proceedure is time rather than money. It is my hope we can restore or improve sequential timing errors related to aging and people adjusting things they should not have. But first we have to establish without a doubt that is the problem plauging the engine and be prepared to have a pump shop do the corrections it if we fail. But once the fault has been absolutly isolated there will be no reason not to try to improve the situation and my guess is it will turn out well for us once understanding and application are understood. It is not rocket science and we want to properly repair these old cars at minumum cost. The last thing we want to do is spend money where it is not needed as in most cases it will not be hard to find another area of the car that can absorb it. By the way if you want to do a rough check of your injectors at little cost. Just move one after another into the same cylinder hole. Read the milli volt output of the glow plug. If they are say all within .2mv you kind of know they are all the same. Thats basically what you are sending them out to find out. Also if only one injector gave a large variation to the voltage reading that is the one to send out. The others are known good by dynamic checking. All the above mentioned items pertaining to using the milli volt reading approach are a probe into the unknown at this point to some extent. So rather than what to do are more food for thought but I have passsed the point myself of only considering them as abstact Ideals. These tests will function well I believe if the user understands exactly what he or she is doing. Also there will be initial resistnce and that is normal. But to enjoy these cars that are on there way to becoming antiques and keep maintenance costs in line we have to prove the validity of cheap and effective tests if possible to keep our cars running as well as possible.

That's the question. Being that you stated you already checked your injectors and compression.

If you did the cam mark method and got the same reading a number of times then it's more than likely a good reading. However I would not choose a woodruff key for my engine on a "More than likely" reading. I would get myself a dial gauge set and do it the right way.
Click here for instructions on checking timing chain stretch

Then pick a woodruff key and check your IP timing. Only adjust if it's off after the woodruff key is installed.

Of course you should replace your air and fuel filters too.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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Danny, he's checking IP timing.......not cam timing.

The methods would be "drip" or "RIV" or "pulse timing".

The crank drives the pump and then the cam. The pump is infinitely adjustable (if you consider that you can jump teeth on timing chain for additional adjustment). Because both cam and pump timing are referenced to the crank, they really don't have any impact on each other. The pump being out of time does not affect the timing of the cam or vice versa. Even the chain being stretched does not mean that the cam and pump cannot be correctly in time once adjusted.

Andrew

Since he appears to be out a lot on pump timing I just though the chain should be checked for stretch and the cam timing put back also as it might be off. When he checks his chain it might be stretched above allowable limits. There is only one accurate method of checking actual timing of the cam to the crank pulley. That proceedure gives you the chain stretch factor as well of course. You have to use a dial gauge as in the archives as someone stated. If he does not do things in sequence he may land up backing up to some extent or leaving a marginal situation behind as he goes along. I think rough idle has been documented in the past on these engines as well if cam timing is off. At least he is ahead somewhat as apparently his compression is good and injectiors already done. He should get through this in my opinion as he has already not been intimidated by checking his pump timing or changing his injectors out. A lot of proceedures depend on how comforatable an individual is to do them. He sounds like he is easily up to them. I7 mpg is pretty bad though and does deserve some serious attention. That is unless he forgot to mention that he is driving around with twenty women in his car all the time of course. But I kind of rulled out that senario as then the 17 mpg would be the least of his concerns. It is always what you forget that gets you. For low mpg it never hurts to make absolutly sure you do not have a fuel leak somewhere as well. I am pretty sure he will locate his problem systematically as well.

[QUOTE=libbybapa The pump is infinitely adjustable (if you consider that you can jump teeth on timing chain for additional adjustment). Andrew[/QUOTE]


Wouldnt it be eaiser to pull the pump, and reset it if the correction needed is beyond the adjustment of the slotted bolt holes?

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Like was already mentioned, the rough idle might be something else.

A friend of mine (good mechanic) bought a hard starting 240D. He checked the timing and it was 6 degrees BTDC
The only noticeable result of the timing being off that far was hard starting.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

should the trottle be at idle or full? or does it matter? when doing the IP timing check.

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1979 300D.

Wire the throttle open full. and dont forget to pull the vacuum line off the vacuum shut of switch.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Your timing is 17 degrees retarded as you quoted present timing of 6 degrees before top dead centre. You want to reach 24 degrees before top dead centre. . So you have to move the pump anti clockwise when viewed from the front of the engine or the top of the pump towards the block if easier for you to remember. Review the timing methods again you used carefully for the welling up in number one element test. You were quite right to question why it is this far out especially with only 40k on present chain. 17 degrees is a long way. You should have more power to start with after the timing is adjusted. Whoever put that chain on is suspect and I hope someone did not move the number one element in the pump. Meaning the two nuts at the base area of the injector line. Was it a mercedes familiar garage that changed the chain 40k ago? You have the records. Pretty soon you may find out why I check everything as I go along but I hope not. You can do no real harm by resetting the timing. It is a piece of cake after you have worked through it the first time. But if any complications arise do not hesitate to post.

Ther is no need to wire the throttle open it has no effect on start of fuel delivery.
Moving the top of the injector pump toward the cyl head will advance the timing which is what you need to do.
1-1/16 socket for crank bolt

Careful with that.

With the rack fully closed, wouldn't it be much more difficult to see the fuel well up in the chamber......or see the drip? It's a difficult process under the best of circumstances.......less fuel would complicate the situation.

Agree??