Greetings all. The more I get into my truck, the more I PUT into my truck. I am not the best person to point fingers when it comes to lack of maintenance but, I have realized that I am following up on a lot of neglect from the previous owner. Having said that, here is my smoke issue:

It has always smoked at start up and there have been too many variables to narrow down why. Luckily (if you don't mind spending the money) my injectors went south last fall giving me an opportunity to replace them. While I was in it, I replaced the 2 bad glow plugs, and had upgraded to the GPR 109. Since then, I have put 300-400 miles on it, so most, if not all the air should be worked out of the injection, and the oil should be out of the cylinders. I have also swapped in a new IH CPS and unplugged the EBPV. It smokes more now at start up than it ever has. My exhaust is broken under the bed so I can't really see if it smoking going down the road.

After reading a lot of info, I decided to check the EOT tube and sensor. The tube was completely blocked. I mean it was so bad, I just bought a new one because it couldn't be cleaned. I also cleaned the EOT sensor as it was pretty packed as well. It felt as though I had gotten it free'd up but I am wondering if it is why I am still fogging a blue tinted smoke. The smoke may have gotten worse once I replaced the tube but I don't know that for sure, just kinda seems that way.I have seen this chart:

You can ohm the EOT sensor to see if it out of spec
K Ohms__Volts____TempF___Temp C
826______4.75______-32______-36
785______4.75______-30______-34
575______4.73______-22______-30
525______4.72______-20______-29
365______4.68______-10______-23
300______4.65______-4_______-20
250______4.63______0________-18
192______4.6_______10_______-12
173______4.55______14_______-10
139______4.49______20_______-7
103______4.4_______30_______-1
98_______4.38______32_______0
64_______4.18______40_______4
59_______4.13______50_______10
43_______3.92______60_______16
37.3_____3.8_______68_______20
33.6_____3.73______70_______21
26.8_____3.53______80_______27
24.3_____3.44______86_______30
21.5_____3.32______90_______32
17.2_____3.08______100______38
16.1_____3.01______104______40
13.9_____2.84______110______43
11.2_____2.59______120______49
10.9_____2.56______122______50
9.34_____2.38______130______54
7.55_____2.11______140______60
6.28_____1.89______150______66
5.34_____1.72______158______70
5.32_____1.71______160______71
4.48_____1.52______170______77
3.84_____1.37______176______80
3.75_____1.35______180______82
3.17_____1.18______190______88
2.8______1.09______194______90
2.68_____1.04______200______93
2.2______0.88______210______99
2.08_____0.86______212______100
1.87_____0.78______220______104
1.56_____0.67______230______110
1.33_____0.59______240______116
1.19_____0.53______248______120
0.38_____0.17______CEL Below This

but I am not sure how to do this test or if it is even worth doing. I hate to throw parts at something but the EOT sensor seems logical. I am sure blow by is a small contributing factor being that it has 230k on it and probably less than average maintenance. If I do replace this, does it have to be OEM or will parts store work? Is this an expensive sensor? Thanks guys.

-Joseph

 

The tube and sensor you cleaned is called EBPS (exhaust back pressure sensor), not EOT. Its purpose is to control the EBPV (exhaust back pressure valve), however since you have that unplugged it basically does nothing. EOT sensor is located on the HPOP reservoir and if you unplug it then you can measure the resistance with an ohm meter, but I doubt that's the problem ... could be though.

Does it smoke cold and hot or just cold? If just on start up as mentioned I would recheck the glow plug system. You could also unplug the MAP sensor to make sure it is functioning proberly. The truck will CEL with it unplugged but will still run OK and if it runs a lot better with little smoke then it could be defective. Here is a picture of the MAP, just unplug the 3 wire electrical connector, start it up and take it for a spin.

 

Just unplug the EOT sensor and use a multimeter to ohm the sensor. Do this with the engine cold. The oil temp should be close to outside temps. So if it's 80* outside then the ohms should be around 26.8

 

Are you talking about the sensor that has a tube running down to the passenger side exhaust manifold? If so, that is not the EOT sensor, that is the exhaust back pressure sensor. It does tend to get clogged with soot and some have noted a performance difference from cleaning the tube out. I've never had one clog, so I'm not sure if it makes any difference. It shouldn't have anything to do with your blue smoke problem though.

The EOT sensor is located on the back side of the HPOP rez. It doesn't have a tube or anything to get clogged.

Is the smoke issue your having just for the first minute or two after cold start up or is it all the time? Maybe it takes 5 minutes or so of driving to clear up?

Edit: I got out run on the key board. LOL

 

Thanks for the clarification. I was associating the 2 sensor incorrectly. Yes, it was the EBPV sensor tube I cleaned. I thought that aside from telling the EBPV when to open and close, it also works in conjuction with the MAP and EOT sensors to give the computer information that it uses for fueling? It seems to smoke at idle indefinitely and I can't see my exhaust going down the road because my exhaust is broken and it is dumping straight under the bed just before the axle. It seems like after driving it for a while, the smoke clears up. Also, if I start it up warm, after having driven it for a while, it won't smoke but, it if completely cools down and then I start it, it smokes. I will try the MAF tomorrow.

Related question: Even if the EOT sensor doesn't have to do with my issue, I am curious how it causes smoking? Thanks guys.

-Joseph

 

So far I don't have the smoking issue but I cleaned the tube out and didn't seem to make any difference.

 

It may indeed be your EOT sensor. But it has nothing to do with that tube. Best way to test the EOT sensor is to put a good scanner on the truck, one that's capable of reading our live data. AeroForce Scanguage, AutoEnginuity software, or Snap-On MT2500 with the right Ford diesel programming cards.

 

The reason the EOT sensor can cause smoking is this. The PCM (which controls engine fueling) uses the EOT sensor to determine the engine temperature. The PCM ignores the coolant temperature all together and uses EOT exclusively. When the engine is cold the PCM changes the injection timing and the High pressure oil pressure (also known as ICP -- Injection Control Pressure). This has a direct affect on the way the fuel is delivered into the cylinder. If the PCM doesn't know what the engine temperature is, it may be fueling incorrectly.....which in turn causes smoke.

 

You can check the EOT sensor, but I have the same issue and the only thing left that I can think to possibly be the problem on mine is valve seals or injectors. LOL

 

I will play with a the MAF and EOT sensors and hopefully one of them will be the culprit. If not, my injectors are new so that would only leave a more internal issue.

-Joseph

 

MAF sensor??? We don't have mass air flow sensors. You do have a MAP (Manifold Absolute Pressure) sensor though. LOL Hopefully yours is a sensor related issue, not a seal or injector or something.

 

First I refer to the EBPV sensor as the EOT sensor and now this..... I gotta quit workin so much.

-Joseph

 

Maybe just put the cork back into the bottle, JK, JK, JK!!! LOL

 

Cork? Screw-on cap, more likely....

 

Your right about that. I've always have liked the saying 'put a cork in it'. Two different meaning though.