Ping problem and Vent Switch problem

[rapidsft]

Ok, I have 2 problems with the 95GT I just purchased, it has 117k miles.
Problem #1 Car pings VERY VERY Easily once it's warm. I only have to give the car about %15 throttle and it's starts to PING.
Problem #2 If you try to switch the Airconditioning/vent/Max A/C/Floor vents the air will only come out the Defrost vent, I am able to adjust the speed of the air, however; I cannot make the air come out anyother vents besides the defrost vents. I have checked ALL the HIGH CURRENT FUSES in the engine compartment and have checked ALL the Fuses under the Steering colum and they are all fine. The vent will switch off and will be variable but only under the defrost. What could be the problems, how to fix them?

Thanks,

 

[click]

Retard your timing like 2 degrees.

Along the firewall there should be a little black rubber hose about 5mm that connects to a AC inlet on the firewall drivers side. Make sure that is connected. I had the same problem as you. And that hose was disconnected.

 

[rapidsft]

response

Are you talking about the diverter for vacuum. It has one tiny black tube that says A/C on the vacuum diverter and it's right next to the brake booster?
that diverter has about 4or5 other vacuum lines. If it's in another spot let me know, thanks.

 

[mo_dingo]

Ok, I have 2 problems with the 95GT I just purchased, it has 117k miles.
Problem #1 Car pings VERY VERY Easily once it's warm. I only have to give the car about %15 throttle and it's starts to PING.
Problem #2 If you try to switch the Airconditioning/vent/Max A/C/Floor vents the air will only come out the Defrost vent, I am able to adjust the speed of the air, however; I cannot make the air come out anyother vents besides the defrost vents. I have checked ALL the HIGH CURRENT FUSES in the engine compartment and have checked ALL the Fuses under the Steering colum and they are all fine. The vent will switch off and will be variable but only under the defrost. What could be the problems, how to fix them?

Thanks,

For problem#2, I had the same exact thing happen to me when I removed my smog tube. I broke the vacuum line that runs across the firewall. The line hooks up to the vacuum tree that is located on the drivers side, to the right of the brake master cylinder. The tree has 4 lines I think, and the one that is broken is labled on the tree as "A/C" or "Vent" or something to that effect. This vacuum allows the air to go into the regular air vents. There is a break in it somewhere. Examine it carefully. You may not have broke it, but either someone else did, or it did on it's own (very common problem).

As for problem #1, there are many things that can cause pinging. But I want you to perform a few tests for me. When the car is bone cold (sat for at least 8 hours), drive the car, and see if it pings at part throttle, and wide open throttle.

Next, once the car is warm, do the same. See if it pings at part throttle and/or wide open throttle.

Wide open throttle = WOT = pedal completely to the floor. It is very important that you test the car when it's cold & warm, and part/WOT throttle during cold and warm states.

The sensors that the computer uses to calculate a/f ratio depend on whether the car is warm & what position the throttle is.

Perform those tests, and shoot me a PM and let me know what happens. Then we can go from there. I have a suspicion, but I want to confirm it first.
Scott

 

[mo_dingo]

Are you talking about the diverter for vacuum. It has one tiny black tube that says A/C on the vacuum diverter and it's right next to the brake booster?
that diverter has about 4or5 other vacuum lines. If it's in another spot let me know, thanks.

Sorry. I just saw this post. Yes, like I said above, that is the right tree. The line that is labeled a/c or vent or whatever is broken. It's very small. I used some electrical tape to fix the break, because it broke at the rubber connector.

It's a ghetto fix, so I wouldn't recommend it. But for a temporary expedient, it works.
Scott

 

[rapidsft]

checked a few things

I checked out the vacuum line labled A/C on the driverside and it looks fine, still don't know what is going on with that. As for the ping problem the car pings only when it warms up or is hot. It will not ping within the first 5 min or running at any throttle.

 

[rapidsft]

fixed A/C vent systerm problem

Thanks for the advise, I found out that the little 5mm tube that runs along the firewall to the vacuum box was the culpret. It was badly damaged about 9 inches before the passenger side firewall. I used electrical tape to patch it up in the mean time while i search for a replacement tube.

Now I just need to figure out what is wrong with my ping problem. I swaped out the ACT from my other mustang into this one and also cleaned the MASS AIR meter with brake cleaner to remove the dirt on the sensor. I still seem to have the same problem after the car is running at 150+ degrees. At 10% on up, throttle; the car still pings!! It will not ping when it's cold, even at full throttle. Going to try higher octane fuel to see if it still pings after it's warmed up. If it doesn't then i suppose i'll have to retard the timing a few degrees.

 

[Trick95]

You never said what the timing was set at?

 

[rapidsft]

Timing

Timing was originally set at 9degrees. I now have the timing at 6degrees just so it won't ping with 91octane fuel. I want to run full 10degrees timing with 87 octane like it should. This is frustrating. I might have to do that mass air meter rear plate mod, jus to fix this mess.

 

[Al J]

What's the MA Meter rear plate mod?