stroker issues- wideband reads somewhat lean but exhaust is super rich

[blondejoncherokee]

EDIT: I think we had a tech misinterpret C02 for CO on the tail pipe readings. We originally thought the tail pipe was rich (He interpreted 13% CO2 as 13% CO) when in fact it is about dead right for 14.7 with 13% co2.


1998 XJ, aw4.
4.6 stroker
bishop Buehl pistons and rings and custom head
ported head with chevy LS valves,
comp cam 68-232-4
almost all new Mopar sensors- map, IAT , CTS, CPS, TPS
full 3" exhaust, and a bay header to replace my old stock cracked one.
injectors have been cleaned and tested. they are 703s.
BBK throttle body.
K&N intake with 6x9" cone filter.

 

[RCP Phx]

What injectors are you using? What are the "fuel trim" numbers?

 

[RCP Phx]

Your build sounds a lot like mine...........

I finally get to p/u my block today so I can get started, I talked to Russ the other day about where my heads and intake are and they're about another week out!
Here's my parts list............

2000 XJ block - decked, bored .030" over, and align-bored w/ ARP Main Stud kit

Clearwater Cylinder Head improved 0331 head - Bishop-Buehl port/polish/62cc chambers/LS1 intake valves/port match w/ ARP head bolts

2000 XJ intake manifold - Bishop-Buehl port match/bore TB 62mm

BBK 62mm throttle body

Banks Revolver header

Hesco water pump

Comp Cams 68-232-4 camshaft - Lift(.460" Int/.476" Ex) Duration(250 Int/256 Ex)

Rollmaster billet steel(crankgear induction hardened) double roller timing set w/ nine position crank gear (+8 to -8 degrees)

Cam bolt with custom length thrust pin(no spring), shooting for .008" of end play

Sealer Power lifters

HarlandSharp 1.6 roller rockers w/ ARP rocker studs

Scat stroker crankshaft

Scat/Bishop-Buehl Chromoly 6.125" connecting rods bushed for free-floating Chevy wrist pins

Auto Tec 4032 Forged pistons/ -22cc D-dish w/ Chevy wrist pins and 1.385" wrist pin height

Sealed Power Moly piston rings

Clevite main/rod/cam bearings

FelPro gaskets/seals

ARP flex plate bolts

Brown Dog motor mounts

Crankshaft, connecting rods, pistons, wrist pins, flex plate, and harmonic balancer all balanced

Reciprocating parts - connecting rods, pistons, and wrist pins I weight matched to within .25grams across all 6 set combo's

Custom 2-1/2" header to downpipe adapter w/ O2 bung for my LM-2 A/F meter

...............the rest of the thread: http://naxja.org/forum/showthread.php?t=1140839

 

[RWKHausSupply]

exhaust is reading super highly rich out the tail pipe
Oil seems to be getting in the gas
wideband will be reading slightly stoich to lean when exhaust is reading 13% fuel which should be closer to 1-2%.

The exhaust reads super incredibly rich when we hook up my buddies tail pipe probe, but the wideband is reading lean and it appears the PCM is dumping alot of fuel.

Ive fixed exhaust leaks, but if I had them why would tail pipe read super rich and downpipes wideband read lean ?

If it helps
4.6 stroker
bishop Buehl pistons and rings and custom head
ported head with chevy LS valves,
comp cam 68-232-4
almost all new Mopar sensors


leaning towards a bad wideband and or a bad PCM.

another odd ball thing , is that in my data logging, the coolant sensor even though its new mopar reads like 70* when the dash reads like 160-170 and the engine is obviously warmed up.

I am going to check yet again for exhaust leaks and I am waiting for a new wideband. Just at a point where its really tough to figure out what it going on with this thing.

What wideband? I have never seen one register a % of fuel?
What are the true ratio (IE 12.3 or 14.6, etc)numbers?

 

[Rockwood]

Did you test the stock O2 sensor/wiring?

 

[Tim_MN]

....... my data logging, the coolant sensor even though its new mopar reads like 70* .......

Good place to start. Seems to me this would keep the ECU in full rich warm up mode.

 

[lazyxj]

Are you sure the catalytic converter is still working?
A super rich exhaust should cause the converter to get very hot and possibly burn up if run long enough with raw fuel flowing through it.

O2 sensors?, yes we have plenty of them.

 

[blondejoncherokee]

What wideband? I have never seen one register a % of fuel?
What are the true ratio (IE 12.3 or 14.6, etc)numbers?

no I have a AEM wideband, and we used a tail pipe sniffer yesterday to check for fuel in the exhaust . the sniffer has one of many outputs that is %unbrunt fuel, and my buddy said that value is normally 1-2%, and mine was 13% . the wideband at that point was between 14.2-14.5, slightly rich but very close to stoic
.

If it helps, I am running a full 3" exhaust, and a very very high flow cat .

 

[blondejoncherokee]

Good place to start. Seems to me this would keep the ECU in full rich warm up mode.

odd thing is when we hook up my buddies snap on scanner was reading the coolant sensor and 02 sensors as just fine. But my data log shows like 70* when I log with live link after warm

 

[blondejoncherokee]

Did you test the stock O2 sensor/wiring?

I probably should. We checked/tested it with a snap on Solus at one point and it checked out fine.

 

[blondejoncherokee]

What injectors are you using? What are the "fuel trim" numbers?

injectors have been cleaned and tested. they are 703s.
my tuner has tuned the thing for these injectors specifically to have them open as much as needed.

As for short term, it changes dynamically every few seconds in the data log, so I can try to upload the most recent data log.

 

[blondejoncherokee]

Are you sure the catalytic converter is still working?
A super rich exhaust should cause the converter to get very hot and possibly burn up if run long enough with raw fuel flowing through it.

O2 sensors?, yes we have plenty of them.

I have a super high flow cat. Super high flow.

 

[blondejoncherokee]

lets see if this works- this data log is from yesterday after clearing the adaptive and swapping in another new NTK front 02 sensor and a fresh mopar MAP sensor and fresh comp cams break in oil.

https://docs.google.com/spreadsheet...mAHjIP1DX9BOj6_t0WBikF_0jE/edit#gid=716319746

 

[blondejoncherokee]

Updated the specs in the post

 

[blondejoncherokee]

Maybe this one will work for the most recent data log- analog 1 is the wideband:

https://docs.google.com/spreadsheets/d/1PyHWG51QXcrz685Y1mAHjIP1DX9BOj6_t0WBikF_0jE/edit?usp=sharing

 

[RCP Phx]

On your data logger, is the temp in Celsius? Does your AFR meter require a "free air" calibration before starting a test, mine does?

 

[blondejoncherokee]

Sent from my iPhone using Tapatalk Pro

 

[RCP Phx]

I forgot to say that I added a "test" port bung in my exhaust, it's just slightly upstream of upstream sensor.

 

[blondejoncherokee]

On your data logger, is the temp in Celsius? Does your AFR meter require a "free air" calibration before starting a test, mine does?

Those are both great questions... I need to find out. I dont know how to calibrate the wideband.

I just talked to a tech buddy at a dealership and he said that the other tech misinterpreted the 13.4% on the sniffer at my other buddies shop. he said the 13.4% co2 is just fine to slightly rich at best. not horribly rich. so maybe the wideband is slightly off, but even then tail pipe readings might differ from a downpipes wideband by a little so maybe not.

 

[blondejoncherokee]

I forgot to say that I added a "test" port bung in my exhaust, it's just slightly upstream of upstream sensor.

yeah I welded up my own 3" exhaust and added a wideband bung just above my regular o2 sensor