Had to retard timing 5 degrees to stop ping?

[pmead]

This is a new car to me. (1983 targa 3.0 CIS, MSD ignition) I have been driving for about a week. I noticed "pinging" under heavy acceleration between 3000 and 4500 rpm. Very faint sound could only hear along guard rails fence etc..... (echo) I dropped the base timing to 0 and the ping stopped. Is this unusual? Worn distributor? Any problem with that base timing? Car runs fine at the new setting. Car has 150k miles and runs well.

[universeman]

The timing spec for these cars is 5deg BTDC at 900+/-50 RPM. Are you saying you advanced it by 5deg, to TDC?

[pmead]

I did not advance the timing. I retarded it about 5 degrees so now it is 10 degrees BTDC This also dropped the idle down to 900. It did idle a little fast before @1000.

[RSTarga]

Jason, do you mean 5 ATDC?
I don't know the spec for an 83, but I always set the timing at whatever total advance should be at 5k and don't worry as much about idle timing.
Make sure you follow the factory instructions as to plugging vacuum advance when checking at higher RPMS.

[RSTarga]

10 BTDC is way too much advance at idle.

[RSTarga]

I think you are both confusing ATDC, (retarded) with BTDC, (advanced)

[pmead]

Sorry I get confused easily!! I have the base timing set at 10 degrees ATDC and my issues seem to go away. Is this common?

[Tippy]

That thing must rev like a dog at 10 ATDC. Ouch.

[Targalid]

Another thing to check is the inside of the distributor cap for carbon tracks and other debris. These can be nearly invisible but can cause ignition crossfire which gives ignition on cylinders that should not be firing. I had a similar pinging which disappeared when I scrupulous cleaned the distributor cap and reinstalled.

[Neel]

Originally Posted by pmead

This is a new car to me. (1983 targa 3.0 CIS, MSD ignition) I have been driving for about a week. I noticed "pinging" under heavy acceleration between 3000 and 4500 rpm. Very faint sound could only hear along guard rails fence etc..... (echo) I dropped the base timing to 0 and the ping stopped. Is this unusual? Worn distributor? Any problem with that base timing? Car runs fine at the new setting. Car has 150k miles and runs well.

Since you appear to be a bit confused, I would think it is best to set your total advance according to the procedure and specs for your year car.. If you don't have a factory or Bentley Manual outlining this, get or borrow one..
Setting timing is not difficult.. BUT, too much advance can ruin your day..

[Flat6pac]

Do you have the 2 hoses connected correctly
Your 5 degrees should be the notch to the right of z1 with hoses disconnected.
At idle the hose with vacuum goes to the back side of the pod on the distributor.
To find the hose at idle with vacuum, touch the hose to your tongue.
Bruce

[porsche930dude]

leave it where it is if its running fine. I had alot of trouble with mine too trying to time it as per the book with hoses disconnected and all that. I couldnt get it anywhere near spec by doing it that way. I dont know why. But I had the same problem with pinging and backed it off a little and its been good ever since. Could be the previous owner used better gas or that gas keeps getting crappier.

[T77911S]

Originally Posted by Flat6pac

Do you have the 2 hoses connected correctly
Your 5 degrees should be the notch to the right of z1 with hoses disconnected.
At idle the hose with vacuum goes to the back side of the pod on the distributor.
To find the hose at idle with vacuum, touch the hose to your tongue.
Bruce

check this first.

make sure you understand which side of Z1/TDC is BTDC and ATDC.

how much did you turn the dist as in how far did the timing mark move?

[Gordo2]

Check for broken head studs...

Good luck,

Gordo

[pmead]

Ok I got some bad advice from a local "expert" who said to set the timing with the vacuum hoses attached. I looked in my Bently manual and it says for an '83 to remove hoses. I will do it again in the morning. The valves were adjusted 500 miles ago by the previous owners shop. There were no broken studs at that time. Another person told me his car will ping occasionally and because the pinging stops as the rpms increase he does not worry about it. That does not sound right to me!

[pmead]

Just reset the timing according to Bently book. With the vacuum disconnected and 950 rpms the car seems happy with about 1-2 degrees BTDC. No pinging at any rpm and car feels strong with good throttle response. Next I am going to check my fuel pressures because I am not happy with my hot starts. Its starts great cold and within 5 minutes after hot. If it sits hot for a while it is difficult to start. It will eventually start but it takes some cranking and then runs very rough for 5-10 seconds. I suspect poor residual pressure. I found a note from a mechanic who said the fuel pump check valve was allowing fuel back to the tank. (fall 2014) There was no record of the repair and it does not look like the fuel pump fittings have been touched in a while.

[T77911S]

good place to start

[kodioneill]

Originally Posted by pmead

Just reset the timing according to Bently book. With the vacuum disconnected and 950 rpms the car seems happy with about 1-2 degrees BTDC. No pinging at any rpm and car feels strong with good throttle response. Next I am going to check my fuel pressures because I am not happy with my hot starts. Its starts great cold and within 5 minutes after hot. If it sits hot for a while it is difficult to start. It will eventually start but it takes some cranking and then runs very rough for 5-10 seconds. I suspect poor residual pressure. I found a note from a mechanic who said the fuel pump check valve was allowing fuel back to the tank. (fall 2014) There was no record of the repair and it does not look like the fuel pump fittings have been touched in a while.

This problem may be the fuel accumulator in the engine compartment l/s.

[universeman]

RSTarga, printed on the decklid label of mine is 5 BTDC not ATDC:



Mine was set to TDC with hoses disconnected, and it ran hot. I advanced it to 5 BTDC and it runs much cooler, and starts a little easier.

[Flat6pac]

The check valve and a couple brass washers a few dollars
Accumulator couplehundred