I recently put in a ported and polished plenum, Edelbrock high flow runners, and high flow intake on my 87 Trans Am. While I was in there....I said what the heck. I bought a new crane roller cam # 104224 with matching springs, new valve seals. I bought a new double roller timing chain and gear set, new oil pan gasket, new Holley adjustable fuel pressure regulator. Well its all back together. I had to get a flat bed and send it to my buddies shop. For some reason its flooding out with gas. I already had to change plugs once. He took it all apart again to check all the fuel injectors and they all look good. He hooked it up to the scope and its not tossing any codes out.
I didnt know if anyone had any ideas on what to check. He said he would have it done by the end of the week....but maybe I can give him some ideas on what to look for.
Thx alot!!

 

Did you dial the regulator pressure in? They don't come pre-adjusted you know. Use a fuel pressure gauge and dial it in to approximately stock fuel pressure, then tune from there. The injector pulsewidth is basically a constant, so the amount of pressure behind the injector will determine the injector's flow. It may take some tweaking to get it just right, keep working it til you get the plugs coming out decent. In my experience tuning my engine: If the motor feels "snappy" down low but kinda flat in the powerband, it's probably a tad lean. If it feels overly soft at low rpms, and it surges or idles poorly, it's rich. Doing this and feeling it out I was able to get my motor dialed into a dead solid 13.0:1 AFR, confirmed by a wideband.

 

yes we did hook up a fuel pressure guage. I think....or he did have it set at 48psi. He might have changed it I'm not sure. I know he said that the fuel pressure was dropping off too quick (I think its suppost to hold the pressure for a couple seconds before it dropps off) . Thats why he thought it was a leaky injector. It starts up after a little bit and you have to keep on the throttle to keep it going. But it does run. With ALOT of black smoke. It was making my eyes water how rich it was running.

 

It's supposed to hold pressure for a fair bit longer than a couple seconds. Lol, my motor holds within 5 psi of normal pressure in the fuel rail for over half an hour.

That leaking down will flood the motor and make it rich on startup, but it should clear itself out. Still it won't run 100% right because the spray pattern is probably irregular. Is the regulator getting proper manifold vacuum?

 

Cold Start Injector stuck open? Try unplugging the wires to it after the engine starts.

The fuel rail should hold fuel pressure for several minutes after you turn off the ignition key switch.

Running at 48 psi isn't helping this situation either. Set it at 43 (vacuum line to the regulator disconnected) until you get it to run better, then raise it later if needed.

 

Ill have him check the manafold pressure. Someone said something like that. Because of the cam. I didnt think the cam was that big to worrie about vaccume. So if the fuel pressure dropps off it has to be the fuel pressure regulator or the injectors. I'll have him check into that.
Thx!!!!!

 

No, no, no... Not Manifold pressure. Fuel pressure.

The size of the cam (mostly duration & lsa) can in fact affect Manifold pressure, but the cam that you have will have good Manifold pressure. Don't worry about that.

You need to know what the Fuel pressure is. You measure that with the vacuum line disconnected from the Fuel pressure Regulator. Once it's set to 43-48 psi (with the line disconncted and the engine running) then you reconnect the vacuum line.

Your problem sounds like it is a Fuel pressure Regulator, Fuel Injector, or Cold Start fuel injector problem. Start to diagnose by setting the Fuel pressure to 43 psi with the car running, vacuum line to the Regulator disconnected.

 

ok thx alot, ill give him these little tips, maybe it will make him get my car done faster. I want to see what the new intake and cam does for my performance.