PLEASE HELP!!!Cant build up on spin tires over in my c5 corvette

[4horseman]

If I had to guess I would start with the easiest things you can do. First clean the MAF and Throttlebody. I would then check all vacuum lines. Make sure they are all connected. I once had a vacuum line rot next to the fire wall by the intake manifold and all hell broke loose with my low end power. Make sure you have no shorts on ignition cables. Next I would make sure my o2 sensors and Cats are ok. Once My cats were clogged and malfunctioned and my car did NOT throw any codes. My mechanic spent two days before he figured out what was wrong.My car bogged like crazy. Only when I got up to speed did it somewhat run ok. When you look at your log file click on gauges and you should see your o2 oscillate up and down. Im not sure what steps you have already taken but I can tell you what I have been through with my 1998 c5!

[4horseman]

Also does your car have active handling ? I know some 1998 c5 later in the production year had it. Im not talking about traction control. If you do turn both traction control AND active handling off. My buddies 2001 bogged at WOT in competition mode. FYI. Meanwhile Im going to go over your log file one more time to see what the differences are.

Is it possible that you can launch the car full throttle without letting up on the gas after your 1st to 2nd shift? Take it all the way till it shifts from 2nd to 3rd keep the peddle to the floor. Be careful you will reach 77 mph more or less. Ill do the same an impose my log on yours and see if I can spot anything out of the ordinary.Remember turn off traction control AND active handling if your car is so equipped.

[pharestutt]

Also does your car have active handling ? I know some 1998 c5 later in the production year had it. Im not talking about traction control. If you do turn both traction control AND active handling off. My buddies 2001 bogged at WOT in competition mode. FYI. Meanwhile Im going to go over your log file one more time to see what the differences are.

Is it possible that you can launch the car full throttle without letting up on the gas after your 1st to 2nd shift? Take it all the way till it shifts from 2nd to 3rd keep the peddle to the floor. Be careful you will reach 77 mph more or less. Ill do the same an impose my log on yours and see if I can spot anything out of the ordinary.Remember turn off traction control AND active handling if your car is so equipped.

my ebcm is no good so i dont have tcs or abs but i will get that log asap

Here it is

[pharestutt]

Also does your car have active handling ? I know some 1998 c5 later in the production year had it. Im not talking about traction control. If you do turn both traction control AND active handling off. My buddies 2001 bogged at WOT in competition mode. FYI. Meanwhile Im going to go over your log file one more time to see what the differences are.

Is it possible that you can launch the car full throttle without letting up on the gas after your 1st to 2nd shift? Take it all the way till it shifts from 2nd to 3rd keep the peddle to the floor. Be careful you will reach 77 mph more or less. Ill do the same an impose my log on yours and see if I can spot anything out of the ordinary.Remember turn off traction control AND active handling if your car is so equipped.

Did you come up with anything I believe something is cutting fuel out. I just started getting a insufficient switching code for my o2s

[4horseman]

Did you come up with anything I believe something is cutting fuel out. I just started getting a insufficient switching code for my o2s

Ok that usually happens when the car is not switching from rich to lean fast enough. That can be a real problem especially trying to generate power.. Have you changed out your 02 sensors recently? Have you installed aftermarket headers? I am looking over your log file now and comparing. Give me a couple of hours.

[4horseman]

Ok I think we have a winner. The concern is with the front o2 sensors. The rears dont really matter as much in this case. At wide open throttle your front o2 are registering 91 mv. It should be around 900mv! Your long term fuel trim are not fluctuating normally It is plain as day.Check it out on my log file.You cant miss it. It is my opinion that your o2 sensors are causing havok with your fuel delivery causing a too lean or too rich condition and causing bog on acceleration.

I think you should re load a stock file to your car and see if you still get the same o2 readings. If you do chances are you have a bad sensor or something is up with the wiring harness to the sensor reporting to the ecm.Always check the easiest things first.

[pharestutt]

Ok that usually happens when the car is not switching from rich to lean fast enough. That can be a real problem especially trying to generate power.. Have you changed out your 02 sensors recently? Have you installed aftermarket headers? I am looking over your log file now and comparing. Give me a couple of hours.

I have had my headers for a year or 2 now and I haven't ever seen that code

[pharestutt]

Ok I think we have a winner. The concern is with the front o2 sensors. The rears dont really matter as much in this case. At wide open throttle your front o2 are registering 91 mv. It should be around 900mv! Your long term fuel trim are not fluctuating normally It is plain as day.Check it out on my log file.You cant miss it. It is my opinion that your o2 sensors are causing havok with your fuel delivery causing a too lean or too rich condition and causing bog on acceleration.

I think you should re load a stock file to your car and see if you still get the same o2 readings. If you do chances are you have a bad sensor or something is up with the wiring harness to the sensor reporting to the ecm.Always check the easiest things first.

OK I will do that and let you know thanks so much

[4horseman]

OK I will do that and let you know thanks so much

Usually with headers you command your rear 02 sensors off especially if you use a no cat system. In this case it is your first bank o2 sensors that are not working . What was the exact code your ecm is reporting?

[pharestutt]

Usually with headers you command your rear 02 sensors off especially if you use a no cat system. In this case it is your first bank o2 sensors that are not working . What was the exact code your ecm is reporting?

P1135 p1153 and yesterday I made the mistake of putting in 1 gallon of 110 octane not knowing it was leaded I was already over half tank when I did but I'm guessing it just killed my o2s since I never got that code before yesterday I guess it works out if they were already bad... also I have no cats and longtubes for 2 years

[pharestutt]

I replaced the o2s and it didnt help

[4horseman]

are you still getting the P1153 and 1135 codes?

[4horseman]

are you still getting the P1153 and 1135 codes?

Run another log and lets see what the mvolts are. Also check this out http://forums.corvetteforum.com/c5-t...ep-inside.html

[Russ K]

The O2 sensors are not causing the low voltage, it's because the AFR is too lean. Unplug the Maf & do another WOT scan, the O2's will then read over 800 mv. If so, then replace the Maf as it is a very common failure on the older vehicles.

Also on the 1997-98, you need to log a max of 24 bytes so the logging speed isn't so slow. Plus logging over 24 bytes can also drop some data.

Russ Kemp

[4horseman]

The O2 sensors are not causing the low voltage, it's because the AFR is too lean. Unplug the Maf & do another WOT scan, the O2's will then read over 800 mv. If so, then replace the Maf as it is a very common failure on the older vehicles.

Also on the 1997-98, you need to log a max of 24 bytes so the logging speed isn't so slow. Plus logging over 24 bytes can also drop some data.

Russ Kemp

Pharestutt Listen to Russ K he is one of if not the best tuners on this board. I have never had my MAF go bad so I dont know what happens in that case but it can cause the system to run too rich or lean, stall or run erratic under WOT load. That being said I always thought a malfunctioning MAF would throw a fault code but I could be and probably am wrong about that. If it ends up NOT being the MAF and being that you have no CATS to get clogged and new o2 sensors the next issue to check would be fuel delivery system particularly the fuel pressure.

[pharestutt]

ok i will get the logs and post them

[pharestutt]

Pharestutt Listen to Russ K he is one of if not the best tuners on this board. I have never had my MAF go bad so I dont know what happens in that case but it can cause the system to run too rich or lean, stall or run erratic under WOT load. That being said I always thought a malfunctioning MAF would throw a fault code but I could be and probably am wrong about that. If it ends up NOT being the MAF and being that you have no CATS to get clogged and new o2 sensors the next issue to check would be fuel delivery system particularly the fuel pressure.

the codes arent there any more im going to try what he said

[pharestutt]

i did 1 run from dead idle and 1 launching at around 1200rpm

[Russ K]

Ok, replace your Maf. Then get a wideband and tune the AFR to 13.0.

Russ Kemp

[4horseman]

i did 1 run from dead idle and 1 launching at around 1200rpm

Yup your voltage mirrors mine now. Russ K is absolutely correct your MAF is bad.