Went to go start my 2005 4.0l the other do and got a crank but no start. Has 4 Bar of pressure at the fuel rail, has spark in time, and has compression. The car drove fine into the shop when we were doing some diag on cel but when I went to leave, it wouldn’t start. The cel was on for an generic engine running lean code is believed to be because of a leaking egr valve. Codes were P0171 and a P0174, battery is at 12.4v, starter activates, tries to turn over, still no start. When we pulled the spark plug it wasn’t fouled out and didn’t smell of fuel at all. Any ideas on why this is happening pr suggestions on fixing it are appreciated.

 

Welcome to the form

Do the 50/50 test
Spray fuel into the engine and try to start it
If it starts runs and dies, you have no fuel delivery
If it doesn't start then you have no spark(or no compression)
50/50 no guessing, instant results

If you have:
Fuel, mixed with air
Spark, at the right time
Compression, above 120psi
The engine fires/starts

So you are missing one or more of these, as simple and as complicated as that
No matter how many electronics "they" add to the outside its still just a gas engine, fuel, spark, compression

2005 Ranger doesn't have PATS, just FYI

CEL should come on with Key on, means computer has booted up
CEL should go OFF when starter motor start to spin the engine, that means Crank sensor is sending a good Timing pulse to Computer, if CEL doesn't go OFF then No Start

 

So if I’m understanding this correctly, the no start would be a bad crank sensor. Injectors all worked when it drove into the shop and it has fuel pressure at the rail, plug was getting spark when I pulled it. And compression is good as it wants to start but isn’t receiving fuel. Which means I would most likely need a new crank sensor.

 

Spark will not start with bad crank sensor

Look at the CEL
Should come on with key on
Should go OFF when cranking over engine<<<<<this means Crank sensor is working

 

Cel stays on because of a engine running lean code from a defective egr valve. I though it was bad crank sensor that stops fuel, and bad cam sensor that stops spark plug from firing.

 

No, CEL should go OFF when cranking engine over each time, CEL can come back on once engine starts(RPMs above 400) if there are codes set
Do this, unhook battery for 5 min, that should clear all codes, then reconnect and see if CEL goes off when cranking engine over

Crank sensor is the main timing sensor, computer uses it for both spark and fuel injectors
Cam sensor was added later on(1995) to fine tune spark advance and sequential fuel injection

If crank sensor is not working or cam sensor is not working then there should be a code set for that

P0335 Crankshaft Position Sensor A Circuit Malfunction
P0336 Crankshaft Position Sensor A Circuit Range/Performance
P0337 Crankshaft Position Sensor A Circuit Low Input
P0338 Crankshaft Position Sensor A Circuit High Input
P0339 Crankshaft Position Sensor A Circuit Intermittent

P0340 Camshaft Position Sensor Circuit Malfunction
P0341 Camshaft Position Sensor Circuit Range/Performance
P0342 Camshaft Position Sensor Circuit Low Input
P0343 Camshaft Position Sensor Circuit High Input
P0344 Camshaft Position Sensor Circuit Intermittent

Problem can be, the Computer has no connection to the START circuit, computer doesn't "know" you are trying to start the engine until it "sees" a timing pulse from the Crank sensor, so it just "thinks" you are sitting there with the key on, lol, has no idea starter motor is turning the engine over, unless its sees the timing pulse
So it won't set a code
If Cam sensor is working though, it should set a crank senor code, if it "sees" a pulse from cam sensor but not crank sensor