Freshly tuned, pings at high boost

dklitzke

Registered User
Just got finished changing plugs (.48 gap), wires (Livewires from SCP), O2s, fixed exhaust leak, deleted EGR, replaced SC with 25k SC, now it pings a little when over 10 PSI. I am running a 5% pulley like before. It has 192k on it, but is in good shape overall. What could be causing the pinging? I always use 92 octane or better when available. Also, with EGR deleted, get CEL once in cruising range. When I first start out, no CEL, but give it a couple of minutes, and it comes on. Any ideas what's happening there? Thanks,

Don
 
New O2's?

I would wipe the CPU memory and let it relearn-if O2's are reading substantially different, the fuel map may be off now.

Nick
 
In addition to clearing Memory.
I have read deleting EGR can throw a code.
SWAG, check codes, you can buy a $30 code reader at any parts store.
My guess is one defective O2 sensor causes CEL, as the engine gets up to temp and goes into 'closed loop'.

Unrelated my wideband sensor shows my new NGK O2 sensors with a A/F = 14.7 at idle, and the old Bosch O2 were at 14.3,
and very happy getting an extra mile to the gallon. (from sparkplugs.com)
 
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Please include more information about your car next time, it sorta helps.

Could be almost anything; maf, fuel system, carbon build-up, Too hot motor / intake air. Try a koeo test, or a koer, it can be very enlightening.
 
More info on my car . . . . .

It's a '95 automatic, 192k, Apten chip (old), BBK 75mm TB, C&L 76mm MAF, 5% OD pulley, SCP exhaust/Kooks headers, stock fuel delivery system. Yes, the tuneup included new long-lead O2s from SCP. I did plug in my OBDI reader and did not get any codes. Drove it to work today, same symptoms. CEL comes on after a few minutes, at cruising speed. When I first start it up, no CEL. One other factor, two open vacuum lines: the one across the front of the engine that hooks into the air intake tube (lost the little plastic piece that plugs into the intake, can't find the right size replacement, and the two lines coming off the bottom of the EGR transducer. I plugged the vacuum line that hooked into the diaphram on top of the EGR assembly. This weekend I hope to rig a way to hook those lines back into the vacuum system and maybe that'll be the difference. Question, how do you wipe the CPU? Thanks you guys. :D
 
Bypassing the EGR without making changes in the chip will cause part throttle pinging. You could try colder plugs, that might help but you should either re-connect the EGR or get a chip that deletes it.

Re-connect the PCV vent tube but that's not really your problem.

There's a good chance you have an O2 sensor issue. When you get a CEL after the car has run awhile that often points to an O2 sensor.

Disconnect the battery for a few minutes to erase memory.

Did you retreive all 3 types of codes? If you get a CEL it WILL record it in memory. Something tells me you haven't completed all tests.
 
haven't had time to follow up but thanks . . . . .

I haven't had time to do anything else yet to locate the CEL source, but hopefully later this week. I did have the battery out of the car the whole time I worked on it, but will try wiping the CPU just to check. I will also read the instructions further on my OBDI code book and make sure to run all the tests :D

I installed brand new extended lead O2 sensors, but I have another new pair I could install if one was bad. Hope not though, expensive. Redoing EGR is not an option. The EGR tube on the header was destroyed and I had it welded shut. I will reroute the vacuum lines to make sure everything is right. Thanks for the helpful comments. If I could afford it, I would get a new chip, but I am set back right now with doctor bills due to a motorcycle wreck. Ouch, in more ways than one! I will definitely get one soon as I can. :D

Don
 
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