Ok, so I've had this pinging problem ever since I can remember with my car. It's a 87 IrocZ, 305TPI, T5, original block, new heads, manifold system is hot-tanked & bead blasted, all ignition parts are new, all fuel system stuff is new, except for injectors. All sensors/switches are new except for TPS & IAC. The timing is set to stock. All relays/modules are new. ECM is new. This is a smog motor I have put in so I can pass (California) smog. Ever since this motor has been in the car it pings under half or full throttle soemtimes. There's no trend or pattern to it either. It's like it just does it when it feels like it. One thing I found out in the past 2 weeks is that I have some kind fuel leak or fuel evaporation originating from the base of my filler neck to the gas tank. I cant tell if it's the neck or the the side near the top of the tank. When I fill it all the way up, it will leak for a while. I was maybe thinking that it's not pressurizing or something. I dont know, but this has haunted me forever. Please help...I feel like an idiot not being able to fix a simple pinging problem!!!!!!!!

Thanks Steve

 

You checked the timing with the timing wire disconnected? Are you sure the balancer is correctly showing TDC? Old balancers like to slip and can drive you crazy with the timing.

I was going to suggest the EGR valve but since it does it at WOT that's not it (EGR only functions at part throttle).

Slap a fuel pressure gague on it THAT YOU CAN READ FROM THE DRIVER'S SEAT. Duck tape it to the windshield (temporarily) and see if you have constant fuel pressure under heavy load/high RPM conditions.

 

Yep, I did check the timing with the wire disconnected. I did not know about the balancer thing. I'll look into that. I'll also try the fuel pressure gauge too...actually, the pinging also does it at half throttle as well. But the all the EGR stuff is new. The EGR valve, the EGR soleniod, the vapor canistor & the canister purge soleniod is all new. Thanks for the info

 

what grade of gas are you using?
My stock 305 pings with 87 and 89 octane. Runs great with 93.

Back the timing down or up the octane of gas you are using.

 

I'm using 91 (CA.). The timing is low as I can have it, without failing smog. I'm wondering if the gas tank have a small leak in it at the filler neck area would cause it to ping, not having enough pressure and all? Ever since I had the car, it has always pinged. Some days I can get lucky, but usually not. In the middle of the night, it usually wont.

 

....I used to have that problem also,it stoped after I changed the pressure regulator to an adjustable type.

T.