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New to site - Need help!

Meli

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Hi! I am the owner of an inherited 99 GMC 2500 Suburban 6.5 turbo. When I got it it started dying while I was driving. Did some research with my son who is helping me with the truck and we figured pmd. So, I got a new black pmd (it had a grey one before), got it installed and it's not starting. It acts like it wants to but is just not happening. When I turn the key on I can hear the glow plugs come on and I wait for the little light to shut off but once it does it pops back on and just goes of and on like something may be up with the battery? Then I try to start and it'll turn over and act like it's going to start and then just dies. Any input would be helpful - thanks.
 

Will L.

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Welcome Meli. Tons to learn here after it’s running again on all the to do, and not do stuff to keep it on the road and improve it to your best use.

first- DONT use starting fluid. Way easy to destroy this style engine. Even if you do it right the glowplugs get ruined from it.

If you can post video to Youtube and link it here that helps sometimes. Pictures do to- we might see something wrong

remove, clean, and reinstall the engine grounds on the engine- especially the ones back by the transmission dipstick. They get bad and mess up the signal. Make this part of the tended maintenance, where you live determines how often. I live near Vegas so once every 5-6 years, folks in rust belt, once a year. All battery connections should get the same treatment for same reason- big voltage can jump and arc the connections but micro volts does

Try plugging in the 120v block heater a few hours and see if the heat helps make up for possibly non working glow plugs.

Where you plugged in the pmd, sometimes the pins get bent. Examine that closely.
Will it run at all with the old pmd and nothing with the new? Having new defective parts is not unheard of.
I will recommend a vendor here- LeroyDiesel.com for new pmd, heat sink, and extension harness to relocate the pmd. His are lifetime warranty.

Once running, you should have a good know working spare, they are like a spare tire for this engine. Maybe don’t need it for 12 years, but when things act weird the only test is replacement with known good one. I believe in mounting two on heatsinks next to each other and put a dummy plug in the spare. Then if you are on the road and it happens it is a fast repair and you are on your way. Then send in the warranty one when you get home later and you have zero down time.

Do you have any codes?
 

Meli

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Welcome Meli. Tons to learn here after it’s running again on all the to do, and not do stuff to keep it on the road and improve it to your best use.

first- DONT use starting fluid. Way easy to destroy this style engine. Even if you do it right the glowplugs get ruined from it.

If you can post video to Youtube and link it here that helps sometimes. Pictures do to- we might see something wrong

remove, clean, and reinstall the engine grounds on the engine- especially the ones back by the transmission dipstick. They get bad and mess up the signal. Make this part of the tended maintenance, where you live determines how often. I live near Vegas so once every 5-6 years, folks in rust belt, once a year. All battery connections should get the same treatment for same reason- big voltage can jump and arc the connections but micro volts does

Try plugging in the 120v block heater a few hours and see if the heat helps make up for possibly non working glow plugs.

Where you plugged in the pmd, sometimes the pins get bent. Examine that closely.
Will it run at all with the old pmd and nothing with the new? Having new defective parts is not unheard of.
I will recommend a vendor here- LeroyDiesel.com for new pmd, heat sink, and extension harness to relocate the pmd. His are lifetime warranty.

Once running, you should have a good know working spare, they are like a spare tire for this engine. Maybe don’t need it for 12 years, but when things act weird the only test is replacement with known good one. I believe in mounting two on heatsinks next to each other and put a dummy plug in the spare. Then if you are on the road and it happens it is a fast repair and you are on your way. Then send in the warranty one when you get home later and you have zero down time.

Do you have any codes?


Thanks for your reply! Here is a link to a video I took this morning. The truck wouldnt start at all right before I changed the pmd. The pins all look fine and no codes.
 

MrMarty51

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Welcome to thetruckstop Meli.
I have returned two new Dorman PMDs after they failed within 30 miles. Always keep a spare, as suggested.
The wait to start lamp will most likely flash like that until the engine is started and begins to warm some.
I dont know what the resistance is on good glow plugs but they can be tested while they are installed, besides being sure to clean the ground connections that`d be My suggestion. Might even pull a couple of them and see what condition the ends of them are in. Try to use a six point socket and to not break them.
 

Will L.

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Why i like videos!
I noticed 2 things. I can give book answers to why on anything- so if you want the info ask if in question otherwise I will type for hours and bore you.

1. The glows shouldnt go on and off like that so many times- they are not all heated up like they should be. It could be bad plugs(most common). ONLY use AC Delco 60 G!!
Could be controller issue but doesn’t sound like it to me. Could be the “wires” to the plugs- NOT Normal wires- it is special fuseable link wire used- do not try rigging test replacement wire- it will catch fire. Carefully examine wires for damage but easier is test for voltage at each plug connector, if all get 12v+ chances are they are ok.

2. You hear the lift pump run when key is on. It speeds up and slows down as plugcontroller sucks power. But it should go from loud to quiet and stay quieter if it were building pressure and maintaining it- yours is not. Your lift pump is toast is my bet.
I am a HUGE proponent of having a dash mounted fuel pressure gauge for these engines to see while driving. The LP (lift pump) fails and people dont know. Then the ip (injector pump) sucks fuel through it and it wears out the ip much faster. $100 pump vs $2000 pump- hmmm. Some 6.5s have a fuel pressure tap port to make it easier to test in shop, others don’t. I always say put a metal “T” at the ip inlet and read from there. Failed rubber hoses has cause many to replace good pumps if both types.

From any hardware store - get clear 1/4” line sold by the foot. You need a 5” long piece snd replace the ip return line with it. Also buy 2 new screw style hose clamps to fit the clear hose. This is to monitor for bubbles- air intrusion (also shows any contamination). About $5 and 5 minutes to do.

I can not determine if you are suffering from lack of heat or lack of fuel.
if you are getting a ton of white smoke out the exhaust that smells like diesel fuel when cranking- that is unburned fuel and lack of heat is your problem. Trying the 120v block heater will help verify that.

if you are not making a cloud the size of your truck bed behind you cranking like that- it could be the fuel.

go plug in the block heater on an extension cord asap. And give a bit of time for othere here to see your video/ post.

I dont want you wasting money on un needed parts. Waste of money and if a New part is bad it complicates things worse.
 

ak diesel driver

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I think the glow plug system is working properly. The glow plug light flashing is simply the programmed in after glow. Usually you try to start it when the light first goes out. And the after glow is to clean it up faster for emissions. You could still have weak or bad glow plugs, but the system is working normally
 

Meli

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Thank you all for the feedback! Going to follow the suggestions and will get back to you.
 

JiFaire

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I'm thinking it's a fuel issue, also ... don't like the sound of the LP. Crack open the water drain (brass T-handle) at the Fuel Filter manager and have somebody turn the key to on for a few seconds so the Lift Pump runs ... fuel should come out of there without a lot of bubbles in it. If it doesn't, you need a new LP. Just because they purr like a kitten doesn't mean they are pumping anything. Sometimes, people replace them with the wrong Lift pump, because they get bad advice or because they couldn't find the right one... if yours isn't 'flow-on-fail', then if it craps out, fuel can't get through it.

If it's good, then loosen the inlet line at the IP and turn the key on again... fuel should come out. Could be a bad filter.

If that works, then crack an injector line and have somebody turn it over... should get fuel from there. If you don't, then start thinking PMD, Optic Sensor, IP, etc.

Oh, and loosen the fuel tank cap. Don't ask. :cool:

Like Will asked, are you making a big grey cloud out the exhaust when you try to start? If you aren't getting enough fuel, it will fart like that, but you won't make a big cloud.

Les is right about the glow circuit in the newer 6.5s.. but your light isn't going out. It should, after the glows have cycled. Could be GP controller, or more likely a few bad glow plugs.

I like the suggestion of plugging it in to heat things up, you can always put a hair dryer into the air inlet line, to heat up the air, too. (Canadian Trick for Winter Starting. Wife hates it.)

Your batteries seem ok, and it seems to be catching quick enough (not turning over a lot), so my guess is fuel.

Check out the Troubleshooting checklist - https://www.thetruckstop.us/forum/threads/6-5-engine-diagnostic-troubleshooting-checklist.6300/

Filling that out both gives you some ideas to look for, and gives us a better idea of what you're working with. I used to go through the whole list once a year on my truck, just as a maintenance guide.



Welcome to the site! These guys are the best; they will help you get sorted out.

Jim
 
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Stoney

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I would have gone with it being bad g plugs but they already covered that. So.... welcome to the truck stop and life with a 6.5td...the biggest headache you will fall in love with.
 
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