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Optic sensor troubles

P

pronghorntractorworks

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Location
Wyoming
My 94 is running like poo and puking white smoke. throttle response is very sluggish. I have set tdc learn and offset. When I pull the optic sensor plug, it starts and runs well in limp mode. if I try running on just the optic sensor, it runs like poo as well. Do I have a bad optic sensor? I have read through many posts on this site, and have adjusted the optic sensor to line up with the drivers side of the securing block as Buddy has suggested. Any thoughts?
 
pronghorntractorworks said:
I have read through many posts on this site, and have adjusted the optic sensor to line up with the drivers side of the securing block as Buddy has suggested. Any thoughts?
Click to expand...

I do not recommend adjusting the OS at all unless you have used a scanner to verify the warm idle fuel rate is not within a range of 6-10mm^3 on diesel fuel. So if you adjusted it without that feedback you can make the issue worse. Or did you mean you adjusted the IP to the drivers side of the timing mark and then set your TDCO? What is the TDCO value?
 
I have already pulled the filter harness. the optic sensor was way to the passenger side when I looked at it. I don't know who the bozo was who worked on it, but.... I have gmtd scan tech. tdco is currently set at -.7 i believe. I will have to verify. desired and actual are 5.1. The IP was also way off. the flange is now just to the drivers side of the timing mark. Buddy, I did not mean to take your info out of context. given how some of the other work had been done on this truck, I suspected they had monkeyed with the Optic Sensor. That is why I looked at it in the first place. I do not recall exactly what the idle fuel rate was... somewhere around 13.

Edit: I checked the offset. It is at -.7
 
OK, well you might be having some different issues here. a 1994 K3500 may have come with a DS4-5068 IP. This has a different cam ring than all other DS4 models and has different IP mapping in the PCM PROM. You may have a PROM mismatch if the IP or PCM was swapped out with another, and the person didnt know what they were doing. So you should check what model IP you have, can use an inspection mirror down under the intake to see the plate on the IP. And pop open the back of the PCM to see what 4-letter code is on the BLUE PROM, starts with a B.

Otherwise it could be the Crank Position Sensor (CPS) that is actually the issue, and the CPS and OS are not in agreement, in which case the TDCO value could be off.

A PROM mismatch will also cause erroneous fuel rate values.
 
Injection pump is a 5068. eprom numbers are as follows. BNTF 1621 5261. it is blue. Also, if the cps was bad, wouldn't it run ok with it unplugged. I tried starting it with each of the two sensors disconnected one at a time, and it smoothed out on the cps, but ran rough on the os...
 
That is the correct chip for you, as long as its not aftermarket that messed it up.

Sounds like you may need to take the OS out, clean it off and put it back in so you get the right 6-10mm^3 warm idle fuel rate, then reset your TDCO.
 
well I threw a cps at it today. no such luck. I tried setting learn and offset. No noticeable change in operation. Idle fuel rate is about 9. It is hard to tell for sure with it running so rough. what do you recommend using to clean the OS?

Also, when the engine is warm, I can unplug either sensor and it will run smoother. Although, with the CPS unplugged, it smokes more....
 
You can clean the OS off with a soft towel and some isopropyl alchohol, I always like to get the highest percentage I can, but at least greater than 90% pure. So there is less water in it. If the stores only have like 70% rubbing alcohol then they usually have 100% acetone in the nail polish removal section. Acetone can eat at plastics though so have to be more careful where you spread it.
 
Well, I cleaned the optic sensor. no such luck. I was thinking however, that perhaps the bozo who worked on it last may have misaligned the timing train... any thoughts? I have a HO water pump coming. I think I will tear into it and have a look.
 
I tore down the timing train before putting the new water pump on, and found the timing was correct. The marks lined up with no1 on tdc. about the only other thing it could be is the IP....:cussing:
 
after a winter of working on this I think I have chased out most of the problems. I pulled the engine and went all the way through it. Found valves leaking so heads were reconditioned. Put it all back together with a new injection pump. Now I think I have the timing set close to correct. It should be close enough to run anyway. The FSO solenoid is close to vertical. tdc offset is at -1.2 . when i fire it up, it runs horribly, grey smoke, and misfiring. If I unplug either the optic sensor or the crank sensor it will run ok in limp mode. I am leaning toward an ecm problem, since it runs ok on one sensor. My theory is either the ecm is getting conflicting information, or it thinks it is. Since base timing is close, I believe it is an ecm problem.... what do you guys think?
 
latest snapshot.

take a look at this. the actual injection pump timing and warm idle fuel rate do not seem right... cant get a snapshot to attach...:nonod:
warm idle fuel rate. 16.88mm3
actual injection pump timing 30.27 deg.

?!?!?!?!?
 
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