fireburdluvr85

8mike9, I did the idle relearn and found that her new IAC was frozen. Now at 650 rpm her idle vacuum is exactly 20". Very smooth idle. Up and down 15 or less rpm either way. Int is 128 and blm is 132. I wouldn't have thought the newer IAC was shot.

8Mike9

Looks like you're on the right track, and don't need to pull the runners again

fireburdluvr85

I am gonna try to bring it down for another test this week maybe. Just have to find the time with work.

8Mike9

Wanted to bring this back up...(seems your allowable limits are not showing tho).

My kid just smogged my '89 to give you an idea...

Dyno numbers:

@15mph
HC (max) 76...measured 27
Nox max 537 measured 102

@25mph

max 56 measured 19
Nox max 494 measured 90

I bring this back up, cause last time I smogged the car was in the late'90's or early 2000 time frame...

But, I'm 99 percent sure it's cleaner now than then (just had a sniffere test thou, no dyno).

Now, trying to get the car back on the road yielded me a plugged up FP and stuffed up injectors...so cleaned the tank, new pump, filter, sock (no effect on emissions) and got a set of Bosch 3's from Southbay...so only real difference over the years, is different injectors.

Also, they showed my timing at 5BTDC...never even looked at it, so need to bump it some...but...just to let you know.

Other than ported stock intake and matching the runners (stock) to plenum and base...only change that could affect anything was my injectors...yes, still had the plugs in it from the 90's, as well and the air filters.

All I can offer Bro!

fireburdluvr85

Those numbers look like what my 305 put out after a rebuild. I may be testing this car on Friday. I'm waiting on my mom to get another day pass. Hopefully it passes. For NOx we are only allowed 613ppm. Our hc is allowed 53. Or co2 is allowed .28

8Mike9

Our CO2 is .5 and .4 (15 then 25mph) I measured .01 on each.

FWIW, I do have the original EGR valve and original cat as well

I only bring these things up (even though we didn't have the dyno test back then) I am sure the numbers are cleaner on the dyno, as I recall them in the static test at idle and whatever RPM...which in my opinion, with more load "dyno), engine should be working harder and make more emissions...if I'm correct, the rebuilt Bosch 3's do a better job at fueling the engine, then the original injectors did.

Just my hunch

I was trying to lead you to checking bleed down rate...if the injectors are bleeding down...or just one or two, then you could be having an issue there...assuming the FPR isn't leaking.

Just more things for you to look at!

lol, like ya need another thing

fireburdluvr85

Well see what this next test shows. Lol. If not I'll really shake it up and swap my 19lb/hr boschIII and just raise the pressure to atomize the spray better. Lol

Also ours are dyno test but I don't know what they look for. I normally get a crappy look from the techs cause they are import owners mostly.

fireburdluvr85

Failed again. The tech told me to stop this none sense and junk her car or put another set of cats on

HC. 122 ppm. Max 53ppm
CO. .29% max .28%
NOx 1128ppm. Max 614.

Int reads 128
Blm was 131 right before I got there. Maybe these cats are shot. Idk. Maybe from cleaning everything out and running ALOT of dry gas thru them I damaged them.

The fuel pressure builds to 47psi and holds for 2 mins. Then bleeds down to 25psi over the course of 20 mins. It was asked and I thought I mentioned it. These injectors have less then 250 miles on them in the last 6 years. I didn't install them since I run boschIII in all my Firebirds.

My mom works a part time job at Walmart. That's why I took this job on. I'm not trying to seem stubborn with testing and changing parts but this is coming out of my pocket for the most part. She's half way to a waiver if a certified ct test station did the repairs but I had no idea it was this bad. Any other ideas fella's?

Ozz1967

iTrader: (4)

This is the crap I've never understood. If it runs better/cleaner, but it's "out of tolerance", what does it matter? NUMBER 1 Gripe!

ramicio

iTrader: (-1)

Maybe your fuel pressure regulator is bad. 47 psi is within "tolerance," but to me it's unacceptable. Injectors are rated at 43.5 psi (3 bar). I'd monitor the fuel pressure throughout various conditions of driving to make sure it's 43.5 psi above intake manifold pressure (1:1). I'm no expert, but is HC and CO2 from running rich, and NOx from running lean? How can it run too rich and too lean? Fuel pressure regulation maybe. The diaphragm doesn't have to be torn for it to wear out.

fireburdluvr85

Very possible. That would explain how it bleeds down so quickly but they aren't leaking (I put them on cardboard and turned the key on).
The tech has seen me 6 times in 2 months so I think he gets the point of being stubborn. He says the cats are shot, I welded in universal units. Then I ran a ton of dry gas, water, brake cleaner thru the intake trying to clean the throttle body. Pointless since I ended up disassembling the intake and cleaning everything. I should have done all that before the cats but but again, I didn't think it could be this bad. I did have a rich condition the first 2x and corrected that when I disassembled the intake.

DENN_SHAH

iTrader: (1)

the engine temp is a bit low, personally i would like it to be ~180-190.
my car will drop fuel pressure to 0 in a few minutes, at key on it goes right back to ~45 PSI and always starts within 3-4 crank revoultions.

high CO is rich, low CO is lean.
HC can be high from both a rich and a lean condition or anything that can cause a misfre/bad burn.
CO2 is an indicator of efficiency of the motor & cat, the higher, the better.
NOx is from combustion chamber temps of 2500 degrees or higher.
to know what the motor is really doing, the readings need to be checked pre cat.

NOx is high, looks like to me not enough EGR flow.
i would normally expect NOx of 1400 or higher if there is no EGR flow at all, but sometimes it can be as low as about 800 ppm with no EGR.
if it has a factory GM EGR valve, a check of the part number on the valve it self will show if it is a back pressure valve or not. if it is a BP valve, then at the end of the part number there will be either a P or a N. P for positive, N for negative back pressure. with a back pressure type valve, the valve will not open unless there is enough of the right pressure in the exhaust system. what that means is without the back pressure and even with full intake manifold supplied to the valve, it will not open. a bit more on this at the end my post.
if no P or N, then its a regular valve.

i don't think the cats would be your problem, but they do get weak and could be some of your problem, but without going thru the checks can't say for certain.
there are a couple ways to check them, use a temp gun to check inlet & outlet temps. after running about 2000 RPM long enough to get everything to operating temp, outlet should be 100+ degrees hotter than inlet.
the cleaner the motor itself runs, the less work the cats will do & will lower cat outlet temps.

for this you would need access to a good gas analyzer.
another way would be to bring everything up to operating temp, then run the motor ~2000 RPM, then shut the motor off & quickly disable the ignition system, then crank the motor and check CO2 output from the exhaust.

putting a hole in the exhaust just in front of the cats & checking pre cat readings Vs post cat readings.

years ago i ran into this on my car and i saw it on other F & G bodies along with other cars.
i don't see it on the VIR, but is there a max RPM range? here the max RPM was 2500 RPM for both speeds of 15 & 25 MHP on the dyno. as long as the max RPM was not exceeded you could manually shift the trans.
getting the RPM up some more by running the trans a gear lower will unload the motor & tends to clean up CO & HC, also it will drop NOx a bit too.

this is the "bit more" part from above.
on the NOx, i have seen too often where the vehicle speed/engine RPM on the dyno isn't enough load on the motor to open the throttle plate enough to activate/generate vacuum for the EGR valve.
this may or may not work, but sometimes i was able to fully tighten up the tv/kickdown cable so the trans would shift later, or maybe put a shift kit in.
correct TV cable adjust is very important, you can find the correct procedure in the trans area on the site.

8Mike9

High CO (my bad on the CO2)...means it's rich, oddly enough, you have high Nox, which usually indicates high combustion chamber temps by lean mixture, vacuum leak..etc.

For sure puzzling...could O2 sensor be reporting bad info?

fireburdluvr85

Its a new stock sensor, she does have headers on this car. They are air equipped. Wow so much stuff to read from that long post. I always wondered if the trans had a lot to do with it. Hers shifts rather late compared to mine. I will tighten up the cable a re adjust. Its feels bogged down a bit. I wish I wasn't pressed for time with this car cause I'd keep tinkering with it. All the gas analyzer stuff would be nice, my MODIS is capable but I can't invest in the kit right this minute. Man that would help tho. I have to keep re reading the post because all you guys have really helped bounce ideas. I wondered about the egr valve, she has a flow master cat back. I'm tempted to put a restriction in line to see if that assist with building back pressure. I had this same issue with my 305 tpi a few years ago. I ended up removing the np10 option and putting a single 2.5 y pipe. It ended up passing but slightly high NOx. I believe I was allowed 700ppm and it blew 674ppm. I was allowed 72 ppm HC and it blew 17ppm. .05% co. I also had a hot ignition. I'm tempted to swap some of the parts to this car since that motor is still sitting here.

On my other car I did the "411" swap. Obd2 is nice... lol

fireburdluvr85

Well, I think I'll put a single cat system on this car. Rereading the last few post really has me thinking. I don't know what it was equipped with but a single 3" is easy enough to fabricate.

I'm gonna change the cap and wires again. My mothers b/f says he replaced them recently. I'll feel better knowing that they are done right. Even tho this o2 sensor reads great the test says different.

greenyone

iTrader: (1)

I think those are Accel/Lucas or Standard Motor products injectors. I have 2 sets of those and a set of Bosch III's. It's my understanding that the Accel and Lucas are actually manufactured by Standard motor products.

fireburdluvr85

I figured that out. Lol. Thanks for the response anyways. Good ole stock injectors. I was surprised they didn't leak when I pressurized the system on cardboard.

Their was a change in data from the other day. After a 30 mile ride from work I plugged my MODIS in. Int 130 at idle of 645. Blm was 136. It wasn't the way before. I also noticed a rattling from underneath so before I proceed I need to see if the new cat broke apart and why. It could just be the air pump line came free again since she lowered this car and my workplace has a lot of potholes. Regardless this happened today.

fireburdluvr85

Update; one of the cats had the rear section break apart. As soon as we cut it off you could tell. Sadly, that was the newest one. The other smelled of gas. Well on the front aide. It now has 2 new magna flow cats. Hopefully I can hang the pipe back up since we have a storm coming with an expected 2.5" of rain/snow. Broke a header stud and had to take it out to bring it to work to fix it. Rough day to be honest.

Also restricted the pipe after the cats down to 2". Hopefully that helps with back pressure and the cats retaining heat. The tech I go to makes sure the car has been sitting for 15 mins. I know that doesn't help me.

fireburdluvr85

OK guys. New test, barely failed.
HC 19. Allowed 53.
CO. .10% allowed .28%
NOx. 659. Allowed 614.

I changed the cats and swapped my msd coil with her stock coil. Runs like a top. What can help lower this that last bit?

She also changed techs. Lol. This guy tested it warm

DENN_SHAH

iTrader: (1)

that is close. i don't remember if you did a decarb or not, at this point i wouldn't do it.
i think pulling 1 degree of ignition timing would do it. if you pull too much, CO & HC will go up.

the emissions is based on the last part of the federal emissions test that was done when the car was new. so i don't know why the guy would let it cool off, other than just a minute or 2 while checking under the hood after i pulled it in from the test drive, i always let the motor run.

fireburdluvr85

I planned on pulling another degree. I removed the Intake manifold and cleaned it fully. The new magna flow cats made a difference. As of right now, the timing I read is 5*. I'll go to 4* and see. I tried water misting the engine as well. My mom is driving it unregistered til this is fixed. I told her a bottle or two of dry gas also. Can't hurt right?

The tech I went to didn't seem interested in whether It passed Or not. She has a friend who won't blatantly pass her but let it stay hot for the test.

ex-x-fire

To lower the nox, make sure your egr valve is clear & the passages are open. Make sure its getting vacuum too.

8Mike9

Noticed you mentioned "one cat smelled like gas"...

Okay, good/new cats can cover things up, but don't solve the issue...if the cat smelled like gas, then the issue of over fueling, is well ahead of the cats.

I wonder also if the techs are doing the test properly testing it without warming it up...heck, even here they make sure your temp is in operating range to ensure closed loop...look into that as well, as they may just be lazy and wanting to push another car through.

fireburdluvr85

I know when I tested I drove for 15-20 mins and went in, had to wait 10 mins then he'd pull it in, turn it off then set up. Then He'd start it up and do the test. She just needs to squeeze thru now. Short of ripping her engine apart ( out of my pocket, not good around Xmas) I did all the external stuff I felt would improve run ability. *I did change the coil and wires with the cats* gas smell may have been from the chaffed wire I found. I'm sure that was misfiring. I suspect she had a mid range misfire that destroyed her cats prior. Or they were hollowed out by one of her x/bf backyard hacks. Idk.

I removed the egr valve to inspect, ran all new vacuum lines with new fittings, and wire brushed/brake cleaned the passages. Lol. If your gonna do it, do it right. The valve held 20" vacuum for over 30 mins which surprised me. The solenoid actually works too. I had to modify a newer solenoid to work with mine in the past and I had that whole system torn off and waiting just in case. It does get commanded on when driving and the gauge showed vacuum, looked like a flutter while driving. The engines vacuum didn't change much while driving tho. I mean usual but it was relatively steady for the ranges I put it thru. Pretty quick recovery to a steady reading after I stabbed it hard enough to break second around 25mph.

fireburdluvr85

Car was tested at 238*... didn't know that til now. Hate to say it but I turned one fan on all the time the car is running til after the test. Stock 195* stat should keep it hot enough. The tech also doesn't see why a fan should be placed in front of the car I guess

8Mike9

Was the bad wire on the same side as the cat that smelled like fuel?...actually, if on the driverside...I could see the following occurring.


O2 sensor reporting a bit rich...and excess fuel coming through the exhaust...high Co..

But high Nox as the ECM is leaning out the injectors due to the O2 info.

Just a theory/thought/ramble.

fireburdluvr85

Any thought or ramble is good til proven otherwise. Hell how do you think I diagnose trucks were I work. Mostly new trucks with minimal training.

Cylinder 3&7. That cat stunk of raw gas. I made a mistake tho. The co was 0.00%. Allowed is .28%. How the hell is that even possible?
The headers mom has dont fit her car right. They are edelbrock but for angled plug heads? Plug wires get way to close for comfort. I'll know if the fan on will help around 4-5 today. If it does then she re registers the car and is done with emissions permanently. I do not plan to remove any emissions devices tho. I keep that stuff intact whenever possible just in case.

fireburdluvr85

It passed.
Hc 52ppm allowed 53ppm
Co .27% allowed .28%
NOx 612. Allowed 614

Next major repair it needs I'll deal but right now she's legal finally.

Ozz1967

iTrader: (4)

Any clue as to what exactly fixed it or just the combination of everything you've done so far?

fireburdluvr85

I'm gonna be honest, I don't know. Personally it needs a valve job. It wasn't maintained well the last 8 years if at all. Basically it was driven to my house and told fix it. I personally sunk 750$ into it plus time, the steering was shot, brakes destroyed, etc etc. I didn't charge my mom labor cost. I've had to put off paying work due to time restraints. Hopefully I get reimbursed.

DENN_SHAH

iTrader: (1)

good deal on the pass.
i take it you pulled a bit more timing. i didn't notice if you had checked it or not, but i wonder if the balancer has slipped.
what i found was normally pulling anything more than 2~3 degrees from factor specs would cause a big jump up in CO & HC.

i don't think the 238 temp mattered, a number of years back some guys on IATN did some temp testing in regards to NOx readings.
what was found was temp didn't really matter much on NOx until the engine was actually overheating. the higher temps up to overheat did improve CO & HC. IIRC, the readings where all taken pre-cat as cat temp will have a big effect on emissions.

running that clean, i wouldn't think it needs a valve job. with valve problems you should see high HC due to misfire. but good working cats can hide a bit of misfire HC.
if it has a problem with valve deposits, i found BG 44K actually works pretty good.

fireburdluvr85

I didn't adjust the timing. I'm sure the balancer has slipped by now. Lol. I think the cats are masking the hc. It blew almost nothing but NOx when it was overheating so I rigged one fan to stay running. After reading what you just said on temperature I'm wondering if she just got lucky. According to the balancer currently on the engine it reads 5*. Sadly my mother will never do much more maintenance to her car. She's one of those women that's just gas and goes and gets all bent out of shape when things break. If you could have seen the shape the car was in you'd cry a tear. I have 2 five gallon pails of broken parts sitting for scrap now.
Hopefully she does follow my lead and Atleast get it to me for regular oil changes. Then I can keep an eye on things. I feel that she developed a misfire, kept driving it til it would no longer run then parked it. Worst thing to do in my opinion.

fokeyman

woops, wrong thread lol