slight knock on sub zero cold starts

[m1garand_man]

Last year I noticed knocking after cold starting in sub freezing temps. the lower the temp the longer it dose it for usually only for a minute or two and of course there is smoke comming out of the exhaust.

I'm wondering if this is normal. the glowplugs are new and are all working properly it dosnt take longer than normal it just sounds like crap untill it starts to warm up.

I just moved to montana and I will be installing a 150w oil pan heater and will be parking it in the garage.

When I was living in washington I started it up on days as cold as 5*f with no problems other than the knocking which I dont know if is normal or not.

 

[91W350]

I am betting it is normal. All of mine knock louder on cold start up than the rest of the year.

The pump not only fast idles, it advances too, so your initial fire up and up until the fast idle kicks off is louder. One of my M1009s is significantly louder than the other two as was my original M1008.

The M1009 with the loud knock must have a weak vacuum pump as it is also slow shifting cold and the brakes are slow to fully recover after a pump down. It sounds like it is going to fly apart at about 15 mph in low gear, so generally, I take the slower side streets in below 20 degree weather until it warms up.

I am sure the guys with way more knowledge and experience than I will chip in too. I learn to fix them as they break, get a book, read the forums, look in the TMs, wade in like you are Superman... It may take me a while, but I have the satisfaction of knowing I did it myself!

Glen

 

[m1garand_man]

now that you mention it I'm wondering about my vaccum too because it now dosnt shift into 3rd around 32-33 like it used to. now it waits untill 36-37mph or so and thats really annoying on 35mph roads.

the shift into 2nd is still around 15mph though.

Your explanation seems to make sense to me. I learn how to fix things as I go on my truck too. I'm glad the TM is so easy to use compared to the civilian manuals with crapy pictures. line drawings are nice.

Any other input would still be appreceated.

 

[Westech]

The M1009 with the loud knock must have a weak vacuum pump as it is also slow shifting cold and the brakes are slow to fully recover after a pump down. It sounds like it is going to fly apart at about 15 mph in low gear, so generally, I take the slower side streets in below 20 degree weather until it warms up.


The vacuum pump has NOTHING to do with brakes. The brakes are called Hydro boost. They use the power steering pump for a power source. As the cold start knocking goes 91 your got it. The cold start advance bumps the timing 10*. The truck really should not be driven till warmed up but if you take it VERY ez you should be ok. Also might be time to replace the glow plugs. I replace mine every year in my cucv/s and I get NO smoke even at -10* starts. If one glow plug is bad/weak it will really cause some trouble.

 

[91W350]

Thanks Westy, I knew the hydro boost and let it roll out one ear. Anyway, I have some sort of problem there when it is extremely cold. They are very slow about recovering. I do drive very easy until it kick off, heck, I drive them very easy about all the time. Heavy pedal and extended idle time is fuel wasted. Some days I will be almost to work before it kicks down to a regular idle. On hot days it is usually within a city block.

My M1008 has started rolling smoke out when I start it up. It smells like a charcoal grill. I put new plugs in it about 10,000 miles ago, I am guessing I will be doing it again soon. It never needs oil between changes, so I am assuming it is a glow plug or fueling issue. Glen

 

[Westech]

A good cleaning or heck for 65 bucks you can replace all 8 injectors. Ask Kipp... he and I talked about replacing his injectors and what a difference he said. 6.2 glow plugs really dont last very long. like I said I replaced mine every fall. I know its a couple bucks but its worth it. As far as power steering goes make sure the fluid is clean.. ether Power steering fluid or I use ATF in my GM pumps.

 

[91W350]

The truck only has around 35,000 on it now, but they are 23 years old. For 140 dollars, I will probably do both. Thanks, Glen

 

[Westech]

Chevy GMC 6.2,6.5 6.5L TURBO Diesel Injector Nozzles: eBay Motors (item 160448681145 end time Sep-22-10 07:45:06 PDT)



That is where Kipp and I got them.

 

[xenocath]

that posting shows two diffrent injectors which ones did you use?