Maybe a new tune??

[cwh19]

Sorry for the long read but hopefully its worth it.


So in April I had my car tuned. Its a 94 with ported gt40s, ported cobra intake, s-trim, etc. At high rpms the car would go super lean. The fuel pump was the main suspect because I bought it with the fuel pump installed. It made 385 on a mustang dyno at that point. I dropped the tank and found out that it was the walbro 255lph standard pressure pump. So I replaced it with the 255lph high pressure unit.

I started driving it and found some serious blow by issues. My dipstick would launch out of the sleeve while under full boost and WOT. I tried some basic trouble shooting methods like a compression test and all my cylinders were within 10% with the lowest being 135psi and highest being 150. I read on corral that a couple people had this issue not because of rings, but because the lower intake gaskets would break and boost would enter the crankcase. I pulled the lower and the gaskets were broke in 5 different places. I replaced them with the steel laminate cored fel pro gaskets.

I installed the distributor and I put it in 180* off. It wouldnt fire and the plugs were covered in unburned gasoline. I pulled it out, found the correct tdc and set 10* base timing. I started the car up and it ran like garbage. Black smoke was present and it searched for idle until it stalled. I checked with a timing light that the base timing was correct with the spout out.

Do you guys think that since I installed the high pressure pump and fixed the leaking gaskets along with the fouled plugs from all the unburned fuel that the car is now running super rich at startup allowing for it to not run correctly? As in I need some adjustments to the tune?

Thanks!

[yeahloh95]

are you still runnnig the pcv ? that could cause the dip stick problem too

[2000GT]

replace the oil fill cap with a breathable one. I had a 93 Cobra with a vortech with the same issue. I replaced the cap and the issue went away.

[PaxtonShelby]

I'm running a breather on my oil fill spout and I still have some blowby and the dipstick issue. I've been thinking my issue is due to loose rings, but haven't done a compression test to verify. The lower intake gasket issue is interesting though...might have to check that out over the winter.

[cwh19]

I have both vavle covers running to a catch can with a line going to the power pipe pre supercharger. So the valve covers never see boost just pure vacuum.

[venom]

So you are running a vacuum line from the catch can to the inlet of the S/C? Breather on your catch can?

I've been debating whether to try that or not. I get a good bit of "oil mist" from the catch can when the motor is cold ever since I ran lines from my valvecover to the catch can.

[Martin0660]

I So the valve covers never see boost just pure vacuum.

Not to your issue, but if you really see vacuum on your inlet side, your filter set-up is too restrictive. There is no vacuum with a restriction.

Your pump change should not have affected idle / low RPM unless the fuel pressure went up.

[cwh19]

So you are running a vacuum line from the catch can to the inlet of the S/C? Breather on your catch can?

I've been debating whether to try that or not. I get a good bit of "oil mist" from the catch can when the motor is cold ever since I ran lines from my valvecover to the catch can.

I do not have a breather on the can. Its a closed system.

[cwh19]

Not to your issue, but if you really see vacuum on your inlet side, your filter set-up is too restrictive. There is no vacuum with a restriction.

Your pump change should not have affected idle / low RPM unless the fuel pressure went up.

I thought about this when I initially set it up. But I can't see how having a line run to the discharge pipe would be good what so ever. it would see boost under wot and put pressure back into the system and not pull it out correct? I think the idle set up would be an exhaust evac kit but I don't know how I feel about my car shooting smoke most of the time from the burning oil mist.

What should good idle pressure be for the fuel. I believe mine is 25psi