Mechanical IP. No cold advance. Help.

[BuffaloGuy]

I've got a '93 mechanical IP. When I had the mechanic put in the new motor this last spring he opened up the pump and turned it up. The truck hasn't started right (when cold) since I've gotten the new motor.

It has new 60G's, a new glow plug controller, a resistor wired per More Powers intructions to extend glow time and a push button glow plug switch on the dash. It still smokes like a beast and runs rough when cold.

Today I pulled the lid on the IP and checked out the solenoid(s). They both work great (fule on/off and cold advance). From past posts I remembered that a lever had to be just right when reinstalling the lid. I found a lever from the cold advance solenoid and as near as I can tell it only goes in one way.

I put it all back together, jumper wired the temp. sender to make it activate and could hear a very slight (I think) difference in motor sound. When the truck was new and the cold advance (or is it retard?) was engaged it was very noticeable. Not so now. I think I still have my problem.

Anything I am overlooking? Any ideas? Anybody have a schematic of the pump? Maybe I have a part missing from my wonderful mechanic opening it up. I sure have found a lot of things he didn't get right.
Ken

[catmandoo]

well i just had that same problem .put my banks turbo on my 92 1/2 and it worked great the day before and after the turbo i swear no cold advance took the pump apart again and there is nothing in there that goes to the cold adv solenoid,and i had power to it so this morning i started it and thought for the heck of it i would check and sure enough it does work evidently the turbo makes the hammering a little quieter.or the block heater is affecting it as this morning i didn't have it plugged in.also the lever you refer to in the pump is fuel shutoff if you get this out of place when you start it it will run wide open from what i'm to understand and you can't shut it off. you have to pinch off the return hose to kill it. definately want it in the right place to begin with.if you can notice a change in the sound of the motor when you connect and disconnect it i would say the cold adv is working.wonder if it's from turning the pump up?

[BuffaloGuy]

Hey catmando! I was hoping you'd reply. I was just searching old posts and saw you had the same problem.

But, I think you might be a little mixed up. The solenoid with the lever is the cold advance. The solenoid tucked way up there is the fuel on/off.

Does your lever just rest against a little flat lever in the bowl? Or does it hook to it?

It looks like when the cold advance gets power the lever goes forward (to the front of the truck) but the little lever it rest against dosen't seem to have much travel in it by itself.

Maybe turning the pump up is the problem. It sure would be nice to get that cold advance back.

Does yours work now or not?

[britannic]

Originally posted by The Buffalo Guy:
Hey catmando! I was hoping you'd reply. I was just searching old posts and saw you had the same problem.

But, I think you might be a little mixed up. The solenoid with the lever is the cold advance. The solenoid tucked way up there is the fuel on/off.

Does your lever just rest against a little flat lever in the bowl? Or does it hook to it?

It looks like when the cold advance gets power the lever goes forward (to the front of the truck) but the little lever it rest against dosen't seem to have much travel in it by itself.

Maybe turning the pump up is the problem. It sure would be nice to get that cold advance back.

Does yours work now or not? Actually, Catmandoo has it right. The high pressure cold advance is comprised of a little glass ball in the nozzle connected to the return line coming out of the the rear of the IP. The HPCA solenoid pushes the glass ball up and allows fuel to flow freely into the return line and drops the housing pressure, so that the IP advances by about 6 degrees.

The rack assembly works by rotating the fuel metering valve to shut off completely - this is actuated by the solenoid in the front of the IP housing.

[britannic]

What can cause the cold advance to fail other than electrical issues (temp. switch, 12v feed to solenoid etc.)?

1. Glass ball stuck in either the on or off position in the check valve.

2. Glass ball has disintegrated.

3. Weak or inoperative HPCA solenoid.

4. Restricted return line preventing IP housing pressure drop.

5. IP pump servo timing advance malfunction.

6. Weak or failed lift pump.

7. Water in fuel.

8. Clogged fuel filter.

9. Timing so retarded that there is no appreciable difference when the HPCA engages.

10. Other causes outside of my experience...

I had #3 happen on my pump and lost the HPCA function, even though the HPCA ball moved when the solenoid energized. It turned out, the solenoid was too weak move it with the IP running and full function returned with installation of a new HPCA solenoid.

[ 11-15-2003, 04:48 PM: Message edited by: britannic ]

[britannic]

This thread (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=002168#000004) on the 6.2L will provide a little light reading for how the DB2 mechanical pump works, in particular look at gmctd's post (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=002168#000001) and mine for details: DB2: How it Works (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=002168#000004)

[catmandoo]

i personnaly think it's from crankin the pump up as mine worked the day i started putting the turbo on and the next day when i fire it up it sounds like no advance but in reality it does have advance it just doesn't clatter as loud as before the turbo.also mine smokes like a banshee now when cold too and has a miss but i think i have some bad glowplugs,just need time to check em.also feel i might have some weak inj's which i hear will give lots of smoke and possibly a miss particularly when cold.

[BuffaloGuy]

I stand corrected and I apologize to Catmandoo! Live and learn.

Now as far as a solution. Brittanic, I read the post you linked to and I am impressed. Quite a reservior of knowledge but a little over my head. I have rebuilt an IP of off an old D-8 Cat so I understand the basics but I need it a little more simplified. You wrote (My response in BOLD):

1. Glass ball stuck in either the on or off position in the check valve. PERHAPS

2. Glass ball has disintegrated. PERHAPS

3. Weak or inoperative HPCA solenoid. PERHAPS

4. Restricted return line preventing IP housing pressure drop. NO, LOOKS GOOD.

5. IP pump servo timing advance malfunction. I DON"T KNOW.

6. Weak or failed lift pump. I HAVE A FUEL PRESSURE GAUGE POST FILTER. ALL IS WELL. 3-6 PSI

7. Water in fuel. NOPE

8. Clogged fuel filter. NOPE

9. Timing so retarded that there is no appreciable difference when the HPCA engages. I HAD THE DEALER SET THE TIMING. HE HAD A HARD TIME GETTING IT TO MOVE FAR ENOUGH BECAUSE OF IT BINDING UP ON THE FAST IDLE SOLENOID (I HAVE THE '97 COOLING UPGRADE) BUT HE SAID HE GOT IT SET.

10. Other causes outside of my experience...


Number 5 is not in my range of knowledge but 1,2 and 3 are. Sounds like a new solenoid would cover these 3.

Do you feel that Catmandoo has a plausible explanation for no cold advance (pump turned up). Or should it still work even with the pump turned up? From what I can gather from the noted post it shouldn't matter if it is turned up, the cold advance should still work.

As I mentioned, I do get a very slight change in pitch (sound) but hardly noticable and not useful at all. In the noted post it said that the sender unit for the IP is on the back of the passenger side head. I jumper wired the one on the heater supply (right by the IP itself) and got power to the fast idle and the fuel rack solenoid (I think). Is this temp sender supposed to effect the IP at all?? Maybe my sender unit is shot? I haven't found it yet.

What do you think would be the best course of action? I sure appreciate all you guys help!
Ken

[catmandoo]

hey buffaloguy no apoligy needed,we are all in this together,this board has been a wealth of info for me and if i can help other that have yet to experience things i've run across it's all for the good. and my cold advance does work it's just kinda like yours as it just changes the pitch of the engine a little instead of alot,and after it sat all day outside today and it's like 40 degrees here when i started it it seemed to hammer more than in the mornings so i'm kinda wondering if its the block heater warming it up thats causing this!

[BuffaloGuy]

Thanks catman. When I plug mine in when it's above 30F the fast idle won't even kick in. She starts right up - no smoke either. Basically it's a warm motor.

The problem is with no block heater it starts real hard and that just shouldn't be. When new it would start -20F with out a block heater, without much smoke at all (not recommended). I doubt it would even start now at 0F without added heat.

I don't know what's different but I'd sure like to get to the bottom of it. It could be just coincedence that our cold advance quit after turning the pump up or maybe your right. There are some guys with tons of knowledge about this out there. I hope one of 'em weighs in smile.gif
Ken

[britannic]

I have turned up the last 2 pumps all the way and the HPCA always kicked in with a clatter. It is very dependant on how advanced the timing already is. The lift pump pressure needs to be at 5.5-6.5psi when cranking or running. To check the HPCA, use a timing meter and look for about 6* of advance. Even if it doesn't clatter, there should still be a 6* shift or so.

I checked my HPCA when it failed for a restricted return line, by simply connecting a hose directly to the nozzle and the other end in a fuel can.

[britannic]

Here's an interesting note from my military manual on testing the mechanical 6.2L lift pump, it will apply to the 6.5L as well:

Check fuel pump operation. Disconnect input fuel line at the fuel filter. Disconnect pink lead from fuel injector pump. Use a quart capacity container and crank engine for 15 seconds. Container should be at least

[taznj63]

I would check your glow plug operation.
Make sure they are getting the right voltage and are drawing about 14 amps each. Resistance shoud be about .9 ohms from tip to ground when wire is off. Each side of engine should draw about 55 amps when all glow plugs are working.

I had the same problem on my truck and thought glow plugs were working fine until I checked each plug and found that out of 8 only 2 were good.

Hope this helps.
Also Kennedy Diesel sells fast glow plugs that will not burn out!!!
That is what I have installed and fixed my cold start problem...

[BuffaloGuy]

Thanks Brittanic. I already have a fuel pressure gauge installed, permanant, post filter. At idle/cranking I get 6 psi. So all is well there.

I will try the other procedure you mentioned to test for a restriced fuel return line. That problem would be consistent with the troubles I have been having. I'll report back later.

If no luck there I guess I'll have to go to the dealer and have them check the timing with and without the advance solenoid energized.

tazhj63: I have 8 brand new 60g's in right now. All eight are getting power (I checked the leads). From what I hear the failure rate on brand new 60g's is nill so I'm a little hesitant to spend the time to take them all out again to test them. Especially, since the motor has had trouble starting since it was newly installed and I know (or least strongly suspect) that the timing advance device is not working. If the timing advance proves to be working then all that could be left is a bad glow plug. We'll see!

Thanks again guys!

[BuffaloGuy]

UPDATE:
I removed the hose from the top of the IP as instructed, installed a long one with a hose clamp and daylighted it into a bucket. Also added an extension on the stub of the hose that now went to the fuel return line since I wasn't sure if it would spout any fuel.

I fired it up. Tested for power at the timing advance lead. All good. I had a very, very small stream of fuel coming out the line from the top of the IP. If it was any slower it would turn to a drip. Does this sound about right?

After the motor warmed and the fast idle kicked down I pulled the timing advance lead off the pump and put power from the battery to it. Again, I could hear an extremely slight change in pitch. No noticable difference in the fuel running into the can. Does this sound about right?

No fuel came from the fuel return line. I could blow thru this line (with the motor off) but it took some effort.

I have one more item to check out before it's off to the dealer to check the timing with and without the cold advance. I don't want to spend any money!

Just a few weeks ago I noticed that the glow plugs were not 60g's but were in fact old corroded 9g's. I pulled the receipt on the motor from Avant and saw that I paid for 60g's. Jamie at Avant credited my card without any trouble and I installed new 60g glow plugs.

This has got me questioning if the injectors are in fact new ones or are they old wore out injectors? So when it gets light and I have some time (pretty hard to do these days) I'm going to look over a couple of easy to reach injectors and see what I have. I WILL be a little TICKED if they are not new!

More to follow.
Ken