I just installed an off road pipe and now I get knock retard up to 16 deg. Bit of background on the car.

The car has now the following mods.

1.6 RR's, Edelb. Tes headers and 3" exhaust, (Msd box, coil, dist), crank pulley, Fuel press reg @ 50.5, no screens maf, K&N, and Air foil.

The O2 sensor is new and heated reading about .880 and my BLM is about 114 all across (rich I believe) also my base timing is 4deg disconnected from the computer. This problem clearly starter when I went to the off-road pipe.

Any help will be greatly appreciate.

 

any body?

 

is anything rattling against the body/frame?

Whats the tune look like now with the off road ypipe? How do the spark plugs look

 

I'd set your timing to factory spec and see if that changes anything (8*btdc)

 

I took the car out today with xray and this is what I found. I get the least knock retard 3* to 4* all after 4100 rpm's when I set my base timing at 2*btdc (did not try retarding the timing more); my o2 sensor reads then @WOT .836. I think it might be a bit lean. Is it a good idea to raise the fuel press a bit more? Right now I have it at 50.5. Also I have a stock tune.

Thanks again for the help.

 

836 is a touch lean...try getting it closer to 900-910 and see what happens. Fuel pressure can help that

 

How high can I go with the fuel press without running into problems? I have a walbro fuel pump and bosh III injectors.

 

Probably fairly high. Your not pushing enough power to max out the pump and those injectors can be run as high as 70psi and not have problems. I"m not sure what all you have done to that motor, but it have to be serious to max out a walbro.

IF your at 50.5 psi now, try 58 to see what happens at WOT. This is likely gonna mess up BLMs at part throttle but may help your WOT stuff. IF this works, i'd recommend getting chip tuning stuff and making the small changes you need to keep optimal fuel at cruise and WOT. Just need to set fuel pressure that keeps cruise BLM's around 128, and then adjust PE mode vs RPM enrichment to get WOT back in line... and you can also taylor the timing table to fit what the motor really wants.

 

Ok

I raised the fuel press to 58 psi and my o2 sensor went to .864 also now i get less retard about 2*to 3* all above 4400 rpm's. I was surprise that with that fuel press I still could not get the o2 sensor to read .900. & BLM's are around 109 to 112's. The cars is now definitely rich at idle but it runs nicely in the mid range. I'm going to try to adjust my rr's again just in case they loose.

thanks,

 

I forgot to mention that recently I opened the spark plugs gag to .045, but I don't think that will be since I have 9:3.1 compression and N/A. but that's the only other thing I changed.