Detonation, AGAIN?!?!

[PKRWUD]

Originally posted by 95mustanggt
What are some of the mechanical things I could check. I've been thinking of the following

4. Carbon deposits on the heads
5. EGR valve
6. fuel pump

Also if you know of a good test for the above that is quick and easy let me know.

Thanks.

Carbon deposits on the pistons would contribute to pinging, but it shouldn't be temp related.

An EGR valve that remains open during WOT would cause pinging. Next time the pinging starts, disconnect and plug the vacuum hose at the EGR valve. Start it and see if it idles okay. If it does, the valve is closed. Drive it hard and see if the pinging reoccurs. if it doesn't, there's a problem with your EGR, and it needs to be diagnosed further. If it does, reconnect the EGR, and check the fuel pressure.

You need an EFI fuel pressure gauge. You need to check several things, including pressure with and without vacuum applied to the regulator, with the engine off and running. After it's run a while, and the pressure has stabilized, shut off the engine and watch the gauge. It shouldn't change (bleed down) at all for at least 1 minute. If it does, you either have a regulator problem (unlikely), leaky injectors (unlikely), or a bad hose going to the pump in the tank (likely).

Any codes (KOEO & KOER)?

Post the results from the above tests, and we'll go from there.

Also, just to rule it out, the next time this happens, you can try removing the chip, making sure the base timing is at 10 BTDC, resetting the ECM, and seeing if that takes care of it. Chips do go bad. I just had one fail after 2+ great years.

BTW, with a chip installed, you need to run the recommended t-stat (usually a 160), use only 92 octane or higher fuel, and leave the timing set at 10 BTDC (with the spout removed).

Take care,
-Chris