Cold weather starting... Glow System checks

[pbknowles]

Philip: Quite right, I had forgotten about that function. In my game playing with cold start I find that mine always starts, the trick is keeping it running cleanly once the key is released. I settled in a max egt of ~1000 deg. f measured in the exhaust manifold adjacent to #4 cylinder exhaust port with a calibrated type K thermocouple. Test conditions were accellerating up a long uphill on-ramp that I take every day, max reading taken at the top end of 3rd gear (by ear, no tach). The only reason for choosing this number is that I own or have owned sever other IDI diesels that maxed out around 1000-1200 deg. f with stock pump calibrations. My smoke screw had been dinked with by the P.O. and I didn't want to melt my new pistons.

[philip]

Philip: -snip- I settled in a max egt of ~1000 deg. f measured in the exhaust manifold adjacent to #4 cylinder exhaust port with a calibrated type K thermocouple.

Thank you And what of visible smoke?

[Lonnie]

Back to the battery...
I bought a new interstate battery yesterday. Didn't help.

Tonight I checked the voltage & at the solenoid & I have 11.25v but at the #1 GP I have 9.85v.
So tomorrow after I get the front end alignment done I'll start checking connections.

Has anyone just wired direct from the soleniod to the #4 GP? I'm thinking about doing this if cleaning up the connections doesn't work. I've got some 8 guage copper wire & some heavy connectors.

Lonnie

[asavage]

Has anyone just wired direct from the soleniod to the #4 GP? I'm thinking about doing this if cleaning up the connections doesn't work. I've got some 8 guage copper wire & some heavy connectors.

Excellent idea. You're losing 1.4v over those two spade terminals. Eliminate them. 10ga is probably sufficient (I use 10ga for loads up to 50a), but 8ga, ah, that's nice

The only thing I'd add to that is solder: solder your ring terminals. But a very good crimp connection, with quality ring terminals (the quality of terminals varies all over the board, with the Harbor Freight variety pack being some of the worst I've ever been asked to use) and some heat-shrink tubing over them afterward.

That's what I did on my '83 Maxima ("Myrna"). The OEM double-10ga-plus-dual-spades mess just wasn't cutting it.

[Lonnie]

Ok,
So I hard wired with 6 ga. from the solenoid to number 4 GP. & checked all that out & it's all working fine. (even the after-glow) After this was done it seems to start better in the morning but still runs rough for a minute or so & lots of white smoke but not as much as there was before I got it fixed.

Checked what I believe is the smoke screw & it looks to be wired from the factory. (on the lower back half of the pump?)

The Injection Pump Controller appears to be working correctly.

Not sure how to check for air in the lines?

I'm a little leary about advancing the timing without all the right tools, or am I just being a wuss?

[philip]

SNIP- Not sure how to check for air in the lines?

I'm a little leary about advancing the timing without all the right tools, or am I just being a wuss?

Customer brings in his diesel because it is running poorly.

The old mechanic takes out a wrench, a screw driver, and a stethescope. He has the engine purring in about 5 minutes.

"That's fantastic!" says the customer.

"That will be $120, please pay the cashier.

"WHAT?!!! All you did was turn a couple of bolts, pry on that thing with the pipes, and listen to the engine!! What a RIP OFF!"

"My friend, I know what to turn and what to listen for. You don't. Please pay the cashier"


Suggest you read up thoroughly before messing with this fuel system.

[Lonnie]

Just as soon as I receive that FSM!

[asavage]

Philip, I doubt that the timing has to be periodically readjusted (much). It's a gear-drive design.

OTOH, a small amount of timing adjustment on a diesel makes a BIG difference, unlike most gassers.

I'm of the "keep the filters clean and the oil changed, keep ahead of the oil leaks, and leave it alone" school of thought on the SD22.

[philip]

SNIP- I'm of the "keep the filters clean and the oil changed, keep ahead of the oil leaks, and leave it alone" school of thought on the SD22.

Ten Commandmentsof diesel ownership.

[Lonnie]

I received my owners manual the other day.
I found it interesting that they consider temp. below 68 deg. as cold weather starting! Well around here we have about 11 months of cold weather starting because even in the summer it will cool down to below 70 at night...

It also says for cold engine & cold weather starting to turn the key until the GP light comes on. Immediatly after the GP light goes out fully depress the throttle & move the key to start. After it starts slowly release the throttle. Then adjust the throttle control knob until the engine runs smoothly.

The last two mornings I've tried this & it does seem to help. It runs smoother right after it starts & it may be my imagination ( the worlds largest nation) but it seems like there is less smoke & for a shorter period of time...

See Philip, I do read these things! But don't think I'll stop asking questions!

Thanks again for everyone's help!
Lonnie

[redmondjp]

Yes, this is the only vehicle that I have ever seen where you are supposed to floor the accelerator pedal while you start the engine (to reduce the cranking effort as well as to inject more fuel I think)--as soon as it fires, however, get off the pedal as far as you can.

During this winter, when starting cold, I have tried the advice to keep off the go-pedal as much as possible, and it definitely helps it to start running quicker, and produces wayyyyy less smoke.

This morning it was 34 deg. F, and after two full glow periods, it started pretty easily with minimal smoke.

[philip]

Thanks Al, -SNIP- I tested each place you said & all but the GP itself showed 10.2v. At the GP it tested 9.9v. -SNIP- Lonnie

While researching an answer to another thread, I put my voltmeter to the #1 glow plug terminal and turn ON the ignition.

Voltage jumped to 8.8v ... and over the next 10 seconds rose to 10v. The voltage rise reflects increasing resistance as the glows reach maximum temperature.

Voltage drop across the single blade/spade connector for the glows while in operation was 0.06v .

[asavage]

Voltage jumped to 8.8v ... and over the next 10 seconds rose to 10v. The voltage rise reflects increasing resistance as the glows reach maximum temperature.

Voltage drop across the single blade/spade connector for the glows while in operation was 0.06v .

Then where is the voltage being dropped? Surely your battery voltage isn't dropping to 8.8v when the GP relay closes. 8.8v is awfully low.

[Lonnie]

That's interesting, since I wired direct from the relay to the glow plugs I'm getting 10.9v. Of course there is a little time from the time I turn the key on until I get around to test it...

It seems to be starting much better now since I changed the wire, still smokes for a bit but not too bad...

Over all it runs great so I'm not too worried.

Thanks!

[philip]

Voltage jumped to 8.8v ... and over the next 10 seconds rose to 10v. The voltage rise reflects increasing resistance as the glows reach maximum temperature.

Voltage drop across the single blade/spade connector for the glows while in operation was 0.06v .

Then where is the voltage being dropped? Surely your battery voltage isn't dropping to 8.8v when the GP relay closes. 8.8v is awfully low.

Is this a trick question? 8.8v at #1 glow just reflects resistance to the collective amperage draw.

Upon completion of one glow cycle, the white/red wire from the duty relay to the glows connector exhibits a little warmth. So ... there must be some resistance along that wire when carrying (briefly) 60-70 amps ... tapering quickly to 25 amps (thereabouts) for the remaining preglow time. Of course the glows themselves further the voltage loss because of their amperage flow.]

WaddaYaThink?