black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
So I put my maf on the cold pipe. Not as much of a lag when I accelerates. Still rough idle not as bad. My exhaust almost has a constant flow now but still stumbles a little. Any idea?
still can't figure out problem
- Thread starter black n yellow
- Start date
black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
how do you add pictures im trying to figure out if something could be a reason for rough idle still.
black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
what sensor is this? is this the hose that goes to the throttle body? should i try replacing it. are they both air hoses? could it cause rough idle?
black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
What's it do?
black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
I was thinking sence none of this other stuff has worked. is it possible that when the guy changed my timing belt could it be that it is off by a tooth? but i dont know if the symptoms of that are what im experiences with my car idling at 500the engine makes a noise of a thump thump thump kind of sound as it idles and the motor moves. The exhaust is not at a constant flow either. its like my car is not catching its breath. their are not hose leaks because ive changed every hose their is. could this be why my car idles like this? does anyone know the symptoms of the car that the timing belt is off by a tooth?
mazdarichie
Member
- :
- 2003.5 Mazdaspeed Protege
I doubt the belt is off. I have never had my belt changed and my car seems to run as crappy as yours and with no mods at all. 41,400 miles
black n yellow
Member
- :
- mazda/ protege/ mazdaspeed/ 2003
So I have two engin codes p0421 - p0300
Reading are these wrong or bad?
Fuel system 2 fault
Iat 60
maf 0.69
Eng rpm 1100
tps 12.16
Stft b1 -7.03
Ltft b1 5.47
Reading are these wrong or bad?
Fuel system 2 fault
Iat 60
maf 0.69
Eng rpm 1100
tps 12.16
Stft b1 -7.03
Ltft b1 5.47
Your short terms are -7 and your long term is positive 5, meaning something changed right then and there. It only takes a few seconds for the short terms to be added to the long terms and zero out if you are steady at the same rpm and throttle.
And you appear to be idling higher now. 1100 is pretty high, it shouldn't be that high when warm. I am assuming the engine was cold? Let it warm up and keep an eye on the trims.
According to the interweb, that first code is a bad cat or bad rear O2. Cats are supposed to last 100k miles, but I've heard of them going out faster than that. It shouldn't really affect your trims though.
P0300 is a misfire. It detects this by variations in crank speed. Misfires can easily mess with your O2 readings, and maybe why you see short term and long terms that are conflicting.
If you have a vacuum leak your trims will shoot up positive to account for the extra air. Since your short term is negative, it kind of rules out the vacuum leak.
The only time I had an idle problem was actually when I had bad grounding. I didn't let it get bad enough for a code. I added some ground wires with 12 gauge speaker cable and that fixed the problem. When I felt a little richer I bought a nice grounding kit.
The grounding was my fault though since I cleaned up some of the wiring when it first started. I don't think that is something that would just happen on its own, but metal does oxidize and lose conductivity over time.
Measure the resistance from the block to the negative terminal on your battey. Should be 0, if not, it could just be poor grounding.
And you appear to be idling higher now. 1100 is pretty high, it shouldn't be that high when warm. I am assuming the engine was cold? Let it warm up and keep an eye on the trims.
According to the interweb, that first code is a bad cat or bad rear O2. Cats are supposed to last 100k miles, but I've heard of them going out faster than that. It shouldn't really affect your trims though.
P0300 is a misfire. It detects this by variations in crank speed. Misfires can easily mess with your O2 readings, and maybe why you see short term and long terms that are conflicting.
If you have a vacuum leak your trims will shoot up positive to account for the extra air. Since your short term is negative, it kind of rules out the vacuum leak.
The only time I had an idle problem was actually when I had bad grounding. I didn't let it get bad enough for a code. I added some ground wires with 12 gauge speaker cable and that fixed the problem. When I felt a little richer I bought a nice grounding kit.
The grounding was my fault though since I cleaned up some of the wiring when it first started. I don't think that is something that would just happen on its own, but metal does oxidize and lose conductivity over time.
Measure the resistance from the block to the negative terminal on your battey. Should be 0, if not, it could just be poor grounding.
