FUEL PUMP TEST 2: Fuel Pressure Gauge Test
This test is for the serious do-it-yourself'er, since it involves using a professional level fuel pressure gauge. Using a fuel pressure gauge guarantees an accurate result.
Now, in case you don't own a fuel pressure gauge that has the adapter needed for your Honda Accord (or Odyssey or Prelude), at the end of the article I'll make some recommendations on which fuel pressure gauge set to buy and where to buy it.
On the fuel rail, you'll find the place where a fuel pressure gauge adapter fitting can be installed. Look at the photo in the image viewer and you'll see that .
Screw in the appropriate adapter from your selection of brass fittings in your fuel pressure gauge set.
Connect the fuel pressure gauge to this fitting.
Have your helper crank the car while you observe the fuel pressure gauge.
You're going to get one of two possible results, and they are:
1.) The fuel pressure gauge will register 30 PSI, or
2.) The fuel pressure gauge will register 0 PSI.
OK, now that the testing part is done... let's take a look at what your results mean:
CASE 1: Your fuel pressure gauge indicated 0 PSI This confirms that the fuel pump is not activating and supplying fuel to the fuel Injectors.
Now, what I have always done (since I always want to be absolutely sure about my diagnostic and this is my suggestion to you too) is to have someone crank the car while I check the the fuel pump is getting power (12 Volts) with a multimeter.
The fuel pump on these Honda's can be reached thru' an access hole in the back of the car and the wiring that goes to it too. This is where I tap into the circuit that delivers the juice to the fuel pump. If when the car is cranking, and 12 Volts are present, then I know beyond a shadow of a doubt that I can replace the fuel pump and this will solve the No Start due to a Lack of Fuel Condition.
CASE 2: The fuel pressure gauge registered 35 PSI while the engine was cranking: This test result let's you know that the fuel pump is working and is delivering enough fuel to the fuel injectors.
This result has also eliminated the fuel pump as the cause of your Honda's No Start Condition. Now, since your Honda is still not starting, I suggest you test a couple of other things, such as the Ignition System, timing belt, etc. You can find these specific ‘How to Test’ articles I've written under the heading Related Articles at the end of this article.
Symptoms Of A BAD Fuel Pump
The most obvious symptom is that your Honda Accord (or Odyssey or Prelude or Isuzu Oasis) will Crank but Not Start. Here are some more specific issues related to this problem:
You've done a Broken Timing Belt Test, and it's not the timing belt.
You tested for spark at every spark plug wire and there's spark being fired off at every single one, so you know it's not the ignition system.
You've done a Fuel Injector Noid Light Test, and all four fuel injectors are getting both 12 Volts and the activation signal.
Although the above list is a not a very complete list of symptoms... the theme that runs thru' them, and any other related symptom, is that the engine will crank and crank, but not Start.
Which And Where To Buy A Fuel Pressure Gauge
What surprises a lot of serious Do-it-Yourself-er's is that yes you can buy a fuel pressure gauge to accurately measure the fuel pump pressure on your Honda Accord (or Odyssey or Prelude or Isuzu Oasis).
Their price (usually around $200 -US) is an investment that really pays for itself when you consider that you are performing a top notch diagnostic of the fuel system with it. To put it into perspective, think about how much you would spend to take your Honda to the auto repair shop, have it diagnosed and then repaired... and you'll see that having the right tools to do it yourself becomes a money-saver.
Not only that, the fuel pressure gauge set that has the adapter fittings, to tap into the Honda fuel system, will also have all of the adaptor fittings for most of the Asian and Domestic (USA) vehicles on the road today. So, if you have another car, that is made by someone else (like a Ford, a Toyota), you'll have the fittings to check the fuel pressure on those cars too.
Alright, now, which one and where to buy it in the next page...