Poor Gas Milage, occasional erratic idle.. Now SES light

[LukeZ34]

Ok, I've got the rubber oil return hose off, and it looks like it's perfect. It's stiff, no soft spots, and it's not plugged at all.. I'm gonna see if I can get to the knock sensor now..

[turby]

Does the oil hose look like it's wrapped with tape and orange inside? If it does it is original. Replace it anyway.

[LukeZ34]

Nope.. it doesn't look orange inside at all..

Advance auto wanted $40 for the knock sensor, and I found it on the car, I just don't trust the $15 jack I bought from walmart a while ago.. cheap thing can't even lift the car up all the way  :evil: .

I'm putting things back together right now.. and I was thinking, would it be possible to remove the cruise control module and not have any ill side effects? There isn't a criuse control cable hooked up to the vacuum module at all, so I figured I could probably remove it. Would the 2 vacuum lines just have to be plugged together to maintain vacuum?

[turby]

The hose was replaced then and should be ok.

[waskie]

I replaced it at about.....88K, give or take a few K.

[Jeff M]

Got a brief break here, not much, been a little busy, just wired funds to couple of banks, got insurance, faxed titles, got loans set etc and bought 2 cars today (I will be nice and NOT say what they are), order total engine rebuild kit, made up and shipped out a pipe package, mowed the lawn, did the shopping, did a few emails, refinanced the house, and that was just today, last few days were about as busy, add that I get an average of 350 TGP emails a month with a lot of pipe and/or chip orders and more, its intense most the time here.  But nuff about me!!!  Luke, a code 43 can be caused by an engine noise/knock, and when the computer hears an engine noise/knock often enough (does not have to knock all the time) it will flat out take off 7 degrees of timing at all times.  This will also make the o2 cross-counts at idle appear worse causing the idle problem you described (there is some puffing as the o2 swings from rich to lean in closed loop).  And since you are 7 degrees of timing less, your power and gas mileage will suffer as well, and 7 degrees less timing will have you running richer, out the back as well, BUT WOT in a turbo car IS rich to be on the safe side and to also use the cooling effect of the extra fuel in absorbing the heat from forced induction, using the latent heat of evaporization like when we sweat.  The turbo oil drain line will not effect engine running, if the drain line was bad it would puff smoke after a long idle, short idle if its really bad, and bad as in look down the inside of the drain pipe for buckling out of the clear liner, they all do it so it?s a good idea to just replace it while you have it off.  If this car is the one Kenny owned then I think he already did the crank position sensor, Waskie did the knock and they are not something that fails very often at all.  A TGP turbo with a K&N air filter is going to woosh pretty loud, I would check the free play first to make sure the compressor wheel it not making contact with the compressor housing, just pop off the air filter and with your fingers grasp the compressor wheel end nut, lift up and down and turn it some to see if you can feel it hang or hear it hit/scraping the housing, also turn it while pulling the nut out, if it does make contact then the bearings are bad, this happens when the oil gets coked from not being cooled down after a hard pull, and shut off too soon.  The coked up oil will restrict proper oil lubrication.  I will swear by these little T-25 turbos as I know a lot of owners with 150K, 180K up to 260K miles on the original turbo, even a few when installing my pipe have sent their turbos in for a rebuild long as it was off, but with 150+K miles the rebuild shops (that were honest) said their turbos were in excellent shape and would last another 100K miles.  The horror stories are not true any more about turbos being such a problem, if they are just treated to proper care, it is common now and has been for a while for turbos to outlast the engine!!  

Well, this is the only post I have done in about a month and that is all I got time for, need to find some plane flights to get one of these cars I snagged.  I think I have covered about everything with your engine, so good luck!!

Jeff M

[LukeZ34]

Thanks for everyone's input!

I replaced the knock sensor the other day, and checked the PCV valve as well. The PCV valve was absolutly fine, in fact, it looked almost brand new, and rattled like it should. The knock sensor, I have no idea when it was last replaced, but it made a big difference in the performance of the car. (in a good way)

I also removed all the stock intake setup that was still in the car. I used the stock hose that went from the turbo to the intake box and attached the K&N filter to it, and then shoved it down right in front of the intercooler. With the AC fins removed, the fan moves quite a lot of cold air through the IC, so the filter also catches most of that now as well. I can actually HEAR the turbo spooling now, and it's an awesome sound! I also noticed a performance gain from this as well. My cutouts at WOT are almost gone (knock sensor may have contributed to that), and the car pulls like a raped ape in all gears now!

Next on my list of things to do is to either gut the cat, or replace it, Accel LT1 injectors (6 of em), new O2 sensor, crank sensor (just to be safe), and moving the battery to the trunk and creating a fenderwell CAI.
I got a nice raise at work too, so I hope to get her running good before the W-Body Gathering!

[jheiv]

Hey luke, I was having about the same problems as you described earlier, what do you think it was that caused it (and fixed it) thanks.