I have a 1994 NA Miata that is giving me some trouble.
A while back, I had a no-start issue that wound up being the coils. In the process of diagnosing that I also replaced the AFM and fuel pump with new units.
Once the car started running, I was getting some SERIOUS rev hangs. Any time you went over 2000rpms, the revs would fall and then hang at 2000rpms for 30-60 seconds. Once it idled, it would often throw a check engine light, but that light would go away if you revved the car back up.
I just replaced the throttle body (and TPS and idle air control valve) with a used unit and new gasket.
Now the car does the same rev hang, but only for about 20-30 seconds. The check engine light at idle that disappears when you rev is back.
Anyone have a direction they can point me in?
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
cyow5
Reader
8/29/24 1:57 p.m.
Appleseed said:
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
One way to check the function of the cable (and throttle) is to see if you can replicate the problem when blipping the throttle by hand while the cable is disconnected at the throttle side.
cyow5 said:
Appleseed said:
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
One way to check the function of the cable (and throttle) is to see if you can replicate the problem when blipping the throttle by hand while the cable is disconnected at the throttle side.
Appleseed said:
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
I am reasonably confident (99.9%) that I operated the throttle by hand and already confirmed the cable is good. It's also wildly consistent as to where it hangs. Doesn't feel mechanical.
What you are calling rev hang sounds more like what I would call an idle control issue. Check things related to return to idle. Someone already mentioned the cable. Go check the dashpot and other things on the throttle body and idle control valve under the throttle body.
The FSM has some good troubleshooting procedures.
In reply to RX8racer :
Dashpot is the only thing that hasn't changed. When I swapped the throttle body to the new-used one the idle control valve got changed too.
Also what code do you get when you check the CeL?
cyow5
Reader
8/29/24 2:51 p.m.
Gimp (Forum Supporter) said:
cyow5 said:
Appleseed said:
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
One way to check the function of the cable (and throttle) is to see if you can replicate the problem when blipping the throttle by hand while the cable is disconnected at the throttle side.
Appleseed said:
Check and lube the throttle cable. Had it happen to a motorcycle. The cable was dryer than a popcorn fart.
I am reasonably confident (99.9%) that I operated the throttle by hand and already confirmed the cable is good. It's also wildly consistent as to where it hangs. Doesn't feel mechanical.
Was the cable attach to the TB when you moved it by hand? If so, a sticky cable would've still been a problem. I beleive you when you say it doesn't feel mechanical, but it would still be nice to rule out the easy mechanical stuff when possible.
It was attached, yes. I'll be back around the car Sunday so I'll try again with the cable detached and also pull the codes. Thanks!
