How long does it take to cold start your 617 engine w/o glow plugs?
 

I just did this test on my 85 300D with 159k miles and it took about 29 seconds (if you subtract the 6 second pause in between).

Engine was cold from sitting over night.
Ambient temp around 85 F.
Glow plug relay connector disconnected.
throttle pedal half depressed.

I have not serviced the injectors or taken a compression test and do not know what condition they're really in but engine starts great with glow plugs in the coldest winter day. I am wondering if 29 seconds is too long w/o glow plugs for a 617 when my VW 1.6 IDI Jetta with 230K miles starts w/o glow plugs in about 2 to 3 seconds of cranking. The VW has compression ratio of 23 to 1 and the 617 is 19 to 1. Could that explain the difference?

Can you try it on your 617 and report results?

BTW, the cranking RPM was 1/2 of reading shown (started at 185 and ended at 195 RPM). The timing light (which was getting the signal from the diagnostic port) was on the wrong setting.

CLICK TO PLAY!
http://i31.photobucket.com/albums/c3...725_154723.mp4

I did that test years ago when I had a 617 and it didn't take 30 seconds. I'll have to hunt for the data and whether the glow plugs were completely disconnected or whether I simply didn't wait for them to warm up.

Jeremy

According to WHunter's Poor Mans Compression Test, it should start within 60 seconds.

Here's the link - http://www.peachparts.com/shopforum/2729902-post1.html

I don't like to do this as it's extremely tough on the starter. Last time I checked mine was months ago and as I recall, with an ambient at 75 or so it took 12 seconds. By comparison with 5 seconds of glow, it lights off in 1-2 turns.

In order for the comparison to be valid, please disconnect the glow plug relay connector and do the test when engine has cooled off over night. Take a video if you can so we can compare cranking speed.

Mach4, 30 seconds of cranking in summer is not hard on the starter. Please test again with video if you can. Now that you have a new timing chain, maybe you won't need glow plugs ever again.;)

... 617 should be 21 or 22 to one, not 19...

Looked it up. It is 21.5 to 1

I just tried this two weeks ago with my OM616 '76 240D (138k miles) on a 75 degree afternoon after sitting all night. Took 10 to 12 seconds to fire up. I have the gorilla knob, no relay. Not sure of that makes a difference.

I would think that this would also depend a lot on starter condition. I just changed the starter in my 240D, and man, what a difference! It used to grind, and now it spins, baby! Like night and day.

I've seen Charlie Lund's 240D start without waiting for a glow at all - he just turned the key and it roared to life in a second or so.

Kurt

I happen to be doing this test (by accident, as I may have a dead glow relay):

Ambient temperature in the mid 70s F today, and the car will start from cold in under a minute. (I am just reticent to exercise the starter that way).

The only time my glow plugs fail is in the middle of winter right before I leave for work. In those cases, I can't start the engine by just cranking it.

Personally there are way too many variables for this to be a viable test. It may make you feel better if it starts fast, but issues with fuel being primed, ambient temp, altitude, humidity, injector health, fuel quality, all could play minor roles. If you're worried about motor health adjust the valves and get out the compression tester, anything else is just you fooling yourself.

Yes I agree a proper compression test is the best, this is the "poor mans" method, and it sure does make you feel good about your motor's health when it starts in 35sec:D
The altitude has minimal effect on diesel combustion within reason not so for gassers if you want to prove it drive a 86 fj60 over the sonoran pass(you might want to bring a book, the ambient must be 83 or above as stated in the directions, Usually these cars have tight exhaust valves when not adjusted in a while and that is a cause of low compression so slow start/low compression should lead one to adjust the valves. The others (fueling issues,bad injectors, bad fuel) are good things to check when every other cause is eliminated.

I've done mine below freezing with dead plugs,takes about 30 seconds,and runs rough for a minute.I added cetane improver.

How long to take to cold start
 

Well just the other day my 85 300 sd would not start. I was surprised as ambient temp. Was about 70. I did not stay on the starter for more then 10 seconds for fear of burning it up. Tried a couple of times and finally it started next morning when temps. Were probably 60 I gave up and had to give it a shot of ether to get it going. When checking glow plugs found 2 to be bad replaced them and starts quickly again now. I do think I want to hook the gp. Up manually because it does seem that I burn them up pretty often and they are a pita to replace. Never did a compression test but I imagine the compression is not up to par as I also have an 89 dodge cummings 12 valve with 63,000 on odom. And it starts very quickly even in 0 degree weather and never had to put gp. In a ounce yet have owned it about 23 yrs. I guess hard starting is one of the quirks of these 617's. For winter I use a battery and coolant heater also. I was surprised that with just 2 bad gp. It was so hard to start in 70 degree weather.q

yuke, with valves kept in adjustment, and good plugs, these cars should start pretty reliably. The glow plugs are a maintenance item - don't know how you'd characterize pretty often, but I surely replace at least a couple each year. I'm sure many here replace the whole set as a standard maintenance regimen. They warrant a full once-over before each winter, certainly.

FWIW, I also installed a block heater about 20yrs ago - after a few -40° F nights at a ski house - and never used it again. Getting on the stick with valve adjustments and fresh plugs sorted me out.