Was lean now rich after BHG

[morris]

Maybe somebody here can help me with this.

I have a turbo GS400 8.5:1 forged pistons. I had been putting down just under 500rwhp prior to my bhg. At the time I had dialed in all the extra fuel that my system would allow me to, basically I was at +50% on my SAFC.

I had a BHG due to overheating, finally got the head gasket replaced and now I find that where I was +50 I am now tuning at -30 or so. I have no idea why I went from lean to rich. The car seems to be running fine and I am running a stock HG

Any ideas?

 

[Lextreme II]

Hey Morris,

I just blew my HG too. I think the reason your are running rich after the HG is possible that when u change your HG you disconnect the battery and the stock ecu reset itself. Did you disconnect the battery? After a while it should normalize.

 

[z8]

Hi Morris,
If you got steam out of your exhaust, you probably fowled your oxygen sensor with antifreez.This will make the system go rich.

 

[morris]

Well I drove about 1000 miles since the replacement so the ECU has probably normalized as much as it is going to and I never got any steam, just overheating.

But thanks for the ideas.

Now I have bigger problems, it looks like all my oil is going somewhere.

 

[Lextreme II]

Did you change both gaskets or just one? Are you loosing oil too? Any oil in your radiator fluid?

 

[morris]

yea both sides were done. The oil loss may be unrelated but I dont see anythihg in the radiator.

It could be as simple as someone increased the fpr when they put it back together.

 

[stevechumo]

Did you mention you tuned the SAFC at +50 before and now it's -30? That means +50 (increasing the pulses) is way too rich and -30 (decreasing the pulses) is lean. With smaller fuel injectors and if you enrich them, they won't last. I'd prefer to go with larger injectors and dial them down (-).

 

[Lextreme II]

Morris,

Are experiencing overheating? Are you loosing water via the radiator cap? If you have those symptoms, you might have head gaskets leakage. I have the same problem. The combustion chamber pressure was escaping through the MLS and create massive pressure in the radiator fluid system. Fluids coming out of the radiator cap. Due to low fluid overheating occurs.

 

[Toysrme]

Leakdown / compression check time.
Were the heads & block checked to be true with an accurate machineists square, or milled flat?

 

[morris]

No no problems with loss of coolant and no over heating symptoms. I'm thinking that the fuel pressure was increased at some point.

Put the car on a lift, no visbile signes of oil leakage under neath. The exhaust has no oily residue and the intake didnt have that much oil in it from the turbo. I am going to just keep a close ieye on it.