ok i failed the delaware 2 speed test for the 3rd time. I have 14 days to figure this out or they will not let me get my tags.. Im failing the CO%

The car has new
opti
plugs
wires
oil and filter

cleaned stock injectors
the car DOES have a cat.

I have tried 93 octane and 87 octane and got almost identical results.

results..

HC PPM
Readings - low 108 high 71
allowed- low 220 high 220
pass

CO%
readings - low 1.94 high 2.51
allowed - low 1.20 high 1.20
FAIL

RPM READING
readings - low 1254 high 2532
limits- low 500 high 2200
PASS

help.... me...

 

Are you getting a check engine light?

You could also look into PCV, air filter, and O2 sensor if they havent been changed in a while.

I would also check fuel filter, MAP sensor, and MAF sensor.

 

No check engine light.


oh, and it has a new fuel filter. forgot that

 

Well, HI carbon monoxide is usually (most always) caused by a rich fuel/air mixture. Either too much fuel or not enough air. If your air filter's clean then you've probably got a sensor problem. It will be nearly impossible to tell which one without troubleshooting.

There are four main things that could cause it. Oxygen sensors, MAP sensor, Throttle position sensor(TPS) and the coolant temp sensor. (ECT) If you have a manual there is a procedure for checking the ECT at a certain temp and a procedure for checking the TPS. If you can't find it let me know and I'll scan it for you. My books are for a 1995 but they'll work just fine.

You could also download Freescan and get an ALDL cable and check all your sensor readings into the ECM.

Sorry I can't be of much more help but your gonna have to get into this one a little bit or just start throwing parts at it.

 

Nevermind,

RPM readings is 15mph and 25mph correct?

 

it is defiantly running rich. there is no smoke out the exhaust, but the car stunk out the testing facility with exhaust fumes. When i got home my wife complained about how much my clothes smelled like gas.


I dont have time to order the aldl cable and go through that. I need this thing fixed or rigged to pass by the 27th. Do the CO numbers look WAY off or just a tad? those numbers are all chinese to me.

 

It's more than double what's allowed. I'm not familiar with emissions testing because we don't have that here. Too many hillbillies in 1968 Chevy pickups with leaky carbs. We'd blow the emissions monitors up with the vehicles we drive.

Usually it's not the MAP sensor. It's pretty robust and holds up well. The ECT is know to cause a problem. Are you any good with a multimeter? If not are any of your friends? If so we can fairly easily check the TPS and the ECT. That would leave the best guess as the Oxygen sensors. We should rule out the ECT and TPS first though.

 

try cleaning the maf sensor, they collect dirt over time and it skews the readings, i dunno how many trys you get in 2 weeks, but you could lower the fuel pressure to try to get it to pass. the ecu will try to make up for it, but its a slow process and you mgiht get thru. try mixing in some e85 if its avaliable, the increased alcohol burns cleaner, or dump a can or two of denatured alcohol in the gas tank. sometimes thats enough to get em to pass, not good to run hard with teh mix

 

do they have the $450 waiver?

 

Do you have 160* thermostat?
Is the PCM tuned with lower fan on temps?
What temp is the engine reading on the gauge when the test is done?
I agree it's rich but why?
What has changed since the last time it passed?
is the cat located close to the mid pipes? Is there an exhaust leak?
How old are the O2's
Are the fans always on?
Smog air valves all working? Pump?

 

Wire the AIR pump so it is on for the whole test and divert it to after the primary O2 sensors. I'd do that or have someone spray shop air into the cat during the test when I was to lazy to figure out why a car wouldn't pass. It has to be after the primary O2s though.

 

do you have a tune? my car when i first got it passed with flying colors one year. then during that year i replaced my cat that went bad and got a tune and failed horribly. since then i said **** it and got rid of the environmental garbage

 

Good question.

 

No tune. I bought the car in december, and have had all that stuff replaced to get it running right. It was bought in NJ and last passed nj inspection in 2009. I have had it tested 3 times since Jan 5th and its failed with almost the same exact numbers each time. I have no idea how to use a multimeter. Never had to use one.

I might have a small leak at the header gasket. could that be fudging me up? And the kid that had the car before me de-screened the MAF.

 

Leaking header gasket can cause a burned exhaust valve. You might want to get that taken care of soon.

 

IF you have excessive leaks before the O2's it can cause a false lean condition causing the O2's to dump more fuel.
No it can't.

 

If you need new header gaskets, I've had great luck with felpro 1470 they seem indistructable, I have the same headers as you. Also pay attention to the drivers side header to y pipe 2.5 inch donut because the drivers side O2 sensor is in the y pipe not the header. A leak there will also give false air to the O2 sensor. I use Edelbrock 2.5 donuts #6937 about $10.50 for a pair from summit or I'm sure you can find that size donut locally.

 

I won't claim to be an emissions expert, but I've dealt with my fair share of vehicles that couldn't pass here in AZ... I didn't notice if you mentioned how many miles are on your motor/car, but when you're running rich, I'd look at the O2s... I realize they're a little difficult to t-shoot - if they're the original sensors on your 94, I'd say replace 'em.
Do you notice if the car seems to run richer after it warms up and goes closed-loop, or does it stay constant? Sometimes it can be hard to tell, but if it seems like it's running richer after it's warmed up, it almost definitely is the O2s, if it's really rich even when cold, it could be any of the items that 1963SS mentioned.
I feel your pain - it's no fun failing smog - my truck has 314k+ miles on it and most of the motor is original, so you can imagine the fun I have had getting that thing to pass the past couple of times. I do the "alcohol trick" to help with my truck, but that won't help in your case - that typically only lowers the HC levels and won't do much for CO...
Good luck!

 

My mistake, you are correct SS RRR.

 

i have a 94 ram that has a gutted cat. put a alright amount of e85 in and it passed after 7 times put about 5 gallons to the 24 it has. although thats kinda a bandaid its what i had to do and saved me about 300 bucks. runs like **** until it becomes diluted enough