Question
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Feb 9, 2009, 06:57 PM
| | New Member | | Join Date: Feb 2009
Posts: 20
| | | 92 Honda Accord/no start/good spark/ k-test My 92 honda accord will not start. A quick spray with starting fluid and she runs, meaning good spark, compression, timing ect..... All fueses checks good.
The main relay only clicks once when the ignition is turned on and has been replaced with one out of a running car. If you jump the grn/blk wire to ground, on the main relay the fuel pump will start. I tesed voltage on the MAP sensor for the k-test. There are three wires on the right hand connector. from left to right 0 ~ 4.5 ~ 5
I pulled back the carpet on the passenger side to expose the ecm and there is moisture on the cover plate and minor rust.
The CEL stays on when the ignition is on.
What to check next? | | | | | | |
Answers
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Feb 9, 2009, 07:01 PM
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#2
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| check for fuel pressure |
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Feb 9, 2009, 07:12 PM
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#3
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| Quote:
Originally Posted by tritt check for fuel pressure | I did pull the fuel line off when I first started testing. There was no fuel when the key was on or the engine was cranking. This led me to the main relay. When I jumped the main relay and the fuel pump turned on, it had plenty of fuel. I had it jumped for about 1 sec and it pumped close to 2 cups of fuel in the container. As for fuel pressure I have no way of testing this without a special adapter and gauge.
Back to the main relay... The only way I get the fuel pump to run is by jumping it.. I belive I am not getting a ground from the ECM to the main relay for the fuel pump to run.
I am not sure why. Bad ECM or something else to check? |
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Feb 9, 2009, 07:29 PM
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#4
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| think you are on the right tack pcm grounds the relay. and moisture on the pcm isnt a good sign. if you have a good wirering diagram you may be able to ground the fuel pump though a relay some other way |
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Feb 9, 2009, 07:32 PM
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#5
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| I tried to start it while the main relay was jumpered.. No go.. =( |
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Feb 9, 2009, 07:44 PM
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#6
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| have you checked contnuity of the wire from the pcm to the relay |
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Feb 9, 2009, 07:53 PM
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#7
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| I have not got that far yet. I guess I figured if that wire was the problem the car would have started when I jumped the ground on the Main relay.
The part I am trying to figure out is: I can jump the main relay to get fuel pressure. If I have good fuel pressure to the EFI the only thing I would be missing is EFI actually injecting fuel which is controlled by the ecm.
So, what tells the ecm to fire the injectors? Crank shaft sensor? |
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Feb 10, 2009, 06:41 PM
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#9
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| I tinkered around with the car for a few hours tonight until it got dark. I re-checked the starter signal fuse.. Everything looks good there.
I don't mean to second guess your advise becasue you are very well versed in the elecrical system. Please explain why you think the starter signal fuse could be the problem. When I ground the grn/blk wire to the main relay the fuel pump will turn on. To me that would mean I have power, just not the ground that comes from the ecm.
The other things I noticed today are. The check engine light stays on while the key is in the on position. I am not sure how to read the codes.
When you turn the key in the on position you hear a few clicks under the dash. One is the main relay and I am not sure about others. If you turn the key past the run position before the starter engages there is one more click from a relay under the dash... If you turn the key alittle farther (again before the started engages) You hear another relay click (neither are the main relay) followed by 5 audible beeps. This makes me think that the ignition is working properly.
What else would casue a "no ground" from the ecm to the main relay? Could I test the ignition wire at the ecm to make sure It's getting power there?
The other thing I did tonight was remove the ecm and cover plate to inspect it. (I removed the battery cables first) There was no visual damage to it. Did not smell burnt.
Thanks for you help! |
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Feb 10, 2009, 07:03 PM
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#10
| | | Senior Cars & Trucks Expert
Join Date: Jun 2006 Location: Undisclosed, Republic of Texas
Posts: 7,751
| The Starter Signal Fuse and the ignition switch must work properly, in order for the second relay inside the main relay to work. If either doesn't work, the fuel pump won't run when the ignition switch is turned to ON (Position II). I would also clean the main ECM ground, located on the thermostat housing.
When you turn the ignition switch to ON (Position II), does the Check Engine Light (CEL) come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) fuse, in the underdash fuse/relay box; ECM (perform the K-Test); Main Relay; or the Ignition Switch. Perform tests in that order.
Be sure to read the link I gave you earlier. It's by far the best material you will find anywhere on your problem--guaranteed! I've simplified a very complex system to allow you to easily identify the problem. |
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