2006 GX470 Sport - from Chicago

[Rednexus]

No visible issues with my connectors.

If you can't take the rig off the road, I'd just get a set of Dirty Deeds 12 holes. They are reconditioned OEM Denso injectors and are legit. I tried some eBay remans before that and I'm pretty sure they were counterfeit.

 

[CarGuyCarl]

Good news: the proxy pack got rid of P0148 code AND the factory O2s were very easy to remove.
Bad news: I goofed and ordered downstream ones instead of upstream. Man are they pricy lol
If the O2s don't do it then I'll rebuild the MAF connector, then injectors. Then fuel pressure test?
Hoping the O2s do the trick.

 

[CarGuyCarl]

New O2s gave me a ray of hope. Was running great for a bit. And then all problems returned, along with weird gear shifting behavior, holding gears, etc.

Unplugging and replugging the MAF whether through the Hewitt bypass or direct, sometimes made it run okay. But not consistently. Sometimes MAF reads around 10g/s other times it reads 5g/s. Honestly not sure what to look at next. Will post the data here in a bit.

 

[Rednexus]

Mine had very similar behavior. At idle (no AC on) it should read around 4 to 4.8 g/sec. If it is jumping all over the place it's likely you have a problem with the MAF or the MAF connector.

 

[CarGuyCarl]

 

[CarGuyCarl]

The two data sets above are like 1 minute apart and all I did was disconnect and reconnect the MAF. I can’t replicate it every time. And sometimes while it’s running rich it’ll start to run normal and vice versa. Very odd.

 

[Rednexus]

I'm pretty sure that's a MAF issue., If you notice on the first screen shot, you are at idle and a MAF reading of 4.7 g/sec, which is very normal and within spec. Your combined fuel trims are about +15%, which indicates the computer is having to add fuel to reach the designated air fuel ratio.

On the 2nd screen shot, your MAF reading then jumps to 6.9 g/sec, which is nearly 50% higher despite a 100 or so RPM increase. Your combined fuel trims then go to around -3%, indicating that the computer is having to pull fuel to reach the designated air fuel ratio. This is probably happening due to the MAF reading more air that is actually coming in - so the computer thinks is needs more fuel - but the O2 sensors then tell it to back off the fuel.

Either way, you have some really weird fuel trims going on. Long-terms are around -5% in the first one and -20% in the second one, which indicates your computer is always having to pull fuel. They should be pretty close to zero. I'm not sure if that is related to your MAF issue or something else causing it to run very rich (like a fuel injector).

I'd suggest adding the new MAF connector, re-setting the ECM learned values (either via Techstream, if it can do that, or by unplugging the battery for 10-15 minutes), and seeing how it runs. If it's still running super-rich with those negative fuel trims, you probably have another problem causing that - whether an injector or something else.

 

[CarGuyCarl]

Thanks for all your help. Will give that a shot.

Wanna note for future readers, I’ve swapped between the original MAF and a new Hitachi MAF with no changes

Checked over the EGR block off plates that are a part of the SAIS bypass. They’re still tight and still fully inserted.

 

[VSPro9]

If you want some banger campsites east of the key lmk

 

[CarGuyCarl]

If you want some banger campsites east of the key lmk

Heck yeah I'll take em. Not sure when I'll be going out that way again. Was gonna do it in Fall but lots of family events have popped up.

And this whole rich code debacle.

 

[CarGuyCarl]

New MAF connector installed. Also really cleaned up the air box. Noticed the air filter gasket was pinched. Idk if enough to affect anything but did my best to spruce it up and may grab a new filter. Truck is running and driving great now. Although, I’ve only idled it for maybe 15 mins and did a 15 min drive. But MAF numbers look good and it doesn’t have any weird shifting behavior. Will post a screen grab of the numbers I’m seeing now shortly.

 

[CarGuyCarl]

After 15 mins of idle and a quick 10-15 minute drive 0-50ish mph. No more gas smell from the exhaust.

 

[Rednexus]

Great news! Seems to becoming a common issue with these rigs.

 

[CarGuyCarl]

Yes! Thanks as always for your suggestions. Should have attempted this sooner but I can't be mad at new O2 sensors either. Hopefully it holds up.

Given that I used to have an intake and I was getting lean codes from that or something else, there was a lot of MAF plugging and unplugging going on. Maybe that contributed to the situation.

 

[Rednexus]

My MAF problems also showed up after adding an aFe CAI. After replacing the connector and addressing vacuum leaks, it's been fine for a few years.

So it definitely seems just unplugging the MAF can break the connector.

 

[HomersCanyonero]

My MAF problems also showed up after adding an aFe CAI. After replacing the connector and addressing vacuum leaks, it's been fine for a few years.

So it definitely seems just unplugging the MAF can break the connector.

Good reading…about 3 years ago I had issues with my cats, O2s, MAF.

I cleaned my MAF like 3 times during that time and I’m glad I didn’t break the connector. I didn’t know it was that fragile.

I ended up replacing all 4 O2 sensors and both integrated cat exhaust manifolds to get rid of my P0420/P0430 and other codes P0171.

I’m in Calif and I needed to pass smog for many years to come, so I ended up fixing it with oem parts.

 

[Rednexus]

My MAF connector showed no outward signs of problems and still "felt" just fine when it clicked onto the MAF. It must have been a loose pin, poor crimp, or corrosion inside the connector. Perhaps de-pinning it and putting new pins on the factor wiring could have worked, put a new MAF pigtail was easy enough to splice in.

I've also had the same problem with the engine coolant temp sensor. No outward signs of a problem but it had a really bad connection. Actual sensor connectors that I have physically broken include one of the knock sensor plugs and several fuel injector connectors (which oddly enough, use the same type of plug!). Replacement connectors are pretty easy to find online.

 

[CarGuyCarl]

My connector was the same. Visually okay. Honestly felt just as tight on the MAF as the new connector does.

Changed the oil today as a precaution. It didn't necessarily smell more of fuel than the S2000, but I felt I might as well. Driven about 100 miles now since the connector was installed on Saturday and it runs great with no issues. Knock on wood, but I might call this one resolved!

 

[CarGuyCarl]

Happy Saturday! Truck continues to run well, probably driven over 1500 miles now. Got my refund for the downstream O2 sensors I accidentally ordered.

Might be taking the ole girl down to the smoky mountains again in October so that's exciting. Car camping and light trails.

Also been thinking about retiring her from daily use, getting into either a CT200h or ES300h. If that happens I can really start attacking all the small issues and original parts from LCAs, UCAs, tie rods, rear control arms, maybe some frame work.

With how expensive dashes have gotten I think that money would be much better served towards maintenance. Saw someone do a pretty good job in GXOR on FB with just wrapping the old dash. Might try that since removal of just the dash pad is very easy.

 

[Rednexus]

If you watch sales, you might be able to find a OEM dash for a decent price. Got mine for $600 from Lexus of Mobile and picked it up when we went to Gulf Shores for Spring Break last year. There were $800-900 at local dealers, which is just too much for an older rig.