Not so typical won't start

[farmerpatrick]

Firstly, I have read all of the 6.2 no start/troubleshooting in the member's area as well as the glow plug troubleshooting article. I have also read through dozens of other similar posts.

91 6.2L K5 Blazer. 225K miles. Won't start.

Changed fuel filter. Fuel seeps from injector line when loosened.
Glow plugs are all getting voltage.
Tested glow plug controller per article. Seems OK.
Motor turns over fine, and puffs of white smoke are emitted from tailpipe, which leads me to believe that the motor is cycling fuel through it.

It's hot here in NW Florida (98 deg. F today). Had block heater plugged in as well (for extra heat to aid in starting, not sure if it really helps). So I would think even if glow plugs weren't working it should still start. Have a charger/starter hooked to one battery and I have my other truck jumper cabled to the other battery for plenty of starting juice. Turn-over does well, and I'm sure starting RPM's are fine.

Unhooked glow plugs and tried a little ether.. No start, of course, I'm doing this by myself, so It's spray and then run over and turn the ignition switch.

This all happened "overnight" so to speak. I was letting a buddy drive the truck and one day he came by the shop (work) and turned it off. 30 mins later he tried to leave and it wouldn't start. I changed the fuel filter and bled the lines right then. We also tried pouring a little diesel into the intake. Eventually, this got it started. He was able to make it around for a few trips (100 miles) and then when he got back home and turned it off overnight it wouldn't crank again. He claims that it was running just fine while it was running. He said he was able to crank it again by putting a little diesel into the intake. He also said that he could turn it off somewhere for a few minutes and it would crank back up, it just wouldn't crank after it sat all night. So of course, I'm assuming glow plugs.

Now, it's been a month since I dragged it back to my house to work on it, and this morning, I finally found time to do some troubleshooting. I can't get it to crank at all now. Not with diesel in the intake or Ether.

I'm thinking about going ahead and replacing the glow plug controller and all glow plugs, just so that I can eliminate that. I'm sure this would be at least 100 bucks though, and I hate replacing good parts, just to find out later they were fine.

I'm also thinking about dragging it to shop, but it's so darn hard to find a good diesel mechanic that really knows what he's doing.

Any suggestions (I will try the ether again later, when I have someone to help)?

[DmaxMaverick]

If it doesn't fire, even if you have fuel weeping from the injector lines, and does fire when you pour fuel in the intake, it's not a GP issue.

Sounds like someone put the wrong fuel in the tank. Gasoline, depending on %, will run fine (or seem to), but will have serious starting issues, hot or cold. My wife has done this many times. In most cases, the result is exactly the same as your experience. Don't worry, though. It's not likely to have caused any damage. If the engine will run, there's enough #2 left in the mix. I do not suggest running it any longer than is necessary.

STOP using ether!!! Although it works, it should be reserved for absolute emergencies. Even with the GPs off, it can still cause serious damage if abused.

How much fuel is in the tank? If under 1/2 tank, try topping it off with fresh #2, and try again. A dose of lube additive would also be a good idea, as the gas can degrade the fuel's lubricity.

[farmerpatrick]

My first thought was that he (guy borrowing the truck) may have put gas in it or bad diesel. But after he got it running, and then then when he said it would start again when hot, I kind of ruled that out. He also said that he went and topped it off with good diesel (and tank reads full). Today, poured some additive in it.

Now, It seems that the ignition switch has went kaput. It's been poor for awhile, always had to jiggle the key quite a bit. Sometimes, it would crank without the key. Somewhere in the process of me working on it today, it gave out. I've never changed an ignition switch before, so we'll see.

Is it possible that the ignition switch could have had anything to do with it.

[DmaxMaverick]

....Is it possible that the ignition switch could have had anything to do with it.

If it fails to crank with the key, sure. If it's the lock cylinder, the ignition switch may not be bad. The switch and cylinder are different parts. The cylinder is non-electrical, and only operates a rack/pinion that pushes the ignition slide. The '91 may have the later ignition switch setup, but the principal is the same. The ignition switch may be bad, but if you are getting fuel to the injectors, and it turns over, it's not causing your no start issue. When you say it cranks, do you mean the starter rotates the engine, or it starts? Your post is kinda' vague in that regard. Early in your post you state it turns over fine.

If the machinery doesn't make you crazy, the terminology will.

All that being said, IF there was gas pumped into the tank, what would be the most it could have? There is a gray area between 25-50%. Most all Diesel engines will run fine with less than 25%, many will run with up to 50%, and start OK, some will either not start, and/or run poorly with up to 50%, and over 50% will usually shut them all down. Much depends on the condition of the pump, injectors, glow system, and compression.

Once again....
If you have fuel to the injectors, and you have hot glow plugs, and you have good compression, and it doesn't start, the fuel quality is questionable. Could either be bad #2 (not likely....these things will run on just about any oil), or diluted fuel. This is assuming the valve and pump timing is good. If it started and ran after it didn't, rule that out.

[farmerpatrick]

To clarify, yes the starter motor is turning over the motor.. but not right at the moment, because the lock cylinder has decided to quit acccepting the key. That's a minor issue though.

If it had gotten gas in it.. I doubt he filled it up. Also, I have a locking gas cap, and explained to him that the only reason its there is as a reminder to people that borrow the truck, to make sure they are grabbing the correct pump nozzle at the station. But anything is possible with this guy.

So your suggestion would be to drain the tank. What's the easiest way to do that? I'm assuming if you drain it, you would purge the fuel line or something as well. With a full 26 gallon tank, it will be a lot of diesel to dispose of.

My gut feeling, is that it's not a fuel quality issue, but I'm definitely not an expert.

Now, I know ether is bad bad bad. But, really, if the glow plugs are disconnected, what damage is it going to do. I grew up on a farm, and it was not uncommon at all to start up the john deere's on a cold morning with ether. I guess, i don't really understand why its so bad for these motors.

Also, why didn't it start on ether? I probably hit it with about a 1 sec shot directly into the intake. Also, why won't it start when diesel is poured into the intake? If I'm going to try that route, how much diesel should I pour in?

So there's got to be a way to get it started just to verify that the motor is still running fine, and to run a tank of diesel through it. How can I get it going? It's not a manual so I know I can't pull it off. If diesel or ether in the intake won't work, what will?

Realistically, glow plugs wouldn't be an issue on a 100 degree day out in the sun, would they? Especially with the block heater plugged in. When I turn the key (when the lock cylinder was working) the water temperature gauge was reading 100 + degrees.

So, any suggestions on how to get it going without damaging the motor? If I can get it running and burn a tank through it, I will feel a lot better about narrowing problems down.

[wthif]

Now, I know ether is bad bad bad. But, really, if the glow plugs are disconnected, what damage is it going to do. I grew up on a farm, and it was not uncommon at all to start up the john deere's on a cold morning with ether. I guess, i don't really understand why its so bad for these motors.

My understanding as to not use ether, is you could put too much in and cause a runaway engine for a few moments. Due to the ether fueling the engine and not the IP there is no more rev limiter to govern your RPMs; so the skys the limit.

[DmaxMaverick]

Same goes with puting ANY fuel into the intake. Be it #2, gas, or motor oil. It will run until all the fuel is exhausted, and at as high an RPM as it can.

Puting Diesel into the intake is a bad idea. It doesn't vaporize very well, and by the time you get enough fuel in to fire it, it's too much.

[jogl]

To test if fuel quality is an issue just hook up a temporary external tank. Set it on the roof and let the fuel gravity feed into the IP and rule out LP problems at the same time. But don't forget to unhook it because the fuel will run through the IP and return to your tank and could over fill the fuel tank. (Don't ask how I know).

Good Luck,
JP

[DmaxMaverick]

OK. Re-read the thread. Just because you have power to the glow plugs, doesn't mean they are heating. You need to check each plug to be sure they aren't fried. They could have been on the way out, and the ether finished them off.

Unplug and test each plug. You can use either a test light or ohm meter. Clip to bat+, and touch the probe to the plug spade. The tester should light. With an ohm meter, there should be a near closed circuit, with very high resistance (very low number, less than 2000). If half or less are good, that's probably your problem. Some of the engines need a glow cycle to start, even when hot. My '85 will start at any ambient temp above 90

[Robyn]

Just a note here
Ether explodes in the engine instead of burning. Its like setting off dynamite in there. The precups take a horrible beating as does the rods, pistons and rings. If its a dire emergency either can be sprayed on a rag and the rag waved in front of the air cleaner. Dont hold it over the open manifold as it may get loose from yor hand and be sucked into the engine. We wont go into the consequences of that here but rest assured you dont want to do it.
I would check to make sure the starter is spinning the engine at the proper speed. If the starter (or batteries) are not up to snuff the engine is going to be tough to start.
If this is ok spot check the compression on a few cylinders. High 300's is good.
Glow plugs ?? if glowing good and red when on their ok.
If this stuff is ok then suspect fuel lift pump. if lift pump goes completely sour they will be a bitch to start. The IP can do it if you crank enough but its hard on it.
Also pump out some fuel into a clean jar and look at it. it should be green to amber in color.
If all these things are good the Ip may have gone south.
OH BTW as previously mentioned stop dumping stuff down the intake.
Keep us posted
Robyn

[ZZ]

I learned the hard way about using ether on GM diesel engines. It took this dumbass twice to get it to finally soak in. I did it both times after I changed the fuel filters. I was trying to save wear & tear on the starters and blew head gaskets or heads or both. I thought I was using it very sparingly, but any how? The first was an '81 Chevy Caprice with the 5.7L and the other was an '83 Olds Cierra with the 4.3L. I was too onry to attempt to repair them and parted ways with them. I owned these before I owned a 6.2L I won't let ether get within 50 ft of my diesels since.

I too grew up on a farm back in the 60's and 70's and we used ether on everything heavily; gas burners and diesels alike. I reckon we didn't hurt them.