I have the motor listed in sig. I have a problem that has been very frustraing.

At idle the right o2 will throw a code MALF 64: Right O2 Lean.

I have replaced both O2's to rule that out. I had brand new Denso's at first. Now running brand new Bosch's. Both have done this from the start ( as soon as I put them in. ) If i even give it a slight rev the problem will go away. I have a data log from data master if anyone is interested in looking at it and helping me. There are no exhaust leaks before the O2.

I am thinking maybe its something with the injectors but have no idea. I am not sure if this is hurting my motor or not and really wanna get this problem taken care of. I have ruled out all I knew, searched the board and just dont really know what to do.

Again this is only @ idle. Once the car starts to move or rev the blm's start to level back out. and everything looks all cosher.

PLEASE HELP !!!

Mike

Datamaster log

 

The best advice is to have the car dyno tuned with a wideband O2 sensor. A temporary fix would be to bump up the fuel pressure. By the way, most people on this board have had the best success with AC Delco O2 sensors.

 

Thanks foremost for your response.

I have tried raising the fuel pressure to no avail. Ran injector cleaner threw car to see if maybe had a dirty injector. I just dont know what would affect only one bank. It has been mail order tuned by mad wolf. Can one bank be that far off from the other?

Its so weird @ idle is the only place the right O2 just kinda sets there. give it a little gas (lets say 2,000 rpm's) and its off an running and acting just as it should. If its tunning I can send Ion maybe a datamaster file and he can tune it out?

Again I really appreciate your response. All help is definately appreciated. Just getting agravated want to get this thing sorted out so I can start enjoying it.

Mike

 

Sounds like infamous BLM split caused by a large cam, aftermarket throttle body, exhaust leaks and possibly combinations of them all looking at your mods. Ill take a look at the datamaster logs if you email them to me. I assume the Lterms look something like in the range of 108-128 on the left and pegged at 160 on the right. Is the right O2 stuck down in the .000-.100 range? You can always richen up the idle but the problem you start to get into is too much fuel on the left bank to keep the computer happy with the right bank.

 

Why don't you swap the left and right injectors? While your there, just for laughs, power up the pump using the fuel pump prime connector with the injectors sticking up out of the intake manifold right before you swap them. See if any on the left side are dripping. It would interesting to see if the problem stays on the right side or moves with the injectors.

 

TurboZ, You hit it on the nail. Thats exactly what I am dealing with.

Lterm look more or less around 140 on left and pegged on the right side. Is that BLM split problem only common @idle?

Cam isnt very large. We'll compared to some that is. Little larger than 306 but has a tight lobe seperation. I wonder if thats is alot of the problem.

I will email you the datamaster log, I will send you one of a short drive and one @ idle, just to see if you can see anything going on during driving that may be causing it. I cant thank you enough for taking the time to do this.

Sloporodrigez,
Thanks for your response as well. That is actually something we are going to try. One of my friends suggested that as well. Definately is one way to rule out injectors.

Thanks,
Mike

 

Switched injectors, from left side to right side. No luck. Problem still persist. I am out of idea's. I am looking for any advice on this, as im sure there are others that have dealt with this. (or atleast I hope so) What could cause it to only affect the left bank and only @ idle.

I have turned up idle @ 1000 and seems to help some I dont get a code but the blms on the left side go through the roof @ idle only. I can give it enough rpm's 1,200 and it levels off. I just have no idea what to do here. HELP!! PLEASE!!

Mike

 

My car has done the same thing since the I had the motor rebuilt 2 yrs ago. I have been though 3 different .lt1 programs, 2 mailorders and 1 dyno tune. I am positive its a "fake" lean condition. I just pulled all my plugs yesterday and they all look exactly the same: about a 7.5 on a scale of 1-10, 10 being completely fouled black. I wouldn't worry about it. You will drive yourself crazy trying to correct it. Its just the big cam causing it, I believe its called cam reversion.

BTW- I run a CC306