I have a 2000 Z28 Camaro that recently had a bad Crankshaft positioning sensor, the engine light was on and i fixed the issue. Now i am having the same issues i had before with the car but no check engine light...What could this be? The issues i'm having are the car is running until it gets hot than shuts off and will start again when cool.

 

First off Welcome to the CamaroForums!!

If you have replced the sensor with new and the issue is still going on then check for loose or bad grounds, bad wiring (chaffed or broken) or the car is falling out from another sensor once the car switches to closed loop. MAF (kinda), O2, knock, MAP sensors are not used in open loop. The engine cannot function missing the CKS, MAF or O2, TPS, sensors. The CMS, MAP, Knock sensors if failed will put the engine in limp home mode and basically run in open loop again. I would find a way to get the codes read and try to pull memory codes if you can, most medium to advanced grade scanners can do this. If you get spark at any time your CKS is good it does not change function in different modes. The MAF does change function in the different modes and can work well enough for open loop and not as well for closed. Most of the air/fuel adjustments in open loop are done with the TPS and the MAP sensor. after a time the MAF will start to come into play before the engine hits closed loop. Once in closed loop the MAP give the computer altitude readings, the Air charge temp sensor helps determine air density and the MAF and TPS assist the engine in air intake and engine load. The O2 sensors have the final word in the A/F department once the car is in closed loop. I hope that gives you some idea of how your car operates.

Massey

 

Oh and doing a KOEO test may also help get your problem traced down as well.

Massey

 

Thanks for the advice I am going to check these out and post what i find!

 

I realized I left out a piece of information, the CATS on this car are gutted and have been for a year with no issues expect for 2 weeks ago i had to replace the Crankshaft sensor after the check engine light came on, now i have the check engine light came on now for system too lean bank 1 and 2

 

That is usually a fuel delivery issue. Low fuel pressure, clogged filter, incorrect MAF readings. Gutted cats will usually end you up with a Catalyst efficiency above threshold code (cant remember the #) and nothing more. (well other than failed emissions tests but whos counting). again see what is in the memory and let us know. I am guessing there is a open loop/closed loop issue with your car.

Massey

 

I am not familiar with the open loop/closed loop can you explain more? Thanks

 

open loop is the mode your car is in whenever the engine is not up to operating temp. The computer uses a set of known parameters for fuel metering and timing to allow the engine to run. Your fuel mixture is going to be slightly rich and you will not get the maximum amount of timing advance. Durring open loop some sensors are not ready to be used yet. O2 sensors and MAF sensors need to achieve a certain temp before they give accurate readings. o2 and MAF sensors will reach operating temp in about 5 minutes but the engine can take 10-15 minutes to reach temp.

Once the engine reaches the operating temp the computer changes modes. It now will recieve inputs from all sensors and change fuel mapping and spark timing based on the inputs from all sensors rather than from a "profile" This allows for maximum performance with maximum economy. Your air fuel ratio will be very close to the perfect ratio of 14.7:1, your timing will be advanced for the maximum burn time without knocking or pinging. This is why when you go for emissions testing they tell you to get the car out on the road and drive it for 20+ minutes before comming into the test center.

Does that explain things better for you

Massey