Ping Gone Finally

Thought that I was going to go crazy.. Did the MAF thing, Cleaned the carbon, changed the plugs & regapped. intake bolts, etc - etc
When checking all tye vacume lines. I found that the cruise cont. line was pretty wimpy, ( it was not a fuel/vapor type hose) some oil fumes had gotten in and deterroated the hose to the point that it was not fitting real snug. I put a small tye-wrap on each end for a temp fix and keep on looking... Found the connection from the intake (near the thermostat) that goes down to the transmission modulator valve to be also slippery. (it's a rubber adapter connection from the 7/32 intake bib to the 1/8 plastic line going to the transmission.) I put a vacume pump on the tranny hose and was able to hold 25# of vacume for several minutes... This made me think that the modulator was good.. but where was the oil comming from??? Very small amount... just enough to get the Q-Tip a tad pink when I cleaned out the formentioned adapter.. Thought that the previous owner had replaced the modulator valve and had not blown out the lines.
I removed the Cat-Converter section of the exhaust so that I could get to the heat shield that covers the modulator valve. When I pulled the hose off the modulator from under the tranny about a spoonfull of tranny fluid ran out...So!!! The valve was really bad.. small enough leak to not show up on the vacume pump meter but enough to make the lines wimpy .

Replaced the mudulator valve and hose down below.. - Replaced the adapter for the tranny line up on top, then replaced the cruise control hose with a 1/4 " fuel/vapor line..Disconnected the battery for appx 10 min to reset the comp. DROVE all weekend in Las Vegas with 107 outside temp and aircond. and only got a faint ping now and then... WOW !!! About time !!!

Now I need someone to give me some good inputs on my Rear Axle problem before it leaves me stranded.. I posted a thread on 6-4-05 Starting out with (94 Limited Rear ) I got 57 readers but no comments.. Surely someone out there knows limited - slip / traction - lok axles..... HELP!! HELP !!

Old and Retired. . Jack3

Thats good info.

Whats wrong with your rear axle?

that is good info. But wait a minute. What does the transmission modulator have to do with pinging? Do you mean if that line has a vac leak, it would introduce air into the system (causing a ping)?

Ping gone

BINGO - - - Vacume leak = extra air in intake system = lean mixture = PING !!!

I was thinking about that modulator also. my 94 only pings when hot or under load, more ping w/ a/c on. do you have any pics of the modulator?
the pping is driving me off a CLIFF........

my '93 pings at mid-range RPM at mid to high throttle levels (going up hills etc). i solved the problem by running slightly higher grade fuel (89 or 91 octane)

Just had my modulator valve replaced. Valve was leaking tranny fluid into lines causing rough idle, stalling, poor performance. Those lines had to be replaced as well cause the fluid swells the hose.

Rhett said:

that is good info. But wait a minute. What does the transmission modulator have to do with pinging? Do you mean if that line has a vac leak, it would introduce air into the system (causing a ping)?

Click to expand...

not only that, it can introduce tranny fluid into the line and it gets into the fuel mixture. Cleans the top cylinde and valves like nothing else but also dissolves the vacuum hoses.