Got a stumper here. Here's the most common scenario:

I'm in a drive-thru, sitting in neutral waiting for the line to move. Finally, it does. Clutch goes in, shift into first, a bit of throttle and let the clutch out enough to bring us ahead. Now were almost where we want to be and so we push the clutch to the floor. She's still in first.

The engine climbs to 1100-1200 and makes a thrumming/throbbing noise as it does.

Stick out your tongue a little and and blow (like you're giving someone a raspberry.) The sound is almost identical to that.

It doesn't stop on its own after a few seconds. It keeps going and going... Popping the shifter into neutral kills it instantly.

Any ideas? My 7 is far from undrivable, but plainly something somewhere needs attention.

 

Wow. Is it a series of popping noises? Can you reproduce the issue? Does it happen only when warm?

Vacuum leak test? Flamethrower/sledgehammer test?

 

Do it and keep doing it. It sounds just like that, only the 7 version (deeper and motorier.)

I can reproduce it with ease. It only happens when warm cuz I only drive her when she's warm.

Will do a vac leak check again. Just did it repeatedly over the past 2 weeks to track down my leak at the primary injector grommets, but I'll do it again...

 

 

ttt

 

Mine does that too. It has something to do with the TPS and the neutral switch, but I haven't figured out exactly what yet.

 

I'll have to look, but I'm pretty sure that my neutral switch is not connected.

What are your reasons for suspecting TPS/neutral switch?

 

well putting my car in gear will lower it to the a nice 750 idle and if I pull it out of gear it stays the same 750 solid, though if I'm cruzing and put it in nuetral and coast to a stop my idle is more around 1100 smooth but missing a bit.

This same thing happend to me before and it turned out being the idle stop screw was screwed in too much opening the throttle plates abit to much...

 

The Neutral Switch Is only used for the 3 grand start up...so that can be ruled out.

 

Negative, Ghostrider.

The neutral switch is so that you can't start the car unless the clutch is to the floor, thus ensuring that you don't start it in first with the clutch out and get a nastyu surprise.

I've always been able to start my 7 without touching the clutch.

AFAIK, only that sensor on the bottom of the rad on the driver's side is responsible for the 3k start-up. It wasn't until I unplugged it that the 3k start-up stopped kicking in...

 

Hmm...I remember HAILERS saying that. Thanks for the correction.

 

Neutral switch is also used for cruise control, and 3K startup. Try it. Start your car in gear as opposed to neutral when cold.

 

Oops! Right! I've disassociated the clutch with the cruise in my mind since, again, my switch is disconnected and the clutch doesn't disengage the cruise.

And you're right about the 3k start-up association. I took silverrotor's post to mean that he was implying that the switch was *solely* responsible for the 3k start-up, as opposed to being integrated into the circuit.



The last time I tried to adjust the idle I didn't do the proper procedure as shown in the manual. So maybe my idle screw *is* way the hell out of position. I'll hit it next chance I get and hopefully return with good news.

 

Okay, I set the idle using a jumper this time. She's a hair over 700 with the jumper in place. The timing was checked during the winter and is spot-on. The only thing I didn't get to checking was the fast-idle cam, but I think I'm gonna have to pick up something like a dental mirror for that - I don't see how the hell anyone can otherwise get a look at it without taking the manifolds out of the car.

Anyway, tried to reproduce the problem afterwards and... it persists. I didn't check for vacuum leaks (loooooong day at work and I just wanted to get the home) but I will by the weekend.

 

Well, I have progress to report, but it's in the form of a screw-up.

I spent Sunday working on my car and pulled the manifolds off. I broke the LIM gasket in the process. Not having a replacement, I put the broken one back in and RTV'ed it.

Now she idles at 1500, jumping between 1500 and 1300. No adjusting will bring the idle back down so I'm assuming I now have a big-*** leak at the broken gasket. I can't get another 'til Thursday.

Now here's the thing. If I put in the clutch and put her in first, the idle drops to 1100 and does the thrum. I take this as a clue, but I'm not sure what it's a clue of...

Here's to Thursday - it can't come quickly enough! Driving around like this is embarassing.