"...Start / Crank
This is the start (I know, bad joke). The EEC needs to senses several things to start an engine:
* Power to EEC and fuel pump(s)
* Slow and irregular PIP signal from the distributor
* MAF/MAP low and irregular
* TPS is closed
* HEGO shows lean
These tell the EEC that you have just checked the dash, want the engine to start, and have turned the key. Even though you�ve heard the fuel pumps whirr, the injectors haven�t released any fuel until it senses engine rotation. Even when the engine does turn over EEC hesitates almost a full second to begin fuel and spark; this is to support oil lubrication. ECT and ACT determine the amount of fuel; the colder it is the more fuel it dumps in.
ECT and ACT determine the amount of fuel; the colder it is the more fuel it dumps in.
Cold Start & Warm Up
The engine has just started and we have to get adjusted. Well EEC does anyway, this strategy is kind of like you waking up with a hangover next to a stranger. Where�d I set my pants, should I run fast, should I sneak quietly! EEC�s first reaction is to keep the throttle air bypass open 100% or else we�ll be back to engine crank mode. RPM will drop however, usually to around 1000RPM after a few seconds, then drop down to base idle as she gets warmer (about 160�F). EEC looks almost completely at ECT and TPS; both indicate what will occur next. The colder the more fuel gets dumped in and the more timing added. When she gets warmer (about 170�F) she will lean out the mixture. This logic will speed up the time it takes to heat up the engine and converter
I redid the intake on my 96 351 and had to chase down s fuel smell as well. Remember that the fuel is under high pressure on an EFI system. Turned out I had a fitting that was leaking under pressure. It was just a drip drip drip. It dropped right onto the rear of the lower intake where it immediately flashed to vapor.
You should check around each injector and the two quick connects into and out of the fuel rail. They are all sealed with o-rings which, by now, are pretty old. Also be sure and check the vapor canister and make sure the lines are all intact and properly routed. However, I spent a lot of time diagnosing the Evap system which is a likely cause before I finally found the leak. No more smell for me. If there is a high pressure fuel leak in the engine bay, it is VERY dangerous so be sure to rule that out.