Intermittent No-start 1996 F150 302 EFI

[rt9]

Hi guys - I'm hoping you all can enlighten me on the workings of the 302/EFI setups you put in the Broncos. I have a '96 F150 with about 80K miles that has developed an intermittent no-start issue. The engine cranks, but nothing happens. Last week was the first time this happened and we had a tow truck come take it to the local fix-it shop, where, of course,,, it started right up and never had the problem again. (it was a rainy day)

This morning I had the same issue. (rained all night) Engine turns over fine but no indication it wants to fire. The fix it shop last week said the fuel pressure was good and no-codes on the computer.

Suggestions, places to start looking?

Rick

[Viperwolf1]

Look for spark.

[Kinder]

Wet weather & no start always points Click & Clack to the spark plug wires.

[Digger]

You need fuel, air, compression and spark to make the engine go. Compression and air are pretty consistent, so you need to check the other two.

When it doesn't start, listen for the fuel pump and check fuel pressure, but odds are if you hear the pump, you're making pressure in this case.

Also check for spark. Pull the coil wire and hold it near the block (use gloves and pliers to avoid shocking yourself) Look for spark. The most likely culprit would be the ignition module if there was no spark. If you do have spark, pull the cap on the distributor and check for moisture that could be shorting the spark power to the ground or wrong cylinders.

Check condition of the cap, rotor, plug wires and plugs while you're at it.

[rt9]

Thanks guys - just got home and checked spark. The truck still wouldn't start, but I do have spark. (bought one of those fancy little spark testers - cool)

I played around with it a while, checking all the cable connections, still no luck. Rolled it back down the driveway a bit so I can get the Bronco out tomorrow morning, and sure as s*#t it started then. I did hear the fuel pump give a little short growl this time. Tried it again about 10 minutes later, heard the fuel pump run about 1-2 seconds and she started right up.

Fuel pump? Relay? Controller? Gremlins?

[Digger]

Thanks guys - just got home and checked spark. The truck still wouldn't start, but I do have spark. (bought one of those fancy little spark testers - cool)

I played around with it a while, checking all the cable connections, still no luck. Rolled it back down the driveway a bit so I can get the Bronco out tomorrow morning, and sure as s*#t it started then. I did hear the fuel pump give a little short growl this time. Tried it again about 10 minutes later, heard the fuel pump run about 1-2 seconds and she started right up.

Fuel pump? Relay? Controller? Gremlins?

Original fuel pump? Making growling sound occasionally? Probably dead/dying fuel pump. Fuel pumps should make a crisp, high pitch whine when its healthy.

[rt9]

Yeah, definitely worth looking at.

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[Kinder]

'96, fuel pump on the driver side frame?

[landshark]

If it's similar to my old 94 bronco the pump is in the tank. I had similar issues with mine until I replaced the pump. The replacement pump from an auto part store was either too weak or crappy and replaced it again shortly after with a better brand.

If you replace it I would get on the forums for your truck and see what others are using as it's a common failure point.

[rt9]

Thanks again everyone. Yes, today I will determine if it tank or frame mounted. The truck started fine this morning and is sitting in front of my office. I first want to make sure, when it happens again, the relay is firing to tell the pump to run. I'm thinking of making a little test light that will come off the relay into the cab. Then we will look at a pump. LandShark - good info there, I'll check out the forums for F150's.

Rick

[Jesus_man]

My thought was relay. For some reason, some of them get picky if they are not upright with the connector facing down. Find your relay and see if it's free to move around.

[rt9]

My thought was relay. For some reason, some of them get picky if they are not upright with the connector facing down. Find your relay and see if it's free to move around.

Yep we pulled the relay and fuse yesterday, cleaned all the connections and gave them a stern talking too !!! The relay is in the main power distribution box and well protected, but I gave it due notice not to act up.

Rick

[rt9]

At this point I've hooked up a light to the relay leg showing when the pump is energized. Next time we'll know what side of the relay we tackle. Hopefully we'll never talk about this again...... but thanks.

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[Jesus_man]

Sometimes the best defense is a good offense.

[rt9]

On a side note,,, does anybody have a picture of a fuel pressure gauge permanently installed, and the parts needed?

[landshark]

I think you can run one off the fuel rail, should have a schrader valve on that rail if you want the easy route. I ran a gauge from it to the inside cab in my 94 bronco and tapped into the fuse panel on the bottom left hand side of the dash if I remember right

[Eck]

The fuel rail should have a schrader valve in the passenger side. You can put a 1/8 to 1/4 reducer like this in its place: https://www.zoro.com/parker-reducer-ada ... lsrc=aw.ds

Then you can attach a 1/4 male to 1/4 female elbow (found easily at ACE). Then just buy a fuel gauge with 1/4 npt male thread. Just be sure to get one that goes up to at least 80 psi (I'd suggest liquid filled too).





This is obviously if you want the gauge under the hood. You could run a line into the cab if you'd like to be able to see it in the cab.


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[rt9]

Awesome - Thanks!!

[Justin]

You might check the thread on your rail. I just ordered the stuff to add a gauge to mine. Gauge was 1/8 npt and needed a 1/16 npt adapter, but I'm running later model stuff than Eck.

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[rt9]

You might check the thread on your rail. I just ordered the stuff to add a gauge to mine. Gauge was 1/8 npt and needed a 1/16 npt adapter, but I'm running later model stuff than Eck.

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Will do. Thanks.

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[rt9]

So,,, after a little less than a week of good luck, it started acting up again and luckily at the local mechanic shop. Fuel pressure, with or without the filter, is 10 psi. New pump and filter going in now.

[Unaweep]

I had this same exact problem on a 1988 Ford Ranger V6.

Very random problem.

Turned out to be the inertia crash sensor switch for the fuel pump.


Erik

[rt9]

Yeah that was one of the first things we crawled into and checked. Unfortunately it was the fuel pump. On a good note, it runs a lot better now!!!!

[Digger]