347 runs lean, won't run fat

[gitrdrunk]

Hi there newcomer here. Can't find anything about what I'm experiencing so here it goes

Just got a new 347 together, got my 500 break-in miles on it and took it down to the shop for a tune. He hooked it up to the wideband and it was jumping back and forth from 14:1 to 18:1 then holds at 18:1, he tried to fatten it up by increasing the pulse width but then it won't stay running, idle hunts from 500 to 1800 rpms then chugs out. He sends me home telling me to start checking sensors, come on i thought a dyno shop was supposed to actually tune somthing.

I'd really appreciate it if someone thinks they could help out.

 

[Rick 91GT]

Most shops with a dyno can help find the issue but you get charged by the hour, especially if the car is sitting on the dyno....atleast that is how I am.

Running 16:1+ at idel is very normal. Did you make any pulls? Did it fatten up?

Whats the complete combo?

 

[FastDriver]

I agree. If it's idling nicely but the gauge reads lean, don't worry about it. When you're under load that's where the AFR really matters.

Chris

 

[LarsD]

If you idle is hunting it is possible you have other issues. Is your maf matched to your injectors? What size injectors? Actually, just list the whole setup.

 

[03ghoststang]

at idle it should bounce a little on the AFR but as mentioned before once its under load its where u need it to be right on

 

[gitrdrunk]

oh sorry the setup is 347, A9L, sct 4 bank, pro comp 210cc heads, track heat intake, 75mm tfs tb, 90mm lightning maf, 36# injectors, 255 lph, adjustable fpr, 40 psi fuel, and no pulls were done, said it wasn't going to be safe. it idles lean but sounds good, when i got home i pulled spark plugs to check they were all white and number 1 and 5 were pure white with bright yellow. I have seen white plugs, but never school bus yellow.

and thats another thing i have both mafs he tried to fatten it up with the stock 1 and the 90mm, oh the idle only hunts like that when he increased the pulse width to make it richer

 

[2000xp8]

Lose the chip and run a calibrated meter and i bet your issues go away.

Mistake #1 by the general automotive public, chips fix issues.
They don't.

The lightning meter setup on a fox is not very good. Makes a simple situation complicated for no reason.

My buddy who owns a dyno shop wouldn't of worked on it either.
Well, he would of, but not for free and i assure you he would make you pull the chip and change the meter.

 

[gitrdrunk]

so what meter do you have in mind?

 

[2000xp8]

95mm pmas velocity calibrated for your injectors

 

[gitrdrunk]

I wouldn't have to swap out the complete meter housing would I, couldn't I just swap out the sensor that would be calibrated to 36#'ers

 

[2000xp8]

I wouldn't have to swap out the complete meter housing would I, couldn't I just swap out the sensor that would be calibrated to 36#'ers

You need a meter with sensor.
Never, ever just swap the sensor.
The sensor is flowed on a bench and calibrated for each individual meter housing.
For all intensive purposes, the meter and sensor should be considered as one unit, inseparable.

 

[gitrdrunk]

ok sweet, I'll order one up. hope thats all I need I already checked everything else like o2's, tps, ect, iac, sprayed everything down with brake kleen for vac leaks and everything checked out as good,
because even while driving at constant speed like 3rd gear below 30 mph it jerks bad but if I accel it evens out, doesn't matter what gear I'm in. Just cruising at constant speed in any gear it chugs bad like it's missing. I'm at 10 base time with spout out and 600 rpm with iac disconnected.

 

[Rick 91GT]

PMAS is out of business from what I know, im a Pro-M dealer because of it...

If you want some pricing on a meter let me know. [email protected]

 

[2000xp8]

PMAS is out of business from what I know, im a Pro-M dealer because of it...

If you want some pricing on a meter let me know. [email protected]

Finally happened huh.
Heard some rumors at the shop a couple months back, but it wasn't anything solid.
Guess that's why the guys were testing the Pro m and dabbling in the DBX.

 

[Rick 91GT]

Yeah, I really liked the 95mm also I have one used one on the shelf at the shop 30# 94-95 ecu. I

Pro-M 92mm is awesome so far in testing, reads 360 degrees of airflow. They have a new 117mm coming as well . I personally didn't have luck with the dbx

Pm me if you want more info...