6.2l Diesel trouble starting

[andreasballs]

Hey guys, this is my first time posting here. A few months ago I picked up a 1987 GMC suburban diesel. 188k miles on everything, mechanically its in decent shape. However, the dash gauges are a little finicky - and as a result I accidentally ran the engine out of fuel last week. I filled her up with half tank of diesel and cranked the engine a few times. It would start, run for a second or two, and then stall again, as is expected with the air in the lines. After doing this a few times it finally started working again. I drove it around town with no problems. I thought this would have been the end of my problems.

However, the two times I've tried driving it since, I've been having alot of trouble starting it fresh. It will crank and start like it used to, run for a second or two, and then stall. When I try to start a second time it will crank for a while, and even with my foot on the gas it wont start. Usually takes me about 5 tries to get it going. Once I've gotten it going, it will run with out any problems. I've even parked it for a few hours, and started it up flawlessly again. However, if I let it sit for more than a day or two, I'll experience the same starting problems.

Any ideas what could be causing this? I would normally think it would be a leak in the fuel line, but since this started happening right after I ran out of fuel, I was wondering if it could be something else.

Thanks guys.

 

[89Suburban]

andreasballs lol

 

[marks86]

I would replace the fuel filter add a can of seafoam and see if that helps

don't forget to bleed the filter out!

 

[Jims86]

Sounds like a Fuel pressure issue.

May be a problem with the lift pump...if it has one. Also, the injector pump may need to be rebuilt, and is not holding pressure in the system. Where in the bay are you?

 

[andreasballs]

Sounds like a Fuel pressure issue.

May be a problem with the lift pump...if it has one. Also, the injector pump may need to be rebuilt, and is not holding pressure in the system. Where in the bay are you?

That could be right, it definitely sounds like some sort of pressure issue. I'm from marin county but im at school down in san luis obispo for the year. I dont really have a garage to mess around with the truck down here, so I guess I'm bringing it into the shop tomorrow.

 

[Jims86]

That could be right, it definitely sounds like some sort of pressure issue. I'm from marin county but im at school down in san luis obispo for the year. I dont really have a garage to mess around with the truck down here, so I guess I'm bringing it into the shop tomorrow.

We have a guy near you I think, who may be able to suggest a shop. Austinado16

 

[austinado16]

Got your PM Andreas, and hit you back. Aaron's Advanced Automotive in Grover Beach (805)474-1386 is the only shop that touches my Suburban when it needs work that I can't do. He's GM factory trained and used to work for the big GMC dealership here, before opening his own shop. Tell him I sent you.

I don't have any GM diesel experience, but I do have a ton of Mercedes/Volvo/Audi/VW/BMW diesel experience.

I would start by looking for leaks. Any damp/oil stained area of the fuel system is a leak that will cause the fuel to siphon back to the fuel tank on a diesel. They may start after a couple hours, but usually leaving them for longer, or overnight, or parked with the nose up hill, and they'll siphon all the fuel out of the mechanical injection pump, and then not start. Sometimes they'll self prime if you hold your foot to the floor while cranking the engine, and give them a good amount of throttle on initial start so that the pump creates enough suction that it'll prime itself and fill the filter down stream.

That said, if you ran it out of fuel, there's a chance you've sucked something off the bottom of the tank. Usually, this means a chunk of algae, which grows in diesel fuel. If this is the case, the cure would be to remove the fuel cap, and then disconnect the fuel lines from the filter and blow backward into the tank. Then do the same thing to the line between the filter and the mechanical injection pump. I've seen hunks of algae get jammed into the fittings at connections to pump or filter, and block the fuel flow.

The cure for algae growth is treating the fuel with Stanadyne Diesel Treatment, and you'll find that at our local NAPA, down at the end of Marsh St. near the 101 freeway offramp coming into town (across from Fast Eddie's Car Wash). Volkswagen used to speck 10% gasoline added, so on a 14 gallon tank, 1.4 gallons of gasoline could be added at time of fill up. This killed the algae, and in areas where winterized diesel wasn't available, it kept the fuel from gelling at freezing temps.

Post back and let us know what happens. I'll be happy to help if I can.

 

[cramezl]

andreasballs lol

Haha

Sent from my HTC Hero S using Tapatalk 2

 

[austinado16]

Any news Andreas?

 

[andreasballs]

Sorry for the late reply. I brought it in to Aaron's and he confirmed that the lift pump wasn't working. He replaced the lift pump, but the truck still had problems starting. Turns out the fuel pump's push rod had snapped, and messed up the sleeve in the engine block. The sleeves aren't readily available to replace, and replacing them would require hefty front-end disassembly. So what he ended up doing was replacing the mechanical fuel pump with an electric pump from the 6.5l. Now it works as good as before, and the idle even seems smoother.