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Well Used 720 Diesel Won't Start... its like banging my head against a wall


TrouseLife

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I parked my truck a few weeks back in the mountains of NC and forgot to crank it for a few days in a row as it turned colder and colder (had a few days in a row below 32). There have been numerous problems keeping this truck cranking as is. So it sat for about 5 days before I tried jumping it off with another truck to no avail. I get puffs of black smoke from the exhaust but nothing too promising.

 

I figured it would be time to replace the glow plugs anyways, ordered them up, and now there are 4 new glow plugs installed. Still no go.

 

While even being jumped from another vehicle, the first few cranks would be OK sounding but never fully turn over, but a minute or two into trying to start up (6th or 7th crank attempt), there was hardly enough power to turn the starter.

 

Then I tested the battery; tested A+ working condition and charged. Still no.

 

After that, I assumed that perhaps it was the starter that was begining to go out on me and I should warm the plugs and try to push start it down a hill. Still no luck. Pushing black smoke, but no luck.

 

Now I'm nearly at the bottom of a hill and quite disheartened with the circumstances. Any pointers? Wayno still around?

 

 

Thanks in advance and happy turkey day,

TrouseLife

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What is the temperature outside?

These engines get hard to start when it is below 40 degrees, and they are really hard to get started below freezing, you need a block warmer in cold weather.

 

The starter aperture can get ruined if you turn the starter over with a less than fully charged battery, it's very hard on these and all starters to turn them over on a half drained battery.

Once it starts to turn over slow, it's over with, it will start clicking a lot also, hope you have another starter around, as it's likely the one in it will need rebuilt. 

I have not heard of any folks getting these engines started by coasting down a hill when they are cold, I can do it when it is warm, but it totally surprised me when it did start the first time I tried, I also had a bad starter, it would turn over regular speed maybe one turn, then almost stop turning, then do another 1/4 turn then almost stop again.

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One thought - You might put a test light on the wires right at the glow plugs just to be sure they are getting power. All my experience with glow plug diesels is Caterpillar tractors. When starting those in cold weather, Cat recommends a much longer time heating for the glow plugs before cranking. I don't know what Datsun says for time for glow plug heating. You might even hurt the glow plugs by heating them too long.

But if the engine is turning slow due to a iffy starter, you probably need to fix that. Do the Datsun diesels use a different starter than gas engines? I use a Maxima/280 gear drive starter on my L series gas engines. Spins them over a lot faster than a standard starter. But that starter may not fit a diesel.

I've got a friend who bought a 720 diesel a couple of months ago. It is supposed to get cold here in E WA by Sunday (high about 27F). If I see him, I'll ask him to try starting his in cold weather and see how it works for him.

 

Len

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Yeah, the SD22 is a tough start when its cold.  I'm still trying to learn a few tricks.

 

Its been recommended to me to leave the glow plugs on extra long.

 

The Boy Scout/engineer in me thinks that trying to warm up the engine is worth a shot.

If you have time, here is what I'd attempt:  Build a fire, away from the truck.  Boil water in metal buckets.  Set a bucket on the top of the engine.  Maybe set a bucket below the engine near the oil pan.  Maybe put just a little bit of hot water in the radiator.  The water has a high enough specific heat where if you let it sit for a couple hours, it should gradually warm the engine to the point where it might turn over if the starter isn't gone.           

Or you could just get it towed... but where is the fun in that?

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The diesel engine has the starter on the driverside, and it is huge compared the the L series starter.

Making sure the glow plugs are getting power is a good idea, but I don't even try to start my engine below freezing without a block warmer, I just drive the work truck(gas engine), as it starts easy compared to the diesel.

One thought - You might put a test light on the wires right at the glow plugs just to be sure they are getting power. All my experience with glow plug diesels is Caterpillar tractors. When starting those in cold weather, Cat recommends a much longer time heating for the glow plugs before cranking. I don't know what Datsun says for time for glow plug heating. You might even hurt the glow plugs by heating them too long.

But if the engine is turning slow due to a iffy starter, you probably need to fix that. Do the Datsun diesels use a different starter than gas engines? I use a Maxima/280 gear drive starter on my L series gas engines. Spins them over a lot faster than a standard starter. But that starter may not fit a diesel.

I've got a friend who bought a 720 diesel a couple of months ago. It is supposed to get cold here in E WA by Sunday (high about 27F). If I see him, I'll ask him to try starting his in cold weather and see how it works for him.

 

Len

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I used to live dangerously and put a can of sterno directly under the oil pan.  Do you hear your glow plug relay click when you turn the key to start position?

I'de wire the glow plugs to a switch so you can keep them on for longer during really cold weather. I'de also put in a new set of glow plugs.

 

Edit: push button switch. NOT toggle switch. Don't want to forget you have them on and burn them out

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If you want to warm up the glow plugs longer, just cycle the key twice, they can be burned out if they are on to long.

The electrical components have some bells and whistles, one of them is to turn off the glow plug power when they are hot enough, a switch or button cannot distinguish this fact, once the glow plug has been on to long and has been compromised, it will be really hard to start the next time it is cold.

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So, I'm not doubting at all that the starter is on its last leg, but any time I try to push start the truck I make sure to cycle the glow plugs two or three times (and this isn't the first time the starter hasn't wanted to play nice).

 

The glow plug relay still clicks, and there are four brand new NKG glow plugs in the engine as of a week into this debacle. I haven't tested to see if all four plugs are receiving power or how many of the old plugs worked though.

 

Also, now that I've gotten towed to the other side of the mountains and back into TN, the weather is substantially warmer. It has been over freezing since I got back over here. It was fairly warm in NC (over 60) a few times I tried to start it, and the day I tried to push start it here, the weather was quite warm and was well into the afternoon.

 

The biggest thing for me is the expense of diagnostics. Even $50 for four new glow plugs is a pretty penny. I live out of the camper and am pretty lame without a drivable truck. Rebuilding the starter (as I don't have a spare) has been on the list of things to do while temporarily stable, but I just haven't gotten around to it yet (...or being stable). The most confusing aspect of this quandary for me is the newfound inability to push start the truck after cycling the glow plugs. It has always worked in the past.

 

Oh yes, there is fuel in the tank and a proper amount of oil, coolant, etc. in their respective places.

 

Is there something else I'm missing?

 

-TrouseLife

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There are a few things that have to work together for this truck to start, one is the engine has to get fuel, now I cannot remember if your truck works off the key, or if it is working via a choke cable(push to run, pull to turn off), if I were trying to start my truck by coasting down a hill, I would disconnect the injection pump controller if you have one.

The system Nissan made to turn on and off the engine works great when it is working, but if it doesn't do what it's supposed to do, it's not going to start, you need two people to make sure it is working properly, while one person turns it over, the other person needs to watch the injection pump(IP) arm to make sure it moves to the start or run position, if you don't have a helper, then remove the IP control arm so it moves to the run position, it will move there by itself, at least then you know it is getting fuel if your by yourself.

Have you checked your Valve lash lately, no compression, it will not run, but it also might turn over easier.

It was running properly before you had issues, correct?

You checked to make sure the glow plugs have power when you turn the key to the on position, correct?

Sometimes the fusible links get blown, or there are connection issues at where the plug is at the positive battery post, the photo below is of the fusible links and the plug I am referring to.

See how my fusible link plug at the battery post looks melted, this plug is a problem area.

DSCN0080.JPG

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There are a few things that have to work together for this truck to start, one is the engine has to get fuel, now I cannot remember if your truck works off the key, or if it is working via a choke cable(push to run, pull to turn off), if I were trying to start my truck by coasting down a hill, I would disconnect the injection pump controller if you have one.

The system Nissan made to turn on and off the engine works great when it is working, but if it doesn't do what it's supposed to do, it's not going to start, you need two people to make sure it is working properly, while one person turns it over, the other person needs to watch the injection pump(IP) arm to make sure it moves to the start or run position, if you don't have a helper, then remove the IP control arm so it moves to the run position, it will move there by itself, at least then you know it is getting fuel if your by yourself.

 

 

Wayno, here is a photo of what you're talking about. There is an exess fuel or start position on the injector pump. It acts like a choke on a carburator to add extra fuel when the engine

is cold. Yes,  if the pump is not in the correct position it won't start.

 

I've forgotten if you've checked to see if you're getting fuel into the pump. When is the last time you changed the fuel filter?  I just bought a vw diesel not running for cheap and all it needed was a new fuel filter. The kid that sold it tried everything BUT a new filter. 

 

Edit: Just googled hard starting datsun diesel and found some frozen canadians have fashioned intake heaters.  So in a pinch you might try using a hair dryer. Maybe pull off the air cleaner

element and stick the dryer up that. Curious to see if it helps.

 

SmokeScrew-r.jpg

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Nice photo, a photo can explain a lot, where it can take 100s of words to try and get the idea across.

The deal is that one cannot see it move from the drivers seat, and one cannot hear it move while turning the engine over, it's just easier to have another person to turn it over for a few seconds to make sure it is working, and unfortunately it doesn't move to the run/start position until it is turning over. 

This might all be in vain, he might have a choke cable to turn it on and off, and maybe the cable mount came loose on the injection pump end, maybe the hose from the filter to the front of the injection pump got a crack in it, maybe, maybe.......................................there are a lot of maybes here, he has not replied about the key/cable question yet, so we wait for more information.

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I had some trouble with my truck last winter. Is it possible that the lines aren't primed or there's air in the lines? Thats what happened with mine when it got super cold and the fuel gelled. I had to open up each fuel line individually while someone turned over the truck until fuel came out and then I sealed them back up to get all the air out. All the while using the manual pump to prime the fuel. I got started and haven't had any troubles since (especially since I made sure to stick to B50 or B20 when it starts getting cold). I also got heater but I was lazy and just got the external magnetic one so I don't think it did much good.

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So my IP controller is broken (luckily stuck in the "run" position). I've been meaning to install a push/pull choke cable in order to have all three original options - off, run, and start - but havent gotten around to it yet. As the truck sets currently, I have to open the hood and choke the engine to turn it off. Was planning to fix this over xmas when I have an indoor garage to work in again. I also have a possibly working IP controller I'm considering installing, but the idea of a manual cable sounds better to me in the long run. There is a coolant block heater in my box of parts to install as well. Also, I run straight petro diesel in the colder months and have run more than plenty to flush any biofuel out of the fuel system.

Haven't checked compression. Left access to that tool in NC. I wonder if thats a loaner tool at auto parts stores. hmmm

Haven't checked if glow plugs are receiving power. Lost my multimeter... somewhere... Alternatives to the proper tool?

My fusable links look ok, but what do they run to exactly? And why might this keep the engine from push starting? As I said, I've had to push start the truck before whenever I couldnt get the starter solenoid to kick.

Truck was running fine before mysterious No Start Condition. Normal amount of black smoke; normal fuel economy; normal minimal power.

Fuel filter was changed in July. Been looking for a replacement to carry with me, but cant track them down anywhere. Ought I opt for a universal canister filter as a backup? Also, I do get smoke puffs when attempting to crank, and that would cause me to assume that I'm at least getting fuel past the filter and IP. I could be wrong... again...

It has been nothing but mild weather here in TN since I got back. Hooray.

Will more thoroughly inspect the fuel lines once it stops raining. Haven't seen any more drip spots than normal (mostly oil drips, some tranny fluid), and I do keep an eye on my levels every week.
 

I plan to get the starter rebuilt this week at a starters and alternators shop here in Chattanooga. Been slinging xmas trees to earn some money for the rebuild. I'd rather be covered in oil than pine tar any day.

 

Here is a link to the thread on my cold start issue. Maybe it will help. http://community.ratsun.net/topic/58872-frozen-fuel/?p=1017529

 Thanks for the link, Java&Whiskey. Seems like you got a good number of opinions on biofuel that don't have much background in it. Plenty of help too though. I started making B100 ten years ago for a landscape company in Houston then learned about biodiesel gelling after driving my TDI Jetta to New Hampshire one winter... oops.

 

Finally, can diesel gelling in my fuel lines cause air bubbles? Would a simple injector prime solve this entire debacle? Will definitaly need to solve my starter problem before attempting to prime injectors though.

 

 

Thanks all,

TrouseLife

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What do you mean by choking the engine?

Why don't you just hold the brake down, put it in gear and let out the clutch to kill it?

Remove the arm that goes from the injection pump to the injection pump controller and put it in a baggie with all the little parts and save it, then once you get it running, and you decide to shut the engine down, you just push the injection pump control arm towards the firewall and watch the injection pump controller down there under the injection pump, does it move?

If it doesn't move, turn on the key, unplug and plug back in the plug that goes to it, did it move to the lower shut off position?

Sometimes the connection is lost in the plug, I see it a lot, I try to tell the owners to cycle the plug, but they come to my house, I unplug it and plug it back in and it works fine after that.

Sometimes for one reason or another people also adjust the injection pump timing, that jams the injection pump controller for some reason and it quits working.

White smoke puffing out the exhaust when you try to start it, or right when it starts is unburnt fuel, black smoke is to much fuel(rich).

once you get the starter out, test it, does it run full speed on the ground?

If you get the starter to hot, it ruins it, if you use the starter with a half drained battery, it ruins it over a short period of time.

The fusible links are very important, everything in the truck goes threw them, I mean everything, if you grab the wires with your fingers and squish down on them, you should be able to feel the wire inside of them, if it just feels like rubber, it is blown, the red wire goes to the light switch, the white with a black line goes to the ignition switch, the white one in the same plug as the red wire goes to the glow plug relay which warms the glow plugs, and the last white one in the plug with the white/black wire goes to the alternator, DPC module(black box), and the fuse block(B1/B2), all these need to have power for the truck to start/run properly.

So my IP controller is broken (luckily stuck in the "run" position). I've been meaning to install a push/pull choke cable in order to have all three original options - off, run, and start - but havent gotten around to it yet. As the truck sets currently, I have to open the hood and choke the engine to turn it off. Was planning to fix this over xmas when I have an indoor garage to work in again. I also have a possibly working IP controller I'm considering installing, but the idea of a manual cable sounds better to me in the long run. There is a coolant block heater in my box of parts to install as well. Also, I run straight petro diesel in the colder months and have run more than plenty to flush any biofuel out of the fuel system.

Haven't checked compression. Left access to that tool in NC. I wonder if thats a loaner tool at auto parts stores. hmmm

Haven't checked if glow plugs are receiving power. Lost my multimeter... somewhere... Alternatives to the proper tool?

My fusable links look ok, but what do they run to exactly? And why might this keep the engine from push starting? As I said, I've had to push start the truck before whenever I couldnt get the starter solenoid to kick.

Truck was running fine before mysterious No Start Condition. Normal amount of black smoke; normal fuel economy; normal minimal power.

Fuel filter was changed in July. Been looking for a replacement to carry with me, but cant track them down anywhere. Ought I opt for a universal canister filter as a backup? Also, I do get smoke puffs when attempting to crank, and that would cause me to assume that I'm at least getting fuel past the filter and IP. I could be wrong... again...

It has been nothing but mild weather here in TN since I got back. Hooray.

Will more thoroughly inspect the fuel lines once it stops raining. Haven't seen any more drip spots than normal (mostly oil drips, some tranny fluid), and I do keep an eye on my levels every week.
 

I plan to get the starter rebuilt this week at a starters and alternators shop here in Chattanooga. Been slinging xmas trees to earn some money for the rebuild. I'd rather be covered in oil than pine tar any day.

 

 Thanks for the link, Java&Whiskey. Seems like you got a good number of opinions on biofuel that don't have much background in it. Plenty of help too though. I started making B100 ten years ago for a landscape company in Houston then learned about biodiesel gelling after driving my TDI Jetta to New Hampshire one winter... oops.

 

Finally, can diesel gelling in my fuel lines cause air bubbles? Would a simple injector prime solve this entire debacle? Will definitaly need to solve my starter problem before attempting to prime injectors though.

 

 

Thanks all,

TrouseLife

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As for the fuel filter, there are two types that fit. One is the preferred type and has a water sensor in the bottom. This one is getting pretty hard to find. The other is smaller and does not have the water sensor in the bottom. It's still pretty common. I bought two of the latter ones (part no. MGD 33386) but haven't had to install one yet. They're still in the truck under the front seat.

It is possible that you have more than one problem. That makes troubleshooting really difficult. Without a multi-meter? How do you survive?

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Another day of truck work -

 

Tested the glow plugs with a flashlight bulb. All four are receiving power.

 

The rod from my IP controller to my IP is disconnected. I don't stall the engine because I believe the transmission to have more issues than the IP, and why stress it if there is another option. I don't notice any movement of the IP controller (though disconnected) at all while choking. Also, after stalling the motor in the past I have noticed that my starter has a higher chance of not wanting to work the first try.

 

When I say I choke it, thats the only way I know how to describe it. Please see attached picture. I just rotate the controller rocker towards the firewall til the engine chokes out. Apologies for the shabby picture and editing.

 

IMG_20141205_125726654_zps425f4e85.jpg

http://i780.photobucket.com/albums/yy87/trouselife/IMG_20141205_125726654_zps425f4e85.jpg

 

 

The fusable links are still OK, yet I don't understand why they would be required to run properly as the engine is 99% mechanical.

 

The smoke puffs have been black.

 

I pulled the starter and got it tested today. It confused the maching testing it and caused a bit of smoke to occur... slightly confusing. The auto parts store (AutoZone) was able to track down the starter but wont be able to get it here til monday afternoon. SO my big question with that is if its better to order up a new starter with a warranty or to rebuild the OEM starter. Part # 16771 according to them. $90 before core charge or tax. (link to 16771 though rerfurbished in the link: http://www.rockauto.com/catalog/moreinfo.php?pk=3371937&cc=1210374)$62 before tax and core charge for refurbished.

 

I also found an AC Delco model on RockAuto. Part # 3361396 (link http://www.rockauto.com/catalog/moreinfo.php?pk=1001070&cc=1210374)for $82

 

Does anyone have any experience with these or any suggestions? My quote for a starter rebuild around here was $100 - $150.

 

 

Lastly, without the proper tools... I still manage to get by. Here's hoping for my grandpa's multimeter for xmas.

 

 

 

Thanks again,

TrouseLife

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That is pretty cheap for a starter. I had to rebuild mine myself and wouldn't have if I could have found one for that price.

Have you taken a look at the metal prongs on the fusible links? If they're corroded, clean them up as well as you can. Sometimes, as Wayno has mentioned with the injection pump controller, just unplugging it and plugging it back in makes a better working connection.

As for the injection pump controller, how does it look inside? They're pretty basic and can often be repaired with a soldering iron and a steady hand. 

Also, I've skimmed back through and can't see where you've made sure you're getting fuel to the injectors. You can see the line that goes to all of the injectors. When you disconnect it from one of the injectors and pump the fuel with the manual lever, you should see it come out of the line where you removed it from the injector.

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You have to disconnect the injection pump control arm from the pump to prime the system, if you leave the pump in the off position, it will not prime the injector lines, as the fuel is cut off, I do realize that his is already disconnected, but I don't want others to think that priming the system worked that way.

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