ihave a 90 3.1 camaro and here is a list of what i have already replaced map sensor, egr valve, o2 sensor ,k&n air filter, catalitic converter, throttle position sensor, oil, spark plugs, distributor cap & rotor, ignition contoll module, ecm,fuel filter, emission evaporative canaster filter, fuel pressor regulatorand i have cheaked the fuel injectors engine coolent temp and thermostate. any help would be appreiciated.

 

when you replaced the tps, did you adjust it per the tech article? just wondering......

 

First off, what are the readings? A lot of people don't know how to interpret the numbers to give them an Idea of where to start, hell, a lot of auto techs don't know what they mean.

Post the numbers or PM me and I'll give you my best guess at where I'd start.

 

WELL THE FIRST TIME I PUT THE TPS ON IT IDLED REALLY HIGH, SO I TOOK IT OFF AND DID IT AGAIN AND IT IDLED FINE. I HAD THE CHANCE TO LOOK AT THE NUMBERS YESTERday and i passed at 875 rpm but not at 2255 rpm and that was after i replaced the egr and the air filter but i do not have the numbers right now maybe tomarro thanks so far.

 

well, your doing a Two Speed Idle Test, so I bet you probably failed for HC. Let us know what the numbers are and I'll be able to help you out more.

 

THIS IS THE RPMN I FAILED AT

RPM 2554 (READING) (LIMIT)
HC 156) (140)
CO (6.35) (1.00)
CO2 10.6
O2 .2
NO(X) 54
P.E.F. 0.470
THIS IS THE RPM I PASSED AT
RPM 810 (READING) (LIMIT)
HC (70) (120)
CO (.01) (1.00)
CO2 13.1
O2 2.1
NO(X) 72
P.E.F. 0.470
HOPE THIS HELPS THANK YOU FOR HELPING THIS FAR

 

when exactly did you replace the O2 sensor? Was it with a cheapo or a quality sensor?

It looks like it's not even in closed loop at RPM, which could be attributed to a lot of things which unfortuantly are impossible to test without special tools.

I suspect a problem with either the O2(most likely) or with the air/fuel metering system(MAF, TPS, or CTS)

 

you have an air restriction of some kind. the CO is getting worse with rpms and your CO is getting high enough to cause the HC to get high also

 

That's a very rare problem, especially with 3rd Gen camaros because the first thing people do is gut the airbox and install K&N's . You could check the air filter, but that's the only restriction there.

Here's the 100% test. Hook up a vacuum guage to manifold vacuum and go for a short drive. When you go WOT in 3rd gear, you should see 0 vacuum the entire time you are WOT. if that's the case, there's no restriction.

I still stand by my closed loop problem. It's just not there when you speed up the engine. GMs have this issue because the O2 ends up flat-lining and the ECM goes open loop as a safe-guard. It's a very common thing.

As a tech, that's where I would start looking. Don't assume that just because it's new that it's good. I've installed more than one O2 that was bad out of the box, unfortuantly it happens.

 

all of the parts listed as replaced have less than150 miles on them because i dont have my dL yet but i get it this month

 

Unfortuantly none of that matters when you are trying to diagnose a problem. The part may be new, but it still might be bad. You'll ahve to check them out. If they were all working properly, you'd pass.

YOu don't by chance have air injection, do you?

 

i like your WOT test, thats a very good idea. the only thing i guess i dont understand is if he's not going into closed loop then wouldn't fail or all most fail at idle? maybe i'm reading too much into this, i'm still kinda green to gas analyer readings. the only reason i said that is that would be one of the simplest problems that could cause those readings. he said he put a K&N air filter on the car maybe he used too much oil on the filter?

 

Nobody asked about ignition timing yet... ? Have you checked it? Bad timing will raise HC's. If you did set it to spec, did you also check your balancer to make sure the outer ring hasn't slipped?

Oh and next time just use a regular "brand new" paper air filter for the test. After you pass, put that "brand new" filter back in the box and use it again for the next inspection. That way you don't have to worry about cleaning/oiling the K&N.

 

This would be a very good point if he had failed for HC, but no CO. Timing doesn't make you run richer.

What seems to be happening is that for whatever reason, it's in closed loop at idle, but the closed loop parameters are not met when the RPMs are up. GM cars need 4 things to enter and stay in closed loop operation:

1) Coolant temperature has to be above a specified level as indicated by the ECT

2) A certain amount of time has to have passed since the car was started. This time varies depending on how warm the car was when it was started, but on cold start it's typically right around 2 minutes.

3) The O2 sesnor must be warm and sending a signal to the ECM. If it's too slow or dead, closed loop won't happen.

4) You can't be WOT. Any time that you go full throttle, the computer jumps to Open Loop mode and dumps in fuel for power enrichment. It no longer cares what the O2 sensor is saying.

Don't jump to conclusions and blame the ECM. A lot of people have been doing this latley and spending money on crap they don't need just because they don't want to take the time to properly test something.

Here's the cheating way to see if you're in closed loop or not...ready for this?

Start the car and jump A and B on the ALDL just like you were trying to read codes, but with the engine running. The SES light will blink fast if you're in open loop and will flash slow if you're closed loop. Once it's in closed loop and blinking slowly, you can also see if it's mostly rich or mostly lean by seeing how long the light is on for. If it's on longer than off, it's rich, and vise versa. Just a little secret for you all.

 

nice tip man, i didnt know you could tell if you were in open loop or not, thats cool.

 

could water it down with E85 gas.

That is a trick muscle cars guy do. Run a little bit of gas water down heavy with alcohol, retarted timing and sometimes a hidden vacuum leak.
All done just to pass then they un-do it.

 

Uh, wait, he did fail for HC's too. Unless I read his smog slip wrong? His reading was 156 but limit was 140?

And earlesimers, if you try that closed-loop/open-loop "test" trick, make sure you follow 2_point8_boy's message closely- start car, and THEN jump the A&B pins together. Don't have those pins jumped before you start the car!

 

That's correct, but the reason that the HC reading is so high is because of the CO problem. Once the CO issue is resolved, the HCs will come WAY down. This is the order that you repair smog problems: CO, HC, NOx, in that order because each one affects the one after it.

 

thanks 4 the tips and advice so far just so you know i didn't wast my money on the ecm cant afford to do that type of thing. it was so shot that my car wouldnt idle with it and i didn't oil the k&n it was already oiled when i bought it thanks again i will do that test this weekend

 

TomP this is how i was taught CO can effect HC, but HC cannot effect CO basicly an air/fuel mixture problem can cause you to have a misfire, which is exactly what HC is telling you, that you have a misfire.

 

That's pretty close, it's better to think of it like this. HC is unburned fuel. You're always gonna have a little left over because of the corners of the chamber and other things like that, you just can't burn every little molecule. CO is the indicator that you have way too much fuel for the amount of air in the cylinder. The more fuel you have generally, the more that you're gonna have that you can't burn.

 

i did that jumper wire test and the light flashed fast, slow, and it even stayed on for about 10 seconds, so i got another sensor and it stayed off longer than on ,but it still flashed fast and slow. iam wondering if it coul;d be a computer problem what do you guys think thanx.

 

I seriously doubt the computer is at fault. People like to blame them, but the fact is that they rarely go bad. So it looks like you are reaching closed loop at least at idle, so now what you have to do is watch the light at idle and make sure it's flashing evenly, you might have to raise the RPM to about 100 to get this, then take it up to 2500 rpm and see if it starts to blink fast or if it stays on all the time.

If it stays on all the time, the O2 is telling the ECM that it's rich, but some other sensor(s) is(are) overriding the O2 signal and forcing it rich. It could be a multitude of things all the way from load sensor(MAP in your case) that's gone bad all the way down to a CTS that's freaking out.

I know it's tough to diagnose your smog failure, but that's why I get $65/hour at my shop to do it, because I have the correct equipment to do it and the knowledge to hunt down the problem. Without the equipment for the job, it's hard, but if you want to do it yourself, push through and you'll figure it out and learn something in the process.

The computer is the LAST thing that you replace after you have verified that all the other sensors are giving the correct information, because it only makes decisions based on info it recieves. If it gets the wrong information, it makes a bad decision.

 

I BOUGHT A MAP SENSOR AND THE FLASH TEST IS BETTER BUT I TOOK IT TO BE SMOGED AND THEY DIDN'T TEST IT BECAUSE THEY SAID IT HAD A GAS LEAK SO I HAVE YET TO FIND OUT IF I HAVE MADE HEADWAY

 

where did the fuel leak come from?

 

THE FUEL RAIL AND MY GRAND PA TOOK IT TO GET SMOGED TODAY AND MY CO LEVEL AT HIGH RPM HAS COME DOWN TO 4.1 INSTED OF 6.? IF ANY ONE COULD TELL ME WHERE TO GO FROM HERE PLEASE HELP.

 

Well, that's a start. As I said before, don't trust that a component works just because it's new. You replaced a component that you said you had already done, and it helped, that means that it wasn't doing something right...

Now, recheck the CTS. That's a component that not many people know how to check properly. Tell me how you checked it before. What temp t-stat do you have?

The other reason why I suspoect that it's not truly in, or falling out of closed loop operation is because you're not getting a Rich Code. The ECM won't bother to set the code is it's not in closed loop to correct for the extra fuel.

 

how do you check the cts?

 

You back probe the harness connector, with it hooked up to the sensor and read the voltage. What you are reading is the voltage drop(usage) across the sensor. Since they are negative temperature coefficient sensors, the resistance goes down as the temperature goes up, which means that the use less votage, so the reading goes down. The voltage table for it might be somewhere here on the boards already, but I'll get it for you guys in the morning and post it for you.

 

I have a 195 degree thermostat and this is how i checked the cts the first time i took it out ran hot water on it and used an ohm meter to monitor the resistanceis that the correct way to test the cts

here are my current numbers at 761 rpm
reading limit
hc..........................ppm 58...............120
co..........................% 0.01.............1
co2........................% 13.3
02..........................% 1.6
no(x)......................ppm 22

p.e.f.............................0.470

and at 2602 rpm
reading limit
hc..........................ppm 99...............140
co..........................% 4.05.............1
co2........................% 12
02..........................% .2
no(x)......................ppm 52
here is the same test but differnt rpm 2596
reading limit
hc..........................ppm 99...............140
co..........................% 4.07.............1
co2........................% 11.9
02..........................% .2
no(x)......................ppm 50


p.e.f.............................0.470
wanted to give you guys as much info as possible thanks so far

 

Is this car being tested on a Dyno?

 

I DONT THINK SO THE FIRST SHOPS I WENT TO JUST DID THE TESTS IN PARK NOT ON A ROLLER

 

but the second shop did? If it didn't go on the rollers, you shouldn't have a NOx reading on the sheet.

THe reason I ask is so that I can at least warn you that as soon as you fix the rich problem, your NOx is going to climb, and fast. What's your ZIP code, I'll be able to track down if you're in a basic or enhanced area that way, you can PM or EMAIL me if you wish and don't feel comfortable leaving that info on a post.

 

Oh thanks, I didn't know that! I thought they were their own "separate" problems... that CO was gas that did burn- just not with enough air. Good to know they affect each other. No wonder I never had any NOx problems

 

my zip is 96003. so your saying that the shops with rollers wont look at the nox, and did i test the cts right I really apprieceate the help thanks

 

LMAO.. Im in 96002 Now I know a few good shops that can help U pass.. I just did mine a few months ago.. and it was a mess to start with...

 

No if the car does go on the rollers, then we measure NOx, if it gets the idle test, then it shouldn't measure NOx.

OK, I just looked it up and Shasta County is a BASIC area, which means that your car SHOULD NOT be going on the rollers, which means that there is no NOx measurement made. Just as long as your EGR system functions, we assume that you don't have a NOx problem.

So the CTS tested ok?

Check the cold start injector switch: Check at the CSI harness, not the swithc harness. WIth the car warm, there should be 12 volts on both wires and with it cold there should be near 0 volts on both wires.

If you have AIR injection, kame sure that it does vent to atmosphere once the car is warm, if it still pumps into the exhaust, the O2 will see lean and dump fuel in and cause a rich condition too.

 

where do i find these parts on my car?

 

Nevermind on the Cold Start Injector, you don't have one, so it doesn't matter.

Do you have AIR injection(Smog Pump)? It would be on the passenger side at the bottom.

 

KRACKER JACK .. I live in Redding and just went thru SMOG and had a hard time.. Maybe I can help.. Message me or PM me..

 

ISTILL DONT UNDERSTAND WHERE IT IS ,WHAT DOES IT LOOK LIKE

 

i found it sorry but i noticed that it pump air to the cat,exaust & the intake but i dont have any thing running to the intake or cat just the ports. and where is the diverter switch oh yea and what does WOT mean thanks

 

WOT mean Wide open throttle AKA Full throttle

 

Our systems are only designed to pump into the exhaust at the manifold during cold start. That's the only time it's needed, so the way yours is routed is totally normal. The Diverter Switch is right behind the air pump in the big tube that goes up to the exhaust manifold. What you need to see is if the air is coming out of the tin can looking thing down at the bottom. I'll take a picture of it for you tomorrow so you know what to look for

 

I DID THE JUMPER WIRE TEST AGAIN AND RAISED THE RPM AND THE LIGHT STAYED ON THE WHOLE TIME DID NOT FLASH AT ALL WHAT DOES THAT MEAN?

 

it finally passed i took it to the shop and it turns out it was the vaccum hose on the map and the o2 sensor again