A little help needed...

[bLac K aBriOleT89]

Hey Homies!
As some of you now Spoiled decided to start giving me headaches....the car sudenly started idling crappy. Strong rich gas smell form the exhaust.
William and Moljinar helped me during BAP in april to diagnose and was adviced to replace the Frequency valve.
I heard the frequency valve's buzzing wasn't even, kind of missing, like buzzzz....buzzzz.....buzz (like a morse code) and the idle will surge at the same rithm...so I went ahead I put a new used one. It buzzes normal and even, and the idle improved a little, and starts much better, but still not good, the rich gas smell persists, and it sputters when just started.

Then I disconected the O2 sensor and improved a little more but still, the wrong iddle is more noticeable when cold. Not sure if this is emission related, fuel pressure related or air leak related. I have checked the obvious for air leaks and checks out ok. I've noticed a blak shadow arount the throttle body joint but is apparently not leaking, I'm going to replace the gasket anyways since is so cheap. I'm also going to replace the spark plugs and fuel filter while at it. Check the timing would be a ggod idea too.

What else do you recommend?

[Briano1234]

Replacing the o2 sensor with a generic.. 35-45 bucks

[bLac K aBriOleT89]

What do you mean with GENERIC? The ones I get at the "Cheaperzone"?

[Briano1234]

What do you mean with GENERIC? The ones I get at the "Cheaperzone"?

o2 sensor for the cabby is 120-150

o2 sesnsor for a 1989 Mustang 5.0 is 40.00 and works fine.

You have but to splice the wires off of it to your connector.

Bosch 13913 or 19342 will work.

[gull]

Wiggle the O2 sensor harness while the engine is running. If the idle changes when you wiggle, you have an intermittent circuit in there. This happened to me, and it drove me nuts trying to find it. The wire was shorting to ground where it was stressed entering the connector. I didn't figure it out until I pulled the Lambda control unit and checked the wiring with an ohmmeter.

[kamzcab86]

I'd check the thermoswitch (could be faulty thereby sending a constant signal to the controller that extra fuel is needed) and the cold-start valve (it might leaking).

[bLac K aBriOleT89]

Thanks guys. CIS no CIS-E (Thanks Kammy)

I checked the o2 sensor wiring and seems to be good. Took the CSV out and checked ok, a nice and even cone-shaped spray when cranking-No leaking. This rules out the Thermo Time switch as well.

So far I have checked the o2 sensor, idle stab. valve, cold start valve and frequency valve (replaced) all these are good. Going to go over air leaks again.
I'm thinking it's more mixture related, I'm gonna try to adjust the mixture and check the auxiliary air valve today. What I know is the mixture has never been tuned before, cause the metal seal still plugged in. I found Oran's write up and I think I'm gonna go with it and see what happens.

[Briano1234]

You could swap it out for a Digifart....

[gull]

I'd recommend checking the control pressure before adjusting the mixture. I've seen bad CPRs cause running problems, before, and the only real way to test it is to check the control pressure.

[mbailey]

o2 sensor for the cabby is 120-150

o2 sesnsor for a 1989 Mustang 5.0 is 40.00 and works fine.

You have but to splice the wires off of it to your connector.

Bosch 13913 or 19342 will work.

How do you know which wires to splice together?

[Briano1234]

there are 3 wires.
Two are white, that it don't matter which one you connect to which, and there is the black one that connects to the black one.

It is best to Solder and heat shrink the wires.

[bLac K aBriOleT89]

Well I finally got to the cabby this weekend, I was checking fuel pressure and all what I got was some drippings from the line....now all is pointing to the fuel pumps....It does starv for fuel at low RPMs but when I floor it, it goes strong....so I dunno. I'm might get a used main pump and swap it to see what happens....

[gull]

Mm, something isn't adding up. A bad main pump wouldn't cause idle issues, at least not without other symptoms. If you only got "drippings" it's likely the pump wasn't running. Did you jumper around the fuel pump relay? With the relay in the circuit the pump will only run if the engine is turning.

[bLac K aBriOleT89]

YEah, you were right. I wasn't jumping the relay correctly, pumps are fine. I decided to go ahead and replace the TB and inteke mani gaskets to rule them out, and guess what, two ot the intake mani bolts were missing! and the 3 more were on their way out! the gasket was definetly toasted. Put a new one, the car is running like a champ!

[Briano1234]

YEah, you were right. I wasn't jumping the relay correctly, pumps are fine. I decided to go ahead and replace the TB and inteke mani gaskets to rule them out, and guess what, two ot the intake mani bolts were missing! and the 3 more were on their way out! the gasket was definetly toasted. Put a new one, the car is running like a champ!

So you were having a Vacuum leak extraordinaire.