Still fighting emissions

[haydenm315]

I can't seem to get this right.. and am so frustrated. I thought I'd finally pass emissions today after having my bad cat replaced. My car spikes Hydrocarbon emissions on decel. I'm putting out 1.43 grams per mile hc when the limit is 1. On the graph I am under 1 gpm for the most part except when decelerating. I don't think my car is running rich all the time because I get 24+mpg driving responsibly. My thoughts are it isn't cutting off gas quick enough when you get off the gas. what could cause this?

I have cleaned my maf a number of times, along with the orange temp sensor in the airbox. I've done decarbon a number of times. My TPS sensor was replaced not too long ago. It wasn't original motorcraft though.

Within the last 5k I have done another 60k. I replaced a bad thermostat, installed a new knock and cam sensor. I also had a cat replaced. I had a bad plug wire for a while and I think it did bad things to my cat.

Pulling SPOUT last time only made my HC go up.

 

[Devin]

When my car failed emissions the garage guy told me to just hammer it on the highway for about half an hour and then take the test. I passed, though I don't remember if it was my CO or HC that was high.

 

[aggiesho]

haha ya same problem here. i didnt pass the first time. so i just drove out of the garage and drove it real hard for a while came back and passed but i just barely passed. good luck.

 

[JSHOAz]

Post up your numbers,I can help.Here are the basics.

High CO : rich mixture,poor cataylist effiency,engine wear (rings valves)
High HC : rich mixture (o2`s,maf,cold engine temp),misfire,compresion loss
High NOX : very lean mixture(o2`s,maf,vacuum leaks),inoperative egr,******** timing,advanced timing,low cataylist effiency(dead cat converter)

High NOX results from high combustion temp,high HC results from unburnt fuel/misfire.So as you could see a misfire would lower NOX(cooler combustion temp).So all the numbers interact.
So high CO and NOX would likely be a cat.
High CO and HC would likely be rich mixture.

 

[NoSHOAllGo]

Ya you should run it kind of ******* the freeway for awhile. If you did all your maintenance than the only thing could be the carbon buildup in the engine. Which will be cleaned out if you do run it hard for awhile. At least thats what worked for me. And I also noticed on my Emission Test sheets that they ran the engine at different RPMs and speeds on seperate tests. That can make a little difference in pollution to. Or maybe a scam to get more money out of you and make you also think/spend more money on your car even tho theres nothing wrong with it.

 

[Sho Amo]

High CO : rich mixture,poor cataylist effiency,engine wear (rings valves)
High HC : rich mixture (o2`s,maf,cold engine temp),misfire,compresion loss
High NOX : very lean mixture(o2`s,maf,vacuum leaks),inoperative egr,******** timing,advanced timing,low cataylist effiency(dead cat converter)

Thank you

 

[haydenm315]

haha ya same problem here. i didnt pass the first time. so i just drove out of the garage and drove it real hard for a while came back and passed but i just barely passed. good luck.

If I drove it hard for a while on the highway, chances are I'd get a ticket. The next ticket I get is gonna be more than just a slap on the wrist.

 

[haydenm315]

Post up your numbers,I can help.Here are the basics.

High CO : rich mixture,poor cataylist effiency,engine wear (rings valves)
High HC : rich mixture (o2`s,maf,cold engine temp),misfire,compresion loss
High NOX : very lean mixture(o2`s,maf,vacuum leaks),inoperative egr,******** timing,advanced timing,low cataylist effiency(dead cat converter)

High NOX results from high combustion temp,high HC results from unburnt fuel/misfire.So as you could see a misfire would lower NOX(cooler combustion temp).So all the numbers interact.
So high CO and NOX would likely be a cat.
High CO and HC would likely be rich mixture.

Thanks for the info. Below is my graph. I took notice to how the HC spiked on decel. CO didn't though. That decel crap is failing my car, whatever it is!

It also spikes bad around 160 seconds. That is where the tester shifted my car prematurely, bogged it, and downshifted.

 

[jedhead]

One more idea since your HC spikes when the throttle is shut. How is the IAB? Maybe not enough air is going into the engine when the throttle is shut and causing the engine to run rich before the ECU can compensate. Just a wild guess.

Bob

 

[JSHOAz]

I`m sorry I cant read the graph very clearly.What you say is it fails HC only.The decel thing is pretty normal.If the iac malfunctioned it might retrurn to idle slowly/too quick,but the maf and o2`s should still keep the right mixture.Not much carbon really comes out of your engine hard driving.Any carbon that would affect driveabilty would actually be built up on the stem side of the intake valves.A beat run just fires off the cat.
I would start off making sure the plugs are fresh and gapped properly.Be sure you have NO misfires.You could have a leaky injector but you would probally have other symptoms(hard start,fuel smell,high fuel trim on that bank).After that its pretty much mixture(maf/o2`s).I would be after those items.A qualified dealer should be able to tell for about $100.Or I would go o2 sensors,retest.If it fails,your probally going to find a bad maf.Cleaning works 50/50.I never clean them on customer cars too hit or miss.And yes K+N filters **** them.Remember it could be skewed 15% and you would never know.I`m thinking a pair of o2`s,ford parts if you can.But be certain you have no misfires.

 

[aggiesho]

If I drove it hard for a while on the highway, chances are I'd get a ticket. The next ticket I get is gonna be more than just a slap on the wrist.

haha ya that wouldnt be good. i love the miles and miles of unprotected back roads in texas. (i probly just jinxed myself and the next time i go out on my favorite back road theres gonna be a state trooper sitting right passed the first turn ha.)

 

[Devin]

Heck, I was just talking about going sixty.

 

[haydenm315]

I`m sorry I cant read the graph very clearly.

If you zoom in you should be able to read it. I guess I shrunk it too much. Sorry.

What you say is it fails HC only.The decel thing is pretty normal.

I am failing HC only.

1.4317gpm HC
4.9783gpm CO
1.9547gpm NOX
344gpm co2

If the iac malfunctioned it might retrurn to idle slowly/too quick,but the maf and o2`s should still keep the right mixture.

SO cleaning the IAB probably won't help.

I would start off making sure the plugs are fresh and gapped properly.

My plugs have about 5k miles on them. I used the motorcraft fine wire platinums that replace the discontinued ones I had before. I gapped like it said on the radiator shrowd under the hood. It couldn't hurt to pull a couple to see what they look like. I'd hope they still look new.

Be sure you have NO misfires.

How do I test for this? I am pretty sure I'd be able to identify one under load but that isn't the case here. The car has more than ample pickup. It feels strong at 55mph in 5th on the highway. It rips through the entire rpm band pretty effortlessly.

Idle is a bit lopey, but I do have some parts of which include some old shoshop stage II cams. If I had a misfire at idle, how would I test for it? It seems to get out of the hole pretty easily without too much throttle and doesn't seem to lack response.

You could have a leaky injector but you would probally have other symptoms(hard start,fuel smell,high fuel trim on that bank).

I did pull the fuel rail recently to replaced the knock sensor. I don't smell gas though. I'd expect that condition to throw a code.

After that its pretty much mixture(maf/o2`s).I would be after those items.A qualified dealer should be able to tell for about $100.Or I would go o2 sensors,retest.

My O2's are about the same age as the plugs. If a cat is toast, how likely will it damage an o2? I'm guessing it would receive greater heat exposure. If it failed, shouldn't I throw a code?

If it fails,your probally going to find a bad maf.Cleaning works 50/50.I never clean them on customer cars too hit or miss.And yes K+N filters **** them.Remember it could be skewed 15% and you would never know.I`m thinking a pair of o2`s,ford parts if you can.But be certain you have no misfires.

I do have another MAF. I grabbed a 73mm C&L from the yard some years ago. People complained about it not running real good with the sho. I feared it leaning my car out and scorchign something, so I took it out. I may have gotten the electronics part swapped between my original and the one from the yard.

I ran clean koeo and koer tests yesterday afternoon.

 

[JSHOAz]

The idle is lopey? Are the aftermarket cams in the car? Lopey idle=high emissions

 

[haydenm315]

The idle is lopey? Are the aftermarket cams in the car? Lopey idle=high emissions

The cams are in the car. I have passed in the past with the cams installed, but that's not to say they aren't killing me now. I'm not gonna pull my freaking cams just for these emissions punks. If nothing is horribly wrong with my car, I'm fine with the waiver. I just don't want there to be something wrong with my car that I could've prevented that leads to problems not so far down the road.

 

[haydenm315]

I know to look at the MAF and O2's but Is there any chance a crappy throttle position sensor could cause my problems. I've also read that the vehicle speed sensor can affect decel emissions. What about the temp sensor in the airbox. If that thing is damaged could it exhibit these problems? I spike almost 4gpm HC on decel a number of times. Otherwise the numbers look like I should pass.

 

[JSHOAz]

The sensor in the box is the intake air temp.Mostly used by pcm for timing adjustments to prevent detonation.Its probally the cams putting you closer to the threshold.Idle lope is overlap which is unburnt fuel out the tailpipe.You could have a small problem like a lazy (slow to respond) O2 sensor but the cams will put you at the limit to begin with.

 

[haydenm315]

How much does passing emissions have to do with the driver of the car or the tranny type? I would assume it's easier to pass in an auto because the revs are probably gonna be lower. Do they follow certain shiftpoints and do shiftpoints make a difference?

If the driver bogs my car, I would think it would spike HC. I only see one real bad spike on accel and I'm pretty sure that's when Mr. Tester bogged my car enough he had to downshift to keep up with the arrow.

He really shouldn't of bogged it. The car feels like it's got the power of a ***** ape, like it's back to normal. It looked difficult for them to keep the car from going too fast on the test.


I'd like to blame the driver and just go back for my free retest. Then again I've had a number of people drive it over the last year and failed everytime.

 

[JSHOAz]

The bog aint gonna help,but the test machine should dump the test if the rpms go outside the limit.There is a small rpm window when performing the test for that reason.Aftermarket cams and IM240 type tests = problems.