This makes no sense!
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,400
Likes: 0
From: Oceansaide CA
This makes no sense!
Help!
1. start car, things seem normal
2. Once in operating temp, idle goes to ****
3. Something starts rattling
4. very annoying
5. goose the throttle, RPMs go up, rattling stops, but I can still tell that it's mis-firing
At the cap, #5 makes no difference so I figured it was a plug wire. OHMed at 5k. Swapped spark plugs, same thing. Put a spark tester on the end, grounded it, it sparks. So there's spark in there.
Did a compression test, got 150 psi.
Unplugged it's injector while it was running, drops the idle even lower, so it's getting fuel.
WTF is going on!!
Also that "rattle" that start when the motor is shaking at this lumpy idle seems to be coming from the transmission (ZF 6) - and I think it's setting off the knock sensor causing the ECU to pull timing making the idle even worse. The rattle was always there when i shut the motor off, but now it's there as soon as the car starts to idle crappy. It's very loud, and pronounced - is this the "gear rattle"?
What's my next step guys?
1. start car, things seem normal
2. Once in operating temp, idle goes to ****
3. Something starts rattling
4. very annoying
5. goose the throttle, RPMs go up, rattling stops, but I can still tell that it's mis-firing
At the cap, #5 makes no difference so I figured it was a plug wire. OHMed at 5k. Swapped spark plugs, same thing. Put a spark tester on the end, grounded it, it sparks. So there's spark in there.
Did a compression test, got 150 psi.
Unplugged it's injector while it was running, drops the idle even lower, so it's getting fuel.
WTF is going on!!
Also that "rattle" that start when the motor is shaking at this lumpy idle seems to be coming from the transmission (ZF 6) - and I think it's setting off the knock sensor causing the ECU to pull timing making the idle even worse. The rattle was always there when i shut the motor off, but now it's there as soon as the car starts to idle crappy. It's very loud, and pronounced - is this the "gear rattle"?
What's my next step guys?
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,400
Likes: 0
From: Oceansaide CA
That's more like it 
I was thinking that too, wanted some feedback without pitching my own ideas out.
What's the rattling though? How loud is that gear rattle everyone talks about when they go to single-mass FWs and all that? My rattle doesn't stop untill it's in gear - clutch reduces it a little, but not much. Sounds atrocious, and LOUD. I can hear that crap banging around in there from 15 yards away in my driveway.
So when it stops raining - O2. I only have one to worry about too
I was thinking that too, wanted some feedback without pitching my own ideas out. What's the rattling though? How loud is that gear rattle everyone talks about when they go to single-mass FWs and all that? My rattle doesn't stop untill it's in gear - clutch reduces it a little, but not much. Sounds atrocious, and LOUD. I can hear that crap banging around in there from 15 yards away in my driveway.
So when it stops raining - O2. I only have one to worry about too
Race Director
Joined: May 2000
Posts: 17,101
Likes: 4
From: No more yankee my wankee, the Donger is tired!
o2's as well.
The rattle you hear is normal. You can bump up the idle speed to smooth it some. Also, you can run a different disk that will eliminate some rattle as well. It should sound like rocks in a washing machine.
The rattle you hear is normal. You can bump up the idle speed to smooth it some. Also, you can run a different disk that will eliminate some rattle as well. It should sound like rocks in a washing machine.
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,400
Likes: 0
From: Oceansaide CA
Originally Posted by Jeffvette
o2's as well.
The rattle you hear is normal. You can bump up the idle speed to smooth it some. Also, you can run a different disk that will eliminate some rattle as well. It should sound like rocks in a washing machine.
The rattle you hear is normal. You can bump up the idle speed to smooth it some. Also, you can run a different disk that will eliminate some rattle as well. It should sound like rocks in a washing machine.
Just went and loaded up some rocks into a washing machine.. yup same sound
Seriously though, thanks guys i feel a little calmer inside now. Cause it sure sounded like rocks in the crank case.........
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Unless you disable the IAC, pulling a plug wire won't tell you anything as the computer will maintain idle.
I'd scan it and check the readings from the Coolant Temp and Air Sensors. Start with a cold engine and make sure both are about the same. Then monitor the increase as the engine warms up. Coolant Temp should be close to the dash read out. If there's a large variance, that could be the reason for your idle problems.
I'd scan it and check the readings from the Coolant Temp and Air Sensors. Start with a cold engine and make sure both are about the same. Then monitor the increase as the engine warms up. Coolant Temp should be close to the dash read out. If there's a large variance, that could be the reason for your idle problems.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
I would be careful about dissmissing "the rocks in washing machine" sound. Could be the catalytic breaking apart... and at low RPM, it may be enough to shake the cat back and forth to give that washing machine effect.. I check my cats by banging them with a rubber mallet, while listening for loose chunks of catalyist material......
just my $0.02
just my $0.02
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Race Director
Joined: May 2000
Posts: 17,101
Likes: 4
From: No more yankee my wankee, the Donger is tired!
Originally Posted by MikeC4
I would be careful about dissmissing "the rocks in washing machine" sound. Could be the catalytic breaking apart... and at low RPM, it may be enough to shake the cat back and forth to give that washing machine effect.. I check my cats by banging them with a rubber mallet, while listening for loose chunks of catalyist material......
just my $0.02
just my $0.02
Unless you've never heard it before, it is quite unmistakable. The sound lessens when you push in the clutch.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Clarence - I don't think it's the throw-out...
Tell me about your clutch? Is it new?
This sound just started? Sounds like its coming from the crank case?
I am betting $$$ that its either a cat (but that would result in different problems) - OR - the flywheel is breaking up.
Tell me about your clutch? Is it new?
This sound just started? Sounds like its coming from the crank case?
I am betting $$$ that its either a cat (but that would result in different problems) - OR - the flywheel is breaking up.