Hey all,
Well I hate using the poor women card, but hey guys i'm in distress and my baby won't start. I own a 1989 F150, 4x4 5.0 5 speed. She's been wonedrful and problemless since I bought her a year and a half ago. I do all my own maintenance, oil changes, plugs ect. I read my haynes manual faithfully like a bible. It seems that I can't cure my baby and I feel stranded. I wanted to quickly add that before I bought her, the previous owner removed the front gas tank(I think it might have been propane but still not sure) and switched the poor girl from fuel injected to a carb. As I mentioned I have never had a problem. I have gone to the extent that I'll blow threw puddles that will make a chevy cry. Anyway, heres the problem.

Last week I started and warmed her up as normal. Drove a block away from home and she died right there. I have always had a small problem with the relay switches so I broke down and bought new ones as well as new wire harnesses. Replaced them with no luck. I towed her home in hopes it was the fuel pump. I dropped the rear tank and changed the pump. No luck. As I normally hear the pump kick in before I start her I didn't this time. I figured it was a bad pump and went out and bought a new one. I dropped the tank again, and still counldn't hear the pump kick in. So I tested the wires and I have power and a solid ground. I played with the intrga switch, no luck. I had all three pumps checked and they all work fine. Where am I not looking? I would assume there is a fuse somewhere but the manual doesn't tell me there is one. Last I was under her I noticed a block box sort of near/under the drivers seat(under the truck). I would assume this has something to do with the duel tanks, but as I mentioned I only have one tank and have never had a fuel problem. Any ideas??????

 

When you say you tested the wires, are you talking about the connector right at the fuel pump? If you have power there then the inertia switch, and fuel pump relay are fine.

Since you have a carbed setup. Get some starting fluid and spray it down the carb. Crank the engine over. If it fires up briefly then you have a fuel problem. Doesn't do anything then a spark, timing issue.

Next check for spark. Yank a plug and hook it back up to the wire and hold it against the block w/ a pair of insulated pliers. [gloves are nice too] Crank the engine over and look for a spark.

Good luck

 

Hey, thanks for the suggestions. I tested the wires by the tank, and yep they are ok. I've tried the starter fluid in the carb and she fires over but as the pump won't kick in it runs out quickly. I just put new plugs and wires and a new dist. Cap on as well. Like I said, I'm getting power down there just not sure why the pump won't kick in(I have also had all three pumps checked and there all good. I guess If I can get her started i'll never have to worry about buying e new fuel pump again... lol) I have tried every thing I can think of and everything the manual has provided. Still Found On the Road Dead, but still a true Ford owner for life.

Tesha

 

First off Tesha, welcome to the board !!!

Don't fret, someone will have an idea for ya to get the truck fixed. It is early yet and more people will be by to do some reading.

I do have a stupid question though. I know that with a fuel injection system there is a pump in the tank and then another pump (high pressure) on the frame rail by the driver's door. I would think that they might have gotten rid of it when switching from F.I. to carb but didn't the older trucks have a fuel pump in the tank along with another fuel pump on the side of the block as well ???? Check to see if there is another fuel pump on the side of the block, it might be bad. I know Dad had an old '81 that he had to replace the pump on and it was on the driver's side of the engine. Not sure but worth a look, if that is what they have done. If there isn't a pump there, follow fuel line from the tank to see if they put another one in-line to help the tank pump but it won't be a high pressure like the one on F.I. Just an idea ???

Have Fun & Keep on Truckin'
Dean

 

Thanks for the suggestions. The 'black box' under the drivers seat (under the truck attached to the frame) must be for the duel tanks. Now would there be a fuel pump in there and if so would it still be connected regardless if I don't have a second tank? I didn't even think about that, always assumed that black box was just wasting space and catching mud when i'm playing. Hmm, well I'm finished work in an hour or so, I'll see what I can learn regarding that box. Thanks

 

Since you have tested the pump and you know there is juice feeding the pump then there must be a blockage.

When you move the throttle do you see gas getting shot down the venturi? You may have to prime your carb.

I had a no fuel problem on my mustang after I installed a new carb and fuel pump. Primed the carb and it fired right up. Worth checking.

Hope this helps

 

Rustbucket, Yeah I primed my carb, and my truck started and ran for a second, but died quickly. She wants to. What I have been able to pin point is there is power to the pump, the pump0 works, but I can't get the pump to kick in. Normally I hear the pump hum before I start the truck. I don't hear it now.

 

I am puzzled. If what you say is true then it should work. Only thing I can think of is start from the beginning and retest everything. If the pump is good, you have power to the pump, It should run.

Are you absolutely sure you have juice at the pump? Don't mean to call you out, but the situation just doesn't jive.

You say the pumps are good. How were they tested?

You have me stumped. Sorry I can't be of more help. I am sure you are yanking your hair out by now. I know I would be.

 

Well, I have pulled every hair I have, and still want to cry. I miss my truck. It's snowing here in Calgary and I miss being high up looking around to see if someone needs to be towed out. Well as I mention I tested everything. When I tested the wires near the tank the light was quite dim. I mean really dim. I also noticed a black box (assuming it has something to do with the dual tanks, as I no longer have the front tank.). Is it possible there is something in that black box that is not allowing the pump to kick in?

 

Possibly. But I would check the Fuel pump relay first. Pull it and test it. Grab a manual to find out where it is. I don't know off the top of my head.

Random question. Does your gas gauge work?

 

Rustbucket, the gas guage works, (last she started and drove). There are two relays that I found in the drivers side fender under the hood. I replaced them both. One of the wiring harnesses appeared to be in need of replacement, so I did that as well. Like I said I have pulled my hair trying everything they taught in Mechanics and everything I have picked up over the years. No luck. Maybe she's ready for the bone yard? I know i'm ready for a drink.

 

Seems to me you've tried pretty hard to troubleshoot this and fix it yourself. You've thrown a lot of $$$$$ at it, but it still hasn't solved the problem.

Cut your losses, admit defeat (but you get extra credit for trying to do it yourself!), and take it to a mechanic.

Good luck.

 

How did you test the pumps? There is always a solution. Your choice to throw in the towel. IMO give it another few days of troubleshooting. You shouldn't just throw parts at it though. Test the old stuff before buying new. You will figure it out.

It is something simple you have overlooked. I am sure of it. Have you recently charged the battery? Check all the fuses. Start at the tank connector and trace the wiring back and look for frayed spots. Corrosion at the connectors.

From your first post it sounds like you have no problem mudding or running through puddles. Something got wet that wasn't suppose to and now it is catching up to you. You need to take a step back and reasses the problem. Forget every assumption/conclusion you have arrived at this point and start from the beginning. Again don't just buy parts and change them.

Good luck. Any wrenching buddies you can call upon to give a fresh perspective on it.

 

It looks like your right, put my tail between my legs and head to the shop. I was think as i'm working right now i'll wait till next monday to take her in. This will give me enough time to check every thing for the eighth time. (sniff.....sniff)

 

I'm not a mechanic, but you said you used a test light to check for current at the pump. You also said it was very dim. Can you check the amout of current going to the pump with a muli-tester? If there is current but it is too weak to turn the pump there would have to be a short somewhere in the wiring. When you tested the pumps were you using the same amount of current the truck is suppling?