I checked my IAC today *dont know why, I dont know how to tell if its bad anyway* but it had black sutt all over the tip and spring, there was black stuff all in the passages of the throttle body and in the plenium holes also. I've been having a running rich problem latey and cannot find the cause. Could it be the IAC? Would the IAC cause the car to idle horribly and to run rich? Why would it buildup so much black sutt so fast, I just ported the plenium exactly 144 miles ago and it was CLEAN when I put it back in. thanks again guy's & gal's


Post Script
How do you spell sut, sutt or however.
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[This message has been edited by MATEOZ28 (edited March 21, 2001).]

 

i spell it "soot"

 

Originally posted by MATEOZ28:
"I checked my IAC today *dont know why, I dont know how to tell if its bad anyway*"

This surely made me laugh

The black SOOT is normal to some degree. You can clean your throttle body and plenum with carb cleaner if you want, but it will just come back again. I doubt it has anything to do with why you have been running rich, but excessive carbon is a result of running to rich.

Have you changed the O2 sensor lately? What else have you tried to solve the rich problem?

 

Actually I have replaced EVERYTHING in the entire car except the dash, O2 sensor, and IAC. I completly rebuilt the car and put everything in correctly, I'm just tired of runnin so rich. I think I'll just replace the IAC and O2 and see what happens. If you have anymore suggestions please do tell.

 

The black soot comes from the EGR valve. It lets exhaust gas back into the intake, which coats the plenum and runners. There's nothing you can do about it, it doesnt hurt a whole lot. Even if you dont have the EGR, it'll still happen because with a TPI intake, remember the intake charge travels up and down the length of the runners, creating the "ram effect" that builds torque TPI is famous for. When the intake valve opens, some of the residual air and fuel from the combustion chamber enters the intake passage and travels back up the runner. The soot is normal, just ignore it.


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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

"I spell it soot", LOL!!

Hey Kevin91Z, this does'nt pertain to this topic, but I saw your signature, will a 5.7 bolt right in to a stock 5.0 - 5 speed car? Just wanted to know for future reference. Thanks

 

Of course, a 305 and a 350 are identical externally. Everything bolts up.

 

The pcv valve also permits oil & hot gases to coat the intake manifold while the motor is running.
njdaewoo

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86 Tramaro 90% Trans Am/ 10% IROC/Z (nose, hood,& fenders)
Trans Am Mods as of 1/10/01
3inch
T.E.S/Flowmaster setup,gutted cat,gutted maf,relocated mat,373 gears,upgraded factory chip,255 liter h/press. walpro f/pump & throttle body coolant bypass
njdaewoo@excite.com

 

Thanks Kevin...was'nt sure due to 5.7's increased torque factor, I thought the driveshaft or maybe the rear specs were different because of torque... Something for me to look forward to.

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Proud newly acquired '91 Formula 305 TPI 700R4, 34K miles, Factory Black on Black all stock - no current HP mods (might keep that way!). Rims are '91 T/A black Diamond Spoke 16x8s. 20% tint & Black Widow Alarm system. Very near future plans: K&N filter, catback Flows, fresh paint job, new 255ZRs all around.