Running far too rich, and don't know why.

SON240sx Automotive
1

Ok, we’ll start with specs. And I know they seems odd, and I know I’m the only one to ever do this in NA (that I know of)

1994 SR20DE
Yes, that’s DE not DET, it has a distributer drive, not coil on plug.
T25 Turbo

The engine compression is about 10.5 to 1
I’m running stock 270cc injectors.
I have an SAFC installed and set up for Dec Air to correct deceleartion, and bov purge.

There’s an AEM FPR, and it’s stable at 32 ish psi of fuel

There is no IACV (yet)
the Knock is not connected (yet)
There is a charcoal canister (but that doesn’t do much anyway)
it has a 2.5 inch high flow cat

Here’s the interesting part.
The engine runs perfectly well, off a 91 KA24DE harness and ECU, the problem is as follows:

It will foul the sparkplugs, and spit nasty smelling black smoke from the tailpipe (disgusting I get complaints from everyone when I turn it on in the garage) Unless I adjust the SAFC to lo-tht -30% across rpm, and hi-tht -20% across. these are rough settings. At which point the black nasty smoke goes away, and regualr vapour from the catalityc process, which doesn’t smell at all, comes out.

Now, the issue is that with 270cc 32psi of fuel, there should be no possible way of it running piggy rich when the SAFC is at 0 across both ranges.

I was thinking MAF, but I’ve tried 3 different ones, and am preparing to swtich to my cobra.

I don’t expect anyone to have much input on this as I doubt many, if any have come across a similar setup.

thanks

2

Actually I just had a brain storming session with HeatW, and it seems like a fairly basic answer that has eluded most of use for almost 3 months now.

The KA ecu presents a duty cycle for a 270cc inj to utilize a 2.4L engine. I am attempting to use the same duty cycle in a 2.0L engine, thus a differnce in 16.7% duty (if my math is correct which is unlikely at 2 Am)

So, if I follow this comclusion, I am over flueling by 16.7% per cycle and thusly running far richer than necessary. And it explains why -30% reduction across lo-tht range seems to clean up the exhaust, and not foul the plugs as much.

This may take a while to dial in correctly, and even longer to get it to pass an E-test. And even longer still to reach 7psi of boost safely.

Hmm things to think about and tinker with.

3

Ok, we’ll start with specs. And I know they seems odd, and I know I’m the only one to ever do this in NA (that I know of)

1994 SR20DE
Yes, that’s DE not DET, it has a distributer drive, not coil on plug.
T25 Turbo

The engine compression is about 10.5 to 1
I’m running stock 270cc injectors.
I have an SAFC installed and set up for Dec Air to correct deceleartion, and bov purge.

There’s an AEM FPR, and it’s stable at 32 ish psi of fuel

There is no IACV (yet)
the Knock is not connected (yet)
There is a charcoal canister (but that doesn’t do much anyway)
it has a 2.5 inch high flow cat

Here’s the interesting part.
The engine runs perfectly well, off a 91 KA24DE harness and ECU, the problem is as follows:

It will foul the sparkplugs, and spit nasty smelling black smoke from the tailpipe (disgusting I get complaints from everyone when I turn it on in the garage) Unless I adjust the SAFC to lo-tht -30% across rpm, and hi-tht -20% across. these are rough settings. At which point the black nasty smoke goes away, and regualr vapour from the catalityc process, which doesn’t smell at all, comes out.

Now, the issue is that with 270cc 32psi of fuel, there should be no possible way of it running piggy rich when the SAFC is at 0 across both ranges.

I was thinking MAF, but I’ve tried 3 different ones, and am preparing to swtich to my cobra.

I don’t expect anyone to have much input on this as I doubt many, if any have come across a similar setup.

thanks

4

Actually I just had a brain storming session with HeatW, and it seems like a fairly basic answer that has eluded most of use for almost 3 months now.

The KA ecu presents a duty cycle for a 270cc inj to utilize a 2.4L engine. I am attempting to use the same duty cycle in a 2.0L engine, thus a differnce in 16.7% duty (if my math is correct which is unlikely at 2 Am)

So, if I follow this comclusion, I am over flueling by 16.7% per cycle and thusly running far richer than necessary. And it explains why -30% reduction across lo-tht range seems to clean up the exhaust, and not foul the plugs as much.

This may take a while to dial in correctly, and even longer to get it to pass an E-test. And even longer still to reach 7psi of boost safely.

Hmm things to think about and tinker with.