rich fuel/air mix? emissions failure.

[Oizarod115]

yea its all hooked up right.. and my 5v is red/white

 

stopped by and got a pack of assorted ones including a 250ohm and two 200ohms... i'll burn the 250 in tonight... i figure if 25 ohm can move it .1 then 250 will move it 1.0ish right? idk, we'll see.

[Oizarod115]

well i soldered in the 250 ohm potentiometer and perfectly as i suspected i can now vary the voltage from 5-4 which is perfect. :cheers: :cheers:

 

i set her to 4.7~ (thats a very unprecise measurement considering I'm using a few year old analog multimeter on a scale of 1-10 through 90* of motion.

 

now how should i go about seeing if that is a good setting or not, its still got good power, i smelled the exhaust, seems a little cleaner, maybe not 100% burnt though. but its never gonna be perfect right?

 

..thanks for all the help on this one hornbrod

[HOrnbrod]

Since you don't have a wide or narrow band A/F meter to monitor Stoich, pull a spark plug every 50 miles or so and look at the color.

[HOrnbrod]

How did this work out for you? A couple of guys on the stroker forum are having a rich condition too.

[FxRacing282]

 

i set her to 4.7~ (thats a very unprecise measurement considering I'm using a few year old analog multimeter on a scale of 1-10 through 90* of motion.

 

~? i think you mean DC

[Oizarod115]

 

i set her to 4.7~ (thats a very unprecise measurement considering I'm using a few year old analog multimeter on a scale of 1-10 through 90* of motion.

 

~? i think you mean DC

 

i mean ~ about. wasn't thinkin elec. symbols, but yea DC

 

in other news on this thread, i pulled a plug w/e its set at is just about perfect, but someone brought to my attn that my k&n is dirty to the point it might be hindering my airflow which might be contributing to the rich-ness in the first place :roll:

[FxRacing282]

no your O2 sensor adjusts for the lack of air. and your MAS or MAP should adjust for it

[Oizarod115]

alright guys! success, wanted to update the thread for future searches on the topic..

 

my numbers on the origional test were as follows

223/189 HC 259/194 FAIL-FAIL

6.56/2.36 CO 6.48/1.74 FAIL-FAIL

129/1233 NOx 177/1340 PASS-PASS

 

after building an adjustable map sensor my numbers dropped to

(guestimated from what i remember, can't find the sheet from this run, i know i failed the one section only though)

these are my 4.8V trial results

150/189 HC 160/194 PASS-PASS

2.1/2.36 CO 2.4/1.74 PASS-FAIL

500/1233 NOx 600/1340 PASS-PASS

 

i acheived that much by adjusting my MAP sensor (go-jeep has a writeup on building an ADJ one) to 4.8ish volts (5v normally)

 

these are my 4.1ishV trial results

82/189 HC 89/194 PASS-PASS

1.01/2.36 CO 1.03/1.74 PASS-PASS

703/1233 NOx 1168/1340 PASS-PASS

 

:popcorn: :deal: :clapping:

 

these test results were all on premium gas fully warmed up ~210-215* motor

NO OTHER MODIFICATIONS were made between tests, just MAP sensor, and you can see how much it affected the results.

 

note: pay attention to NOx emissions as reducing voltage will cause a leaner fuel-air ratio which lowers HC/CO but increases NOx, this will only help you to pass emissions if your truck has LOWLOWLOW NOx emissions like mine did, and HIIIIGH CO/HC (an indicator of rich fuel-air mix)

 

reducing the voltage at the MAP sensor can also increase gas mileage, but be careful to not reduce it to much and F the motor up.

 

happy searching!