Engine self reving, sounds like a siren

[timothy_nd28]

The engine mechanically runs fine. It doesn't miss and no excessive vibration. When the throttle is opened quickly from idle to any rpm above 3000, something overrides the throttle input and the engine changes speed from anything above 3000 rpm to about 1500. It changes rpm about 2 times a second, and it can go on forever aslong as you keep your foot on the gas pedal, relatively floored (70%). It really sounds like some sort of siren.
I thought this was due to a failed decoupled supercharger, and when the rpm got hi, no boost was seen by the map, which confused the computer. Willwren and his informative website about superchargers proved me wrong on this theory. I removed the supercharger, and behold the rotors DO turn with the pulley, despite all the clanking noise it was making! Although I did discover a huge vacuum leak on the supercharger bypass throttle shaft. The new supercharger is in the mail. All vacuum lines in the car are new and redone. Any thoughts on what may cause such a problem

[J Wikoff]

The shaft for the bypass valve leaked? Huh. I'd have tried to get a new brass bushing before I bought a new SC.

The computer doesn't see the MAP signal until full OBD2 in 96 models.

[timothy_nd28]

My brother was trying to convince me of replacing that bushing and rebuilding the SC ourselves. Just to much screwing around, and it's way easier to just buy one that has already been rebuilt.

[00Beast]

Definitely send them yours for the core charge, then.

[Cheetah]

Do you get a code when this is happening?

[944-LT1]

When the throttle is opened quickly from idle to any rpm above 3000, something overrides the throttle input and the engine changes speed from anything above 3000 rpm to about 1500. It changes rpm about 2 times a second, and it can go on forever aslong as you keep your foot on the gas pedal, relatively floored (70%). It really sounds like some sort of siren.

What you are describing is the factory rev limiter that engages at ~3.7-4.0K RPM in only park and neutral. Its a safety feature. When a fool decides to floor an engine in park or neutral, many parts of this particular engine can quikly fail....probably the reason you had to replace so many parts recently.

If youre thinking what I think youre thinking, dont do it. Disabling that feature through your fancy software will ruin the engine the way your going so far.

Furthermore, (1) try researching what youre working on a bit before posting all these questions. The very forum you are on has all these questions answered already (2) when you DO find something else wrong with your car and HAVE to post a question, the most helpful part of your post is your description of what its doing. A siren; a rev limiter does not sound like.

MK

[00Beast]

When the throttle is opened quickly from idle to any rpm above 3000, something overrides the throttle input and the engine changes speed from anything above 3000 rpm to about 1500. It changes rpm about 2 times a second, and it can go on forever aslong as you keep your foot on the gas pedal, relatively floored (70%). It really sounds like some sort of siren.

What you are describing is the factory rev limiter that engages at ~3.7-4.0K RPM in only park and neutral. Its a safety feature. When a fool decides to floor an engine in park or neutral, many parts of this particular engine can quikly fail....probably the reason you had to replace so many parts recently.

If youre thinking what I think youre thinking, dont do it. Disabling that feature through your fancy software will ruin the engine the way your going so far.

Furthermore, (1) try researching what youre working on a bit before posting all these questions. The very forum you are on has all these questions answered already (2) when you DO find something else wrong with your car and HAVE to post a question, the most helpful part of your post is your description of what its doing. A siren; a rev limiter does not sound like.

MK

Woah. What he never said was whether the car was in park or on the road.

[timothy_nd28]

Kinda resembles a european siren! Man, why didn't you chime in a couple days ago, you could of saved me about 100.00 dollars and alot of pointless work!!! After replacing the supercharger, the car runs like it came off the assembly line. Very very smooth idle and it feels like I got some power back also, but in park, you can raise the rpm up to about 3.7k before it drops out. As you stated, I did replace every sensor in this car, including the ECM and PCM. I installed a new cam sensor, with a new magnet, and a new crank sensor 2 months ago. Since the fuel pressure wasn't dropping out at 3.7rpm in park, I assumed it was ignition related. The cam sensor doesn't help the timing much at high rpm, so I concluded it had to be the crank sensor. I just bought today a new crank and cam sensor. I started with the easier of the 2, and replaced the cam. Ran the car, same thing. I replaced the crank, and restarted the car, and it does the same exact thing. I was getting ready pull out my piece and put a couple rounds through the block. After reading what you posted, I feel like such the retard. Thank you for rectifying this issue with me, but next time you don't have to be so rude. This is a learning/helping type forum, have some tolerance for peoples ignorance

[944-LT1]

Jigs up. I thought I had him going. Anyway, he's my brother....just messin' with him.

[J Wikoff]

You guys sound like you know each other.

[00Beast]

You guys sound like you know each other.

They sound like a pair of bickering 4 year old twins, to me.

[willwren]

This is what I suspected would happen, considering I have the luxury of knowing the WHOLE story between these two. And it's affecting the topic, so let's dump the bickering you two, even if it is just friendly jabbing, and get this back on topic.