Mechanics

FUEL PUMP RELAY

1998 Honda Accord • 6 cylinder FWD Automatic • 145,000 miles

98 Honda Accord 3.0 v-tec sometimes wont start, can this be the main relay (fuel pump) going bad? The check engine lite never comes on and there is no trouble codes.
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Knocklebleeder1
December 5, 2010.




Sure, it's possible but so are dozens of other things. You really need to do some testing during the failure to have any idea if you are on the right track or not.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Wrenchtech
Dec 5, 2010.
You need to test what is missing when it could nor start, fuel or ignition.

If it is fuel that is missing, the PGM-FI main relay can be the cause.

KHLow2008
Dec 5, 2010.

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