Sometimes. Will rev to only 5000 on takeoff...

[scooper77515]

I have had this problem for a while, and would like to find a solution.

About 2 out of 3 takeoffs in the 97 Challenger, when I throw the throttle to 100%, it will hit about 5000rpm and not go faster, making the time to plane WAY too long.

Sometimes, it will go straight up to 6500 and plane in just seconds.

I just replaced a bunch of RAVE valve components, including one valve and all the rubber and plastic components trying to fix this.

Today, I experimented and found that if I put it in neutral and let it bounce off the rev limiter for about 5 seconds before taking off, it will take off just fine, straight to 6500 rpms. I just put it in neutral, bounce off the rev limiter for about 5 seconds, then quickly put it to idle, put it in gear, and slam it into 100% throttle and it hits 6500 and takes off like a champ!!!

What could be causing it to take off slowly in this case? I don't mind having to rev it in neutral, but it would be nice to not have to do this.

 

[timmyboy76]

carbs...?,fuel delivery...?

 

[scooper77515]

Wouldn't cavitation just let it spin to redline without catching?

I am thinking the plugs are fouling while at idle, and don't clean up for a few seconds after they start to rev.

In my theory, by bouncing it off the rev limiter at 3500 for 10 seconds in neutral, it burns off the plugs so that when I gun it next time, they are clean and letting it fire all the way.

Sound legit?

If so, I will lean out the idle mixture. It is hard to start after idling for a while too...like if I idle up to a beach, kill the engine, and later try to start it back up, it is a major hassle to start. Starts fine if I try to start it if it hasn't idled for long before I kill it.

 

[robin savell lloyd]

Sounds legit to me. but allso water regulator could be flooding exhaust at idle and leting it run at 3500 for a few seconds could clear it out as well. You do seem to be taking a logical aproach. :cheers:

 

[scooper77515]

So, the water regulator still fits in the picture? Would that also cause the difficult starts?

Is it safe to mess with that? I have heard it can be very dangerous to make adjustments to it.

I have all the manuals, so I should be able to check and adjust it if that is a solution.

What do you guys think?