I am working on a 2004 accord with the 2.4 L engine and manual transmission. I installed a different engine out of a 2005 Accord. The engine ran got computer to reprogram idle then took for a test drive . Parked car now there is no CEL or Battery light when you turn ignition on. The scan tool will not communicate and the car turns over but will not start. There is no spark at plugs and I don't think there is power getting to computer. Need to know the wire color of hot wires to computer so I can double check. All the relays in the interior fuse box checked ok. Looking for Ideas as to what to check and how to get CEL working again. Thanks

 

Why did you install a new engine?

Have you tested all of the fuses? If you have a test light, there is a quick way to test for power on both sides of the fuse. See video below:

 

Installed new engine because old engine variable clutch on cam went bad and valves hit pistons broke and fell into cylinder and ruined piston and head. Cheaper to replace engine then to rebuild. Yes checked all fuses and relays all tested good. Cleaned all connections with contact cleaner still no power to engine computer.

 

just my input is when no cel and no dtc data you dont have ecu ground double check the harness and grounds

 

1. Under-dash Fuse No. 19 (15A) provides Ignition Input power (+) to ECM/PCM when ignition switch is in ON (II) or START (III) position. - Via Blk/Yel wire to terminal no. 9 of ECM/PCM Connector E.
2. Ground to ECM/PCM is from Ground G101 located at middle of engine (under plastic engine cover that is over the intake manifold). Ground G101 wires go to ECM/PCM at terminal nos. 4, 5, 8, and 9 of ECM/PCM Connector A.
3. Under-hood Fuse No. 8 (15A) provides power (+) to the Data Link Connector (DLC), aka OBD port.

 

It was the Ground on intake cleaned rebolted and working now. Have 2 codes now High idle rpm ( how do I adjust ) and intake vacuum leak which I can't find. Any more suggestions Thanks for the help.

 

Idle jumps from 1000 rpm to 2200 rpm at idle only when warm when cold sits at 1000 rpm

 

What are the trouble codes? Post the alpha numeric codes.

 

P0507 RPM high idle control system
P2279 Intake Air System leak

 

An idle learn probably has to be performed.


There was a May 2013 Honda Service News article for the following. A different Honda Service News article, which I can't find right now was for both those codes and had to do with a idle learn to be performed.


MIL On With DTC P2279 After Throttle Body Cleaning or Replacement

Currently Applies To: ’08–13 Accord L4, ’06–13 Accord V6, ’14 Accord Plug-In, ’12–13 Civic, ’06–13 CR-V, ’06–13 Odyssey, ’05–13 Pilot, and ’06–13 Ridgeline
Just cleaned or replaced the throttle body and now you’ve got a fluctuating idle, the MIL is on with DTC P2279 (intake air system leak), or both? What’s probably happened is the throttle plate is now in a different position from the one the ECM/PCM had learned.
To fix this problem, the ECM/PCM has to relearn the current closed throttle position. Here’s how to do it:

1. Go to INSPECTION MENU in the HDS, and select ETCS TEST.
2. Select TP POSITION CHECK, and clear the throttle position learned value.
3. Turn off the ignition, then, turn it back on.
4. Reset the ECM/PCM.
5. Do the idle learn procedure.
6. Recheck for DTCs. If DTC P2279 doesn’t reset, you’re done. If it does, continue with normal troubleshooting.

The following is generally the idle learn procedure:

Make sure all electrical items (A/C, audio, lights, etc.) are off. Disconnect battery for a short while (3 minutes would be fine). Turn ignition switch to ON (II) and wait 2 seconds. Start engine and hold engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until radiator fan comes on, or until engine coolant temp. reached 194 degrees F. Let the engine idle for about 5 minutes with the throttle fully closed. (If radiator fan comes on, do not include the running time in the 5 minutes.)