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IP Temperature Sensor

I

ireburb

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I have an interesting theory on my IP code 36 now.

I first had the problem towards the tail end of winter/spring last year and it always went away when my WVO system kicked on.

I added some SAE30 to the diesel tank and code 36 eventually went away after a few tanks. Well now it's back again and only on diesel.

Makes we wonder now if it is temperature related since the problem went away over the summer on the diesel SAE30 combination. I am ruling out viscosity since you would think the colder weather would make for a slightly more viscous diesel/SAE30 combination(I know a stretch). I only add 1-2 quarts in a full 42 gallon tank.

Anyways, I was going to try fooling the IP temperature sensor into thinking the diesel temperature was a little warmer and see if the code goes away. I figured a resistor would be cheap and I have nothing to loose right now.

I think IP failure is imminent but if I can hold on to the one I have a little longer....

So my question is which wire and what ohm resistor could I use to test this theory? I would want to fool the PCM into thinking the diesel fuel was 160 deg. F.
 
When your truck is at operating temp the diesel is above 160 degrees. Your fuel temp in the tank actually increases the longer you drive. The cold fuel circulates through the IP and any excess is sent back to the tank heating the cold fuel. In theory you don't need a heated veg tank (except to make the pump work easier) because as the wvo works its way up the back of the hot engine it heats. It gets heated more in the fuel filter manager, and again as it runs across the top of the engine (under the intake manifold) into the hot IP and into the injectors. The excess wvo is sent back to the tank heating the wvo.

If you are taking shorter trips that could be the reason for the code. The fuel doesn't heat up enough. Your heater on the fuel filter manager may be bad as well because it heats the fuel up until it is 80 degrees or so.
 
No more theories now. IP is shot.

Symptoms: no stable throttle controls at 2k rpm at first, then touchy throttle on diesel, then code 36, then yesterday a runaway IP when I started the truck in the driveway. I shut her down and plan to start the ip removal this weekend.

At least it went in the driveway instead of on my camping trip last weekend towing the trailer.
 
IRE,

Do you have any estimates on the number of miles on that IP?

Good luck buddy, take lots of photos.
 
Veg_Out said:
IRE,

Do you have any estimates on the number of miles on that IP?

Good luck buddy, take lots of photos.
Click to expand...

Only about 60k on a rebuilt IP. I have been fighting fuel pressure issues for a while so I am pretty sure I killed it from too much starvation.

For some reason with my looped WVO return I was still getting fish-biting and going through filters like mad. Took the loop away this weekend and no more fish-biting.

I just hope I didn't kill anything else when the engine revved up to 4k when it ran away. Coolant pressure was so high it blew out the coolant heater slightly. I was able to turn it off fairly quickly so fingers crossed.
 
Unstable throttle and run away symptoms are a sign of a bad PMD/FSD. I'm not saying it isn't the IP but I would try a good fsd/pmd first.
 
One other thing you can try to see if it is the ip or fsd is unplug the optical sensor and try and drive it. It will take longer to crank over but it should.
 
Since it was running good on WVO and the FSD is remote mounted I ruled out that possibility. I would think that if it were FSD related that you would get the same symptoms on diesel or WVO correct?
 
Rodd said:
When your truck is at operating temp the diesel is above 160 degrees. Your fuel temp in the tank actually increases the longer you drive. The cold fuel circulates through the IP and any excess is sent back to the tank heating the cold fuel. In theory you don't need a heated veg tank (except to make the pump work easier) because as the wvo works its way up the back of the hot engine it heats. It gets heated more in the fuel filter manager, and again as it runs across the top of the engine (under the intake manifold) into the hot IP and into the injectors. The excess wvo is sent back to the tank heating the wvo.

If you are taking shorter trips that could be the reason for the code. The fuel doesn't heat up enough. Your heater on the fuel filter manager may be bad as well because it heats the fuel up until it is 80 degrees or so.
Click to expand...

I'm not sure how much fuel actually returns to the tank. I am curious about this myself. Do you know?

I also know that when I had gelled up gasoline sock on my new FSU that even after 12 hours of plowing, my in tank temperature never got warm enough to resolve the gelled sock.

I think on a common rail system you get alot more return flow to the tank than in our systems, leading you to believe that the tank heats up signifcantly.

AFAIK the only fuel that returns to the tank is just the amount that didn't get pressed through the injector during that stroke, which is probably a couple dribbles worth.
 
ireburb said:
Since it was running good on WVO and the FSD is remote mounted I ruled out that possibility. I would think that if it were FSD related that you would get the same symptoms on diesel or WVO correct?
Click to expand...
You're right if you are good on wvo and bad on diesel that would rule out the fsd.

If the IP is worn out then the thicker WVO could mask an ip going bad. Here is some chemotherapy for your IP....
On a hot engine and empty wvo tank, Mix a gallon of clean fuel, a pint of Stanadyne Jr. additive and a pint of automatic transmission fluid. Put them in the wvo tank and idle until fully consumed. This recipe came from Diesel pro at the old place. If that doesn't work I would try blending 50% wvo and 50% diesel and put it in your diesel tank. It should be thick enough to fix your problem.
 
Ordered a re-built IP from Pensacola.

Installation hopefully begins this weekend if the weather cooperates.
 
changed mine on my burb in a little under 4 hours.....i got a PD rebuild....been 18,000 miles and no troubles....
 
ghitch75 said:
changed mine on my burb in a little under 4 hours.....i got a PD rebuild....been 18,000 miles and no troubles....
Click to expand...

I am not worthy. Worked from 10AM to 4PM until it rained and still not done. Did you have to re-time yours? I am trying to be exact in positioning it where the the other one was but I also have heard how sensitive they can be.
 
ireburb said:
I am not worthy. Worked from 10AM to 4PM until it rained and still not done. Did you have to re-time yours? I am trying to be exact in positioning it where the the other one was but I also have heard how sensitive they can be.
Click to expand...

There is only one way the IP shaft will line up w/ the timing gear. There is a little pin on the IP shaft and a little hole in the timing gear that it fits in. All I do is turn the pump till it fits and twist it till the pump is straight up. A little trick is barely tighten (maybe 15 torque lbs. not w/ a torque wrench) the two lower bolts on the ip so you can adjust it left or right. Then tighten the top on tight, check timing/tdco and adjust again if need be by just loosening the top bolt. Hope this helps.
 
OK I got it finished today and the issue was definitely the IP. Runs much better now. No codes and the throttle control is back to normal.
How do I know if it needs to be timed? It was running rough at first but seems fine now.

I am going to take it for a few more test spins this evening on the highway.
 
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