Hey all, Ive done a fair amount of research on this but cant seem to find an answer. Ive got a 94 B3000 or ranger that I just finished replacing the engine in, it is a 92 without egr I'm guessing the original 94 had egr. Ive replaced everything except the maf but it will run fine when its cold and as it warms up it starts to run rough. No issues when driving only at idle but I can smell gas while its running rough so I'm assuming the ecu is telling the engine to dump fuel?? I'm really starting to bang my head into the wall on this one. Any help or ideas would be greatly appreciated! Thanks in advance.

 

Welcome to the forum


Cold engines need to run Rich, Choked.

EGR valve is only used after engine is fully warmed up and under load, never at idle.
Computer will turn on the CEL(check engine light) if it needs an EGR valve connected and there isn't one.
Engine will also Ping/Knock, after warm up, when accelerating if your computer needs an EGR but doesn't have one to control.


Computer uses the ECT(engine coolant temp) sensor to read engine temp.
This is a TWO wire sensor only used by the computer.
There is a separate ONE wire SENDER that the dash temp gauge uses.

Make sure the ECT sensor is plugged in, may be you missed that connection
As the ECT sensor warms up the computer will start to run engine Leaner.
On Cold Start the idle should be 1,100+ RPMs , then slowly drop to 750 over the next 5 minutes as engine(ECT) warms up
If that isn't happening then ECT is not connected or not working

 

Yes it's a brand new ect sensor and the cel goes on and off for egr. Under cold start idle is rough between 750-900 once warm its struggling to maintain 500 and I can smell nothing but fuel.

 

I guess to clarify the truck has a new ect sensor, iac, plugs and wires, new intake gasket, and this truck has the upper intake with throttle body that is a single piece.

 

On the fuel rail on the engine will be the FPR(fuel pressure regulator)
The Return fuel line will be attached to it.
It also has a vacuum hose attached, remove this vacuum hose and check it for fuel.

If the FPR diaphragm leaks fuel can be sucked into the engine, causing your symptoms.

A leaky fuel injector can also cause similar problem.

Clear Flooded engine test
Warmed up engine
Key on engine off
Press gas pedal to the floor and hold it down, this tells computer to SHUT OFF fuel injectors, to Clear a Flooded Engine
Now try to start engine, still holding gas pedal to the floor

It should not start, or even fire, spark is on but there should be no fuel to start engine

If it fires then fuel is leaking in to the intake from some where

 

I do not have fuel coming out of the vacuum nipple of fpr however could a malfunctioning fpr cause these issues? As for the test I will do that when I get home.

 

Finally got around to doing the mentioned test and it does not run so I'm guessing its not fuel injector related, and no fuel out of fpr.... Still banging my head...

 

Try cleaning the MAF. There is a spray you get to do it. That controls the fuel to air mix. A clean air filter might be good since you are there.