1hotroc

Thank you I stand corrected about the injector pulsewidth. I gather the fuel pressure should be 38-42 psi. with the vacuum line on, correct. I was not able to monitor the o2 sensor at wide open throttle. The injectors were at the same values you stated at idle but what about 3/4 to full throttle. What kind of values am I looking for from the important sensors such as o2, injector pulsewidth, timing advance. Also a gray area for me is setting base timing. What difference does it make if your setting the timing at 10 degrees BTDC or 6. I thought all the advance if needed is controlled by the computer. Oh do you think that if my fuel pressure is too high or timing is too advanced that this could be why my plugs are sooty? Thanks for all your help.

aklim

Fuel presure is measured with the hose OFF!

Don't know what the pulse width should be at 3/4 throttle. It depends on your combination and how the person sets it up. That is why I take Diacom readings and send it to Fasterproms. So they can see what the car is doing at idle, mid range, wot and cruising. They can adjust the pulse width based on what they see going on.

It makes a difference to your result. The ECM is stupid. It doesn't know what timing is set at. If you program it so that it assumes it is 6 and you give it 2 then it will advance to what it thinks is say 30 deg when it is actually 26. Think of it like your check register. If it says you have $30 and you write a check for $25, you should have $5 left, right? If you screwed up and log $30 when you have $10 and write a check for $25, it will bounce.

If the fuel pressure is too high, you could have sooty plugs because there is unburnt fuel. Your headers could glow red too. If your timing is too advanced, you might have other issues. Make sure it is at 6 deg with the wire disconnectd.

85irocrebuildtpi

change your plugs or clean them up....i am having same problem.......

onefastgta

If you have access to a scanner, log some data, then plot it on a spreadsheet and send it to ed wright after you have checked the basics, like tps voltage correct and idle air speed set correctly, cleaned iac motor, no vacuum leaks, fuel pressure at 42 psi. Ed assumes that your pressure is at stock levels and the initial timing is at 6.

It sounds like you have a vacuum leak to me or something isn't adjusted right, computer controlled cars only know what the sensors tell them, they are not 'smart'.

Also if you don't have an aftermarket ignition box, then put some new plugs in.

1hotroc

Ok I,m going to get the car back down to 6 degrees base timing. But the fuel pressure? With the vacuum line OFF I should set it at 38 - 42 psi? Then when connected the fuel pressure will drop even more? I,m going to have the car on the chassis dyno with the wideband 02 on tuesday.

aklim

That is correct.

That is correct too. With the hose off, there is no vacuum. Of there is no vacuum in the manifold, what conditions exist? Probably WOT. With the hose in place, you are signalling that you have less than WOT conditions. Less than WOT means what? You will not need as much fuel so the pressure is lessened.

Ok. Your call. I never had to use a wideband sensor. With fasterproms, the road was my dyno and it worked perfectly.