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Discussion Starter · #1 ·
Just bought the truck last month, have put about 500 miles on it. Main problem is the Service Engine light comes on during lower speed cruise (up to 50 mph or so) and light power, and the cruise will disengage when it comes on. It doesn't come on at idle, slow speeds (<15-20 mph), under power, or highway speeds. Overall, power seems good, it runs smoothly and isn't excessively noisy.

I'll go through the "Diagnostic Checklist 1.1" by the numbers:

1. Lift pump test - describe results
Pass. Good flow while OPS engaged.
2. Service Engine Light - on/off/intermittent
Intermittent. Comes on under city cruise speeds & light throttle, goes off under power and no throttle. Does not come on at steady highway speeds 65+.
3. Model year
1995.
3a. Odometer reading
285550.
3b. Miles on major engine components if been replaced
Per receipts from the previous owner (miles work done will be noted along w/date):
257k, 8/04 - Recall #03023, p/n 12463090 Module.
247k, 12/03 - Alternator, NAPA rebuilt.
Miles unknown,10/03 - Batteries, matching pair, 875 cranking amps, 700 CCA.
229k, 3/03 - Injection pump p/n 12561307 & fuel separator p/n 10154635 (Chevy dealer installed). The PO also stated this was done at ~100k, but I didn't see the receipt for it.
161k, 12/00 - oil cooler lines replaced (they're leaking again).
69k, 9/98 - drain gasoline from fuel system, purge, replace with diesel.
48k, 10/97 - Replace lift pump & OPS.
A bunch of receipts for oil changes. About 3-5k between, always used Delo 15W40.
4. Do you have any engine codes? Yes or No?
Yes.
5. If you do have engine codes - what are they?
When originally checked 29, 35, 36, 49, 57, 62, 78. After replacing ground cables (see #8), fuel filter, and glow plug relay, taking it for a drive on city streets and on freeway for about a 15 mile drive, only 36. I'll check it again tomorrow after we drive & tow for about 35-40 miles.
6. Air Filter condition (visual check)
Replaced last week. The old filter was getting dark with drop light shining thru it.
7. Fuel filter condition (freshly changed or condition unknown)
Previous condition unknown, didn't see any receipts indicating it was changed (haven't poured through all of the oil change receipts though). Changed today.
8. Condition of Battery terminal connections (cleaned and tightened)
Terminals were clean. Passenger side battery had a side-to-post adapter for the ground cable. Neither ground cable would tighten up. Replaced both ground cables today with 2-gage; new side terminals tightened to battery fine. Jumper wire to fender was only 12 gage on the new cable, routed a new jumper from driver's side battery ground cable to mate with passenger side jumper @ fender. Positive cables clean and tightened fine. Had both ground cables off at the same time while replacing.
8A. Known condition and age of the batteries.
Replaced 10/03. Walmart 875/700 amp, 3 year replacement warranty. They turned the engine over fine during the cold spells we've had the past few weeks.
8B. Are batteries of differing age or are they a matched set?
Same age, matched set.
9. Upon cold start, does the radiator hose get hard quickly? Yes/no
No.
10. Upon cold start, do you have excessive white smoke? Yes/no
Yes. Was particularly bad last weekend, didn't clear up for a couple of minutes, sounded terrible, I restarted it twice before it finally cleaned up. Normally, lasts for a few seconds to half a minute and the engine sound changes dramatically when the smoke goes away.
11. Do you have excessive cranking time before the engine starts?
Varies. Sometimes takes a few tries when cold. Normally starts right up when warm.
12. Have you used the block heater, and does this effect engine starting?

Yes, particularly helps during extreme cold.
13. During hard acceleration, do you have excessive black smoke? Yes/no
No, haven't seen any black smoke, even when towing a horse trailer up hill at 60 mph.
14. Do you have any unusual exhaust smoke issues?
Just cold start white smoke.
15. Turbo check out - pass/fail
Wastegate actuator closes wastegate, can't push open by hand. 6" vacuum at actuator and solenoid (may be affected by our high elevation, not sure how much but my gasoline engines are about 5" lower here than they are at sea level). The actuator does not open the wastegate when there is no vacuum on it - not sure if that means anything. Haven't checked vacuum directly at pump.
16. Do you have an EGR on the engine? (An F or an S engine code)
Engine code F.
17. Indicate if you know if it's a 1500, 2500, 2500HD, 3500, 3500HD.
2500HD.
18. Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1 Diesel, SVO/WVO, other
It's whatever low-sulfur diesel they have at the normal consumer gas filling stations.
19. Are you using any fuel additives? If so, please list.
AMSOIL Diesel Fuel Additive Concentrate, and AMSOIL Cold Flow Improver at last fill-up.
20. Please indicate geographic region you are in: (example: Texas or Canada)
Colorado, Denver metro area, elevation 5800'.
21. Do you have any service history available that might pertain to the problem you are having?
Nothing beyond PO receipts, what I've done since buying it, and current codes.
22. Please indicate any modification to the vehicle that might help us diagnose better.
This is the most factory stock used vehicle I've seen in a long time, especially one 12 years old and with this many miles on it. It has a trailer brake controller on it, that's it!
23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes/no
It isn't a big whoosh. Kind of what I would expect based on what the owner's manual says.
24. Location of PMD/FSD? On the pump/remoted over intake/remoted out of engine bay (please specify specifically)
Unmodified. Stock location.
25. Are ALL glow plug in proper working order as per this thread?
Haven't gone through all of that yet. My guess is they are the originals and need to be replaced. Went ahead and replaced the relay today.

So, that's what I know. Now, your turn.
 

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Good job on the Checklist, dude........

DTC36, where the FS takes excess time to seat, can be caused by low voltage -

check the grounds at the passenger-side rear intake manifold

unplug and reconnect the IP harness connectors, checking for frayed\broken wiring, oxidized pins

Can also be caused by failing Inj Pump, but do the other stuff, first.

You should also consider remote'ing\replacing the FSD\PMD and the IP harness
 

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Discussion Starter · #3 ·
Just got back from the weekly horse tow. Same intermittent SES light under same conditions as described above.

The cold start-up was the best it has been. We were under a blizzard warning, so I plugged it in last night. Only got down to 30 degrees, never saw a single flake (they got pounded about 15 miles east of us and beyond). Started on first try, only a couple of seconds of white smoke before it cleaned up and smoothed out. The truck sat for about 4-1/2 hours after that, nose to the wind, ~40 degrees, when started then about 3 seconds of white smoke and it cleaned up.

36 is still the only code it is setting.

The intake ground wire is fine as far back as I can see it into the harness.

The IP harness looks okay (part of it looks new, in fact - I assume that's the part that comes with a recently-replaced part), the engine was still hot and I didn't want to fuss with it right now.

I'll have to study up on the remoting (read a little about it already, don't understand the details yet).

Other than the annoyance of the SES light coming on and no cruise while it is on, is there any harm to this condition? I understand I have to take it through emissions testing, will it fail if this is going on?
 

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I have had a code 36 off and on for months. I know a lot of the guys say it's a bad idea, but I dump about half a quart of clean motor oil in the fuel when it codes. The 36 goes away for a long time after the oil. When you get emision tested, make sure you clear codes right before getting there.
Ted
 

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Discussion Starter · #5 ·
In Colorado, for OBD-I vehicles, an SES light is not cause for failure, as long as all required equipment is in place & operating, and the exhaust sniffs clean enough. OBD-II, that's a different story.

So, will a too long injection pulse make the exhaust too dirty to pass the sniffer?
 

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That will give you less fuel, actually - start with 8oz of power service cetane improver mixed with 16oz ashless two-stroke engine oil per 20gals Diesel fuel.

Normally, thicker viscosity fuel can cause longer closure times, but try that brew when you up-load a full tank of fuel, see what happens.

Your '95 hoss is 12 years long in the tooth, and probably was rode hard and put up wet, more often than not, so I'm still suspectin' bad wiring problems, but try the liniment first, see how it responds.

Remember - motor oil was not formulated for combustion chamber service - two-stroke motor oil is specifically formulated to burn, ashless, and can up your fuel mileage, as well as lubing your Inj Pump, whose only source of lubricant is the fuel it is pumping.
 

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Discussion Starter · #7 ·
Hmmm, I guess I'll have to bone up on the theory how "injection pulse width error (too long)" gives you less fuel.

I assume the cetane boost is to compensate for the 2-cycle oil in the fuel.

12 years old is "long in the tooth"? It's the newest vehicle in the family!!! :D
 

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Yeah, but it was new 12 years ago.......

Injection begins when the valve is closed.

The quicker the valve closes, the more fuel is injected - the longer it takes for the valve to close, the less fuel is injected.

DTC35 is when the valve closes too quickly, as when air is in the chamber.
 

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Discussion Starter · #9 ·
I'll take your word for it, but I still need to get a better understanding how all this works (and how the computer measures pulse width).

I've put a little over 100 miles on the last fill-up. I'm trying to decide whether to put in the 2 cycle oil now, or burn more off and put it in when I am a little more sure it's at around 20 gallons (probably around 24-25 gallons in the tank now).
 

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Keep putting it off - that'll give you more time to look for a replacement injection pump.............
 

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Discussion Starter · #11 ·
That pretty much puts it into perspective.

I had decided after I posted that to go ahead and add the 2 cycle oil. Only to discover I've gotten low on it. So, I added what I had, and will be getting more today.

Was there an "improved" injector pump that came out later? The seller thought the last pump put on was somehow better than the original.
 

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Check the serial number on the plate in the back of the pump.

The optical sensor encoder, engine shutoff solenoid have been upgraded over the years. Also the rollers where changed to ceramic on newer ones. Maybe some other improvements, not sure.
 

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Post the DS4-xxx-xxxx numbers on the model number plate for an idea of it's chronology - might have a small green tag on the top front.
 

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Discussion Starter · #14 ·
I'll get out and look for that when I have a chance. It's taxes night tonight.

Okay, next dumb question: The full dose of 2 cycle oil is in now. How long to take effect? What's the best condition to get it "worked in"? Where it sets the SES light? Under power or idle or highway cruise where the light doesn't come on?
 

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The lube will blend as the fuel sloshes under driving conditions - when you hear engine noises quieten down a little, it's on the job.
 

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Discussion Starter · #16 ·
Okay, that's kind of what I figured. It's quietest under load currently. I've only driven about 5 miles with the "full dose" of oil, I'll drive it again tomorrow.
 

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Discussion Starter · #17 ·
I managed to check the 5 "easy" glow plugs tonight. All read <<1 ohm, just barely off where the needle went with the leads shorted (analog ohm meter, in case you hadn't guessed that). Getting cold and getting late, so I didn't try 4, 6 & 8.

Did note that the blade terminals were pretty loose on the odd side. From other threads, I take it that's not so good. So, I'll attempt to snug those up this weekend and see if that helps the white smoke. Voltage at the plugs was about 11 volts. Thursday I drove the truck to work and it sat for over 9 hours in 20 degree temp, snow, and 20 mph winds. The smoke screen I made starting it when going home will live on in legend with co-workers for years to come.
 

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I prefer the analog meters for this type of testing - the DVMs use ua in the ohms circuit, where the analogs use current well into the ma ranges for continuity\impedance testing.

Analog meters are best for checking relays, as sample-time is 100% - only way you can miss a cc is if you're watching the babe next door mowing the lawn in a thong
 

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Discussion Starter · #19 ·
I was doing the checks from about a week-old memory. When I got back inside, I looked at the diagnostics & glow plug threads again, and saw it said to use a digital ohm meter. I was hoping they weren't current-sensitive (can't imagine they would be).

I've got about 110 miles with the 2 cycle oil now. Still setting Code 36.
 

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Not many good analog v-o-m's left - the dvm's are accurate for most all measurements, but I like the analog-type for continuity checks.

The glow plugs are current sensitive - 8-10amps sensitive - your analog meter put maybe 20ma thru the gp, so it probably didn't glow much..........
 
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