Two questions fuel comp sensor and power steering.

[Chris2144]

Ok so hopefully we can knock out two birds with one stone. So the first I think I have figured out however I cannot verify because I don't have a scanner to monitor while I'm driving. I think the fuel composition sensor is going out. It gets really bad fuel mileage I've done all the normal things tb clean maf clean filter clean new plugs oil change fuel filter change it runs good just about 12 miles a gallon maybe 13 if it's all highway. I do not have any codes. Just wanted to know if any one else has had bad fuel milage because of this sensor. I think I'll be replacing it with the replicator as I don't ever use e85.

Second power steering is goofy. Sometime it is hard when I'm stopped then all the sudden is easy then other times hard all the sudden when I'm driving. Guess it likes to keep me on my toes lol. Anyway I know there is the electronically actuated orfice to control this can someone give me the part number to change to fixed one. And will there be a code thrown if I do that

 

[SnowDrifter]

For the fuel comp sensor, it should be largely irrelevant. You could use a scanner (try autozone, etc) to view your fuel trims and oxygen sensor activity. Fuel trims should be within +/- 10%. And oxygen sensor activity should bounce up and down between about 0.2 and 0.8v. They're narrow band, and really only provide a binary lean/rich indication respectively, with stoichiometry being around 0.45ish volts. Normal operation is a regular switch between lean and rich as the ECU teases it around an average equilibrium, with some rich tendancies normal under sharp changes in throttle input. If you find it tending high, say bouncing between 0.5 and 0.8-0.9v, then that would indicate you're running rich.

The sensor data you want to read is bank 1(driver), bank 2(passenger) sensor 1 for both. Sensor 2 would be post cat and serves only to verify catalytic converter operation for emissions.




For the power steering, usually those valves fail open - too much assist at speed. A good first pass would be to verify fluid level, condition, check for binding in the steering, check for belt slip, then remove the belt and verify end play + the pulley is tightly fit to the p/s pump shaft. I'm not sure if a failed variable assist valve would throw a code so I can't speak to that.

 

[HiHoeSilver]

Ok so hopefully we can knock out two birds with one stone. So the first I think I have figured out however I cannot verify because I don't have a scanner to monitor while I'm driving. I think the fuel composition sensor is going out. It gets really bad fuel mileage I've done all the normal things tb clean maf clean filter clean new plugs oil change fuel filter change it runs good just about 12 miles a gallon maybe 13 if it's all highway. I do not have any codes. Just wanted to know if any one else has had bad fuel milage because of this sensor. I think I'll be replacing it with the replicator as I don't ever use e85.

Second power steering is goofy. Sometime it is hard when I'm stopped then all the sudden is easy then other times hard all the sudden when I'm driving. Guess it likes to keep me on my toes lol. Anyway I know there is the electronically actuated orfice to control this can someone give me the part number to change to fixed one. And will there be a code thrown if I do that

What year/make/model is your truck? If you want to know if your sensor is wonky (if you even have one as opposed to the vffs), check the fuel comp% with a good scan tool. You can fill up with some good gas, then reset ir, drive a bit, and check it again to see what it's coming up with.

 

[Chris2144]

2002 Tahoe z71. It has the l59 or l33 I can't remember of the top of my head which one is which but it is def flex fuel. I don't have a scanner wish I did. I've been thinking about getting hp tuners and start tuning here and there but that's a different story. The local parts shops around here have the cheapo one that just tell you the code.

 

[Chris2144]

The belt is good replaced it not to long ago checked the tensioner it's good too. Ps pulley seems to be tight. I've read somewhere that its seems to be a common problem with the active assist one in particular changed the orfice valve out for a fixed one and never had another issue. Can't for the life of me find that now. I had the same problem years ago and changed the power steering pump. I left the orfice in the old one and just hooked everything else up and tied the plug up. Never had another issue. That was on an obs 97 though. This pump works just fine it seems like. It's full on fluid. No binding. Just when at very slow speeds like in a parking lot turning and every so often going around a slow corner. I remember there being some kind of tsb on this issue also but don't remember exactly what it described

 

[HiHoeSilver]

2002 Tahoe z71. It has the l59 or l33 I can't remember of the top of my head which one is which but it is def flex fuel. I don't have a scanner wish I did. I've been thinking about getting hp tuners and start tuning here and there but that's a different story. The local parts shops around here have the cheapo one that just tell you the code.

2002 should have the real sensor on the frame rail under the driver's door. The only way you're going to know I'd it's goofy is by reading the comp% with a capable scanner. Find a local shop. They should be willing to help you out. It will take them 30 seconds to read and reset. DO NOT reset it with e85 in the tank. You will need to fill up with gasoline.

 

[swathdiver]

2002 Tahoe z71. It has the l59 or l33

L59 "Z" unless someone swapped in a 2005-2006 L33.

 

[YukonXLMan]

I had the same issue regarding mpg on on a 2004 Yukon I owned. Out of desperation one day, I disconnected the batter for approx 30 minutes to see if I could reset something that might fix the issue. It worked! To this day have no idea what the issue was, but it's a low cost fix attempt. See if you can get the codes read first so you know what the system captured. if not, see if it helps. worst thing that can happen is the problem remains.

 

[HiHoeSilver]

L59 "Z" unless someone swapped in a 2005-2006 L33.

My 06 has l59. What's the difference, just aluminum vs cast? Which trucks got which?

 

[swathdiver]

My 06 has l59. What's the difference, just aluminum vs cast? Which trucks got which?

The L59 was available then too. The L33 was basically a Gen IV motor with Gen III parts, 310 HP, same camshaft grind as the later 2007-2009 LC9, LMG, LY5, which was a single pattern as they do not have VVT. The L33 also have the 243 heads.

 

[Tonyrodz]

2002 Tahoe z71. It has the l59 or l33 I can't remember of the top of my head which one is which but it is def flex fuel. I don't have a scanner wish I did. I've been thinking about getting hp tuners and start tuning here and there but that's a different story. The local parts shops around here have the cheapo one that just tell you the code.

I have a scanner that reads live data, you're more then welcome to use it. Hopefully I can learn something about it too. I know you're a little far from me. I'm in Keansburg 07734.

 

[Chris2144]

That would be a hell of a road trip lol. Thanks though. I'm sure I can find one of the local shops around here to scan it for me. I will let you know when I figure it out. I don't plan on replacing it as I never use e85. If I remember correctly it was like 4 hundred something dollars vs the 160 dollar plug in simulator.

I have a scanner that reads live data, you're more then welcome to use it. Hopefully I can learn something about it too. I know you're a little far from me. I'm in Keansburg 07734.

 

[Chris2144]

I had the same issue regarding mpg on on a 2004 Yukon I owned. Out of desperation one day, I disconnected the batter for approx 30 minutes to see if I could reset something that might fix the issue. It worked! To this day have no idea what the issue was, but it's a low cost fix attempt. See if you can get the codes read first so you know what the system captured. if not, see if it helps. worst thing that can happen is the problem remains.

Yea I'd like to actually see what it's doing that way I can post back with the results. My 99 sbec Silverado got way better mpg than this it was not the l59 this one is. It's not throwing any codes and runs good so I'm assuming its think it has e85 or at least a mixture of it and it's running richer according to that which in turn drops mpg.

 

[Tonyrodz]

That would be a hell of a road trip lol. Thanks though. I'm sure I can find one of the local shops around here to scan it for me. I will let you know when I figure it out. I don't plan on replacing it as I never use e85. If I remember correctly it was like 4 hundred something dollars vs the 160 dollar plug in simulator.

Lol, sorry thought you lived in NJ.

 

[HiHoeSilver]

Yea I'd like to actually see what it's doing that way I can post back with the results. My 99 sbec Silverado got way better mpg than this it was not the l59 this one is. It's not throwing any codes and runs good so I'm assuming its think it has e85 or at least a mixture of it and it's running richer according to that which in turn drops mpg.

This happened to mine, although I have the vffs, not the hard sensor. Somehow in a refueling event it landed at 30% with e85 in the tank and threw lean codes until I ran through the tank, filled up with gas and reset the comp %.

 

[Fless]

Lol, sorry thought you lived in NJ.

I'd be sorry, too, if I lived in NJ. LOL

 

[Tonyrodz]

I'd be sorry, too, if I lived in NJ. LOL

Ooooo, thems fightin' words!

 

[HiHoeSilver]

I'd be sorry, too, if I lived in NJ. LOL