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Hey, so I just bought a 2003 ex 5 speed manual with a blown head gasket to fix up. Previously I fixed my 02 ex head gasket, with a huge amount of knowledge gained from you guys here. Can't thank you enough! But I've run into a weird situation with this car. Someone along the line had swapped out the motor with a d17a1. I don't know if the guy I bought it from was driving it in limp mode at 4000 rpm tops or what? Would it be better to change out the ECU or to put a d17a2 head on it? The wiring harness is there with the egr and vtec plugs hanging and the cel on with the p1259 code. On one hand I need to take the head off and send it to the machine shop plus getting a new ecu and prob a new O2 sensor I think? On the other I get a new head plus egr which works with the ecu but is on a block with lower compression? Also not sure if thermostat housing and such will match up and bolt on to new head. Any help you could give me would be greatly appreciated. Thanks

 
Rep Power: 512

The ECU is looking for a VTEC solenoid to control, but it doesn't, so it's putting the car into limp mode (RPM limiter at ~4000). That's assuming that the previous owner kept the -a2 ECU in there. Technically speaking, the D17A2 tops off at 80mph (don't ask how I know that) with the car running in limp mode.

If you change out the ECU, you'll have to get your keys reprogrammed, usually at a dealership, and you have to show proof that you didn't up and steal it from someone, blah blah blah. If it were me, I'd be slapping on the -a2 head. You'll be fine with the lower compression. It'll make a hair less power than an otherwise stock D17A2, but it'll work. Loads of people actually did that back in the day -- ran a D17A1 block with an -A2 head -- mostly for turbo purposes and/or to utilize the vast selection of aftermarket parts for the -A2

 
Rep Power: 119

The ECU cant tell the difference between powering the vtec solenoid or powering a 12v relay.
The ECU expects to see appropriate oil pressure before it will engage the “relay” and then expects to “not see” appropriate oil pressure while the “relay” is energized.

EGR system relies on input and sensing movement, strangely it can be oblivious the valve is actually connected to the engine by something more than a grounding wire from the valve to chassis.. So maybe try getting a EGR valve off a junker, plug in the harness, use one of the mounting tabs to run a ground wire, and zip tie the valve to the intake or whatever you can and give it a drive cycle.

 
Rep Power: 0

Ok, so I think I'm going to go ahead and get the d17a2 head and throw it on there. I'm actually planning on putting a turbo on it anyways somewhere down the road so it looks like it should work out nicely! I've looked a little online and it seems like eBay might be a good choice and then take it down to the machine shop here to get resurfaced. Unless there is a place I'm missing you guys would go with instead. The nearest junkyard that has one where I'm at is 116 miles away from me. That is a really interesting trick with the VTec and egr to get the car out of limp mode btw I'm definitely going to have to remember that.