Make the FixYa experience better for everyone by voting.Hi,
My name is Ben and I'm your guru, i.e., mentor, an influential teacher or popular expert: a management guru. - origin from Sanskrit, 'weighty, grave' for today.
As you evaluate my advice. solutions and suggestions, there are a few things you must keep in mind:
• A thorough diagnostic approach involves the use of technical equipment, such as voltage meters. scanning equipment and other sophisticated devices. Diagnostic tools can be borrowed from AutoZone for FREE:
• Lastly, fixing one problem can very easily reveal a problem with something that you might consider unrelated.
Subject: Engine starts and then cuts off.
Customer's exact description: the car will turn over but will not stay running. the car has not ran in
three years. when last put into storage it would run for 30 seconds and
then shut off.
Discussion: Late model vehicles are highly computer controlled to reduce emissions, maximize fuel economy and improve consumer comfort. The various control systems in vehicles are interrelated and controlled by multiple computers that constantly monitor vehicle performance through a myriad of sensors located throughout the vehicle. Based on information received, the computers adjust the vehicle performance through a series of valves, switches and motors.
If your check engine light turns on, the vehicle actually stores information on the problem.
• When you ignore a check engine light you risk:
• Further engine damage
• Poor gas mileage
• Vehicle performance problems
• Serious repair costs
A Scan Tool can be used to read and erase trouble codes, display, record and play back LIVE diagnostic data and perform other tests allowed by the vehicle maker. Scan tools that cover vehicles 1982 to present are available at your local auto supply dealer.
A Code Reader can be used to read and erase diagnostic trouble codes as well as other additional features depending on the tool. These tools work on all vehicles 1996 and newer.
A Code Scanner reads diagnostic trouble codes generated by the vehicle's system. Codes are displayed on the vehicle's dashboard and/or identified through audio prompts. These products work with 1981-1995 vehicles.
The customer doesn't indicate any diagnostic tests to date. A dealer or your local mechanic will charge $100-$200 to perform a diagnostic scan. However, AutoZone will provide a thorough scan for FREE. All of the suggestions cited below will require the use of a code scanner or a code reader.
This is how your problem is solved in my shop. Out of the box, I'd say that you have a problem with the fuel management system or one of the system sensors that is causing the on-board computer to make adjustments as best it can. However, there's a good chance that it's something simple and inexpensive like a clogged fuel filter, a bad fuel pressure regulator or water in the fuel tank. Anyone who tells you that a modern vehicle can be diagnosed without a scanner with the problems you have set forth is merely guessing. You car has a computer and memory and probably knows exactly what the problem is. That on-board computer is just waiting for you to ask, "What's wrong".
This is where you'll start.
Difficulty: Moderately Challenging (AutoZone will loan you the instrumentation FREE of charge)
Instructions:
- Check the entire fuel delivery system if the engine starts running rough, stalls out in traffic or won't start at all.
- Relieve system pressure. Disconnect the negative battery cable and loosen the gas cap to let pressure drain from the system. Attach a dual tube pressure gauge to the test port and drain fuel into an approved container.
- Disconnect the fuel pressure sensor vacuum hose. Check for fuel in the line. If there is fuel present in the line, the fuel delivery problem is likely caused by a faulty fuel pump pressure regulator. If there is no fuel in the line, reattach the vacuum hose and continue with the fuel delivery diagnostic.
- Twist off the fuel pressure test port cap and attach a pressure gauge to the fuel pressure valve if one is not already connected. Reconnect the negative battery cable and turn the key to the first position. Do not start the engine.
- Check the pressure gauge. It needs to register between 45 and 48 psi. Start the engine and let it idle. Check the gauge again. It needs to register approximately 46 psi. Leave the engine on and remove the vacuum hose. Check the gauge one last time. It needs to register approximately 50 psi. Pressure that's too high indicates a malfunctioning pressure regulator. Low pressure indicates a clogged fuel filter or a broken fuel pump that needs to be replaced.
- Cut the engine off, relieve system pressure again and remove the negative battery cable.
- Clean the fuel filter inlet with compressed air to remove any dirt that might come loose and contaminate the fuel supply as you remove the fuel filter. Pull the filter out at the male filter fitting and disconnect the remaining connections to the filter. Remove the filter.
- Examine the filter for clogs and replace it if necessary. If there are no clogs, the fuel delivery problem is probably caused by a breakdown in the fuel pump itself.
DO NOT RUN OUT AND A NEW FUEL PUMP YET! This was only the opening act.
First a little background for your edification. You may be aware of all this but we've never done business before and all assumptions are off the table.
For an engine - make that any engine and irrespective of manufacturer - to run, you need three things to happen inside the engine, compression, fuel and ignition, without any one of these components the engine will not run.
- Compression - Engine compression caused by crankshaft rotation and pistons moving up and down inside the engine block. If the timing belt or timing chain fails it will cause the camshaft to become out of correlation with the crankshaft or allow the camshaft to stop rotating. Either of these conditions will cause the engine to lose compression and sometimes cause internal engine damage.
- Fuel Delivery System - The fuel system includes: fuel pump, fuel injectors, pressure regulator, fuel filter and pressure lines. This system is used to supply fuel under pressure to the fuel injection system, the lack of fuel pressure or volume will cause the fuel delivery system to fail and the engine to stall or not start.
- Ignition Spark Delivery System - The ignition system components include: spark plugs, spark plug wires, distributor (if applicable), crankshaft angle sensor, camshaft angle sensor, ignition coil, ignition module, knock sensor and PCM (powertrain control module). The engine relies on the ignition spark to be delivered to the combustion camber at the correct time. If the ignition spark stops or is delivered at the wrong time the engine will not run or run poorly.
All of the above systems are monitored by the GM Powertrain Module (a.k.a. on-board computer). A diagnostic scan retrieves any inform related to the malfunctioning parts and tells you precisely what is wrong.
Whenever your engine cranks but does not start, runs rough, staggers, sags or cuts off, follow this Troubleshooting Guide. Some of these steps require a code scanner. They are costly but remember that AutoZone will loan you one for FREE.
If you have trouble using the code scanner or interpreting the codes click on the following link and use my access code (
carrepair):
Free Automotive Repair information for Users of a Code Scanner
I know that the above is wordy but I wanted to do more than just tell you that your problem is complex.
All the best,
Ben