Rep Power: 0

[B][/B Hi , i was driving on the highway and then my engine light started to turn on and off(04 si) and each time the EL came on/shut off, the car would sputter or hiccup. If i let her idle she'll run fine for about 10 seconds and then she'll bog down but she'll catch herself. Occasionally the rpms will show 0 and then the battery light comes on and she'll start to idle a little more violently.I checked the volts with a volt meter and the battery was reading just under 13V with engine off and over 13 with it running . Anybody have this trouble and/or know what the problem is?

 
Rep Power: 221

well if you have access to a code reader, see what code is stored in the car's ecu to start. otherwise look in the engine bay for anything disconnected/broken/cut like wires, vacuum lines, sensors, etc. If you think its electrical, see how well the car runs with no electrical accessories on, then start turning on different loads one at a time and see what happens. If that doesn't affect anything, start checking the engine, it needs air, fuel, and spark to create combustion. Check your air filter, is it clogged? Does the engine idle better without the filter? Do your spark plugs look ok? Is each cylinder getting fuel ok? Is the compression ok?

 
Rep Power: 517

Canada, eh?

It's got 1.7 engine, and whomever did the timing belt job or replaced the alternator (or any similar work) forgot to fully tighten the alternator mounting bolts......

If I'm correct, and this problem is allowed to continue unresolved, it will ruin the PCM....if it hasn't already ruined it. If a code reader no longer communicates with the PCM, it may be too late.

 
Rep Power: 0

Me and my friend plug the code reader into the car yesterday and it would not put out any codes maybe that is the problem plus now and then the alternator belt it makes a squeaking noise

 
Rep Power: 0

OK so I done a check around the engine and there is no visible signs of any vacuum lines are sensors or wires broken I removed a air filter and cleaned it and it made no difference I removed the coil's and use another set that I had there and clean the spark plugs and still no difference however I took the car for a ride and it idled down a couple times but then The RPM gauge went to zero while driving and the coolant temperature hand dropped down to zero as well . When the RPM Drop to zero there was very little power in the engine it felt like something was limiting the power to the engine idk
The only other thing is when the Engine idles down and almost shuts off a relay over on the need the glove box clicks I switched out the relay and still no difference
Thanks for you help

 
Rep Power: 517

It sounds like your PCM is already ruined.

You need to find and correct the root cause.
I told you what the most common cause is in my previous reply.

If you don't fix the root cause of this problem, it will continue to ruin PCMs....and that ain't cheap.

 
Rep Power: 0

hi thanks and I think you might be right but is the pcm and the ecu the same part and will the ecu work from an 05 civic se on my 04 civic si ?

 
Rep Power: 517

PCM and ECU refer to the same computer.

IDK if one will work in place of another, you have to research each and the part numbers to see if compatible.

If you do a swap, the engine will not run until the immobilizer is programmed.
If you manage to get it to run, you can ruin the next computer if you haven't fixed the original problem.

 
Rep Power: 0

ok sounds good I think I will swap ecu and alternator . One more thing is it possible to re program the other ecu myself

 
Rep Power: 517

The alternator itself is not the usual problem. Read my post again.

No you can't DIY programming without some special equipment.

 
Rep Power: 0

ok you're referring to the mounting bolts correct?

 
Rep Power: 517

If the belt is squealing, it probably needs adjusted a bit tighter anyway.

 
Rep Power: 0

ok I'm not really sure how to remove the ecu ; I searchrd it on google and youtube but never found anything
thanks

 
Rep Power: 0

I just called the Honda dealership and gave them the serial number to my car and they looked up the ECU part number and it doesn't match the one for the ECU I had there to possibly try
The guy said I could try it but it might not work considering mine has VTEC plus I still have to take it to a dealership to have it reprogrammed
I'm just wondering if you know if it will work in the SI or not

 
Rep Power: 0

just called the Honda dealership and gave them the serial number to my car and they looked up the ECU part number and it doesn't match the one for the ECU I had there to possibly try
The guy said I could try it but it might not work considering mine has VTEC plus I still have to take it to a dealership to have it reprogrammed
I'm just wondering if you know if it will work in the SI or not

 
Rep Power: 221

dont do this double post thing.

So the ecu that is currently in your car doesnt match what was originally supposed to be in the car?

Or you found another ecu that you want to buy and honda is saying the part numbers dont match? If this is the case, what are the specs of the car that this ecu came out of? you have an '04 SI, did this ecu come out of a SI as well? Is it the same year? I dont think the year matters too much as long as the ecu is for the same engine.

 
Rep Power: 0

Yes I have another ECU here but it's from an 04 DX and the part #"s don't match

 
Rep Power: 517

VTEC (or no vtec) has to be the same, and trans type has to be the same.

Then there are differences between model years, and emissions types (not sure about Canadian versions though).

2001-03 use O2 sensor 1/1
2004-05 use AF sensor 1/1


Did you fix the alternator bolts yet?
If the bolts were not left loose, have you checked all the ground cables from battery to frame and engine/trans yet?
If you don't figure out why this car burned up the computer and fix it, you're doomed to repeat it.

 
Rep Power: 221

Post was no longer necessary.

 
Rep Power: 0

Ya I had a guy check the bolts And one was loose I'm thinking that might be what caused the damage to the ECU