My car won't run faster than 15mph! Please Help
My car won't run faster than 15mph! Please Help
A few weeks ago my car wouldn't want to accelerate past 15mph. This usually occurs when my car is warmed/hot. No matter how hard I push on the accelerator, it wouldn't exceed 15mph. Even if I were to put my car in neutral from a parked position, and rev it, the problem would still occur. The RPM itself, wouldn't rev past 2-3000rpm from what I believe. I just had my MAFS replaced with a used, but working MAFS that I bought from a local 240sx shop. I don't believe it's that cat because I had that replaced several months ago. My car has been in the shop for at least two weeks now, and so far they said the computer was throwing codes about the knock sensor, but they said that wasn't the problem. The next thing they assumed was wrong was a certain wire connecting towards the intake manifold. They said that I would need a new harness, valve assy-aac, and gasket aac valve.
Re: My car won't run faster than 15mph! Please Help (VinceSez)
Are you sure the MAF is good?
A disconnected MAF will basically behave like that - won't rev past around 2.5k rpm.
A cat shouldn't do that to your car, just make it stinky if it's bad.
Are you auto or manual transmission?
Have you checked your timing etc to make sure those are correct?
A disconnected MAF will basically behave like that - won't rev past around 2.5k rpm.
A cat shouldn't do that to your car, just make it stinky if it's bad.
Are you auto or manual transmission?
Have you checked your timing etc to make sure those are correct?
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eastcoastchaos
- Posts: 307
- Joined: Mon Jan 20, 2003 2:59 pm
- Car: 95 240sx
fail safe mode. the computer thinks something's screwed so it won't let you rev higher then 2500ish.(i don't remember the exact #)maybe the MAFS isn't connected properly. or some other sensor, tighten all the sensors and reset your computer then try again. if it throws any codes after that then fix what it says
yea, my car is an automatic. the MAFS itself is good, but I dont know about the wiring. As for the sensors, the mechanic I currently have my car with told me that it might be a sensor, but so far he hasn't found the issue yet. the only codes the mechanic has shown me, was something about the knock sensor, but so far everything seems to be in check with the ecu... so we really dont know what could be the problem.
Re: (VinceSez)
Ok, hmmm. Well, w/ auto, when you go into failsafe mode, which is prob something to do w/ it, it should be in 3rd gear all the time no matter what. I believe there is a way to pull codes from the transmission control unit from what I was told.
However, you should be able to go well past 15mph even in failsafe mode - lags like no other, but will go up that high.
It has to be a sensor or something, because if it was the ecu, I'd think it would do it all the time.
Check your timing, spark etc like I said, which will eliminate the easy stuff.
However, you should be able to go well past 15mph even in failsafe mode - lags like no other, but will go up that high.
It has to be a sensor or something, because if it was the ecu, I'd think it would do it all the time.
Check your timing, spark etc like I said, which will eliminate the easy stuff.
If it does it at a stand still [not moving] It sounds like a bad airflow meter. If this is a constant problem your mechanic should be able to nail it very quickly. It is much easier to diagnose a failing car then it is to diagnose an intermitten failure. Have him check all 3 wires to the maf for voltage readings 1 should be 12volts,1 should be less then .2 volts [important one] and 1 should be 1.3 to 1.5 volts at idel and go to above 4.0volts and snap throttle. If it cant do that the maf is bad. if the .2 volt wire is higher then that then an additional ground needs to be added to it.