SC99RUNNER

Hi, I'm new to the forum and have been have been reading and searching for some time trying to find a fix for my 4Runner.I bought the 4Runner almost 3 years ago and it had already had the supercharger installed on it. Truck has upgraded fuel system to fix the lean running condition and was dyno tuned. I have put about 30k miles on it since I bought it and haven't had any running issues until recently. The truck started hesitating and loading up. Then the check engin light came on. I borrowed a friends obdII scanner and it read "engine too lean bank 1 sensor 1". I did a lot of searching and found that most people fix the problem by cleaning the MAF sensor, but that didn't solve my problem. I then replaced the MAF with a new one just to see if that would do it, but no go. I also replace the o2 sensor in front of the cat and that didn't fix the problem. Then one of my friends that builds a lot of turboed nissan 240s told me that it sounded like I had an air leak and should pressure test my intake. Well we did that and found out that my injector o-rings were leaking. I replaced them and it didn't fix it. So I pressure tested it again and the injector o-rings are still leaking. I aslo smoke tested the intake with the supercharger off and smoke clearly came from around all the injectors. Is this definately my problem? How do I stop the leaks? I have new o-rings. And will an exhaust leak behind behind the first o2 sensor cause the sensor to read lean. I just need some input because I have been at this for a while and I'm just ready to sell it. I will post some pics tomorrow of my 4Runner and setup.

vital22re

iTrader: (2)

what are your fuel upgrades? Have you checked your fuel pressure? when was the fuel filter replaced? when were the injectors cleaned professionaly?

SC99RUNNER

All I know is that it has bigger supra injectors, and I think it has a bigger pump. There has only been about 40k miles put on the injectors since the everything was installed. How often would they need to be professionally cleaned? I do not know what the fuel pressure is. I will have to get a guage to install. I have not changed the fuel filter either, but I want to get my injectors sealing first while I have the supercharger off. What do you think I should do about the injectors sealing? I just installed new o-rings.

jdmaccord6

I had the same problems with my supra injectors on my truck. I have since switched back to the stock injectors but I would like to tackle it again before the summer here. Did you use any kind of sealant with the o-rings to make sure there are no "leaks"? Did you just throw on the new o-rings and it works like a charm now?

SC99RUNNER

When pressure testing the intake am I supposed to block off the IAC valve hose. That's where the air is leaking from. I found out that the vaccum hose coming off of the IAC valve splits at a tee and attaches to 2 nipples on the back of the intake manifold. Whats wierd is that those 2 passage ways lead to all six injector ports, but above where the injector o-rings actually seal to the intake. So what is happening when I pressurize the system is that the air is flowing through the IAC vaccum hose and leaking out around all six injectors. This doesn't seem right at all. Can someone exlplain this too me?

I will take some pics this evening to show what I'm talking about.

In my original post I stated that I had replaced the o2 sensor in front of the cat. I replaced it with a bosh one from autozone. The reason I am bringing this up is because I read another thread that said do not use aftermarket o2 sensors, only oem. Could this be the issue.

The truck will run fine, but under load it will go crazy rich and black smoke will come from the exhaust. And if it idles for a while, like at a stoplight the truck will progressively get richer and richer until the idle quality is poor and drops in rpms. I have had it cut off at a stoplight due to this.

I also checked the plugs and they looked fine, not showing any signs of running lean. I also checked the voltages on my tps and the gm 2 bar map sensor that was installed with the sc. There is also a urd box mounted on the firewall. I think that its a maf sensor calibrater. It is also tied into the gm 2 bar map sensor. It also has a safc mounted on the steering column.

I'm also going to get a fuel pressure gauge and install it.
I will take some pics this evening of everything and post them.

jdmaccord6

have you made sure all the vacuum hoses have been connected to the proper location? I switched up 2 hoses on mine by mistake when I first installed the blower and I had similar issues with black smoke and sporadic rough idling.

SC99RUNNER

Yeah, everything has been the same since the dyno tune. Now that I know that I don't have an air leak, it has to be a sensor. I'm still going to check the fuel pressure and change the filter, but I beleive that it has to be a sensor making false readings. I can reset the computer and the truck will run fine, but the longer it runs the worse it gets and then the check engine light comes on.

Oh and one time the engine light came on and after running for a while the light cut back off.

vital22re

iTrader: (2)

DO NOT USE ANYTHING OTHER THAN OEM FOR TOYOTA!!! LEAVE BOSCH TO THE GERMANS!
My experience is that bosch is not anything more than a problem maker for the toyota fuel injection.
Also.. another member had a bunch of crappy after market controllers for his sc and 315cc injectors and his would go super rich up steep grades then actually stall on him after. So we gutted it all out and ran some new stuff from urd to control the bigger injectors and his runner runs awesome now but just leans out at 5k.... A.wilson i believe is the user. maybe the tune has gone bad and it needs to be retuned.

SC99RUNNER

What will make a tune go bad?

Texas_Ace

What are you using for tuning? I am not a fan of running larger injectors with a piggyback personally unless it is a good piggyback like the Emanage ultimate.

I just re-sealed my injectors as well, first i would really think about going back to the stock injectors as they are heard enough to seal. I ended up having ot add an extra o-ring under the isolator to get them to seal.