New electrical gremlin, lights, fuel gauge, and volt meter.

[eodcoduto]

I was messing with the injection pump timing on my '85 K20 6.2L diesel Suburban tonight because there was a little more rattle than I liked. While I had the engine running and moving the fuel pump, I was getting a spark where the advance solenoid touches the throttle linkage. I thought this was odd, and it did this 3-4 times.

I fixed the timing, get in to start the thing and the volt gauge is pegged all the way to the left, well below the 8, I also notice my fuel gauge has gone from 3/4 tank to under 1/2 tank, and when I turn the lights on the reminder buzzer comes on. I could watch the fuel gauge slowly dropping the longer I had it running.

I threw a fluke on the batteries and with it running I am getting 14.1-14.3 volts, my grounds from battery to chassis and battery to engine are good, and the ground from engine to chassis is good. I unhooked the advance solenoid and throttle solenoid and nothing changed. Fuses aren't popped so I know a new ground circuit has just established itself but I have no idea where to start. Any suggestions?

 

[obijuank5]

I had crazy electrical stuff on my 6.2. Major ground issue was at the ground above the brake pedal.

 

[eodcoduto]

NEVERMIND! It was a blown fuse that I thought I had checked, its weird that it would be the INST/IDLE fuze. They should label that fuse box! I did this so that you all can learn from my mistakes, all on purpose of course. I do need to get a new fast idle solenoid, if it is sparking there must be a breakdown in the insulation, and holy crap-$100 for that thing!

 

[diesel4me]

Yup..some of those small parts you'd think would be cheap and readily available aren't..the VRV valve that operates the transmission modulator on the injector pump is about the same price IF you can find one,few aftermarket places even list them now..(a sucky setup IMO to begin with also)..

The wires going to that idle stop /cold start advance solenoid are controlled by a temp sensor in the rear of the passenger side cylinder head,mine decided to blow the plastic and contacts out one day,so I had to rig a toggle switch to it--found out my engine was running in the "cold advance mode" constantly for years till that happened and never knew it..

Part of the reason I bought the '85 Suburban 6.2 was the fact even if I never put it on the road at least I'd have an extra running engine or all the parts my pickup might need--what I gave for it was less than any one part would cost me at a salvage yard--IF I ever see another diesel truck in one here again..
I also scoffed up a blown up 6.2 a friend had for parts,it broke the crankshaft,was in an '87 C30 ramp truck...unfortunately the few things I needed off it ended up not being the same as the 6.2 in my pickup or Suburban.
--the injector pump has a different setup,no cold start advance,slightly different fuel shutoff solenoid too--but the whole pump would swap on my engine..it also has a J code intake ,and no vacuum pump (which I needed!),because it was coupled to a SM465 4 speed...the oil pan and sending unit is the same though,and the heads are probably useable,it ran great till it made the big "bang"..

I tell you this so you'll be aware when shopping at a salvage yard that not all the parts are exactly the same,though at first glance they appear to be..

 

[campfire]

--the injector pump has a different setup,no cold start advance,slightly different fuel shutoff solenoid too--but the whole pump would swap on my engine..it also has a J code intake ,and no vacuum pump (which I needed!),because it was coupled to a SM465 4 speed...the oil pan and sending unit is the same though,and the heads are probably useable,it ran great till it made the big "bang"..

Do you have pictures of this different injector pump setup?

And I'd toss a few bucks your way if you want to sell the vaccum pump delete plate.

 

[campfire]

Yup..some of those small parts you'd think would be cheap and readily available aren't..the VRV valve that operates the transmission modulator on the injector pump is about the same price IF you can find one,few aftermarket places even list them now..(a sucky setup IMO to begin with also)..

You just need to find someone parting out a TH400 rig. I gave mine to Greg when he bought the tranny. But you're outta luck, as I only had one.

 

[diesel4me]

The 6.2 with the busted crank is sitting on an engine stand under the eaves of my house garage,wrapped up in plastic and duct taped--its snowing heavily here right now,got 6" when they said 2-4",since midnight,with 40+ mph winds--so it might be awhile before I can try taking a picture of the IP...

The vacuum pump delete plate I'd part with,I see no need for it,seeing both my trucks have a vacuum pump for the TH400 and the Burb needed one for the heater controls and EGR,(that one is dead too,unfortunately,I was going to scoff it when the one in my pickup crapped out,but another member here kindly sent me one from CA--now the diaphram in that one is failing too)..

Finding ANY 6.2 parts here is difficult,as I stated earlier--none in junkyards around here really,most were crushed in recent years and few diesels seem to have been sold around here to begin with in the '80's...and if you do come across one with useable parts ,the yards either wont break them up or want top dollar for a part that may be junk after sitting out in the weather forever..not many guys parting out vehicles that old around here either,and they charge the same prices if your lucky enough to find anything on craigslist or other sources locally..