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AxleIke
06-04-2012, 11:49 AM
Hey guys,

I have an issue right now with Baby Beast II. Quick specs on the truck:

218k miles, 3.4L, stock exhaust, gen 1 (grey) supercharger with stock pulley.

The SC was installed 2 months ago, and everything was hunky dory for a month.

Now, I am having a very strange CEL, P0171, System too Lean (bank 1), which I will explain. I have an OBDII scanner, so on my trip last week (I'll post some trip photos soon) I was able to narrow down the symptoms leading to the CEL.

The CEL comes on ONLY after running for a bit, and then stopping for more than a few seconds, say at a long traffic light, or stopping on the side of the road to take a picture or read a map. It ONLY comes on at idle, not under any load.

Originally, I thought this was an issue of the fuel system not being able to keep up with the SC, but that would only occur at WOT, not at idle.

UB suggested the O2 sensors going funky, but unfortunately, my scanner (at this point) doesn't read the sensors, only the CEL codes. I'm looking into whether or not I can upgrade. However, online, the other symptoms are the MAF, or a vacuum leak. I've checked the vacuum.

I need to get info on the sensors coming in, obviously, but for those guru's out there, can anyone think of any other things I can check into?

The code doesn't send the truck into limp, so performance isn't affected, but emissions will be a problem, as well as the fact that I personally cannot stand anything to be broken on my trucks.

Thanks!

Red_Chili
06-04-2012, 12:17 PM
Check to see if your TB gasket is backwards. DAMHIK. I would think you would notice crappy running though, so that is doubtful but possible.
Do you also have a fuel smell in the cab?
I had to add a hose clamp to the evap line next to the brake vacuum line, and even put in a check valve inline. Not sure the check valve is needed... but the hose clamp certainly was. Check valve couldn't hurt.
Old O2 sensors put a variable in the pot that is hard to account for... ND or Toyota only if you choose to replace.

thefatkid
06-04-2012, 12:19 PM
Hey guys,

I have an issue right now with Baby Beast II. Quick specs on the truck:

218k miles, 3.4L, stock exhaust, gen 1 (grey) supercharger with stock pulley.

The SC was installed 2 months ago, and everything was hunky dory for a month.

Now, I am having a very strange CEL, P0171, System too Lean (bank 1), which I will explain. I have an OBDII scanner, so on my trip last week (I'll post some trip photos soon) I was able to narrow down the symptoms leading to the CEL.

The CEL comes on ONLY after running for a bit, and then stopping for more than a few seconds, say at a long traffic light, or stopping on the side of the road to take a picture or read a map. It ONLY comes on at idle, not under any load.

Originally, I thought this was an issue of the fuel system not being able to keep up with the SC, but that would only occur at WOT, not at idle.

UB suggested the O2 sensors going funky, but unfortunately, my scanner (at this point) doesn't read the sensors, only the CEL codes. I'm looking into whether or not I can upgrade. However, online, the other symptoms are the MAF, or a vacuum leak. I've checked the vacuum.

I need to get info on the sensors coming in, obviously, but for those guru's out there, can anyone think of any other things I can check into?

The code doesn't send the truck into limp, so performance isn't affected, but emissions will be a problem, as well as the fact that I personally cannot stand anything to be broken on my trucks.

Thanks!

Clean the airflow meter. Make sure to clean the hot wires "inside" the sensor. Electrical parts cleaner only as most others leave residue.

rover67
06-04-2012, 01:20 PM
Clean the airflow meter. Make sure to clean the hot wires "inside" the sensor. Electrical parts cleaner only as most others leave residue.

Great suggestion. usually NAPA carries the CRC brand cleaner specifically for MAF Sensors. Use that as suggested above.

Does it have a K&N filter that may have too much oil on it? that can also contaminate the MAF sensor.

Other than that it could be something like an exhaust leak upstream of the o2.. but those have to get pretty bad for crap to go wonkey.. you'd probably hear it.

thefatkid
06-04-2012, 01:28 PM
Usually the oxygen sensor monitors are tight enough that they will catch a faulty o2 prior to setting a p0171. This only goes for 96-2002 4runners.

If cleaning the airflow meter doesn't work, check fuel pressure. You should not see a drop under load and a starting pressure around 38psi. Next, check the supercharger bypass pipe (1st gen charger only). The o-ring gets dry in that pipe and cause an air leak. Your Data list for the code should tell you what direction to go, lean idle=air pipe, lean heavy cruise=fuel pump.

AxleIke
06-04-2012, 02:26 PM
Thanks all, I will check those.

Brian, the fact that it throws the code at idle only tells me it could be the air pipe. I am not sure where that is though?

The PO put a KN filter in, which I removed immediately upon purchasing the truck. I will try an clean out the MAF.

Bill, I don't know what sort of smell I have, but I certainly have something. However, it is not just my runner. My dad's runner (97) has the same thing, and it is there pre and post SC. Sort of a strong oil smell. Doesn't smell like gas. I don't think its related, but could be.

thefatkid
06-04-2012, 06:51 PM
Remember that the light only turning on at idle. The fault could have set while on the throttle earlier. The light and a "logic" code have no relation to when the problem occured, only when the ECU determined that it was out of range. If it was a hard fault (open electrical circuit) the light would be indicator of actual fault time.

If you get time bring it by the dealer so I can check the datalist.

4runner luv
06-04-2012, 07:11 PM
Probably not what you got going on, but I was reading a build thread just last night that had the same code coming from a supercharged 3.4

http://www.tacomaworld.com/forum/1st-gen-builds/138220-jasons-long-travel-toy-taco-4.html

AxleIke
06-04-2012, 09:53 PM
Cool Brian,

Thanks 4Runner Luv, unfortunately, that is one of the first things I checked. However, I did the SC plumbing from memory and some very vague diagrams on the net. So, it could be totally wrong.

Also, it seems I may need a Hood scoop. The SC and throttle cable hit the hood. Only noticed it after a lot of bumpy roads. Bummer.

corsair23
06-05-2012, 10:18 AM
Clean the airflow meter. Make sure to clean the hot wires "inside" the sensor. Electrical parts cleaner only as most others leave residue.

x2

That is what was causing the code on my '97 FZJ80 with the MAF Mod and later year MAF.

We chased a bunch of stuff including installing new O2 sensors. CEL would come on ONLY at idle and fuel trims were fine at all other times. Even just having the AC on with the resultant bump in idle was enough to keep the CEL from coming on at idle.

Get some MAF cleaner and I'd be willing to bet that in less than a 1/2 hour your problem will be resolved :thumb:

Red_Chili
06-05-2012, 10:44 AM
Also, it seems I may need a Hood scoop. The SC and throttle cable hit the hood. Only noticed it after a lot of bumpy roads. Bummer.
Trim the braces. You should be good. Or a 1" BL gives many forms of unanticipated goodness.

AxleIke
06-06-2012, 10:49 AM
I cleaned the air flow sensor with CRC electronic cleaner, the no residue stuff. Hopefully that works.

corsair23
06-06-2012, 11:49 AM
I cleaned the air flow sensor with CRC electronic cleaner, the no residue stuff. Hopefully that works.

Did it look dirty? I could visually tell on mine right away that it was dirty. Hopefully that does the trick because we all like quick and easy fixes :thumb:

AxleIke
06-06-2012, 02:03 PM
It looked like it has some stuff on it. I hope the cleaning took care of it. I wasn't sure if I should touch it or not, so I just blasted it really well with the cleaner, and let it evaporate. I also cleaned out the tube and air box a bit.

AxleIke
06-09-2012, 02:57 PM
That wasn't it. I havent driven the truck all week (don't usually commute with it), so today after detailing it, and taking it to the car wash, I drove around town a bit. As before, stopping for about 30 seconds caused the light to kick on.

I'll try to swing down and see Brian at somepoint this next week.

corsair23
06-11-2012, 02:30 PM
Bummer :(

AxleIke
06-11-2012, 06:04 PM
Looks like Brian found it today.

I used regular old vacuum hose from O-Reily Auto to make all my vacuum connections. That is fine for everything except the PCV system. That hose is not rated for oil, and had "ballooned". Basically, it was no longer making a seal on the PCV valve.

In addition, after clamping down the hose (just a temporary fix, I already have replacement fuel line for the PCV system), the hose started to collapse on itself, which means its likely got a bad PCV as well. So, I picked up a new one upon further consideration, and am going to install both.

The issue was found through Brian's uber sweet computer OBDII stuff, and he read the long term fuel trim at 42%, and short term at 26%. The long term should be no higher than 10%, with not much going on in short term.

Closing the leak down with my fingers, Brian was able to see the LT fall into the teens, and shortterm go negative, which was good.

In addition, I never installed the IAC check valve, which is a must have, so I'm hunting those down. I found the part number, but its an old one, so the good gentlemen at Boulder Toyota are tracking down the new part number, and I should be good to go.

Just adding zip ties to the PCV connection kept the light off all afternoon driving around with plenty of idle time. I'm excited that this looks like a 20 dollar fix.

I'll update in a while after the repairs are made.

rover67
06-12-2012, 12:37 AM
NICE!

So it was a vacuum leak basically?

Glad you guys got it sorted. Could have been a lot more tail chasing than that.

Jacket
06-12-2012, 09:52 AM
Great news! And so nice to have a guy like Brian out there willing to help.

Red_Chili
06-12-2012, 10:19 AM
Sounds identical to the issue I had with the fuel smell in the cab. Same cause, same fix. I also used an IAC check valve inline with the fuel canister, you might think about that to prevent pressurizing the evap system. Put a hose clamp on the evap line where it attaches to the blower (right next to the brake vacuum line, which not coincidentally has a clamp and check valve as well!).

thefatkid
06-12-2012, 10:58 AM
Bill, if your evap system is getting pressure from supercharger boost you have it routed wrong. Evap sould be going to a vacuum source behind the throttle plate but before the charger impellers.

AxleIke
06-12-2012, 10:58 AM
Bill, mine doesn't have that second port (first gen blower). The brake booster, evap, and diff vsvs are all t'd together and have hose clamps on them.

Marco, yes it was a vacuum leak, but caused by the hose ballooning up, and thus why I had no trouble for a while.

Red_Chili
06-12-2012, 11:10 AM
Bill, if your evap system is getting pressure from supercharger boost you have it routed wrong. Evap sould be going to a vacuum source behind the throttle plate but before the charger impellers.
I actually don't know if it is or isn't. But I DO know that a new hose and hose clamp stopped the fuel smell in the cab. The IAC check valve was just something I threw in for guesstatroubleshooting, and since the brake booster had one I figgered it couldn't hurt. So far so good. The evap is routed per the hose diagram, to go right next to the brake booster hose.

AxleIke
06-12-2012, 12:11 PM
Great news! And so nice to have a guy like Brian out there willing to help.

Yes. Brian is a godsend. I owe him a couple of six packs.