Hi, iv got a question about my 1994 Honda Prelude Vtec Si Vtec. The car drives absolutely perfect, but for some reason in first it hits vtec ok and revs to 6,500 and what sounds and feels like a rev limiter kicks in. Vtec works fine in every other gear and revs to 7,500. I took it to a honda dealership and they said it looks like a rev limiter has been put in on the wiring loom for first gear????. They can't touch it because its an import. Has anybody had this or know how i can remove it.

Cheers rob

 

Vtec has temperature parameters, speed parameters, uh - what else....oil pressure parameters..........a lot of different things. Oh, it also has throttle position parameters.

TO remove it - get hondata or something. But those parameters are for engine safety.

There shouldn't be a limiter in just "first" - try resetting the ECU.

 

Thats what i was thinking, there shouldnt be a rev limiter in first, and there isnt in any other gear. The oil is ok, and im sure everything else is ok as it kicks in and works fine in every other gear.

 

Let your car warm up properly. Your car needs to be at operating temperature before VTec will engage. You know what operating temperature is. It has to be half way. If you were to get in your car one morning with it being cold...if you pulled out and went to engage VTec the temperature parameter would halt it(rev limit). Please let your car warm up before you engage VTec. Oh and you said you took it to the Honda dealership...there's your first problem. The dealership will never touch my car.

 

My car is at optimum temperture when it happens. I never try and engage vtec when the car is cold.

 

Make sure the crankcase is full. The VTec silenoid may need cleaning. Are you throwing any codes? KingPin made a good point...several things can be solved by resetting the ECU. Just take off the negative battery terminal for about 5 minutes. That should clear the ECU.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VTecLude1994 &raquo;</TD></TR><TR><TD CLASS="quote">Make sure the crankcase is full. The VTec silenoid may need cleaning. Are you throwing any codes? KingPin made a good point...several things can be solved by resetting the ECU. Just take off the negative battery terminal for about 5 minutes. That should clear the ECU.</TD></TR></TABLE>

I thought he had to pull the clock/radio fuse to reset the ecm?............

 

Either should work...most of the time when I need to reset mine I'm working under the hood anyway so I just take the negative terminal off the battery while I'm cleaning up.

 

i believe you are either low on oil or your pickup is clogged....either way im sure you have inadequate oil pressure at the solenoid

 

i mean correct me if i'm wrong...but you have to meet all the things required for the vtec to kick in, or it wont switch to the high cam profile at all. he says his vtec is kicking in... i cant see why the ecu is letting the vtec engage but limiting it, especially if its fine in all the other gears. personally i dont see how it could be the vtec system's fault.

 

It will engage but if you don't meet the parameters it will limit it out. It's strictly for engine safety so somewhere he has something wrong. I think he's low on oil or he doesn't have enough pressure at the silenoid.

 

i doubt vtec is actually hitting

 

this happened to me once at the track, hitting the rev limiter killed my 60' time. Vtec was working fine, and I could rev over 6500 in any other gear. I checked my oil level, and it was fine. No dents in the oil pan to hurt pickup, solenoid screen is perfectly clear, and the wiring was fine. That was also my 4th pass at the track that night, and I know the car was warm. I couldn't figure it out, but it hasn't happened since (this was about 6 months ago). Just that one time. Subscribed for an answer.

 

Hi guys i have an update on this with a bit more information. Ok this is whats going on, ill try and explain as best as i can. Ok if i am parked with the handbrake on car totally warm and i rev the car all the way to 6,500rpm it will limit out like its hitting a rev limiter. Ok when i started driving i got up to a speed of 40mph on my clock and i put the car in neutral and revved the car, it reved all the way to 7,500rpm. If i dropped my speed to below 30mph or at 30mph and put the car in neutral and reved the car it would limit out at 6,500rpm. Now when i excellerate in first and hold the power down it will hit the rev limiter at 6,500rpm but than shoot past it very fast. Someone has suggested to me it could be the distributor or the ecu which is causing this. The power is very held back in first and only comes to life if you hold the power down and it gets past the limiter. Has anyone got any ideas.

 

you need to be going over a certain speed for vtec to engage. I thought it was 25mph but maybe 30. that is why when you are in neutral reving it , it won't go over 6500.

how does it hit rev limiter then shoot past it?

Vtec won't engage if you don't have a certain percentage of throttle like more then 50%.

Has you speedo ever been messed up or does it jump at all?

 

the speedo doesnt jump at all and it has been converted to MPH as it is an import. When i say it shoots past, what i mean is that it hits this point at 6,500 in first gear and if you hold the power down it will get past it and suddenly the revs with fyl up to 7,500rpm and i mean very quickly, how it should be. Is it because it been converted to MPH, and the ECU is confused somehow????

 

vtec doesn't sound like its engageing right. and the ecu might be a little messed up because of the change but I can't see as long as you are going over the certain speed and you have more then 50% throttle.

I don't know why you have a stumble at 6500.

when you hit vtec your car should accelerate harder then when you are not in vtec (are you spinning the tires, is the clutch slipping). so anywhere above 5000 should be pulling hard.

 

Would it be worth taking out the MPH conversion and seeing if it works. I have no idea where it is??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robpreludevtec220 &raquo;</TD></TR><TR><TD CLASS="quote">Would it be worth taking out the MPH conversion and seeing if it works. I have no idea where it is??</TD></TR></TABLE>

by mph conversion, do you mean a different guage cluster? If so, I don't see how that would have an effect on your problems.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kulrevon &raquo;</TD></TR><TR><TD CLASS="quote">you need to be going over a certain speed for vtec to engage. I thought it was 25mph but maybe 30. </TD></TR></TABLE>

that's 30 km/h or ~18 mph

 

No the guage cluster is the original one, it has been converted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IHateJDM &raquo;</TD></TR><TR><TD CLASS="quote">

that's 30 km/h or ~18 mph

</TD></TR></TABLE>

but his is converted so who knows. it could be because the gauge now reads 30 mph where 30km/h used to be. I wonder how the computer reacts to this.


when do you hit 6500 in first gear. is it around 30 mph?

 

yeah thats right i think when it happens its just before 30mph. When it hits the rev limiter its like it hasnt reached the correct speed, than when it jurks and carrys on its like the 30mph has been reached if i make any sense??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kulrevon &raquo;</TD></TR><TR><TD CLASS="quote">
when do you hit 6500 in first gear. is it around 30 mph?</TD></TR></TABLE>

should be closer to 25 mph.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robpreludevtec220 &raquo;</TD></TR><TR><TD CLASS="quote">No the guage cluster is the original one, it has been converted. </TD></TR></TABLE>

what did you use to convert the signal?

 

ill have to check the mph again to make sure but i have no idea what was used to convert the signal. I am the 3 owner in the UK and it was converted when it was imported in 2003. My friend said the unit is normally under the steering wheel???

 

The speed is around 25mph. Would it be worth cleaning out the vtec solenoid filters and replacing them. The thing that is confusing me is that vtec works in every other gear with no problems. I understand vtec works by oil pressure, coolant temperture and engine load and speed. The only one out of the four that could be effecting mine is the speed??? Can anyone else help on this.