Generic question

[Truenorth]

Posted in the 6.2 forum but no replies. This is a fairly generic question so I was hoping someone here has some ideas.

I have an 86 3/4 ton 6.2L van and it has 155K miles on it. Yesterday while pulling a heavy load it began to missfire for maybe a second at a time and then would go good for 10 seconds. After doinf that for half an hour it completly stopped running. At the time it completely stopped it lost all oil pressure on the gauge too.

Now when I crank it over with the starter it still does not show any oil pressure, and does not fire at all.

So, any ideas of things that might be relatively easy to fix to get this running? Or is it rebuild time? If it is rebuild time, then the van is scrap - not worth a rebuild. Only good thing on it is the proffesionally rebuild auto in it (5K miles on the rebuild and working great) anyone want to buy one of those if the rest of the van is scrap?

[rjschoolcraft]

Drain the oil and see if it smells like diesel fuel. First, check it to see if it is overfull. You may have had a lift pump failure. The 6.2's use a fuel lift pump very similar to the fuel pump on small block Chevy V-8's. If the diaphram ruptured, you could have filled the crank case with diesel. A failed lift pump can also allow air into the injection pump as it draws down the line in suction.

[Truenorth]

Did more checking

Update from last night:

Oil pressure is back, just had to clean the sendign wire. So oil pressure looks normal.

Popped the purge valve open on the fuel filter and fuel flows when cranking - so the lift pump works.

Pulled one of the ruber low pressure lines off an injector and fuel flows out of there too.

Pulled the hard lines off the injectors and nothing but the occasional air bubble comes out it seems - maybe a tiny seepage of fuel.



So questions:

How do the 6.2L injectors work? Why low and high pressure? Does high pressure air, or high pressure fuel flow through the metal lines to the injector?

How do I test the injector pump? Electrical tests? Mechanical tests? Need adjustment? Need replacement? Best place to buy one?

What else should I check?

[Marty Lau]

I don't know much about 6.2's and this is basic but..... how about the fuel filter?

[whatnot]

Are you sure you have power to the shut off solenoid in the pump?
You can turn on the key then take the pink wire off the pump and touch it to the terminal. It should click when you touch it on.

[damork]

I owned an 83 Jimmy with a 6.2, my brother owned an almost identical 1984.

The 83-84 changes were small, but something that was very hard to find in my brothers unit was air sucking into the Stanadyne pump through the pump body seal. Another area of concern is the fuel screen in the tank - if it gets gunked up you may have a temporary restriction you don't see while under load. Also check the tank fill cap for restrictions.

The advance pistons in those pumps were known to hang up as they corroded from moisture in fuel over time. Try to read the lift pump supply pressure to the Stanadyne pump while you are under load. If your pressure is good there and you are stalling out, then it may be internal to the fuel pump.

To my knowledge this vintage never had an electric lift pump, they were mechanical.

[Truenorth]

Well I had a look, and unfortunatly it is not just an electrical solenoid.

Looks like the injector pump, bled it and the fuel is barely seeping out. Turns out the hard starting I have been having for almost a year is another symptom of a bad injector pump.

So I called the logal GM stealer and they have the injector pump for the low, low
price of (he even said "are you sitting down?" on the phone ;) CDN$2100
plus CDN$1350 core charge.

A friend told me that some place named Diesel Injection Service in Ottawa
rebuilt his old ones a few years ago for around CDN$1000. Going to call
them today.

Anyone here on the board got a good hookup for a cheap injector pump? Let me know please if you do.

[JohnC]

You should be able to get a rebuilt pump for a 6.2 for less than $300 US. Try some of the advertisers. I think at least one is in Canada.