Good Morning everyone from sunny NY. I am a contractor who does my own mechanic work in all my cars. My working truck is a '96 V6, 4WD, 1/2 Ton, 5 manual speed, and extremely dependable. Since I got it a few years back, that truck has always started right up on the first try without needeing to push the gas pedal. For about 3 weeks now, started to need 2 tries, then a few days later, three tries with the key ignition before it would start; until today, when it decided not to start at all. The engine just turns and turns like it is out of gas, but there is gas in it The truck was up a hill, so I tried to let it roll down the hill and start it in gear, but the truck whent down without even trying to start. It rolled just dead!

So I just called my customer to inform her that I am having car trouble with the hope anyone here can give me some suggestions on what I could check. Is it a gas problem? Is it an electrical problem?

Your help would be extremelly greatly appreciated,

Many thanks for taking your time in reading my post,

Steven

 

Your engine needs to have air, fuel, and spark to run. You will have to determine which is not present. Because it's relatively easy and inexpensive and a likely culprit, I would start with the fuel filter to see if it's plugged up. If it's clear, check to see if the pump is working and up to pressure. If fuel is flowing, then sparkis next. The old fashioned way (not recommended if you have a pacemaker)is to pull a plug wire, insert screw driver into the wire end, hold the screwdriver blade with one hand and put your other hand on a good piece of the vehicle's metal surface and have someone crank it over. You'll know pretty quick if there's a good spark.

 

Thanks Ron for your suggestions.... The air filter is about 2 weeks old, and the gas pump was replaced about a year ago. Never changed the gas filter so I make sure I get one right away. Also, I got a new os sensor plug for the driver side front about 2 weeks ago (but have not replaced yet...) so I am doing that today. How can I check the the gas pump is working correctly?

If the spark plug test fail that would mean that the coil is bad?

Thank you again,

Steven

 

Since you have changed the fuel pump and not the filter, the filter may wellbe the problem. As for as the pump test, you need a fuel pressure gauge. No spark... it would just mean that something is causing it not to fire... not necessarily the coil.

Good luck

 

Well... a friend told me to listen for the gas pump anyway to just ruled out and I cannot hear anything when my friend passed the key. I then drop a bit of gas into the carb entry and the truck tried to start.... Can it be possible that the pum is failing again?

 

My brother has replaced his pump 3 times within 2 years. Those years have also had trouble with the pump relay located in the fuse box under the hood. Sometimes the plug assembly melts and does not make a good connection. Have someone turn the engine over while you bang on the bottom of the gas tank. I have done this to get a couple started. (stuck fuel pump) which means you will be replacing it soon.

 

definately. let us know what the culprit is when you get her working again. good luck

 

Hi!!
Sounds like the fuel pump relay.. Available at NAPA for around $12.00..., at least 2-3 years ago... My '93 3500 was doing the same thing... Should be locared under the cover on the cowling on the passenger side..., near the blower motor...I'm thinking 3 plastic nuts, and it comes off.., and theyare marked..., if I remember correctly...Sometimes..., if I would turn the ignition on and off several times...,usually leting the warnig buzzers do their thing,75% of the time it would start... A friend finally told me what may be the problem... Tried it..., been starting first time..., every time since...
A safety feature built in...., that till the sensor..., senses oil pressure, it won't pump fuel.. Something to prevent buring up the engine, if you loose oil pressure while driving...,supposedly, as was explained to me...
Hope this helps...
DJ

 

That's confusing.... the oil pressure comes up when the engine is running and the engine will only run when the fuel pump is working. The ECU controls the fuel pump.

 

There's a backup system. Here's how it works:

Fuel Pump Electrical Circuit

When the ignition switch is turned to the ON position (before engaging the starter), the VCM energizes the fuel pump relay for 2seconds causing the fuel pump to pressurize the fuel system. If the VCM does not receive the ignition reference pulses (engine cranking or running) within 2seconds, the control module shuts off the fuel pump relay, causing the fuel pump to stop.

As a backup system to the fuel pump relay, the fuel pump oil pressure switch can energize the fuel pump. The switch has 2 internal circuits. One circuit operates the oil pressure indicator or gage in the instrument cluster. The other circuit is a normally open switch which closes when the oil pressure reaches about 28kPa (4psi). If the fuel pump relay fails, the fuel pump oil pressure switch runs the fuel pump.

An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump oil pressure switch energizes the fuel pump as soon as oil pressure reaches about 28kPa (4psi).