Trouble starting in 17*f weather
 

ive been having trouble with my 81 300sd lately, but only when cold out. its never seen the snow before so ive never had any trouble getting it started before, but the first trip to cold weather i killed the battery trying to start it. i gave it two glows before starting, waiting until the relay clicked off both times. i checked the glow plugs at the big connector behind the driver headlight. they were all around .8 ohms. i brought the battery inside and charged it, then just cranked maybe 3 or 4 times and while i was cranking, my friend unscrewed the oil fill cap on the valve cover, and right when he unscrewed it the engine started. this was about a week and a half ago, i thought it was a coincidence until tonight when the same exact thing happened.

it decided to snow yesterday, so today its freezing out and i try starting the car, figuring it would work fine because its been nicer out the past couple weeks.. killed the battery AGAIN! this time i pulled the glow plugs and replaced a couple.. noticed the first one had a loose connection to the wire harness. (maybe thats why my car's been stumbling a little bit for the first few minutes after it starts up??) i ended up getting the size 49 battery because i realized the one i had in there was the wrong size. it just died too quickly after trying to crank and glow only a couple times. so i put the new one in and cranked for a good 5-10 seconds, after doing two glow cycles. tried again. and again. then same thing- my friend unscrewed the oil cap thinking it would work again and it did.

just a side note- ive done a valve adjustment within the past 100 miles and i ran diesel purge through the engine, about 2000 miles ago. when it ran through it came out clear and didnt seem to have any affect on the running of the engine. the shut off valve at the back of the ip was replaced about a month ago, in case you were thinking somehow it was keeping the engine from starting. and im pretty sure it isnt air in the lines, i pumped the primer pump and could hear the overflow coming back out the ip, i just wanted to make sure the fuel wasnt frozen soild!

i don't think i have excessive blowby; the oil cap will just rattle on the valve cover when its unscrewed, it doesnt fly off.

anyone have any insight as to why unscrewing the cap helped the engine to start? i know there must be something else wrong, because today (before the battery died) i tried unscrewing the cap before cranking it, thinking, "just in case i can't get it started, this is what worked last time". maybe my glow plugs are all bad?? maybe its the excessive cranking that heats up the engine enough to get it started? and somehow pressure is building up in the valve cover, keeping it from starting? i dont know..

I would check timing chain stretch. No idea why taking off the oil cap would change anything.
Probably before that though, I would check the glow plugs in their sockets. Sure it involved removing the injector lines and injectors, and replacing the heat shields, but you can watch the glow plugs burn. Physically seeing something work is a better test for me. Might be more involved, but for me it's piece of mind, and I'm simple like that.

To check glow plugs I unscrew the wires off the plugs.Then check with ohm meter for continuity.
If they are Bosch Duratherm or Monarks just replaced the ones that are bad.Warning Autolites will break apart.Oh yeah touch ohm meter to engine ground and the center of glow plug.
Two alot of glow plugs can test good but when taken out,and using jumper cables to see if they light,they don't work.

Firstly, three separate incidents of removing the cap and starting cannot be ignored, if factual.

If...........and this is a big if............crankcase pressure can build sufficiently during cranking to pressurize the crankcase, the shutoff valve will partially close making starting very difficult. However, the only possibility for this to occur is if the breather tube on the top of the valve cover is completely obstructed. This tube extends to the air cleaner and provided crankcase ventilation for the engine.

Check for any obstruction in this tube and eliminate it. Report back with results.

the only thing I can think of with the cap is you may have a frozen oil separator. the hose that is on top of your valve cover goes to the oil separator in the bottom of your air cleaner. if water is collecting in it, you would freeze up in cold weather, and it would pressurize your motor and force the fuel shutoff to keep the car from starting. you could also have gunk in the tray in the top of your valve/cam cover and it could be blocking gasses from escaping.

Brian, like minds think alike...

..........as always...........but I like the frozen block of water.......;)

I'd remove and check with direct 12 volts all the glow plugs to make sure they are glowing red hot and ream the holes. Reaming the holes in my SD reduced cold starting ability by about 7-10 degrees.
I'm a doubter on the pressurized crankcase. I don't think the crankcase could build enough pressure while cranking with the starter to push on the shut off diaphragm. If it was doing that, it would seem the engine would shut off after it was started and the oil cap replaced.
I think most of your problem is related to the smaller battery you were using. By the way, 10 seconds of cranking is not long in cold weather. MB says you should keep the engine cranking until it starts. I've done this for well over 30 seconds in cold weather. Typically one or two cylinders will start firing but you still need to keep the starter engaged to keep it running long enough for more to start firing. If you read the threads on here on cold starts, you'll learn that you only really get one attempt. Subsequent attempts, after the first, are very unlikely to get the engine started in cold weather. You can't think of starting a 617 in the cold the same way you think of starting a gasser. Glow twice, hit the starter and keep it engaged until its running.

cold checklist
 

Valves (done)
Cables (done)
Battery (done)
Synth oil (?)
Starter speed (listen to other 617 cars) is critical on a diesel
Procedure (as mentioned: glow. Press/release pedal to loosen rack (Dr Booth). Crank until running. )

Your name is biotour, so can I assume you are running biodiesel? Most B100 gels before 32F. Are you using B100?

Edit: I just noticed you listed you have a two-tank conversion in your sig. Are you running D2 in the main tank and veggie in the 2nd? Short purges of the veggie would cause cross contamination into the diesel tank. If you don't keep much D2 in your main tank the % of veggie in there could become high and thus gel at cooler temps.

Also I'm assuming you filled with D2 in a warm area where there is no blending done with pump diesel. Then you drove to a colder area (17F). 17F is about the low point for D2. Alone, D2 should be okay at that temp but if it is somewhat contaminated with veggie then the gel point becomes higher.

I would try adding some kerosene or anti-gel additivie to the main tank. Or at a minimum top off with blended diesel in the area you are now in if this is the case.

Ye ole' strip fuse.
 

12V at the glow plugs??

Jay.

would buying new fuel injection nozzles help the cold start issue? the engine in this car was from the junkyard and i have no idea what the current injectors are like. same with the glow plugs, but i never had an issue with them so i never thought they were bad until i moved to colorado!

i'll pull all 5 next time its warm out, and hook them all up to a battery to see which ones glow red. is there anything i can diy to make a glow plug reamer? or where would i buy one? thinking i'll also stop by harbor freight and get a compression tester just so i know what im dealing with. will also check crankcase breather tube. ill try blowing through it with the oil cap off and see if air comes out.

im running mobil 1 synthetic, i got 5 quarts of 15w40 and topped off the rest with 5w40 rotella synthetic from autozone. its been in there for about 2500 miles, and is my first time using synthetic. when would be a good time to change it? i was told this oil is good for at least 5000 miles.

i usually only have between 1/4 and 1/2 tank of diesel since i try to run mostly on veggie oil. i havent been using it as much because ive been doing a lot of short trips, but there is probably some veg in my diesel tank. ive filled up a few times here but i only put in a few gallons at a time.

The easiest/best starting point is the glow plugs. You can verify the resistance from the connector on the relay without removing them. They should read less than 1 ohm when they're cold. They will normally read infinity if they are dead.

If the injector(s) are bad you should also hear some injector knock, especially with a cod engine.

How does it run in warmer weather?

Not just cold. Elevation may also be an issue. Thinner air, lower compression. What's your elevation? When's the last time you replaced the air filter?

Fuel gelling then doesn't seem like an issue if you have put fuel in a few times in the new location and you aren't dumping tons of veggie in the main tank.

Once the glowplugs are in order, IMO oil weight makes the biggest difference in cold starts. I would run exclusively 5w40...actually I do. :P

And since you are running veggie you will want to run shorter oil change intervals than someone using the same oil running D2 since the veggie doesn't burn off in the oil like D2 does. I would think 5k on M1 or Amsoil would be the max for running veggie. If you are using dino I would probably stick with 3k. Rotella, probably somewheres inbetween.

I would go back and verify exactly if the loosening of the oil cap is really involved. With it on and someone cranking watch the shut off lever. Remove the oil filler cap and watch it again. Any difference and you should pay some attention to this item.

I base this on the two time occurance kind of ruling out coincidence maybe. Does a loose cap blow off when just cranking? I know it does not blow off when the engine is running. You mentioned that.

Run Diesel #2 or #1. get it running right before you switch back to veggie crap. oh i mean oil.

Another thing I just thought of that happened to me that you can check-

You say you just did a valve adjustment. I would go back and double check the clearances and the pattern of exhaust/intake is correct. It shouldn't take more than a half hour to check. One time I messed up the pattern of E/I and I couldn't start my car in 20F weather unless it was plugged in. Redoing the valves correctly solved the problem.

Consider me #2 . I've always had problems starting in cold weather. Been trying all morning . I read this thread went back outside loosened oil cap and cranked . Starter speed picked up oil cap blew off smoked like a freight train out the valve cover but it started , same as it would when its warm. ???????:eek:


Oh car is 79 240D temp is a "frigid 40*" glow plugs recently changed as well as valves , breather tube wide open

Barry please explain what I'm looking for on the shut off lever .

I think your on to something.

i checked the glow plugs and they all seemed to measure up fine. i had some extras lying around including the two i pulled from my car the other day, and tried hooking them up to a battery and they all glowed. i noticed some took a little longer than the others to turn orange, but it was only a few seconds difference. im thinking ill pull all 5 tomorrow and put in the ones that heat up the fastest. they are all bosch or beru plugs. i picked up a set of drill bits and will try reaming the holes (very carefully) before installing the new plugs. i don't have access to a glow plug reamer nor know where i'd get one or i'd use that.

what does injector knock sound like? whats the difference between that and nailing? i don't know what noises are good and which are bad, does anyone have a video or audio clip that explains it all?

the car runs great in warm weather, it started fine today at around 40* F. i have been noticing ever since i did the valve job that when just pulling away from a parking space or going slow i have no power at all. it takes a while to get it going up to 20 mph, but once its up to speed it roars to life. The power above 20mph is much better than before the valve job, and ive noticed that it idles a lot smoother. I removed the bowden cable when i took the valve cover off, so maybe i might have just knocked it out of adjustment? i don't recall touching the adjustment screw on it.

elevation is 5280 ft and i believe its been 3 months since the filter was changed.

the oil cap does not blow off when cranking, it just rattles a little and oil squirts out onto the valve cover. Next time its cold out i'll try watching the shut off lever, to see if i notice any difference in its position. Just as an aside: I don't believe this situation would prevent starting. I think it would start for a second and then shut off. I have a 300D that doesnt have a keyed starter switch; its just 3 electrical switches soldered to the round connector, with a ball valve controlling the vacuum shut off. (bought it that way) I once tried starting it with the ball valve open, and it would start and then immediately die. (the ball valve kept the shut off valve engaged) only possible difference is that the shut off valve was under vacuum whereas in this case the shut off valve would need to be under pressure to be engaged, not sure if that would even be relevant.

Another interesting point is i'm on my 2nd engine for this car (nasty oil leak developed that i couldnt find). Before that mess, i had trouble starting my car where it'd do the same behavior of starting for a second and dying, it started when i removed the oil cap. see this thread.

i have added some diesel, not sure if its #1 or #2, im assuming they sell "winterized" diesel around here since theres been snow on the ground for the past month.

i double checked the valve adjustment after i did it, and i always look at the manifold so i know which is which.

Denver diesel is not winterized. The blends of winterized diesel get stronger the higher you travel into the mountains.

That sounds like normal operation to me. The turbo doesn't kick in right away.

Since, this is your 2nd engine and you have the same problem along with your description of your starting/shutoff system, I am led to believe your odd start/shutdown system has something to do with it. As was previously stated, you should look at the linkages when trying to start to see what happens.

Biotour thanks for posting the oil cap thread did you ever come to a conclusion on what was causing the problem?

I went out again this morning took the cap off had it started within 5 min.

I had the same problem with the glow plugs slow ones were tossed . Mine wouldnt even start in warm weather back then. There is a thread on making a reamer from a drill bit using the old glow plug body, drilling it out for the bit and welding on a nut . search glow plug reamer I made one last spring. I kept the length as long as the glowplug to prevent damaging the prechamber.

Found the link : http://www.peachparts.com/shopforum/diesel-discussion/262239-homemade-glow-plug-reamer.html?highlight=homemade+plug+reamer

im hoping the bigger battery fixed things. its been starting fine the past couple days, except today i had to crank longer than usual. it was odd- it started right up, then did the usual cold stumbling that it does (not sure exactly why). i put it in reverse and gave it some gas and it died. tried starting again and cranked for 5 seconds or so and just sounded like there was no gas. pumped the primer but there was no air in the lines. so i unscrewed the oil cap, and it fired right up. still continued to stumble for the next couple minutes but then was fine. and it wasn't even that cold out today!

i saw the thread about making the glow plug reamer- looks like he's using a 5/16 bit. i tried using a 1/4 bit and couldnt get it through. it felt like i was drilling into the metal so i stopped because i didnt want to damage the engine. im now thinking (and kind of hoping) that my glow plug chambers are just all gummed up with carbon and not working effectively, and thats why im having the stumbling and difficult starting when cold. I do run vegetable oil some of the time, only when the engine reaches around 90*C. id like to build that reamer but do not currently have access to a welder. is it possible to clean out with a drill bit? do i need to spray anything in there to loosen up the carbon before trying to twist the drill bit? like i said i tried it once with a 1/4 bit and didnt seem to be getting anywhere. the 15/64 bit went all the way through just fine

i never came to a conclusion about the problem with the last engine, it was just a one time occurrence and never happened to me again. it was very odd!

Are you sure the vacuum is being released from the shut off diaphragm before you try to start it? It sounds as if there is still partial vacuum on the diaphragm in some conditions, hindering the flow of fuel thru the system. That could be why any slight pressure in the crankcase would activate the diaphragm fully.
Can you explain what mechanism you have in place of the ignition switch that releases the vacuum from the diaphragm prior to starting? It sounds to me from your description of the system that you have a valve which sends vacuum to the shut off valve to shut off the motor. You then turn this valve off to stop vacuum going to the shut off valve to start it. But stopping vacuum going to the shut off valve is not the same as bleeding off the vacuum you induced in the system. I think this is where your problem lies and it's why both motors had the same problem.

Unfortunatly excess base pressure is shutting the fuel shut off valve off. There is excess pressure inside the crankcase when trying to start cold. It seems after the engine starts the blowby is less. Or at least lower so the shutoff is not activated.

If car was on vegatable oil at one time a good cylinder soaking with marvel mystery oil might loosen up the rings a little. All the smoke you see when the engine starts from the oil cap hole is excessive product getting by the rings.

The engine may have severe wear problems if the rings do not loosen up. My guess is once the engine is actually running the added combustion pressure is helping the rings seal somewhat bettter.

Pretty well would have to be or base pressure would still get even higher and shut the engine down. I often wondered if this was an intentional safety feature or accident of design. In theory if too much oil got past the rings the engine might self fuel.

Other than soaking the rings or a teardown after establishing by leakdown testing if problem is across all cylinders or perhaps only one. You can live with the problem by starting with the oil filler cap off and reinstalling it after the engine has run a little bit.

Honestly I feel it is not stuck rings but instead excessive wear in the engine. I can be wrong though. I would in fact be pleased if I was proved wrong in fact. I dislike stating the possibility of what amounts to bad news. Although with a little effort a good replacement engine might be found cheap with a little dilligence if a leakdown test indicates the need.

I wouldn't follow this line of analysis until it's shown that vacuum on the other side of the diaphragm has been allowed to bleed off.

Good thought, try removing the vacuum line from the injection pump shut off before trying to start the engine cold. Especially if the car shows the ability to hold vacuum well. There might be a possibility of a vacuum defect aiding any blowby pressure. As stated earlier I would preffer to be wrong.

I will try that instead next time it's cold out.

Is there a mechanism in your homemade shut off system for bleeding the vacuum out of the shut off line or is it depending on just a slow deterioration in vacuum once the ball valve is turned closed?

sorry about the confusion. when i was talking about the homemade switches and ball valves, that was in another car. it had the two brown vac hoses going to either side of the ball valve. this valve would remain closed during starting and running (so no vacuum was getting to the shut off valve). when i wanted to kill the engine it would be cracked open, allowing vacuum to activate the shut off valve, killing the engine. then it would be closed again.

this car (the one that im having trouble starting cold) has a regular stock keyed ignition. i did replace the shutoff valve recently, the old one wouldnt hold vacuum and the engine was taking a little while to shut off. even the shut off arm didn't work. i believe my linkages need adjustment, but i dont know where to start!

DO YOU HAVE A BLOCK HEATER INSTALLED? NO? THEN I SUGGEST THAT YOU BUY ONE.
UNDER $50 BUCKS DELIVERED. PLUG IT INTO AN OUTLET AT NIGHT. YOUR DIESEL WILL START EASILY EVERY TIME WHEN IT GETS DOWN TO THOSE TEMPS. I LIVE IN THE PGH. AREA. I DRIVE A 1991 350SD. THE BLOCK HEATER WORKS GREAT.