Stalled While Driving

[beastpath]

Driving home today at about 50mph my engine suddenly cut out. I pulled over to the side and tried turning her over but although the starter was trying to get the truck to start it wouldnt.

I let it sit for a moment, and then tried again - turned on, and I drove away, but then about 20 feet later it died again.

 

Let it sit, but this time I couldnt get it to turn on. The starter was still trying though.

 

Does this sound like a fuel pump failure? I couldnt hear it hum when I turned the ignition, but thought that might be because I had just been driving it.

[edicer2]

i would take a fuel hose off after the fuel filter and see if it sprays if it doesnt then try the hose before the fuel filter and if it does then then you have a closed fuel filter. if it doesnt spray any house before the fuel filter then u have a problem further back toward the fuel pump possibly the fuel pump. check the fuel pump fuse also. next thing to do is check for spark on your spark plugs possibly replace them if they look bad

[beastpath]

K, ill check all that.

 

I've read that the pump sending unit wires can get corroded also correct?

Is the sending unit on top of the pump itself? Can I just clean up the connection, or is it the unit itself that corrodes internally?

[Precise1]

Check for spark first, it is the easiest.

Check for fuel.

Check the ECU.

 

That should give you a starting place.

 

B

[beastpath]

To check spark I just unplug a spark plug and hold it against a ground and crank correct? What serves as a good ground? body?

 

will it have thrown a code if the pump went?

[Kingman]

Possibly.

 

All that's required to check spark is holding the plug against the block while the motor is cranking. There should be spark...

Check your codes!

[Simon]

Sounds like a short at the sending unit. I've had it happen twice. Check the wiring on top of the sending unit, as the design is terrible, and prone to corrosion.

[Precise1]

To check spark I just unplug a spark plug and hold it against a ground and crank correct? What serves as a good ground? body?

 

will it have thrown a code if the pump went?

Yes, Sir, that is correct. I use the engine block so you don't burn any paint.

 

I have no idea if there is a fuel pump code, but it is a quick easy check...

 

B

[beastpath]

Quick update. The only code I am getting is "21 Ignition". There is indeed a fuel pump code, but it is not showing. I also can hear the fuel pump working, and the fuel lines in the engine bay increase in pressure when the key is turned to the ON position.

 

If I take the coil off my car will checker auto or somewhere be able to bench test it for me?

[Alkorahil]

I would guess the power transistor to the coil. I seriously doubt they would be able to check it, or know what it is.....

The proceedure to check this part is difficult and the part has to be on the vehicle to properly test it.

Edited May 25, 2010 by Alkorahil

[beastpath]

My brother finally got home so was able to do a spark test. Came up negative, no spark.

 

 

 

power transistor to the coil? excuse my ignorance, but is that a part of the coil itself?

[Simon]

No, it's a little grey box situated behind the coil on the intake manifold.

[beastpath]

so I should replace that?

[Precise1]

so I should replace that?

Download a FSM for a 1994 (pinned at the top of the Garage section) and follow their diagnostics. That's what I would do.

 

Can't hurt to go to Alkorahil's web site (in the Classifieds/Services section) to see what the unit costs and depending on price, check around for people parting out cars...

 

B

[beastpath]

I found the test section in my FSM, lol.

 

Continuity should read 0 ohms correct?

[GrimGreg]

I was going to suggest coil, that is how mine ran when the case cracked on it causing it to arc out the side rather than through the coil wire. Check that the plastic casing on the coil isn't cracked anywhere.

[Alkorahil]

Yes it is a box mounted behind the ignition coil. Has a harness going into the back of it.

 

I would not completely rule out the coil, just suggested starting with the transistor first since you had a total failure situation.

Coil would tend to be more intermitant.

[beastpath]

Well, I tested both my coil and my transistor per the FSM. Bought a new coil - and it tested exactly the same as my old one. Tried it - No go.

 

Figured it was the transistor as it was showing a resistance of 2 ohms - FSM doesnt state if there should be any resistance, just to establish that there is continuity. Was going to look for one on thurs at a junk yard and give up for the night.

 

Was looking through the FSM and realized I had not tested the ignition coil power wire for power when the ignition switch was in the ON position. I did so and got no reading, even though I was supposed to get ~12V. I have an MSD Offroad box spliced inbetween, so I followed it to the original wire and checked there.

Hmm, there was power. Removed the MSD wires from the set up and reconnected the ignition in the stock set up. Power tested good again.

 

Turned the key and she started right up.

 

So, turns out something must be wrong with the MSD box.

 

However, although she starts and runs, she is running really really rough. One of my spark plug wires came apart at the cap so I had to jimmy rig it back together and I think that is making it run on only 5 cylinders. Not 100% on that though, but as I changed the cap, rotor and coil in this process I figure I may as well get new plug wires and plugs.

I'll check the timing to JIC.

[Kingman]

No resistance means an open in the circuit, or no continuity. Basically, nothing there. When you have resistance it means electricity is passing through a working electrical component which is a good thing.

 

A good bulb will have resistance, a bad bulb won't have any.

 

MSDs have warranties right?