Just got done with my cam/heads install and am throwing 3 codes. one is for EGR and i assume that is b/c i removed it and its not programmed out yet.

the other 2 are low MAP and low TPS. How can i get rid of these? I cleared the codes with datamaster, and they came right back. I believe it to be that the pcm isn't getting the proper voltage from these 2 sensors? How can i test them?

Thanks alot to anyone who helps! I can get you datamaster logs if that will help you out any?

Also, will these 2 or 3 codes cause the fans to run when the car is running, but not when its off and the key is forward? And will this cause the car to idle around ~1000 sometimes, then when you start it again it will like to die and dip down to 500 or below, and you have to gas it to keep it alive?


Thanks again!!!!

 

also, do the blm values matter in open loop? cause the long term were 128 and i think 145. and the short were both 128.

and what should the o2s be at in open loop, i assume those do not matter since the pcm doesnt use em until closed loop.

I havent taken the car to closed loop yet.

 

Need more info from you.

Did you block off the ports where the EGR valve was?

Do you have an aftermarket TB?

There are a couple threads about the TPS floating around recently. You might want to look at them.
Best way is to monitor it is with your Datamaster. Just turn the key ON (don't start) and monitor intitial voltage (should be .3v-.9v). Then slowly depress accelerator and watch that it smoothly and linearly increases in voltage.

Erratic or lower than expected idle can sometimes throw a MAP code. Make sure the TPS is working correctly first and you have no vacuum leaks.

 

i just remembered that the breather hose coming from teh valve cover is not hooked up to the throttle body, could that be causing any of these?

 

both egr passages are blocked off with plates and gaskets. stock throttle body, both sensors were working fine when i took them off.

the TPS should be at ~5v at WOT right?

 

Ya gotta hook stuff up if you want it to work.

 

would that cause the problem rob?

 

It is possible. The bottom line is you can't leave stuff off and then wonder why it is not working right. Hook it up or cap it off, then re-test.


...TPS should be close to 5v at WOT. As long as Datamaster shows it at 100% throttle, then you are ok.

 

im not rob obviously but i can answer this one for ya. YES! you have created a decent sized vacuum leak by not having that hose in place. what was the MAP sensor reading at idle?

 

ya, i totally forgot it wasnt connected, i just remembered it. im done on it for tonight. i'll try it in the morning.

 

Well, i scanned the car with datamaster, and it looks like the TPS is funky. It stays at 0.04V and 5.1% no matter what RPM range its at. I revved it, and datamaster showed no change. And i had datamaster hooked up and went WOT with the car turned off with the key on and it did the same thing.

So most likely i have a bad TPS? Could this also cause the MAP low?

How about these codes turning the radiator fans on? And lastly, when does the car go into closed loop? I had it up to about 150F and datamaster still said open loop.

 

ttt

 

Sounds like a faulty TPS sensor, or wiring problem, if you can't get it to change when you rotate the throttle blades. Did you have the TPS sensor off the shaft? Are you sure its properly located on the shaft? Are the wires reconnected?

Check the harness connector, off the sensor, and see if you get +5V from the grey wire? Make sure you get a good ground on the black wire. That means the PCM is supplying the "reference" voltage, and the wiring is OK.

Then check the TPS sensor. The resistance, measured from the pin for the blue wire to either of the other two pins should vary smoothly as you rotate the shaft connection.

As far as MAP, the line from the valve cover actually vents to a port in front of the throttle blades, and should not cause MAP problems if the line is off. It normally flows air from in front of the blades to the valve cover, for the PCV system. Again, MAP is a sensor that gets a reference voltage from the PCM, and varies the output of the signal wire. What value are you getting for MAP on the scan?

When you start the car, the PCM is in open loop. O2 sensor voltage should be 450mV, because they are cold. It will gradually drop as the sensor warms up, specially if you have the AIR system still working. In order to go into closed loop 1) O2 sensors much reach operating temp - 600degF; 2) collant must reach a minimum temperature, in the range of 120-140degF - varies; 3) a "timer" from start out must count down... usually no more than 2 to 3 minutes in warm weather.

 

i am positive it is on properly, b/c the car was functioning normal before heads/cam and the throttle body was removed as a unit along with the tps and iac. None of those were removed from the TB. The harness is connected to it, wires are not pinched anywhere.

I'll go check the resistance and voltage in a sec here.

Fred, where in datamaster am i looking for the value of the MAP? Is it a volts measurement or a kpa?

 

Fred,

There is 5v on that wire, and the other one is a good solid ground.

The resistance with the throttle closed was like 8k ohms and when the throttle opened it would smoothly go down to about 2k.