Detonation/Pinging Under Load

[mckrishes]

Hello. I have a 1998 Honda Civic LX with the d16y7 engine. I am having problems with detonation/pinging under load. No problems during idle, coasting or very light acceleration. I use 87 octane gas. Using 93 octane will just about eliminate the problem, but I’d like to find the cause. I used a scan tool, and it appears that I am running rich. Here are the values:

At idle:

1. MAP 5.1 – 5.8
2. Short term fuel = -14.8
3. Long term fuel = -11.7
4. O2 pre cat 0.095-0.780
5. O2 post cat 0.8-0.7

At 2300 rpm:

1. MAP 4.5-5.2
2. Short term fuel = -7.0 to -13.3
3. Long term fuel = -11.7
4. O2 pre cat 0.095-0.720
5. O2 post cat 0.095-0.115

From the O2 sensor readings, it appears I have a bad catalytic converter based on Eric’s video. So far I have done the following:

1. Verified the cat is not clogged
2. Verified good intake pressure on the engine
3. Checked for vacuum leaks using Eric’s method
4. Air filter is clean
5. Set the ignition timing to stock (which helped a lot)
6. Ran some injector cleaner in the tank
7. Verified coolant is full with no air in system

I am trying to figure out what direction I need to go in. I haven’t checked fuel pressure, cleaned the MAF sensor or checked for compression. Not sure if something is wrong with the MAF. I appreciate your help.

Topic

[mckrishes]

So now after 9 hours I am at 6psi. That is strange given the other tests.

[Author]

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