I own the same model and had the same concern- did you go through the timing check to see if it were the culprit?

I did do the timing check and it was difficult to get an exact number of degrees. I tried to visually line up the marks on the camshaft and head. I think it is someplace between 2 and 4 degrees of stretch. The proper way of checking would be to get a dial gauge and check it but I haven't had much luck obtaining one.

I may at some point when I have time change out the timing chain since it does have 195K on it.

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

You need the RIV light to check the timing.

If its 4 degrees out that would explain a lot, my guess though is more like 2 at 200k miles.

603's are not 617's, they need to be in time.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I'm not sure if we are talking about the same timing, but I thought the light was used to check injection timing.

The timing I am speaking of is the valve timing and chain stretch. The procedure with the dial gauge is mentioned in the FSM for checking chain stretch. The method for lining up the marks is also mentioned in another TSB as I recall.

I am also aware of the fact that if the chain does stretch it will pretty much throw off the injection timing as well, but I was just checking the chain stretch/valve timing portion.

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

For a datum point, over 13 years of ownership, our 87 300TDT would never go below 24 in town, and never above high 29's in the hiway.

Alda adjustment, dirty air filter, plugged oxidation catalyst could all contribute to the lower mpg.

Of course, so could your right foot.....

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

Incorrect ALDA adjustment will not cause the car to consume more fuel except during off-boost acceleration.

If the cam timing is retarded due to a stretched chain, replacing the chain will correct it and timing the car is not necessary.

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Gone to the dark side

- Jeff

I would still check IP timing. Besides, it might have been adjusted somewhere along the way as the previous chain wore.

Sixto
87 300D

No your right I didn't type clearly enough.

I was trying to say that maybe your pump timing is off.

__________________
2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200