After doing some searching here last night, I'm still not certain I know how to approach this latest issue. This in on the 92 300D (245K mi).

Just got my head gasket replaced (FINALLY -- the car sat for a year!), and it runs, but nails hard at warm idle, and stumbles when cold. I am going to pull the valve cover today and check the timing chain again (before the head gasket went, it was about 3 degrees off, as I recall -- within limits) just to be sure my efforts to get it back just right weren't in vain.

Anyway, the car idles poorly, but the nailing goes away over 1300rpm or so. At at that point, I get occasional puffs of smoke, and under WOT I I get a fair amount of smoke. Smells to me like unburnt fuel (rich diesel smell, not the usual sweet coolant smell), and I have yet to detect any oil in coolant or coolant in oil (though I've only run the car around the block a few times and idled it maybe 15 minutes total).

I had the injectors checked (by a member here) while the head gasket job was being done and they all came back good, FWIW.

I am thinking I ought to check the cam marks, then maybe look at renting the RIV IP timing tool to dial in the IP. As I recall, the car always nailed a bit at idle.

Thanks all!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

I don't believe you can get away without checking both the camshaft and IP timing after a head gasket R & R. There will be those that disagree, but failure to check those crucial operating parameters after such extensive work leaves you with all kinds of questions as to whether it's running properly..........or not.

Agreed, it sounds to me like something is advanced too much.

Thanks, Brian; that's kind of what I was hoping to hear. The RIV tool rental fee is small price to pay to know that the IP timing is right, as far as I'm concerned. I'll check the cam marks and go from there.

Do you have any experience speaking to bad IP timing symptoms? Can it manifest itself in significant nailing at idle, which smooths out after about 1300rpm, and smoke?

Thanks again!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Thanks, Craig. I'll check cam marks later today (this morning's been busy!) and see if that's withing acceptable range, and worry about IP timing afterward.

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Good (?) news... cam timing is right where I left it: between 2 and 3 degrees ATDC. The IP was left "open" (no lines attached, but plastic over the opening for protection) for several momths while I tinkered. Any possibility the delivery valve seals dried up in that time? If so, would air alone allow for unburnt fuel (excessive smoke)?

What's next: compression check or IP timing adjustment?

Thanks again!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)