First time start up, too much fuel. 350 chev 7747,

[live2wheel]

Hello all,

We are working on a 350 chev that came out of a 91 burb with the 7747 ecm that was transplanted into an off road crawler. We have the orig ecm and stripped off some sensors from the wire harness like egr, esc, knock sensor, vss. What we have left is MAP, TPS, IGN mod, IAC, coolant sensor and oil sensor. We tried to fire the rig up with the stock ecm and the injectors were delivering way too much fuel. In the process of finishing other modifications to the truck I modded the ecm with a zif socket and emulated a dloaded bin and tried to fire again. Same results with too much fuel. We swapped injectors, TBI, and even tried a variable pressure regulator in the throttle body. Still too much fuel. (even did a redneck regulator by pinching the fuel line with vice grips to the same result) The fuel pump is 40psi capable.

So, with the stock bin this thing just dumps the fuel and won't start. It sprays a big amount on crank but as it tries to fire and revolutions quicken so does the amount of fuel to the point it floods and can't start. At this point we can disconnect the injectors and crank and the engine will actually stumble for a few seconds while burning off all that extra petrol.

A couple of questions, what modifications to the bin do you see off hand that need adjusting with the deletion of all those sensors? And, can you think of another reason why it's delivering so much fuel?

Thanks for the help guys and gals!!

Jon

[EagleMark]

What does the Check Engine Light do when key is turned on?

What is fuel pressure?

[jim_in_dorris]

ESC and knock sensor control spark advance, and VSS tells ECM your speed. Without them you can indeed tune it, but it will be a challenge. What is the timing set at with the brown/tan wire disconnected? That much fuel isn't normal. What BCC are you using? Some of the real tuners will be along shortly with a better idea of what to check.

LOL Mark posted while I was typing

[gregs78cam]

If your pump is capable of 40psi, you really NEED to know what the fuel pressure is. It is entirely possible for a higher flowing pump to over power the regulator spring and force more fuel through than the return line can flow. That will increase pressure seen by the injectors. This happened to me when I converted my truck. Gotta check pressure.

[live2wheel]

Pressure gauge is @18psi and 0, supply and return respectively. Is that high enough to push that much extra fuel?

Edit Swapped in another regulator and got 16 psi and 14 while cranking. Have actually installed 3 different regs and same result with all of them as to too much fuel.

[EagleMark]

That's pretty dam high for a stock motor and stock chip that needs about 13 PSI.

What is your CEL doing when key is turned on? Should come on, blink, stay on till engine starts and then go off! If something other then that is happening you may be in Limp Home Mode...

[live2wheel]

Double post

[live2wheel]

Cel blinks once when ign is turned on and then stays lit. Haven't reached full fire yet because it floods out and won't start.

We salvaged the hard fuel lines from the doner suburban. Do you think these are too restrictive and are building pressure on the return side?