1993C4LT1

Yes, my IAC counts are at zero. Which means there is a vacuum leak right? Well if there is, I can't find it. I've replaced bad ones already. The 2 way check valve, and two others that go to throttle body. With AC on, IAC counts are at 20. Gas mileage isn't great in the city. Getting 11-12 city, and this is with nornal driving. Used to be at 8, but that was due to a toasted exhaust manifold gasket. Left bank still lean. Highest I've seen was the left BLM at 143(new o2's). No codes.

So I guess my question is, what are common vacuum leaks I need to look for?

Otherwise, car runs great, good acceleration. Idle is pretty good. Used to be horrible.

And yes, car does go into closed loop. It has many new parts.

antfarmer2

get a cheap cigar and blow heavy smoke in the hose that goes to the brake booster in to the engin and see where it comes out. blow a bit into the booster too. does your cruise control work?

1993C4LT1

Sweet! I was gonna ask where the smoke had to be blown into. That brake booster hose goes into the intake and the booster, of course. Does it matter which end of the hose the smoke gets blown into? Will have to ask my neighbor, as I don't smoke

Antfarmer, you help a lot of us out, and I appreciate that.

Oh, and does the engine have to be running while doing the smoke test?

antfarmer2

no not unless your doing something else with it.

TorchTarga94

Idles fine?

If RPM isn't above normal idle you may not have a vacuum leak at all. You're car might be perfectly fine if all feels good. Track MPG by hand not by the computer.

How do the brakes feel? Does your idle surge? Have you confirmed EGR is okay?

scrappy76

So the engine does not have to be running to do the smoke test ? Is it better with the engine off?

1993C4LT1

Oh yea, idle is good. It's cold here in Dallas. On cold start, it goes up to aboit 1,500 rpm amd comes down to about 700 in 30 seconds. Warm idle is like 600 or 650. I have a friend with a 95, that car idles smoother than mine. But 93 is batch fire injection. Brakes feel good, pedal isn't hard. How do I confirm that the EGR is OK? No idle surge.

antfarmer2

with a vacumme leak the engin would suck air in the leak so smoke would not come out. you can blow smoke in many differant hoses till you find it.

1993C4LT1

See the smoke? That was done with the engine off.

antfarmer2

good job

1993C4LT1

Thanks

Thing is, I've already replaced that one. But whatever, it's obviously leaking. Paging 93Vette, cause I know he had to change that same one. Which hose did you buy?

antfarmer2

looks like it is cocked cut a clean edge and try again.

1993C4LT1

Will do

mtwoolford

for the benefit of us old dumbasses, what is "IAC" and what is the significance of "zero"?

1993C4LT1

old dumbasses

IAC= Idle air control

When you have a data logger hooked up, and it is at 0(zero), that means there is a vacuum leak.

93Rubie

If your BLM is 143 what was the integrator? Your adding fuel in the long term but what is the short term doing? I hope you find your leak.

1993C4LT1

What do you mean by integrator? The picture above was the only leaking line. Still seems really high of a BLM, for just that little leak.

93Rubie

I agree its adding fuel in the long term and that is a small leak indeed. That is why I asked about the integrator. That is short term fuel trim. What is it doing?

http://www.gnttype.org/techarea/faq/BLMINT.html

antfarmer2

give it another blow of smoke. how old are your o2's and make sure the wires are not melted.

Kevova

What does TPS read and what happens it you try to block out air to throttle body does it stall? Just thinking you need to check some of the basics min air and tps settings.