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Discussion Starter #1
Ever since I started the truck up back in Sept with the new motor, Ive noticed that the WBC that I have in the driver side reads a full 1.0 leaner than the XFI O2 sensor in the passenger side at IDLE. *I have a 218/228-114 cam in the truck and the guy that built the motor said the lump (or what I think now is a lean miss or too lean than the truck likes) is totally normal. *Now I dont doubt his motor building skills but after me doing all of the work on the dyno because he didnt seem to know what he was doing with XFI im doubting that its just lump. *

Main reason is, when I rev the truck and try to hold it at say 3000RPM, the WBC goes even leaner than the 1.0 at idle, up to 2.5 leaner (as much as 17.0), which in turn makes the truck run like dog crap. *My question is then, what could be causing this? *Im really thinking that I may have an injector having a hard time at LOW PWidth on the driver side. *Reason is, at cruise, or closer to WOT, everything seems better and the truck runs great. *I dont think that its anything to do with how my fuel lines are run... from the 110FI malory pump, it comes up to the pass side, to a T at the front of the rail. *From the point it crosses over to the driver side, through both rails then up to the reg, which then bypasses and dumps back to the tanks.... PICS are below. *I really need to get this figured out, I need to lean out to about 13.5 to get through emissions but I cant cause that compounds the problem on the driver side of course. *Thanks guys!!!

I have 65# injectors, box says Precision Turbo. *The WBC AF readings were verified by an Inovative Motorsports WB from work... they were identical.





 

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Is the EV carb hat divided or undivided?
 

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Discussion Starter #5
random questions...

where is your wastegate?

does this have twins?
rear mount turbo, perfect location, parellel to the pipe at the 90 bend to the turbo.

just a single tc76
 

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Discussion Starter #6

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Undivided, twin 52mm holley TB underneath.

Truck made 537/606 on 9#, 22* timing.
Could be the clocking of the carb hat on the two holer. Can you run some tubing and reclock the bonnet to 6 or 12?
 

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Take your O2 sensors and measurement equipment and swap them from side to side and see if your problem follows. I suspect a sensor is dirty.
If not look at your EGT's on each cylinder. That will tell you all you need to know about the combustion in the chamber.
 

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Discussion Starter #11
Could be the clocking of the carb hat on the two holer. Can you run some tubing and reclock the bonnet to 6 or 12?
Not gonna happen, cant situate it like that at all.
 

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Discussion Starter #12
Take your O2 sensors and measurement equipment and swap them from side to side and see if your problem follows. I suspect a sensor is dirty.
If not look at your EGT's on each cylinder. That will tell you all you need to know about the combustion in the chamber.
The Dynojet WBC installed in the truck was reading lean. I brought home from work a Inovative Motorsports wideband, removed the WBC sensor and installed the Inovate sensor, got the same readings.
 

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Discussion Starter #13

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Not gonna happen, cant situate it like that at all.
The undivided Bonnet will have the most pressure against the longest radius and is most likely creating the distribution issue. Since you can not reorient the carb hat, I would replace the undivided with a divided carb hat. Maybe someone would want to trade....

Of course this is dependent upon the location of the t/b blades in relation to the divider in the bonnet. A four bbl t/b may help but it would need the divided bonnet also.
 

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This would little to no affect under vacuum, ie; at idle. He is experiencing the problem at idle, and light load. He may have the same issue under load, but did not say.

The undivided Bonnet will have the most pressure against the longest radius and is most likely creating the distribution issue. Since you can not reorient the carb hat, I would replace the undivided with a divided carb hat. Maybe someone would want to trade....

Of course this is dependent upon the location of the t/b blades in relation to the divider in the bonnet. A four bbl t/b may help but it would need the divided bonnet also.
You need to pull the plugs. The problem with 02 is you get a mixture of 4 cylinders in this case. It sounds to me like you may have a dead hole for one reason or another. Bad injector, bad coil (if COP), bad wire etc. With one dead hole, you will get a lean reading on your 02 because there is 1/4 of the ox not being burned at all. Figure out which hole it is then track down why it is dead.

Another thing is a weak or dead driver. Is this thing run in batch fire or sequential?
 

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Discussion Starter #16
This would little to no affect under vacuum, ie; at idle. He is experiencing the problem at idle, and light load. He may have the same issue under load, but did not say.



You need to pull the plugs. The problem with 02 is you get a mixture of 4 cylinders in this case. It sounds to me like you may have a dead hole for one reason or another. Bad injector, bad coil (if COP), bad wire etc. With one dead hole, you will get a lean reading on your 02 because there is 1/4 of the ox not being burned at all. Figure out which hole it is then track down why it is dead.

Another thing is a weak or dead driver. Is this thing run in batch fire or sequential?

This is my feeling on the distribution too, in vac it shouldnt matter. Plus, after thinking about it for some time, the IAC is where the motor is getting its air from anyway at idle, which is located at the 12 oclock position so that theory really wouldnt work...

BUT, I took a pic of my plugs... didnt like what I saw. Im not driving the truck on the road right now because of all the salt, so this was after about 15 min of idle, and a few revs. The socket marks the rear right #7 driver side cylinder, 1-3-5-7. Its actually the only one of those 4 that has any tan color to it at all. And #4 on the pass side is the same bone white color.... Im thinking I need to send my injectors back to Precision and have them flow tested, what do you all think? They said $15 a piece, cleaned and flowed. Has anyone used them before? They are Precision Turbo injectors so I thought it would be best to send back to them?

 

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Discussion Starter #17
BTW, thanks for all the posts with help guys... I really appreciate it. Like so many people right now, Im low on cash. Everything as gotten so damn exspensive, or its stayed the same price and gotten smaller. I just gotta be careful how I spend my money. Im fortunate with how I am doing right now, but it has been better. Im no expert at this... Ive built the truck myself except for the motor, but everything has been a learning experience and Ive been lucky with how well it turned out for the most part.
 

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You could swap the injectors from side to side. If the problem follows then you have your answer. Injectors.
If does not follow then it is most likely not the injectors.


This is my feeling on the distribution too, in vac it shouldnt matter. Plus, after thinking about it for some time, the IAC is where the motor is getting its air from anyway at idle, which is located at the 12 oclock position so that theory really wouldnt work...

BUT, I took a pic of my plugs... didnt like what I saw. Im not driving the truck on the road right now because of all the salt, so this was after about 15 min of idle, and a few revs. The socket marks the rear right #7 driver side cylinder, 1-3-5-7. Its actually the only one of those 4 that has any tan color to it at all. And #4 on the pass side is the same bone white color.... Im thinking I need to send my injectors back to Precision and have them flow tested, what do you all think? They said $15 a piece, cleaned and flowed. Has anyone used them before? They are Precision Turbo injectors so I thought it would be best to send back to them?

 

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i have used pte for injector flow/cleaning. pte was very good and actually called as they were flowing mine. got them back with flow sheets in about 1 1/2 weeks.
 

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I didnt think this was supposed to happen with FI . Only blow-thrus can have such a problem .

J/K ............. hope you get it figured out .
 
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