Alright, my mod list consists of a Superchip, K&N panel filter, with airbox mod, 3 in exhaust pipe, high flow cat, and Flowmaster 40 delta series with no tail pipes and I installed a Flowtech 3 in cutout today.

I had the cutout installed in front of the high flow cat. I did not start it up at the shop because we wanted to keep it low profile in town since it's not really all that legal. My town seems to be pretty layed back about some of the vehicle laws though. Anyways, I drove home and everything seemed fine with the cutout closed. When I got home I opened it up and drove around for a while, I noticed that my temperature was a little higher than usual, it was on the R in NORMAL. Usually it's around the beginning of N to the beginning of O, it moves around a little depending on driving conditions.

I kind of expected to see this as I am under the impression that when the engine leans out it will heat up. Am I right about that? I remember from earlier posts I've made that with headers a new program needs to be burnt onto the Superchip because lean conditions will occur from the increased flow and scavenging of exhaust gases. I am convinced that the cutout causes the same conditions now. I may need to get a reburn for that. But first let me explain the rest of my problem.

All of the above was half way anticipated, what came next really has me scratching my head. I went ahead and closed my cutout, and made sure the gasket was put on before the metal cover. I torqued the wing nuts pretty tight to make sure I made a good seal. When I started driving I thought my temperatures would start to come down to where they were before the cutout. I was wrong, the temperature still seems to sit on the R. I know I am not leaking from the cutout, so I cannot seem to figure this problem out, and it's driving me crazy. Is there some way that the extra volume in that part of the piping is causing some sort of flow problems? I would appreciate any answers or ideas.

I am going to take out the chip and see if my temperatures are lower with the cutout closed and opened. If that works, I'm just going to leave it out for a while, until I can afford a reburn of my chip.

 

Was the drive home long enough to allow the engine to heat up to its new operating temp. You should have driven home and then some with the cutout closed before opening it. This would give you a base line to start from. Where is the O2 sensor located? Was it damaged by the installation of the cut out? Was just the cut out installed? Or were more parts installed?

JMC

 

JMC,

Yes, the drive home was definitely long enough to get up to normal opperating temperature. I don't know what the temperature was though. Which is interesting because I always am aware of the temperature in my truck. I look at the guages more than I look at the speedometer.

The O2 sensor is located before the cutout, I think it's on the y-pipe. I don't think it was damaged during the install because the check engine light doesn't come on, and I think if the 02 sensor goes bad, the computer makes the engine run rich right? It seems like I am getting the opposite effect. The cutout was the only new item to be installed, although the high flow cat had to be moved a few inches to make room for the cutout.

Can somebody please tell me the conditions of a lean running engine?

 

I removed the Superchip and drove the truck with the cutout closed. The truck still wants to heat up to the R. The only things I figure can cause this are a bad O2 sensor, or a failed cat. Being that the cat is brand new (installed a couple months ago), and I didn't have any problems with the O2 sensor before the cutout install, the installer of the cutout would have had to cause the failure of either of these. Any other ideas to why my truck is heating up. Maybe the timing of it is just a coincidence, and it really is just a problem with the cooling system.

 

Yet another update. I drove with the cutout open and the Superchip out. The same heating characteristics were there. I am now beginning to think that my O2 sensor is the problem. Does the engine normally run warmer with a bad O2 sensor? It's the only thing that I can think of that makes sense to me.

 

Hi 94,

This might be nothing more than your gauge responding a little bit differently, or you may be onto a lean condition here, for example, that is possible. I do think it would be a good idea to just go back & give the exhaust work a once-over in this case just to make sure the any O2 sensors affected are where they need to be and connected, etc. Any good repair shop can check your O2 sensor(s) for proper response as well.

Iin general, O2 sensors should be considered a normal maintanence item to be replaced at 30K mile intervals we recommend, though it won't be the end of the world if you go to say, as much as 50K miles in a non-performance vehicle. In reality, most people leave 'em in until the vehicle won't run anymore unfortunately, due in no small part to the fact that virtually no automaker puts that in their list of routine maintanence items to be changed at regular mileage and/or age intervals. But they are in fact a routine replacement item that can fail at any time without outside cause.

If an O2 sensor fails, you can't count on automatically running rich, the engine can go lean from a bad O2, and certain exhaust setups can lean out the motor significantly as well.

You may well have an O2 sensor problem, a lean condition can indeed put a lot more heat into the motor and thus the coolant temps rise, as will the automatic transmission fluid temperatures as a result of the radiator being hotter.

You may also have an EGR issue, or a hose giving up, a water pump not up to snuff anymore, etc. If you have more than 30K miles on the O2 sensor, you can always just go ahead and replace it, and consider yourself lucky if that does the trick. If it doesn't cure it no harm done, you just did good maintanance & now it's time to let a good mechanic check it out for you.

Do the basics first, hopefully before you drive it again. Meaning, check your coolant level, look for any signs of leaks in any area of the radiator or any hose, near the thermostat or at the bottom of the water pump, etc. Look where you park, are there any signs of any kind of fluid leaking, etc. If you're ok with coolant level, etc., have the exhaust work looked at just to check it, maybe replace the O2 if you want, but if it's not fixed at that point, get it into the hands of someone to give it a good going over to find the real problem.

Good luck!