PAM as diesel starting fluid? - PeachParts Mercedes-Benz Forum

cmac2012 · #1 09-10-2018, 01:46 PM

I have an '87 Grumman step van on a Chevy P30 chassis with the 6.2 diesel. I recently developed a no-start situation. Long story, I was concerned that it might be bad fuel - it has sat for a lonnng time - 20 years. I start it once or twice a month (have a solar panel on the roof, maybe 20" x 40", keeps the batteries topped up), idle if for maybe 20-30 minutes, give it a minute or so of higher rpms, then shut it down.

I keep it as I once planned to use it as a mobile shop, but liability insurance is steep, I now use it as lockable portable storage. A bit nutty but it was no spring chicken when I bought it (250 K) and I have room for it in my parking lot at my shop.

I cut a hole in the floor (will re-position it as a removable portal about the tank sender point), siphoned out the fuel (about 5 gallons), and cleaned it out with lint free rags on a coathanger. The fuel didn't look all that bad, I found some guys on the web who had not had problems with fuel that old, so I dunno. I replaced the larger filter/water separator thing mid way under the body, topped it up with new diesel before attaching it. The other boxy filter on the motor I have not yet replaced. It won't start, I suspect I have air still but I'm also wondering if the pump is bad. It wouldn't start before I introduced air into the fuel lines. I've read of guys replacing the stock mechanical with an electric.

One guy at Diesel Place recommends PAM as starter fluid, air filter removed. Sounds plausible. I was pretty sure ether based starter fluid would not be a good idea, search confirmed that but no one mentioned PAM.

Diseasel300 · #2 09-10-2018, 03:53 PM

PAM is ok because it's usually just vegetable, soybean, or canola oil. WD-40 is often cheaper and pretty universally accepted as a safe starting fluid for diesels.

moon161 · #3 09-10-2018, 03:55 PM

WD40 is what I hear of for starting fluid. I've used hot vapor (soaked & burning rag over the inlet for cold start problems). Only for the daring & desparate. Hold that rag with something long and have a safe place to throw it.

I've heard of WD40 mist at the intake being used for a diesel air bound by a botched filter changes.

vstech · #4 09-10-2018, 04:11 PM

I HATE that stupid brick filter the 6.2 comes with...

Is yours stock?

I'd bypass the filter, verify fuel flow and crack all injector lines loose and spin it over till I got fuel at the nuts.

SD Blue · #5 09-10-2018, 04:16 PM

If that fuel filter at the motor wasn't changed, and from what you described, may have had prolonged exposure to air, it may be blocked with little black gremlins. Personally, I would want to change it before going any further to prevent the possibility of those little gremlins from getting into the injection pump and injectors. If that happens, the frustration will increase.

cmac2012 · #6 09-10-2018, 04:30 PM

Great advice all. I had not heard of WD-40 as starter fluid either. I’ve heard that it’s basically kerosene.

Good call on the other filter. Pretty sure it’s stock. But yeah, not well advised to stick with it. Who knows, it may have already caused problems.

97 SL320 · #7 09-10-2018, 07:22 PM

Change the box fuel filter element at engine.

Do all of the glow plugs work, prechamber diesels need good glow plugs? Ohm each one out or use a clamp on amp meter to test.

An electric fuel pump near the tank does wonders for injection pumps / systems that bleed down. The ones that look like an inline fuel filter work fine. Wire it through an pressure switch that looks at oil pressure so the pump does not run if engine stalls.

Use a manual button so you can run the pump to prime the system before cranking.

I'm pretty sure these pumps ( Stanadyne / Roosa-Master ) have a problem with a plastic ring breaking affecting injection timing. There also might be a cold timing advance system to assist in cold starts.

vstech · #8 09-10-2018, 08:04 PM

I’m moderator on the Dieselplace site also

I mostly hang out in the 6.5 section but lemme know if you need any assistance

cmac2012 · #9 09-11-2018, 02:28 AM

Quote:

Originally Posted by 97 SL320

Change the box fuel filter element at engine.

Do all of the glow plugs work, prechamber diesels need good glow plugs? Ohm each one out or use a clamp on amp meter to test.

An electric fuel pump near the tank does wonders for injection pumps / systems that bleed down. The ones that look like an inline fuel filter work fine. Wire it through an pressure switch that looks at oil pressure so the pump does not run if engine stalls.

Use a manual button so you can run the pump to prime the system before cranking.

I'm pretty sure these pumps ( Stanadyne / Roosa-Master ) have a problem with a plastic ring breaking affecting injection timing. There also might be a cold timing advance system to assist in cold starts.

I'll check the glow plugs in the next few days. The glow plug dash light works as well as it ever did, not sure if that means anything, I seem to recall reading here that no glow plug dash light was sign of a problem.

Your suggestion about an oil pressure switch sounds right on. I know on my BMW E30s there is a fuel pump relay designed for the same purpose, to shut off the fuel pump when the crankshaft is not turning. Oil pressure would be easier to access in this vehicle than some likely non-existant crankshaft position sensor.

That said, I found a couple of oil pressure switches on the web, they have a pipethread base, not sure where I'm going to find a port to attach such a thing.

cmac2012 · #10 09-11-2018, 02:32 AM

Quote:

Originally Posted by SD Blue

If that fuel filter at the motor wasn't changed, and from what you described, may have had prolonged exposure to air, it may be blocked with little black gremlins. Personally, I would want to change it before going any further to prevent the possibility of those little gremlins from getting into the injection pump and injectors. If that happens, the frustration will increase.

I took it off tonight, I'll have one waiting for me at NAPA tomorrow. Everything looked really clean but who knows, maybe I'll open it up. Could probably safely do so with a sawsall.

I cranked it a bit with the filter off. One of the grommets was spurting fuel so perhaps I do have some pressure.

cmac2012 · #11 09-11-2018, 02:38 AM

Quote:

Originally Posted by vstech

I HATE that stupid brick filter the 6.2 comes with...

Is yours stock?

I'd bypass the filter, verify fuel flow and crack all injector lines loose and spin it over till I got fuel at the nuts.

So are you saying to bypass it until I get it running and then hook it back up? If so, sounds like a good idea. A few ounces of not fully filtered fuel seems ulikely to be a problem, especially with the two filter set-up.

cornemuse · #12 09-11-2018, 10:29 AM

WD-40 has propane as propellant, this is the 'starting fluid'. If you use your small propane torch instead, you wont get all that oily, liquid part in the air filter.

(your unlit propane torch!!)

Propane is like nitromethane for diesels. Some old 'detroit diesels' had propane cold weather starting units on 'em.

moon161 · #13 09-11-2018, 11:43 AM

Quote:

Originally Posted by cornemuse

WD-40 has propane as propellant, this is the 'starting fluid'. If you use your small propane torch instead, you wont get all that oily, liquid part in the air filter.

(your unlit propane torch!!)

Propane is like nitromethane for diesels. Some old 'detroit diesels' had propane cold weather starting units on 'em.

I gotta try that sometime.