Where to start trouble shooting?

[Cdv3286]

Need some help! Driving today and the engine died on me and now will not start. She started up right away that morning. (had been sitting a while); I did notice a little sporadic idle but that leveled out after a short time.

As she ran fine before this so I am fairly confident its not mechanical (i.e. timing, plug wires etc - could be wrong though) and am guessing its electrical.

Where do I start trouble shooting? Thoughts? Thanks!

Ford 4.6 liter 4-cam Cobra mod-motor, Teksid block, stroked to 5.0 with new forged crank, H-beam rods, forged pistons; Electronic fuel injection; Accufab throttle body, otherwise stock intake, heads and cams

Any advice would be great!

[Gumball]

A few ideas / questions.

1) Is the battery charged or flat? If flat, maybe your alternator is bad and it started and ran on the battery until it was out of juice.

2) If the batter has a charge, then maybe a ground - start with the simple ones and work from there.

3) ECU? I know someone who's went bad, but beyond that, I'm out of my league with the mod motors... I'm an old-school carb'd guy.

Best of luck with the troubleshooting!

[Cdv3286]

Battery is good. She turns over fine. I will put a voltage meter on to just triple check. Will check the grounds... which ground it would be is the million dollar question.

I am like you.. if it was a carb'd engine I would have an idea where to go. With the Mod motors not so much...

Thanks.

[Norm B]

I would start with the fuses for ECU power and fuel pump. Check for spark and fuel pressure.

There has to be a mod motor expert out there with some more/better ideas.

Good Luck

Norm

[CraigS]

I would start with the fuses for ECU power and fuel pump. Check for spark and fuel pressure.

There has to be a mod motor expert out there with some more/better ideas.

Good Luck

Norm
In addition to these, either a long skinny screwdriver or a stethoscope to listen to the injectors. They should make an obvious clicking sound as someone else cranks the car.

[luvaz]

On computer-controlled engines, I've found the culprit has been w/an engine sensor. e.g., Crankshaft position, camshaft position, throttle position (TPS), etc.
Although some other more knowledgeable than me may chime in here, it may be prudent to search other forums that cater to 4.6 mod motors.

Good luck and let us know what you find!

HTH,
Will

[Cdv3286]

Ok so I am starting with the crank sensor... So according to the Haynes manual the first thing you are supposed to do check to see if you have voltage to the sensor..but that is all the detail it gives.

In the key on position, I put the lead to both of the two wires... I got ~1.5V at each wire. This seemed odd to me. I would think one would be ground or a return wire (i.e. no voltage unless the sensor returns it to the ECU) Is this correct or does this indicate that I have an issue at the ECU or in my wiring?

When looking at the sensor its self, it was pretty dirty so I went ahead and pulled it to clean it up. And I noticed a possible issue close to where it mounts... see picture at the tip of the probe. Is that a hole where there should not be one!!!!!!??????

54484

Thanks all - I am new to the Mod motor and the associated electronics. Enjoying learning as I go though luckily!

[Timb]

I believe the hole is just part of one used for bolting up the pan from the other side. Easiest way to test I think is to check voltage at one if the injector plugs. Hook up your meter to both pins and turn it over if you see pulses the crank trigger is fine. If that test is ok my money is in a fuel pump problem i.e. No pressure either from a bad pump or connection in the tank.

[dallas_]

I'm assuming you have gas in the tank. :)