Help needed with engine tuning

[2FastLX]

I just bought a 90 GT vert, and it had never been touched before last weekend. I figured I'd do the normal timing adjustment, remove the air silencer, tps setting, etc. Other than this stuff the car is completely stock.

It had a lot of spark knock before I tuned it, and it got a bit better when I replaced the TPS. But it still has a little that I can't seem to track down. Here are the settings (and please tell me if I set anything wrong)...

TPS = .985 volts
Timing = 15 deg (tried everything from 10 - 15 degs with same results)
Plug gap = .044" (I am now seeing this may need to be opened up?)

I also cleaned out the IAB, and the idle seemed to improve quite a bit.

Could the ECT cause spark knock? It only seems to be noticable after the car warms up. The check engine light comes on right around the same time I start noticing it, but I haven't had a chance to go have the codes checked again since replacing the TPS. The first time I had it scanned it said TPS voltage too low, so I replaced it. The light went away, only to return after the car warmed up.

Thanks for any help you can give me.

 

[86bluecobra]

first off I would adjust my timing back a couple degrees and see if that eliminates it.

 

[jtfairlane]

Factory plug gap recommendation is .054" on EFI 5.0s.

 

[7-UP BILL]

15 degrees of timing with regular fuel will make it ping.

 

[vristang]

Timing might be a touch high,

But I would definately get the codes pulled,

I can't think of any way the tps would cause timing issues, atleast not in steady state conditions
Anyone have thoughts on this?


jason

 

[2FastLX]

I really don't know on the TPS vs ping, but it did get noticably better, and all but went away when the new TPS was installed. And the power was a lot better as well. The old one was reading .005 volts, so it wasn't working at all.

I have tried everything from 10 - 15 degrees on the timing. After the car is warm the spark knock is there, but only slightly noticable at load. And it's basically only knocking right after I step on the throttle. Once it climbs it RPM's a little it fades away. Oh and I forgot to mention, I am running 93 octane fuel.

I'll try to get the codes pulled again tomorrow and post a reply as to the results. Hopefully it's O2 sensors because I might as well install a new exhaust system while I'm under the car

Thanks again.

 

[bloopbloob]

are u sure it goes away? maybe your exhaust hides the noise at higher rpms?

 

[ninety15.0]

My buddy had an issue with the ETC sensor and pinging in his SN car. He only had pinging issues once the car was warmed up to. I think it might be worth trying...it seems like you have gone through all the normal stuff. I would regap thos plugs to the stock 0.054" setting.

 

[2FastLX]

I'll try regapping the plugs. I didn't make it out in time to get the codes scanned again. But I drove it all the way to work today (70 mile trip) and it did fine. The check engine light came on again about half-way here. But it goes away when it cools off. I'll update again tomorrow after I regap the plugs and hopefully get some codes pulled again.

Thanks again.