88 GMC k3500 6.2

[murphyslaw]

ok vehicle is as above J code. this will be a continuing thread for my retarded and exhausted questions. I have the 6.2 book from here as well as a chiltons(read useless) for this rig. I am not new to diesels jsut these one's. as I'm not new to chevys just cheys newer then 82.


Ok so first off well start with a list sorta say of my questions then I will provide more info later in the thread.

Glow system dosnt seem to work right

seems to have a posative(sp?) crank case pressure

wires that lead to noware

things that dont look right.



ok first the glow system.

First thing in the am (temp about 49f) turn the key glows for about 7sec then each following glow whether I start it or not only last 1-2 secs. The glow controller(post thing that screws into the head) was recently replaced, and I have wiggled and checked the wires. I have wiggled the wires on the relay all seems well, have tested the glow plugs all seem ok.

Is this a normal behavior? if not could it be the controler? is there a way to bypass the controller with out negative affect? should I just wire a switch to manualy glow the plugs after the first cycle?

on a kinda related part to the glow system, while i was messing with the glow system i had the key on while checking wires and connections the wipers started to turn on like the delay was on the longest setting, I checked the switch and it was off messed with the switch a bunch but couldnot get it to stop but could change the speed and all that, got pissed yanked the fuse ok now it stoped.



Ok now I think the CDR is bad or something cause while the engine is running with the air cleaner on and tight there is a smoke/steam thing comming out the dipstick tube. the book said this means the cdr is faulty. can this be cleaned? or does it need to be replaced?



On the back of the engine there is a large guage black wire with a red tracer on it, I am assuming this is suposed to go to the "resistor" block on the firewall? does it matter what post i put it on?
also on the front pass side there are two wires one that is a flat 2 prong plug that looks like it went to an optional A/C wire tied to it is another plug that is funny looking kinda round with a single prong in the center. where does this go.


now some things that dont look right.

I tested(cold) both the temp sensors the one in the cross over and the one on the front of the head. which does what? both seemed ok from a cont. test but the temp guage is ALWAYS pegged and this worries me.

also the oil pressure guage reads no more the 40lbs at high way speeds dont think this is right. but it dosnt drop less then bout 30-35. when i crank the engine i can watch the pressure rise.

The fuel guage when full reads 1.4 tank was told by someone to replace the resistor on the back of the guage. is there a kit or do i need to solder the thing off the board(is it on a board) and get another one then solder it back on?

Voltage guage dosnt work. period.


ok now I know you all are like WTH, It takes alot of time to trace most these problems and this chilton does d*ck to help. I have got alot of info from it and the 6.2 book from here but they both leave alot of questions unanswered.

P.S I hate computer controled rigs I can do ANYTHING to the 343 in my boat but cant do anything to the one in my truck.

*edit* just went for a drive and the speedo has stoped working from this afternoon to now, WTF i'm about to rip everything out and go mechanical guages and controls as i have on all my other rigs*/edit*

[ZZ]

I personally recommend using a manual switch for the glow plugs when the electronics go down on the early systems. I've converted about 3 vehicles in my time and was always pleased that I did. I used spring loaded toggle switches that turn off when you release them. I ran the power wire to the fuse block on a fuse that only has power when the ignition switch is in the "run" position. I ran the other wire from the toggle switch to one of the small posts on the relay, and grounded the other post. I would turn on the plugs for 6 seconds with the AG-9 plugs, and then start the engine. If it was real cold and engine ran rough; then I'd turn them on for another 3 to 4 seconds every 15 seconds till it smoothed out.

I think the oil pressure is fine for your truck.

[Subzilla]

Your controller is working perfect. These are the normal glow times for mine so don't worry. I do have a power interupt switch on the relay just so it won't cycle when the vehicle is warm. Mine will easily start without the GP for a couple of hours after shutting down so I figure I'm preserving the system.

My wipers can have a mind of their own. At the weirdest times, they will cycle once or twice. I've been told it's the switch but it hasn't been a nuisance so I don't worry.

CDR - you'll always have some steam coming from the dipstick. Diesels will have some blowby but the trick is to identify how much is too much. I don't know but I suppose if it will puffing like a steam engine, that might be of concern. There is a better but crude way to check the CDR and I'll try to remember it correctly. Place a clear tube over the dipstick and run it into a container of 15w40 oil. Start the engine and rev it up. The oil should be slightly drawn up into the tube if the CDR is working correctly but not sucked all the way into the engine. Someone once had the exact amount of inches it should rise but again, my memory is getting old.

Is the large black wire at the back of the engine connected to a blue wire or some other color wire? This could be part of the trailer towing package. This bundle stumped for years until a few years ago when I installed a brake controller and discovered the other end tucked and hidden above the receiver hitch. One of the wires is for the brake controller and the other is just a accessory power wire, I assume, for any trailer stuff. I was happy I didn't have to run another wire!

My temp sensor for the guage is on the side of the driver's side head. I have to clean it every now and then to keep the guage working accurately. I'm not sure of the other one.

I don't about the fuel gauge but mine bounces around like a rubber ball. I've never explored that stuff. Voltage gauge, I don't know.

Speedo, check the obvious: cable connection or broken cable.

Hang in there!

[murphyslaw]

the black wire is of a large guage mabey 12 and goes down to the bell housing area where i can see it.

fixed the speedo i played with the fuse for a while and it started working(damn electrical crud).

[murphyslaw]

ok so for some reason i put the fuse back in for the wipers and they are working properly now.

the resistors that I was told to replace on the fuel guage, is that the bar looking thing on the back of the guage? how do i tell what to replace it with i tested it with an ohm(not sure if this is the right way to test it) and got no response from the meter(read OL) this must mean its bad?

the odometer dosnt work!!sayd 940007 when i bought it and i have but about 200-220 miles on it and it hasnt changed.

all the fueses are good and all the spots in the fues box that takes a fues has one.

[DmaxMaverick]

I don't remember what the gage resistor value is, but you can find a kit at http://www.fix-a-gauge.com/.

[murphyslaw]

THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU.

Im gonna take the shunt up to the electronics shop in the morning to see if they have any, I hate waiting for stuff. thanks for the info.