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baffled

17 is an optical sensor fault
18 is pump cam reference error
35 is pulse width error short (Fuel solenoid-- Internal solenoid)

With these errors I am suspect that the IP may well be on the way out the door.


MGW
 
Maybe just a new Optical Sensor, it may even be contaminated with something that a previous owner was using as a additive. It is cloudy and is not reading properly.
 
Hello all... I was away on course and got back a couple days ago and starting back at the truck again.

A further update on the truck,

I started the truck and this time I added some lubricant additive the a buddy gave me to try from stanadyne. I noticed that after filling up and driving awhile I would still get the engine light frequently any time rpms went above 1600-1700 and then dissappear when I let off on the throtle. When I pulled the dtc it was still 36 but no more 17 or 18. The truck seemed to run ok and not stall out. Over the last couple days I have been taking it to work and have been having the engine light come on less and less but still always dtc 36. It seems that the pump likes the lubricity as far as I can see. Yesterday I drove home which takes 25-30 mins after putting on a new fuel cap as "figment" suggested and I had no engine light at all. I thought that I had it all figured out when I went to town today and noticed the light come on as I had crested a fairly steep hill and making my way downward. The engine light would go out as soon as I let off the throttle below 1600rpms and not come back on for the rest of the trip. I noticed that the light came on again on my way home about an hour later over the same hill in the same situation but on the other side of the hill again going down. Not sure what is going on here but seems to me that lubricity is helping. I am not sure about the new fuel cap or how to tell if it is a good one or not. I still seem to get some vacuum hiss when I loosen it off after shutting down. Is this normal with diesels? I read somewhere that there should be no vacuum at all but is that for only when the truck is running??? Does anyone know a simple test to do on a fuel cap to see if it is Ok??? I made sure that it says "d" for diesel on the cap to get the right one. I took off that rf noise filter off also durring all this and did'nt seem to affect anything as far as I can tell. Let me know what you all think... It seems to make sense to me that the ip is being helped along with the addition of the lubricity... Any thoughts???

Thanks again, Dave.
 
There should be some vacuum, it helps to prevent sloshing and frothing as the fuel level gets lower.

To me, it sounds like you had fuel bubbles, perhaps too much vacuum combined with a crummy source of fuel. The fuel conditioner may be stabilizing particles in the fuel, contaminants or floaty things. The 17 and 18 are that the Optical Sensor can't see through the fuel to read the timing disk or camshaft reference and its missed too many counts. So the Crank Position Sensor is working, PCM compares and says OS missed too many counts. So think about anything that might affect the sensors ability to see through the fuel. Its either cloudy, bubbly, dark, or whatever. Since adding the conditioner helped I would say maybe its cloudy and it settled it. Your tank may be coated with sludge it picks up. Do you use any biodiesel or any harsh cleaners in the fuel lately?

Pump some fuel out and see what it looks like. The DTC36 could be from the same issue, or it could be separate. I would say add a quart of TCW3 2-stroke oil with the Stanadyne stuff. It is a much better lubricator. That or a quart of non-detergent SAE30. The lubrication wont help the DTC17 or 18, but could help the 36.
 
Buddy,

I have cleared up the dtc 17 and 18 and have not had them come back now for a while. I am still getting the code 36 usually as I am just about to head down a hill which is strange. I did some experimenting with my spare fsd and stock resistor. I relocated my fsd cooler to the inside of the front bumper in behind the plate holder and tried running the truck with both #5 and #9 resistors. My thinking here was that maybe the 6 foot extension cable to the fsd is adding too much resistence and throwing off my ip timming or something. The truck definately does not like the extension to the fsd because on both fsd's that I tried using either 5 and 9 resistors it would almost instantly set on the engine light everytime the rpms reached above 1600 or so. So I relocated my fsd and cooler back to the intake manifold with the short harness and only got the engine light to come on once going into town just as I was going down hill. I pumped out some fuel into a mason jar today as well and compared it to some I had in a jug and it looks almost the same. The truck fuel has a very slight darker color likely due to the additive. Now I am not sure if the fuel additive is what helped or if it was the 6' extension harness that has been causing my issues or not.

Buddy, when you say SAE30 are you talkin 10w30 or 5w30 or does it matter??? Can you use a synthetic?

Thanks again...Dave
 
If you do an ohm check on the FSD harness and all of the wires are 1 ohm or less that harness is fine and shouldnt be an issue. Make sure the ground wire is still attached to the top of the IP though.

SAE30 is its own rating, but its common to be in the non-detergent type. Its on any parts store shelf. It wouldnt really matter if it were 10W30 or 5W30 but in the non-detergent flavor so it burns better and doesnt ash.

DTC36 can be attributed to so many things. PMD is common, and sticking IP Fuel Solenoid, which is how lubrication might help when running ULSD.

Its possible your timing is off slightly too. Changes in RPMs causes issues, and this could be timing related. You might benefit from getting it timed correctly, perhaps even advanced to -1.5 TDCO. If IP was moved at all, and no TDCO relearn was done, or PCM replaced or crank sensor replaced, a TDCo relearn is necessary.

The resistor doesnt matter, the PCM wont recognize the change until it has been started 50 times. So it may help you to keep the #5 in and wait for it to update, or you can also get a scanner and do a TDCO learn which should trigger the PCM to learn the resistor value. GMTDScan is a great tool to have for our trucks. You can see all the sensors reporting and timing, adjust timing, etc..
 
Buddy,

Thanks again for all the info. I am going to see if I can get my hands on one of these scanners you speak of...

About two weeks ago I had dissconnected the batteries to clean up the connections and had them dissconnected for a few hours while doing some other things. Would this battery dissconnection wipe out the fifty starts that I had done before it for the pcm to recognize the #9 resistor??? By the way do you find much gain from the wmi and marine injectors??? I was thinking of this down the road...

Thanks. Dave
 
2 quarts of sae30 per full diesel tank cured my dtc36 and it hasn't been back since. I was only getting dtc36 on diesel and not WVO which makes me wonder if the IP is slowly going and since WVO has better lubricity it seems to run better.

I tried all of the other additives without success.

I suspect the SAE30 is only a temporary solution but its cheaper for now than a new IP so I am happy.
 
Would this battery dissconnection wipe out the fifty starts that I had done before it for the pcm to recognize the #9 resistor??? By the way do you find much gain from the wmi and marine injectors??? I was thinking of this down the road...

Thanks. Dave

I do not think the PCM loses the resistor value. Like the TDCO value it is stored in non-volatile static memory, like Flash that doesnt lose memory with power.

I believe the marine injectors help as long as they are real marine injectors. I have no way of knowing if they are differnt because they were "built" in stock injector bodies. That and who knows what the source considered marine injectors. It could just be pop pressure, but thats only a 100psi difference about 2200psi, and there should be slightly larger nozzle. This will help when pushing 40% more fuel with aftermarket PCM tune. A larger nozzle will keep the line pressure somewhat lower that the IP has to push. The DS4 can push 8000psi in line pressure and we are approaching its limit with the performance tunes. If you need new injectors why not? If you dont need new injectors no need to upgrade. The WMI does work very well when towing or even just going up long steep mountains.
 
thanks guys,

I've been driving the truck alot lately just to see if would stall out again but it hasn't. The engine light does come on now and then when the truck is going down a hill but other wise seems to run fine. I will try adding the sae30 in stead of the 2 stroke stuff and see if it makes more of a difference. Will I hurt anything by adding the sae30 to the full tank now when I already added the 2 stroke oil??? I only added a half quart of 2 stroke oil along with the diesel kleen additive. Some times too much of a good thing can be bad.

Dave.
 
I know this sounds random but here is another suggestion. What color PMD do you have. I know on my truck the original was black. Stanadyne came out with a newer style PMD a few years back, they are grey. The PO of my truck had the IP replaced about 6 months before i bought it, hence new PMD. The new ones have gold terminals in the plugs. If you are using extension harnesses with non gold terminals the connection may be compromised. Longshot but it hasn't been suggested yet on this thread. Good Luck

Ryan
 
Diesel Kleen isnt much of a lubricant, scored poorly in that category. So dont count on that. Use the whole quart of 2-stroke with it. 2-stroke was meant to be burnt, TCW3 is the latest ashless kind. More than a quart wont hurt, but also wont really help either for just 30 gallons.

It doesnt make sense to mix the SAE30 with 2-storke, but give it a try next time, at least a quart, maybe two. In tests used motor oil scored poor in lubrication, and I havent seen how new motor oil does. So it may take more SAE30 to do that same as a quart of 2-stroke. SAE30 will burn fine in diesel, but the non detergent type is to avoid ashing that may leave deposits.

It is also possible that no one ever relearned the TDCO value for your timing to be precise. It wont set a DTC88 until the relearn is actually intiated, so if someone replace an IP and never set the timing correctly it certainly might add to a DTC36 issue. Thats why you need a friend with a Tech2 scanner or get GMTDScanTech from Engh Motors. Its software based scanner and is the best tool you can buy if you plan to have the truck a while.
 
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