Turbo Accord revs up to 5000 rpms on its own, back to 500 rpm, then repeats. Using V-AFC II with Synapse Missing Link and a FMU to handle air/fuel on this turbo Accord setup. Drove it with this setup and it ran fine but with a fuel smell. Took it back to the garage, reseated the injectors, then started it back up and this new problem began to occur.

We have reset the ECU. No luck. Same behavior.

Tried disconnecting the V-AFC II, which caused the car to rev to 5000rpms a single time then engine stop.

Tried disconnecting the factory TPS which caused the car to rev to 5000rpms a single time them engine stop.

Any ideas on why my car revs up to 5000 rpms the moment I start it, drops to 500 rpms, and immediately back up to 5000 rpms again, repeating the process until I turn the car off?

 

you might have a really bad vaccum leak, try spraying WD-40 where the injector seals are and see if stops. I have had revving problems but nothing like that. What else have you done besides Vafc II and turbo?

 

I will try to see...but still, i don't see that vacuum source has to do anything with the revs of its own. I thought that the Throttle Cable is too tight or missed place when i tried to reseat the injectors. My injectors/fuel rail is very close with the throttle cable and i had to unscrewed a bolt in-order to loosen the rail. I assumed i did touch the wire cable but didn't really messed with it at all.
P.S. About the vaccuum source, before all this happened. We drove it around and i heard like a wind noise (my bro was beside me adjusting the VAFC) and he heard it also..he told me it sounded like the Vacuum source is leaking. Well, we got home and fixed the injectors and i fixed the Vacuum Source that connects to the Boost Gauge (i thought that's where it is leaking). I had no chance to drive the car again to see if the vauum line is still leaking or not cause the damn engine is acting weird.

 

Well, installed an after market DVD. But that's before the car acting weird. Wouldn't think the DVD either.

 

the my accord revved from 700 rpms to 2500 rpms at one time because my manifold pressure wasnt right, the idle adjustment nut on the throttle body was way out of adjustment. I dont think it has anything to do with your throttle cable either. I think that you have a vaccumm leak at your injectors. Exactly what did you take apart? why did you have to take apart your fuel rail? Did you put some injectors in? From my knowledge there is nothing other then a vaccum leak that can cause that revving problem besides a bad fuel injector.

 

Yea, i replaced my stock Injectors to 450cc DSM. Well, i've installed it before (month ago) and it works fine. But i didn't have the VAFC2 yet to control my fuel pressure...So i took it off and installed my factory injectors back. I just got the VAFC2 couple days ago so i installed the 450 injectors back in again as well as my VAFC (using FMU 12:1). We drove it and noticed a terrible smell of gas leaking. Stopped back in the garage and noticed one of the injectors wasn't tight or something so the Fuel was leaking out of that. Had to took off the fuel rail to adjust the injectors again and installed them back. Started the car so check if there's any Fuel leaking again and that's when the car starts that problem.

P>S My bro and I wanted to tuned up the Fuel Pressure all the way up on the VAFC to make sure that we're not running lean and blow up the motor. We figured if we run rich, the worst it can do is shut off the engine but lean is an Explode. So i don't know if anything has to do with that. Well, we tried to lower the fuel pressure from the AFC down but the car is acting weird at this time so no chance test drive it. Also, we we first drove it around the city for tuning using VAFC, we heard some kinda noise like Vacuum is leaking or something (I think it's the vacuum tube from the Boost Gauge connect to the Vacuum source to run to the Intake manifold, they're diff hoses and connected them together using a 2 sides fitting) I found some forums and people had problem like mine but not exactly. Some think it's vacuum leak, some thinks it has to do with the Throttle Cover Valve..etc. Not sure.

 

The last injector on the passenger's side was the one leaking fuel in my brother's setup above. We pulled the fuel rail and the injectors to reseat them.

Assuming that we didn't reinstall the fuel rail and injectors correctly or in tightly enough could that cause the car to rev itself up automatically to 5000 rpms the moment you start the vehicle, then drop to 500 rpms and repeat the behaviour over and over again until you turn it off? If yes, then we should probably go over the fuel rail and injector connections first.

Also, the rubber o-ring seals that sit between the engine and the injectors themselves weren't all the same size or quality, so we installed the fuel injectors WITHOUT the rubber seal between the engine and bottom of the injector. Would that cause the issue we are describing? That's the only thing that has changed in this setup to my knowledge?

z06@memphisracingscene.com
2003 Chevy Corvette Z06

 

Those seals are quite important, just the name should describe why. They ensure a quality and absolute seal between the two parts. I would suggest repklacing them and then seeing if the problem has been remedied.

 

If you didnt use the injector seals, thats the little o ring that sits on the injector and fits in the hole, thats where you problem is, you have a vaccum leak at your injectors. you should by a new set and dremel them out to fit the dsm 450's

 

Or buy seals that fit the 450's instead of risking an improper seal by boring them out...