Afr #s

joshkoltes · Sep 15, 2014

If I remember right the last test I had on my fresh setup I was lean.
Not across the board lean, just on the bottom.
As soon as boost comes in the dobek is just right at 12-14 all the way up to wot
Its like the stock fueling is somehow way off. Its 14-16 at idle and mid 19 afr's until boost starts just creeping around.
Runs real sharp but just nervous of the numbers, considering vipec

Its a brand new motor par long rod, with the head. Wossners from rkt, i polished the ex ports, new stock injectors, new dobec with the dual map sensors, new turbo kpa self lube2860, I have a fuel pressure sensor that reads a consistent 59-61 psi.

I've been waiting for hi-perf to get a new stock of fuel filters in I guess it could be something simple like that

Snowmow · Sep 15, 2014

Stock maps are scary lean at Idle. 19's while the throttle is open sounds way to lean though. I've seen 16's while idling and unloading. But usually not while riding. I've Gone away from dobec boxes. Not enough parameters to get a turboed sled tuned how I like. Dobec demands that you tune (to a point) with fuel pressure beings you can't pull fuel with the box. This causes inefficiencies. I've never had a problem tuning a dobec box for wot. All ways runs good at that throttle position. Just everywhere else that has given me trouble.

TRS · Sep 15, 2014

Where you have located your O2 sensor has a lot to do with AFR numbers. If you are having trouble tuning with your Dobeck box call them. They can change fuel parameters within your fuel controller. Don't believe all the negative comments. Dobeck boxes are programmed to vendor specs and they may not fit your application. Be proactive to fueling issues, call them.

Snowmow · Sep 15, 2014

TRS said:
Where you have located your O2 sensor has a lot to do with AFR numbers. If you are having trouble tuning with your Dobeck box call them. They can change fuel parameters within your fuel controller. Don't believe all the negative comments. Dobeck boxes are programmed to vendor specs and they may not fit your application. Be proactive to fueling issues, call them.

Can they pull fuel on their base tunes?

joshkoltes · Sep 15, 2014

My issue has nothing to do with dobek, the piggyback doesn't do anything till it senses boost then adds fuel accordingly through the second set of injectors. Correct me if I'm wrong that's how I understand it.
My issue is pre boost. What can I check on the stock injection system?
My Afr sensor is in the same spot as every Silber kit.

bk720 · Sep 16, 2014

Map sensor

joshkoltes · Sep 16, 2014

I guess that could be, since it hasn't been used in the system until now. It was just hanging out in the elements zip tied to the frame. All though I might have replaced it with new knowing where it had been? I will check

joshkoltes · Sep 16, 2014

I just checked all my receipts and couldn't find that so I'll give it a try. I was thinking about this but not sure if replaceing those little discs will affect anything. I assume those are pressure regulators? Too bad you gotta replace the whole rail to replace the discs. I suppose the next step would be a fuel pump
http://www.polarispartshouse.com/oe...l-system-rail-lines-throttle-body-all-options

Wheel House Motorsports · Sep 22, 2014

If your only lean around idle and not when it comes into boost i would be way more suspect of an exhaust leak or bad 02 sensor then fuel supply. Cap ends and pressure test if you have not. also, how many seasons have you had the 02 sensor in that kit? Seems like if a guy gets 2 seasons out of one hes a lucky bugger.

Snowmow, the gen 3.5 controller he has is capable of pulling and adding fuel on stock injectors as well as controlling boost fuel on the extra injectors. Your probably thinking of older gen 3 units which only added.

And just as general info, 14-16 afr at idle is perfectly normal, they target 14.7 and if it misses a rev or two firing, then straigh air goes through your motor and reads a hair lean. If it feels like its running good but its showing 19 afr. im betting you have a problem with leaks or sensor, thats lean missfire teritory on a pro. Also, some sleds at light throttle low speed can draft air into the exhaust causing all sorts of wacky readings.

bk720 · Sep 22, 2014

I had the same problem with my kit. Prongs on the map sensor were the weather pack goes into had just a tint of green corrosion on it. Enough trochanter resistance values. Replaced it and now it runs great.

Snowmow · Sep 22, 2014

Wheel House Motorsports said:
If your only lean around idle and not when it comes into boost i would be way more suspect of an exhaust leak or bad 02 sensor then fuel supply. Cap ends and pressure test if you have not. also, how many seasons have you had the 02 sensor in that kit? Seems like if a guy gets 2 seasons out of one hes a lucky bugger.

Snowmow, the gen 3.5 controller he has is capable of pulling and adding fuel on stock injectors as well as controlling boost fuel on the extra injectors. Your probably thinking of older gen 3 units which only added.

And just as general info, 14-16 afr at idle is perfectly normal, they target 14.7 and if it misses a rev or two firing, then straigh air goes through your motor and reads a hair lean. If it feels like its running good but its showing 19 afr. im betting you have a problem with leaks or sensor, thats lean missfire teritory on a pro. Also, some sleds at light throttle low speed can draft air into the exhaust causing all sorts of wacky readings.

Does the customer have the ability to pull fuel, or is that in the base tuning?

inspector01 · Sep 22, 2014

This is on straight pump gas? And your gauge is set to pump gas conversion?

I'd look to confirm the readings if it's running fine and reading that lean. Even under low load, much more than 16:1 or so will start breaking up/lean misfiring on most engines.

Wheel House Motorsports · Sep 23, 2014

inspector01 said:
I'd look to confirm the readings if it's running fine and reading that lean. Even under low load, much more than 16:1 or so will start breaking up/lean misfiring on most engines.

^^ exactly, that is why I say its most likely skewed readings due to air ingestion. somewhere.

joshkoltes · Sep 23, 2014

inspector01 said:
This is on straight pump gas? And your gauge is set to pump gas conversion?

I'd look to confirm the readings if it's running fine and reading that lean. Even under low load, much more than 16:1 or so will start breaking up/lean misfiring on most engines.

I've been running straight race vp c-12 when it popped last and straight av otherwise

TRS · Sep 23, 2014

Snowmow said:
Does the customer have the ability to pull fuel, or is that in the base tuning?

Yes you have the ability to pull fuel to the parameters set by the vendor. The percentage parameters can be changed by your vendor (if equipped) or Dobeck.

Snowmow · Sep 23, 2014

TRS said:
Yes you have the ability to pull fuel to the parameters set by the vendor. The percentage parameters can be changed by your vendor (if equipped) or Dobeck.

Wheel house pm'ed with all the info in the boxes.

Thanks to you both.

joshkoltes · Oct 12, 2014

Got the new sensor. The website didn't have an updated part number but the one that arrived has a different number than the old one. Oh well must be right

Search

Afr #s

joshkoltes

Well-known member

Snowmow

Well-known member

TRS

Life Member

Snowmow

Well-known member

joshkoltes

Well-known member

bk720

Free Member

joshkoltes

Well-known member

joshkoltes

Well-known member

Wheel House Motorsports

Well-known member

bk720

Free Member

Snowmow

Well-known member

inspector01

Well-known member

Wheel House Motorsports

Well-known member

joshkoltes

Well-known member

TRS

Life Member

Snowmow

Well-known member

joshkoltes

Well-known member

Similar threads