high carbons when trying to smog

[Will-n-SD]

2 days ago I took my 98 Rodeo to the smog place after cleaning my EGR port. I cleared the code and drove it for 53 miles before taking it to smog check. The guy puts it on the machine and it matches the carbon limit but it passes. The part that failed was that after 53 miles, the computer was still reading that not all components checked in so the light was still on. So I decide to drive it to work a couple of days and take it back to pass smog. Well I also put that Guarantee to Pass Smog crap in the take. Well I take it back to smog and now the light is not on of course and it failed the carbon.

So I asked the guy what he thinks it can be. He tells me that it could be a number of things. Being that I have given it a tune up a couple of weeks ago, I know it is not an oil, plugs, or even an air filter. I have had problems with the truck starting. It will keep turning like it is not getting any gas then it starts. So he tells me that since it is hard to start that it could be the fuel pump not keeping enough pressure in the line which could be making the car run too lean causing higher carbons.

So I know that my problem could be either the pump or the catalytic converter

[Ramblin Fever]

Was the truck good and warm the 2nd time you took it in? Did it have enough driving time before the smog for the additive you put in it to circulate?

I've never used any additives such as that, so I'm unfamiliar with it - what's it supposed to do, other then the obvious of what it says.

Generally a bad cat on a +96yr will throw a code for the cat convertor - if it's bad. Could also be a bad intake manifold gasket, which is common for your year.

[Will-n-SD]

My work is an hour away from home and the smog place is by my house. So yes it was plenty warm.

As for the additive, it is supposed to clean out the system so it runs cleaner. I did run it long enough for it to get cleaned but I am thinking that I should have not put it in unless it failed again but since I was matching numbers 2 days before, I figured I would play it safe. I should have waited.

As for instake gaskets. They were just replaced by me since I had the P0401 code and it turns out the that end of the tube in the manifold was blocked. So after cleaning that out and the intake, I put on new gaskets.

On my 97 Saturn, I had only a bad sensor error but I knew the cat was bad since I could hear partss of it rattling around. 2 years before I had the cat replaced on it, the guy told me that the carbons were high and that the cat was probably going on it. No code ever for a bad cat.

What is the code that would be thrown for a bad cat?

[Canucklehead]

Originally Posted by Will-n-SD

What is the code that would be thrown for a bad cat?

Generally a bad catalytic converter will throw either;
P0420 - TWC System Low Efficiency Bank 1
or
P0430 - TWC System Low Efficiency Bank 2.

[95.5 Rodeo]

Originally Posted by Will-n-SD

I have had problems with the truck starting. It will keep turning like it is not getting any gas then it starts. So he tells me that since it is hard to start that it could be the fuel pump not keeping enough pressure in the line which could be making the car run too lean causing higher carbons.

When is the last time you replaced your fuel filter?
When clogged they will not pass enough fuel for the engine to run properly.


Good Luck,
Dale

[trooperbc]

Originally Posted by Will-n-SD

I have had problems with the truck starting. It will keep turning like it is not getting any gas then it starts. So he tells me that since it is hard to start that it could be the fuel pump not keeping enough pressure in the line which could be making the car run too lean causing higher carbons.

Originally Posted by 95.5 Rodeo

When is the last time you replaced your fuel filter?
When clogged they will not pass enough fuel for the engine to run properly.
Good Luck, Dale

if you're going down this path, i'd think of the fuel pressure regulator first. usually a low-volume pump will show itself first when you need fuel the most such as on acceleration and even going uphill. the fpr has been known to leak into the vacuum line, which is easy enough to check. also do a search here, i think there have been some very recent posts on this with similar symptom, iirc...

//bc

[Will-n-SD]

acceleration is fine. It does hesitate a little from time to time but that is when I am going from 40 to 50 or something like that. If I do a hard acceleration it stands strong and gives me everything she has. I have not replaced the fuel filter so I guess I can try that.

I have never seen those codes. The only codes that I have seen on my Rodeo is the P0401 and the P0101.

Could an old or dirty fuel filter cause bad fuel pressure? I am guessing that it can.

[Gizmo42]

Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).

I'm thinking FPR or fuel filter as well since the IMG was replaced recently and seems to be running fine.

[Will-n-SD]

what are the chances it is the FPR? Is it heard of that they go bad on a regular basis?

[Gizmo42]

Originally Posted by Will-n-SD

what are the chances it is the FPR? Is it heard of that they go bad on a regular basis?

Its not unheard of. I've seen a few posts on the forums about them going bad. Start with the fuel filter (cheaper and easier) and if that doesnt do it then replace the FPR.

[Will-n-SD]

Originally Posted by Gizmo42

Its not unheard of. I've seen a few posts on the forums about them going bad. Start with the fuel filter (cheaper and easier) and if that doesnt do it then replace the FPR.

That was my plans. Now if only I can get my CC back from the Mrs since she lost hers.

[trooperbc]

have you removed the vacuum line from the fuel pump relay to see if it has fuel in it?

//bc

[Will-n-SD]

Originally Posted by trooperbc

have you removed the vacuum line from the fuel pump relay to see if it has fuel in it?

//bc

Nope but I will now. I take it that it is not supposed to have fuel in it?

[trooperbc]

Originally Posted by Will-n-SD

Nope but I will now. I take it that it is not supposed to have fuel in it?

correct. like i said in post#6 above when i suggested looking into the fuel pressure regulator, there's been a bunch of posts recently, it seems, on this isssue with iirc your symptoms. you might want to try a search here and other forums if you want.
good luck

//bc