JBA Shorties & Cats on ZL1--Help with CEL

[IcePick06]

Well I recently took my ZL1 to a local shop to install my JBA shorties and Hi-Flow cats that I bought from Maryland Speed (best price I found ) and am running into problems. First off, before this turns into a LT vs shorty debate, I decided to go with Shorties and Hi Flow Cats for now while I'm still under warranty because I was looking mostly for sound (maybe a little extra power ) and didn't want to tune the car for warranty reasons (I've already replaced my supercharger under warranty! ). So as soon as I leave the shop I get a CEL and I notice under full throttle the car sort of "sputters" or acts like it's losing traction when really the engine power is cutting out. The Service Stabilitrak light comes on the DIC momentarily and then goes off after about 30 seconds. So I call the shop and explain and they hook up their computer and it says the #4 power cable/spark plug is not reading on the driver side. JBA supplied a cable for that side, so I'm thinking maybe it's a faulty cable. Anyway, I had the shop go to JBA (they are local in SoCal) and get a slightly longer cable and replaced the old one. I got the car back today and there was no CEL on the car for about 30 miles and then I got on the freeway and floored the throttle...sure enough the car seemed to lose power at about 5k RPM in 3rd gear and then the CEL and Stabilitrak light came out. The Stabilitrak light went off immediately but the CEL stayed on and has not shut off since and I've driven about 50 more miles. Any ideas? I don't want to tune, and the shop owner who installed the headers and cats assured me there are no leaks with their installs. I'm sort of giving up at this point

[DangerZL1]

I doubt a leak would cause the CEL. Can you take it back to the shop and bave them tell you what code is causing the light or have a local parts store scan it for you?

[ZED SLED]

Originally Posted by DangerZL1

I doubt a leak would cause the CEL. Can you take it back to the shop and bave them tell you what code is causing the light or have a local parts store scan it for you?

A flange leak will definitely cause a CEL. I had DT shorties in my SS and it threw a lean bank condition because of this. However, what the OP may be experiencing is a fault from one or both of the rear O2 sensors. Sometimes JBA HF catted mid-pipes will do this because they don't have extenders for the rear sensors. I had Solo HF cats which came with extenders and I don't know of anyone ever throwing a code with these. If you can get extenders to move the rear O2s out of the stream you will probably be fine. You might find more info on this by searching in the exhaust section.

[SlingShot]

I have just the Solo cats, and have zero CEL ... I would say it's the JBA cats

[IcePick06]

Originally Posted by mclark10

A flange leak will definitely cause a CEL. I had DT shorties in my SS and it threw a lean bank condition because of this. However, what the OP may be experiencing is a fault from one or both of the rear O2 sensors. Sometimes JBA HF catted mid-pipes will do this because they don't have extenders for the rear sensors. I had Solo HF cats which came with extenders and I don't know of anyone ever throwing a code with these. If you can get extenders to move the rear O2s out of the stream you will probably be fine. You might find more info on this by searching in the exhaust section.

Does JBA sell the extenders...or do you know where to get some that will fit?

[ZED SLED]

Originally Posted by IcePick06

Does JBA sell the extenders...or do you know where to get some that will fit?

I'm not sure. I know solo does, and they should fit, but I would check the exhaust section or do a search on JBA catted mid-pipes. There's been lots of discussion in the past about this so you should be able to find a good source that has JBA experience to help resolve this. Most people complain about Solos costing so much, but like anything, there's usually a reason for that.
Good luck

[justa25thTA]

at every auto parts store they sell them as anti-foulers

[AMCBimmer]

You have a broken spark plug. I did the same thing on my ZL1 check codes and pull the plug on that cylinder.

[IcePick06]

Originally Posted by AMCBimmer

You have a broken spark plug. I did the same thing on my ZL1 check codes and pull the plug on that cylinder.

That's what the code said the 1st time but I had the tech replace the #4 spark plug on the driver's side and the JBA cable that came with the shorties was swapped out by JBA for a longer one to ensure the cable was fully connected. The code still came back on after a few miles and the power loss problem is still there. I'm now wondering if the rear o2 sensors are the problem and I need extensions. Somebody else said that without tuning you can't run the shorty headers and HF cats setup on the supercharged ZL1 (SS owners run this setup but they aren't blown) because there's too much exhaust flow near the o2 sensors for the stock fuel mapping and the system thinks the cats have failed so the code is thrown and the engine cuts power at certain boost to prevent damage to the engine.

[AMCBimmer]

I have Kooks longtubes and the green cats. I had 2 broken spark plugs. You will not get a miss like you are describing. Did you leave the spark plugs in when you were installing? We did and I believe we had to replace 2 spark plugs. I would pull all the plugs and go over them. We also had an issue where the plug wires kept pulling off. Either way your car will not run that poorly because of what you mentioned.

What does the code say? If it says misfire it is either a cable or another plug. You will not get a misfire code from a O2 sensor.

[IcePick06]

Originally Posted by AMCBimmer

I have Kooks longtubes and the green cats. I had 2 broken spark plugs. You will not get a miss like you are describing. Did you leave the spark plugs in when you were installing? We did and I believe we had to replace 2 spark plugs. I would pull all the plugs and go over them. We also had an issue where the plug wires kept pulling off. Either way your car will not run that poorly because of what you mentioned.

What does the code say? If it says misfire it is either a cable or another plug. You will not get a misfire code from a O2 sensor.

I haven't read the code this 2nd time so I will have to go back to the shop or the dealership for that. But they assured me there are no leaks at all with the headers and they replaced the spark plug and the cable. I spoke to the shop owner today and he said that with the JBA HF cats and headers you really need to tune because you're running too rich at that point anyway and that's why the power is cutting out (aka the "sputter" I'm feeling only under WOT or full boost). I should also add that if I slowly get on the throttle until it's fully depressed the "sputter" is basically non-existent. So I'm thinking a tune maybe the way to go too; I just hope warranty issues don't arise--but I guess I could always revert back to the stock tune for any engine warranty problems . The other option is take off the JBA cats and swap them for maybe SOLO cats which are supposed to eliminate any CEL. But either way I think by running shorty headers the MAP is way off and with hi flow cats added, the whole system is just flowing way too much and I'm running rich and losing boost under WOT

[AMCBimmer]

I'm going to send you a pm.

Originally Posted by IcePick06

I haven't read the code this 2nd time so I will have to go back to the shop or the dealership for that. But they assured me there are no leaks at all with the headers and they replaced the spark plug and the cable. I spoke to the shop owner today and he said that with the JBA HF cats and headers you really need to tune because you're running too rich at that point anyway and that's why the power is cutting out (aka the "sputter" I'm feeling only under WOT or full boost). I should also add that if I slowly get on the throttle until it's fully depressed the "sputter" is basically non-existent. So I'm thinking a tune maybe the way to go too; I just hope warranty issues don't arise--but I guess I could always revert back to the stock tune for any engine warranty problems . The other option is take off the JBA cats and swap them for maybe SOLO cats which are supposed to eliminate any CEL. But either way I think by running shorty headers the MAP is way off and with hi flow cats added, the whole system is just flowing way too much and I'm running rich and losing boost under WOT

[ZO6 Bryan]

Originally Posted by IcePick06

I haven't read the code this 2nd time so I will have to go back to the shop or the dealership for that. But they assured me there are no leaks at all with the headers and they replaced the spark plug and the cable. I spoke to the shop owner today and he said that with the JBA HF cats and headers you really need to tune because you're running too rich at that point anyway and that's why the power is cutting out (aka the "sputter" I'm feeling only under WOT or full boost). I should also add that if I slowly get on the throttle until it's fully depressed the "sputter" is basically non-existent. So I'm thinking a tune maybe the way to go too; I just hope warranty issues don't arise--but I guess I could always revert back to the stock tune for any engine warranty problems . The other option is take off the JBA cats and swap them for maybe SOLO cats which are supposed to eliminate any CEL. But either way I think by running shorty headers the MAP is way off and with hi flow cats added, the whole system is just flowing way too much and I'm running rich and losing boost under WOT

No way just adding headers and cats would throw anything off that far. They might set a code but it won't affect drivabilty at all. Something is screwed up.

[IcePick06]

*UPDATE*CEL magically went off when I started car up yesterday. Drove 30 miles shut sown and restarted and drove another 30 miles or so back home...CEL still gone. BUT as I said if I start to floor the gas I can start to feel the sputter again (almost feels like traction control is fully engaged). Now I'm thinking it is the cats being read too strongly by the o2 sensors under full boost.