Cadillac CTS-V - CEL questions round 2

I had posted a while ago about throwing p0171 and a p0174 codes. I changed the fuel filter and had put about 1000 miles on before it happened again. This time I just reset the code and it was fine for another 1000 or so miles now it has happened a third time. Is it just because of my CAI and exhaust?
It only seems to happen when we have been driving for a while then stop shut it off and start it back up within about 10 minutes.

I check for leaks on the intake and looked over the MAF. I am just puzzled why this keeps happening.

Someone mentioned in the other thread that a tune would help. What tuner or tuning system should I go with? Diablo SCT? thanks fellas.

MC

Did you clean the MAF yet? You shouldn't need a tune with a CAI and catback exhaust, the stock computer should be able to more than compensate.

I had posted a while ago about throwing p0171 and a p0174 codes. I changed the fuel filter and had put about 1000 miles on before it happened again. This time I just reset the code and it was fine for another 1000 or so miles now it has happened a third time. Is it just because of my CAI and exhaust?
It only seems to happen when we have been driving for a while then stop shut it off and start it back up within about 10 minutes.

I check for leaks on the intake and looked over the MAF. I am just puzzled why this keeps happening.

Someone mentioned in the other thread that a tune would help. What tuner or tuning system should I go with? Diablo SCT? thanks fellas.

MC

Just a wild guess but perhaps your fuel pump is on its way out. These codes are for both banks too lean (both sides of your motor). This tells me its not getting enough fuel across the board or getting to much air across the board.

It seems you've ruled out an air leak (I would double and triple check though) so it must be a lack of fuel. See if you can rent a fuel pressure gauge and see what pressure you have at the rail. It should be 58psi.

Are these codes coming and staying until reset or do they go away after a few drive cycles?

You could also "fog" around your intake manifold to see if you have an air leak there.

Did you clean the MAF yet? You shouldn't need a tune with a CAI and catback exhaust, the stock computer should be able to more than compensate. I have not cleaned it, I can sure try that next though.

Just a wild guess but perhaps your fuel pump is on its way out. These codes are for both banks too lean (both sides of your motor). This tells me its not getting enough fuel across the board or getting to much air across the board.

It seems you've ruled out an air leak (I would double and triple check though) so it must be a lack of fuel. See if you can rent a fuel pressure gauge and see what pressure you have at the rail. It should be 58psi.

Are these codes coming and staying until reset or do they go away after a few drive cycles? I can do that as well, They stay until I reset them which is usually a matter of hours after they show up. I havn't left them alone to see if they go away. But shouldnt a fuel pump either work or not work? Is there a half ass way they can work?

You could also "fog" around your intake manifold to see if you have an air leak there. I can google that and see how to do that as well.




Thanks for the help guys.
I just find it weird it is always after the same circumstances with starting and stopping the engine within a certain time period.

If the MAF is in question, just unplug the damn thing and let it run on the MAP sensor VE maps. The MAF can fail within range so that it does not cause any DTC's for the MAF itself, but can cause a whole host of other problems. And yes, a fuel pump can be weak...its not only an on/off deal.

Last dealer I worked at the kid next to me sold a Cat converter on a supercharged Grand Prix that was running like shit and had the Cat converter glowing red hot. Guess he figured the converter was clogged. He installed the new converter and it had the same problem...so he threw his tools around and went home early.

Service manager came to me and asked about the car since the owner was there to pick it up...so I started it, looked at the Tech2 for a minute, and unplugged the MAF. Cleared right up and it never had any MAF DTC's. BTW - $2200 repair bill for a $150 MAF sensor b/c it was misdiagnosed.

I have not cleaned it, I can sure try that next though.

That is the EASIEST thing to do and should be done every oil change anyhow. Buy this and spray the heck out of the wires. It will soak them but it drys quickly similar to brake clean.

http://lh6.googleusercontent.com/public/IM-ynBfBhzlituG2wvaMrnwQmqdLLfRouJJTtTmOJJ8R5Xez9WZyr VjKK3PaMdZzw3EPEJJ6RsDolUjJ-vq0YpiMWuVXLW8-YG1WMvEkcgkEHKn6sACqGN9Wcgyr74BzxiUzH7ewaiXj2Sy16Y sRi55RQDfxUkbfXRbiVSOfvxaJQhemnehy2Q

Report back before you go playing around with fuel pumps etc.

DMM I though you were military and now you are working at GM dealers!? Perhaps a grunt by day and tech by night? :)

Thanks again fellas.

Last night after work I reset the code. I started checking the intake tube for leaks and found that the brackets that hold on the maf and cone were extremely loose (like alot of other things I have found) It was loose enough that the tube could jump up down all around. I also found that the band clamps that connect the tube to the MAF housing were not tight so I tightened them as well. Hopefully this helps.

Also i noticed the MAF is aftermarket. Granetelli motorsports, makes me wonder what the previous owner had on this to need an upgraded MAF? Any ideas

I had posted a while ago about throwing p0171 and a p0174 codes. I changed the fuel filter and had put about 1000 miles on before it happened again. This time I just reset the code and it was fine for another 1000 or so miles now it has happened a third time. Is it just because of my CAI and exhaust?
It only seems to happen when we have been driving for a while then stop shut it off and start it back up within about 10 minutes.

I check for leaks on the intake and looked over the MAF. I am just puzzled why this keeps happening.

Someone mentioned in the other thread that a tune would help. What tuner or tuning system should I go with? Diablo SCT? thanks fellas.

MC

P0171 IS LEAN BANK 1
P0174 IS LEAN BANK 2

when you have BOTH banks showing lean, you've got a vacuum leak somewhere./
check your pcv hoses. check your intake. if you have access to a smoke machine, you'll find this leak in about 3 minutes.

Sounds like it was the extra air getting in after the MAF, that should fix your issue. I would still clean the MAF though, always a good idea.

Is there a screen on the MAF? Some people remove the screens in an attempt to increase airflow, but I haven't seen any hard evidence that it is beneficial. In fact, the screen I believe it used to even the airflow to help the MAF read accurately, so it would potentially be harmful to remove the screen.

These other guys probably know a lot more about that, but it may be one reason you have an aftermarket one. Other reasons for a change would be a broken original or an upgrade to a larger size for more airflow.

Sounds like it was the extra air getting in after the MAF, that should fix your issue. I would still clean the MAF though, always a good idea.

Is there a screen on the MAF? Some people remove the screens in an attempt to increase airflow, but I haven't seen any hard evidence that it is beneficial. In fact, the screen I believe it used to even the airflow to help the MAF read accurately, so it would potentially be harmful to remove the screen.

These other guys probably know a lot more about that, but it may be one reason you have an aftermarket one. Other reasons for a change would be a broken original or an upgrade to a larger size for more airflow.

a leak between the maf and throttle body would be a vacuum leak. ANY unmetered air is viewed as such by most ecus.

Also i noticed the MAF is aftermarket. Granetelli motorsports, makes me wonder what the previous owner had on this to need an upgraded MAF? Any ideas

Get rid of it.

Also i noticed the MAF is aftermarket. Granetelli motorsports, makes me wonder what the previous owner had on this to need an upgraded MAF? Any ideas

A Loose coupling allowing unmetered air would do it.

I hate those Grantelli mafs....Chances of this being tuned into your MAF curve is slim. If you had a scanner, would be easy to see, your STFT and LTFT would be way out
Different MAF, different MAF curve.
Granetelli mafs are junk imo.

My question is: Has this been going on since you owned the vehicle?

Is there a screen on the MAF? Some people remove the screens in an attempt to increase airflow, but I haven't seen any hard evidence that it is beneficial. In fact, the screen I believe it used to even the airflow to help the MAF read accurately, so it would potentially be harmful to remove the screen.


There is No benefit to de-screening. Thought this was common practice in 1999-2003. Ive done both, After extensive testing, Screening is a MUST. the g/sec is significantly choppier without a screen, many postings of this on HPTuners.
the tiny amount of more airflow which you would never notice giving up a smoother (more accurate) reading is not worth it.

A Loose coupling allowing unmetered air would do it.

I hate those Grantelli mafs....Chances of this being tuned into your MAF curve is slim. If you had a scanner, would be easy to see, your STFT and LTFT would be way out
Different MAF, different MAF curve.
Granetelli mafs are junk imo.

My question is: Has this been going on since you owned the vehicle?

Yes it has happend 3 times in the 3 months I have had the car.

Threw both of these codes today...P0171 and 174. I JUST cleaned my K&N filter about 6 days ago. I've never had either of these codes 'til now. I'm guessing I got the MAF dirty or jacked with some hose that I shouldn't have.

You could also "fog" around your intake manifold to see if you have an air leak there.

You can spray starting fluid around the intake to find leaks. If the engine revs up or down you have a leak.

The MAF is one of your problems.

They set those to run lean.

If you want to look for an intake leak, take a propane torch (unlit!) and wave it around the suspected areas.

If the idle goes up, you have a leak.

lean bank codes can also be a sign that you have a leak on the exhaust side. Not sure what your setup is on exhaust but it is worth a check. If there is a leak forward or around the 02 sensors you have a good chance of getting these codes as well.