I came opon this site while searching for emissions help, non turbo buick

[MdFormula350]

If I dont own a turbo buick is it possible to still get help in this regard?

I read alot of the post in the emissions help section, but had my own questions.
I noticed a few guys know ALOT about reading the printouts and was wondering if I could get some help in this regard.

I am in Maryland and have a 1991 pontiac firebird 350 tpi. treadmill test failing HC and NoX, have some room in the Co department. after tweaking fuel injector constant, before that I failed all 3 test.

If it is OK I will post up my reading and pictures of the read outs, if not I will just read up on some stuff since I wanted a TTA or at least do the engine swap into another thirdgen fbody.

 

[mikestertwo]

I am in Maryland and have a 1991 pontiac firebird 350 tpi. treadmill test failing HC and NoX, have some room in the Co department. after tweaking fuel injector constant, before that I failed all 3 test.

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Sounds like you are running too much timing. How new is your cat? Post your numbers.

 

[johnnyttype]

yea def. post the numbers! check to see if ur egr is functioning properly, if it is not that could cause the NoX issue, and like mikestertwo said, high timing can cause a rich condition.

im from maryland and my friend got is 350tbi to pass emissions with no cats!!! what he did was create a vacuum leak and backed off ignition timing before the test!

 

[MdFormula350]

I have been trying to get help off my thirdgen websites but I thought I would try hear since from the threads I was reading on here people really have experience in this stuff. Most of this info. has just been copied and pasted so disregard it sounding weird


Here are the mods/delted stuff that matters most in emissions:

race shorty headers
no cats
no mufflers
no egr
no evap ccp
no a.i.r

Also I use 93 octane gas all the time.

new plugs, wires are good, new injectors, stock fuel pressure and stock regulator. I am using the stock a/c delco plugs that my car calls for with stock gap. aftermarket msd blaster 2 coil. other things that might affect test would be I have a 2800 lockup stall, with the stock torque converter settings for lockup speeds, etc... someone suggested on another board that I should keep the converter unlocked for test which would be speeds under 70 mph i think, might keep my reading more constant.

Test 1: Failure all 3

-chip had injector constant at 22, and I just put in 24s.
-chip 8 base timing, base timing set at 0 on engine.
-stock timing chart as well as stock fuel chart I believe.
-fan 1 I turned off, fan 2 I believe came on with the stock fan switch in the head, since it didnt get to the redline in temp but was def. up there at least 240
-outside was raining and about 58 degrees outside and humid

HC CO NOx
State 1.0000 GPM 20.0000 GPM 2.2000 GPM
My 1.7454 24.2047 3.3139
F F F

Test 2: Failure 2 out of 3

-chip injector set to 26, and I have 24s
-chip base timing set to 12, base timing set at 0 on engine.
-stock timing and fuel charts.
-fan 1 set at 235, off 230, however while I set sitting there it got passed 235 it seemed and I got worried and flipped my fan 2 switch on, so the whole time the fan 2 was on and the temp on the engine was about 185
-outside temp was 65 and sunny

HC CO NOx
State 1.0000 GPM 20.0000 GPM 2.2000 GPM
My 1.1174 16.5176 2.5409
F P F

Just from those readings I am going to double check my fan 1 does come on, and I think I am going to up the base timing in the chip to read 20.
would it be ok to try and lower engine base timing to under zero?

From these readings what else should I touch, since all did lower alot.

Test 3: Failure 2 out of 3

weather was crappy today, not raining anymore but humid and around 55 out.


this is what i tried today.

new chip with engine timing at 0, chip base at 0
lowered max timing from 42 to 30, and lowered all timing -5 on the charts, probably didnt take out enough timing

injectors set at 24 which they are, and for the fuel charts -5 throughout.

1/4 of the usual 93 gas, 2 to 3 bottles of the 91% rubbing alcohol and a small thing of octane booster (i am getting desperate).

fan comes on at 231 off and 225 regardless of vehicle speed.

HC CO NOx
State 1.0000 GPM 20.0000 GPM 2.2000 GPM
Readings 2.1073 GPM 15.6176 GPM 3.8295 GPM

I guess I need to start over again, I dont think it likes to run hot??? At least the NO is always high when it runs hot, maybe I need to cap the temp to 220 and no higher.


test 1 printout

test 2

test 3

I think my best choice to is maybe tweak the tc lockup some, set the chip base timing to 0 and -12 throughout the low to mid range and -15 middle to higher; set the injector constant to 26 again, fan to come on at 228 and off at 220.

with about 1/4 of gas i am going to add the gallon of denatured alcohol I purchased today and I think with decent outside temp and weather it might pass.

 

[mikestertwo]

race shorty headers
no cats
no mufflers
no egr
no evap ccp
no a.i.r
QUOTE]

With that setup your going to have a little trouble getting it to pass. If I'm not mistaken the 91's were a speed density system (MAP), not a MAF system which makes it more difficult. Without a cat, egr, and the a.i.r. it's going to be difficult.

 

[johnnyttype]

man, looks like the 2nd time was pretty close! yea with ur mods it is gonna be hard but im sure it is possible

coolant temp i would not let get too high especially without EGR because there is nothing to cool the combustion chambers anymore. i would imagine higher NOx readings would come from higher coolant temps.

maybe try goin back to setup #2 and take a couple more degrees of timing out from that setup, but not too much, and maybe some Guranteed to pass.

 

[MdFormula350]

yeah speed density, I like not having a maf makes the engine bay look cleaner

anyway yeah this is what I am going to do next good weather day, I have till FEB. 08 something.

both 2 times I have passed with the same exhaust other than tranny work / stall has been idle test only and I have tried to get it again but no dice even with 3 diff. people nope the first time I had to go I went when the car was bone stock and they gave me a waiver for it being too low, now after dropping the car an inch I have to take the test now, lol

this is what I am going to try:

injector constant setting to 27 maybe
setting the tc lockup to over 70mph at the min.
timing engine at zero since the first test, chip base timing setting I am going to set to 0 then just remove -12 to -15 throughout the charts and cap max. timing to 20.
I will leave the fuel charts alone or maybe -1 or -2 throughout.
fan setting 215 on, 195 off regardless of vehicle speed, i do think when it gets to hot it starts getting higher NoX.

1/4 93 with gallon of denatured alcohol then ride to the place which is 13 miles mostly highway.

o yeah usually before swapping in the new chip I unplug the ecu fuse for a minute or two to erase and thinking it has .

If I dont get really close this time I am going to redo the exhaust with some cats and vbands so I can install delete pipes on and off quickly.

why cant they leave sports cars alone!

 

[mikestertwo]

Are you running the stock cam?

 

[MdFormula350]

yeah just a stock internal 350 tpi with exhaust, pulies, tranny mods, and suspension.

 

[johnnyttype]

why cant they leave sports cars alone!

cause they're exhaust nazi's!!! although they did give my friend a waiver for his 88 GMC S15 pickup with dual stacks

i just got historic tags on my car for maryland and now i am rocking them all the way up in Michigan! no more emissions for me

 

[bluettype]

try to find a tester that needs money, my cousin got his car to pass for$80

 

[MdFormula350]

I will try those things in my next chip and see what happens. I am going to try next week sometime when the weather looks a tad better.

 

[ijames]

Looks to me like going from test 1 to test 2 you moved everything in the right direction so I would go further. Take your test 2 chip and advance the timing another 4-6 degrees and raise the injector constant 2-4 to try to lean it out some more. I always wondered what effect timing had on NOx, and guessed that advancing it would increase the chamber temps and raise NOx, but you advanced it and lowered NOx, and then later retarded it a bunch and raised the NOx, so I'm ready to believe I was wrong . You are also so close that if you put any kind of 3-way cat on the car it would pass.

 

[TurboTR]

I'm with you Carl. And diesel inj timing is analogous to spark timing, and advancing that raises peak combustion temps, which raises NOx. But also tends to lower the HC. Conversely, retarding the timing tends to lower peak combustion temps and thus NOx, but then tends to raise HC.

TurboTR

 

[MdFormula350]

test 4: kinda getting somewhere. failed hc, passed CO and NOx

things i did.

1/4 tank of 93 like usual with 1 gallon of denatured alcohol.
fuel injector constant 26
stock fuel charts but -1
timing: 0 on engine, 8 base in chip, -10 on stock spark charts, max timing advance 25
torque converter lockup at 50, instead of 38.
fan on a 225, off at 200.



HC CO NOx
State 1.0000 GPM 20.0000 GPM 2.2000 GPM
Readings 1.7634 GPM 11.9250 GPM 1.8673 GPM

I think since this is my first time running the denatured it might now be too lean now?

 

[MdFormula350]

well i am going to try the injector constant at 24 now, run the gas down to under 1/4 then pour in the 2 quarts of alcohol I have left. and give that a try.

should I mess with any timing also? I am thinking now its mostly fuel tuning only needed.

maybe move up the converter lockup to over 60?


thank you

 

[87GNSteve]

Maybe go into the test with 87 octane & denatured mix.. The 93 might not be burning completely.

 

[MdFormula350]

you may be right, from the Co being so low I assumed it was just running lean, but the higher octane still might be causing the HC numbers to be too high still.

right now I got about alittle over 1/4 of 93 and most of the gallon of the denatured out of the system.

I guess I can run low again, fill up with some 87 about 1/4 tank then pour in just one quart of the alcohol and try that.

so leave everything else alone?

I think ur right maybe with all the timing out of the system I dont need 93 because it doesnt see close to wot anyway so no knocking should occur away.



thanks I really never thought about changing the gas octane much.