MEP 003A No start

helomedic1171 · Nov 16, 2012

after I let it run earlier in the day for about 20-30 minutes, I shut it down and left it alone. later, I came back out after dark, and the only thing that changed was that it was colder out. I used the preheat, and tried to crank. it cranks, but won't start and run. I get black smoke out of 3-4 exhaust pipe, nothing but maybe the faintest smoke out of 1-2, and when i put my hands in front of both pipes, I get the same amount of pressure despite the difference in smoke output. I also noticed the intake manifold is warm, but the 3-4 half of the engine is warmer than the 1-2 half. it seems to gradually get colder from #4 to #1. maybe that's normal. I can't tell if the preheat circuit is working completely, but the relay clicks when i engage the switch and hold it, and i see smoke coming from the glow plugs on #4 and #3, but very little if any on #2 and #1. the smoke is from some oil that spilled out of the rocker cover gaskets, I've since replaced the gaskets since I opened them to do flow timing for the IP yesterday.

I looked at the troubleshooting tables, and it looks like I'm checking filters (which I replaced before I timed the IP) and the strainer, lines, and nozzles. basically the entire fuel system, except for the IP. the engine ran great earlier today, so I'm hoping it's a bad preheat system, coupled with cold weather that's making this difficult. I could always swap preheat relays between my genset and my dad's to see if that's the issue, but like i said, it clicks whenever i turn and hold the switch, like it's supposed to. I'm also going to try moving the stop solenoid plunger because in another thread I saw where a guy had one get stuck and cause a no-start condition.

Thoughts?

helomedic1171 · Nov 16, 2012

messed with it a little more. I have fuel pressure in all the lines, and my fuel cutoff solenoid is working properly; it pulls the plunger when i hit the start switch and releases it shortly after I release the start switch. It WANTS to start. it clunks like it almost fires, but it won't quite fire. I have good black smoke coming from the 3-4 exhaust pipe, nothing from the 1-2 pipe, thought the pressure is the same. I'm leaning towards stuck nozzles/injectors on the #1 AND #2 cylinders. the whole thing seems weird to me and way too coincidental, but that's where all roads point thus far. it's just not cold enough for it not to start, it's only 45-50 degrees out. my air cleaner is set on normal start, and I have 24VDC on my battery bank (1 yellow-top optima and 1 blue-top optima).

one more thing, I also checked the strainers, and a little bit of sediment or something came out, but it was VERY minimal, clear fuel followed it. had I blinked, I would have missed the dirt coming out. the strainer has no water in it, either, and I checked tightness on all fuel lines and strainer/filter canister fittings. the only thing I didn't check was the nozzles/injectors themselves. I also took the 1-2 rocker cover off, and watched the valves actuate while cranking, so I know they're not stuck and are working properly.

Hopefully someone chimes in soon. I'm going to go search for injector/nozzles fixes now.

Speddmon · Nov 17, 2012

Why are you not looking into the preheat circuit any deeper. The glow plugs are all wired in parallel, so all of them should be equally hot or close to it. Use a meter and check the resistance from the spade on the plug to ground, and make sure they are all good. It may be a couple of bad plugs, or the actual connectors themselves being bad. I had several that were broken, or painted over enough times that the would not make contact any longer.

I'm having a hard time seeing the injectors going bad and sticking right after you gave it a good workout of 20 minutes or more just a few hours earlier. I also doubt the IP or fuel issues since you had just redone everything. Along those lines, the strainers and pumps can't be it, because they are common to all 4 cylinders. The only thing that could affect 2 of the 4 cylinders on the fuel side is the IP.

Get the preheat circuitry working properly and go from there. Mine don't like colder weather (even 40 to 50 degree weather) without the preheat cycle.

helomedic1171 · Nov 17, 2012

because I didn't think the lack of preheat would cause a no-start in weather like this. But you're saying it does, so, I'll go back to it. I like your idea better than mine, because I find it hard to believe as well that 2 of them would stick right after running the engine like I did. I just didn't think preheat was THAT important in only 40-50 degree temps. But then, these are older diesels, so maybe it is...

helomedic1171 · Nov 17, 2012

Put a meter on all the plugs, and when I turn the switch to preheat, each one is getting 21.xx VDC. That's using the block as a ground. The manifold heaters are getting 11.xx VDC each. The IP is timed, I took it off and re-checked it for broken parts, everything is working as it should. I get intermittent white smoke from the 1-2 cylinder bank, but still nothing substantial. Going back to injectors/nozzles. Ideas? I'm honestly gun-shy to take those apart because i have no gaskets to put them back together with. Are my concerns valid? And what should I be looking for? Trash or dirt stuck in them?

edgephoto · Nov 17, 2012

40-50 degrees is cold for any engine.

helomedic1171 · Nov 17, 2012

right, but I'm getting decent voltage to the plugs. and I'm either getting no smoke out of the 1-2 cylinder bank or I'm getting a minimal amount of white smoke out of it, while getting fairly thick black smoke out of the other bank. pressure is the same when I put my hands in front of the exhaust pipes. If I'm getting proper fuel flow, shouldn't I be seeing more smoke? more like the black smoke I get from the other bank?

Also, when I look in the -34 Manual, I can only find a way to test the pre heat circuit itself, not the actual plugs. I did a few searches, and the answers I found varied: does anyone know what the resistance should be across the glow plugs? I'm assuming I pull the plugs individually, and put test leads on either end while my meter is set to ohms, and see what i get, correct?

I went ahead and cleaned up the spade connectors a little on the plugs and on the wires themselves, just to be certain.

edgephoto · Nov 17, 2012

Most old style glow plugs are in the 5-6 ohm range. Modern diesel use a different style of glow plug.

helomedic1171 · Nov 17, 2012

cool. I'll pull the plugs, stick a lead on each end, and look for 5-6 ohms. if it's out of range, i know they're no good. Jerry has some for sale and rock auto has them in packs of ten. also, my Dad's genset has 4 in it, so i can check those as well and use some of those to rule out a problem on my genset if need be.

what about the fuel injector hypothesis?

storeman · Nov 17, 2012

If you can remove the suspect glow plugs, test with multimeter to ensure no OL and resistance about 5-6. if wild resistance or OL, plugs are bad. I have a few.

Actually, I think you can do same test between a disconnected plug and the block without removing it.
Jerry

storeman · Nov 17, 2012

helo,
you posted while I was hunting and pecking.. deal with glow plugs first.
jerry

helomedic1171 · Nov 17, 2012

you got it. thanks guys, and special thanks to you , Jerry, for the quick response. more to follow...

1800 Diesel · Nov 17, 2012

Just a few thoughts on "paper":

The black smokes would indicate injector "dribbling" or lack of atomization through the nozzle. Hopefully the filter maintenance didn't cause some debris to get into the clean side of the filter and find its way to the IP or into the two injectors. Probably a long shot on that though. Also, the black smoke during cranking is curious. Every time I do a cold start on my MEP3, I get white smoke as soon as fuel starts entering the cylinders. Today my son & I did a new light-off on an MEP2 and it did the same thing during cranking--white smoke, not black smoke.

On the valve train inspection, did you verify that there were no broken valve springs? This would cause a weak seating of the valves and low compression and no-start. Again, a long shot and a strange coincidence after the 20-minute run.

On the fuel flow to the injectors, I assume you cracked the fuel fittings at each injector and observed the spray or flow with each pressure cycle?

You may want to swap out the injectors acting up with known good ones. I haven't removed injectors on these engines but have on Ford tractors and on my Perkins in my shrimp boat. The Perkins has copper washers at the very bottom of the injector body--this seats the injector into the cylinder head. Don't know if the Onan is similar...

Anyway, hope some of this helps. Wish you well on getting her back on line.....

helomedic1171 · Nov 18, 2012

edgephoto said:
Most old style glow plugs are in the 5-6 ohm range. Modern diesel use a different style of glow plug.

storeman said:
If you can remove the suspect glow plugs, test with multimeter to ensure no OL and resistance about 5-6. if wild resistance or OL, plugs are bad. I have a few.

Actually, I think you can do same test between a disconnected plug and the block without removing it.
Jerry

I did a preliminary check on the plugs, placing my common lead (black) on the hex portion of the plug and the hot (red) lead on the spade. I got between 5.0 and 5.6 on each plug. I plan to pull them tomorrow and check them out of the engine. I'm assuming when i do this, I should put the common lead on the threads of the plug? or should I put it on the probe itself?

1800 Diesel said:
Just a few thoughts on "paper":

The black smokes would indicate injector "dribbling" or lack of atomization through the nozzle. Hopefully the filter maintenance didn't cause some debris to get into the clean side of the filter and find its way to the IP or into the two injectors. Probably a long shot on that though. Also, the black smoke during cranking is curious. Every time I do a cold start on my MEP3, I get white smoke as soon as fuel starts entering the cylinders. Today my son & I did a new light-off on an MEP2 and it did the same thing during cranking--white smoke, not black smoke.

On the valve train inspection, did you verify that there were no broken valve springs? This would cause a weak seating of the valves and low compression and no-start. Again, a long shot and a strange coincidence after the 20-minute run.

On the fuel flow to the injectors, I assume you cracked the fuel fittings at each injector and observed the spray or flow with each pressure cycle?

You may want to swap out the injectors acting up with known good ones. I haven't removed injectors on these engines but have on Ford tractors and on my Perkins in my shrimp boat. The Perkins has copper washers at the very bottom of the injector body--this seats the injector into the cylinder head. Don't know if the Onan is similar...

Anyway, hope some of this helps. Wish you well on getting her back on line.....

It helps A LOT, actually. the smoke starts out white, and quickly goes to black. does that make more sense? it's like as the cylinder gets warmer, the smoke gets blacker. the engine almost fires, also - it's like it just needs one more kick in the rear and it'll light.

I have cracked each injector line and observed spray, but let me ask you this - it should be a SPRAY, or STREAM, not a small squirt, correct? I seem to recall more of a squirt than a stream, and I thought to myself that it didn't look like the same stream I had coming out when I was flow-timing the pump. I think I may have just answered my own thought/question right there...

As for valve springs, I did look at them and put my fingers on them, and didn't notice any broken ones, or bent valves or pushrods. but, I'll check the injector lines and look for a good stream of fuel, then I'll crack the rocker covers and check for bad springs or valves, just so I can check that block. It won't hurt to check them once more just to make sure I didn't miss anything that should have been obvious, right?

I'll use the idea about the injectors if it comes to that. that's what I was thinking, and between what you just told me and something Jerry said to me earlier has me thinking that it could be worth a shot if I wind up looking at the injectors for the problem.

Here's another thought, since I'm about to hit the hay... where is the most likely spot that something would clog up the IP? I was thinking maybe where the injector lines connect to the IP, those 4 ports/adapter fittings with the small hole in them. Then again, I could just be grabbing at straws right there.

Thanks for the great ideas guys, I'll tinker more tomorrow (or more accurately, later today...) and see what I can come up with. you guys are a huge help!! :smile:

helomedic1171 · Nov 18, 2012

One more thing, and this might be a head-slapper.....

I should probably pull the fuel strainer membranes on the bottom of the pumps, and make sure they're not horrible clogged, right? because if I AM having a fuel delivery problem, that could certainly cause it, correct?

I say this for two reasons: A) I forgot to check them and clean them before cranking the engine or flow-timing it in the first place aua

B) I didn't do a super-sterile job of cleaning out the tank before I ran the unit. In fact, I really didn't do much other than rinse it out with some JP8 and fresh Diesel before filling it to run the genset. aua

I'm going to bed, seriously. but tomorrow, I may turn out to be a big(er) Dumbass.

edgephoto · Nov 18, 2012

helomedic1171 said:
I did a preliminary check on the plugs, placing my common lead (black) on the hex portion of the plug and the hot (red) lead on the spade. I got between 5.0 and 5.6 on each plug. I plan to pull them tomorrow and check them out of the engine. I'm assuming when i do this, I should put the common lead on the threads of the plug? or should I put it on the probe itself?

It helps A LOT, actually. the smoke starts out white, and quickly goes to black. does that make more sense? it's like as the cylinder gets warmer, the smoke gets blacker. the engine almost fires, also - it's like it just needs one more kick in the rear and it'll light.

I have cracked each injector line and observed spray, but let me ask you this - it should be a SPRAY, or STREAM, not a small squirt, correct? I seem to recall more of a squirt than a stream, and I thought to myself that it didn't look like the same stream I had coming out when I was flow-timing the pump. I think I may have just answered my own thought/question right there...

As for valve springs, I did look at them and put my fingers on them, and didn't notice any broken ones, or bent valves or pushrods. but, I'll check the injector lines and look for a good stream of fuel, then I'll crack the rocker covers and check for bad springs or valves, just so I can check that block. It won't hurt to check them once more just to make sure I didn't miss anything that should have been obvious, right?

I'll use the idea about the injectors if it comes to that. that's what I was thinking, and between what you just told me and something Jerry said to me earlier has me thinking that it could be worth a shot if I wind up looking at the injectors for the problem.

Here's another thought, since I'm about to hit the hay... where is the most likely spot that something would clog up the IP? I was thinking maybe where the injector lines connect to the IP, those 4 ports/adapter fittings with the small hole in them. Then again, I could just be grabbing at straws right there.

Thanks for the great ideas guys, I'll tinker more tomorrow (or more accurately, later today...) and see what I can come up with. you guys are a huge help!!

Yes you would check them from the connector and the threads. The ground is provided by the engine itself. Also in the preheat mode you should get voltage to both glow plugs.

helomedic1171 · Nov 18, 2012

I get voltage to all 4 plugs when the switch is on, and to the heaters in the manifold as well.

helomedic1171 · Nov 18, 2012

about to go out an check the plugs out of the engine, I'll update once I check 'em. I thought about the filter screens in the pumps, and realized someone posted a reason why that's not likely earlier in the thread: the pumps are common, and while it may be good to clean the filter screens, it's not likely the culprit for my issue. more to follow.

glcaines · Nov 18, 2012

helomedic1171 said:
about to go out an check the plugs out of the engine, I'll update once I check 'em. I thought about the filter screens in the pumps, and realized someone posted a reason why that's not likely earlier in the thread: the pumps are common, and while it may be good to clean the filter screens, it's not likely the culprit for my issue. more to follow.

It sounds to me like you may be trying to work on too many things at once, which can provide the opportunity to introduce more problems. If my 003A doesn't start immediately (blowing white smoke initially), it is always one of two possibilities, either the solenoid cutoff has gotten stuck or I didn't pre-heat long enough. As mentioned earlier, preheating is important, even in warm weather. Have you tried cracking one of the lines to an injector while cranking to see if you are getting fuel to the injector? The fact that it was running good when you turned it off would lead me to believe that your solenoid may be sticking. When mine sticks, it is not obvious as you can easily see the movement. I simply grab it in my hand and work it up and down several times. I also hose everything down with penetrating oil to help keep the solenoid linkage free.

helomedic1171 · Nov 18, 2012

game called on account of rain. time to regroup, re-read, and try again tomorrow.

I didn't know that about the solenoid, I thought if you could see movement, it was good. I think I'll try that before I pull the glow plugs, since that would be quite a bit easier than anything else on my list of possible tests, fixes, or checks. thanks for the input.

MEP 003A No start

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