opac

Hi Guys, I have a 2004 Acura 1.7EL and cant figure out where to start with this issue and was wondering if anyone has experienced anything similar.

I had timing belt changed. Then less than a week later ECU died while driving. Got a used one and put it in - mechanic said it was not communicating, got another used ECU - car was fine for about 20mins into my drive when it acted as if my foot was off the peddle (I was driving maybe 50-70km/h and speed just started dropping) dont recall if it reved while I tried to press on the gas but it didnt accelerate and didnt completely die and was ok a few seconds later.

Next day car started when cranked but wasnt as smooth as usual. Green immobilizer light flashing. With my foot on brake, I change from park to Reverse, car jerks a little hard, put to neutral - slight jerk, and drive slightly harder jerk than reverse. For Park, Reverse and Neutral I see the gear indicator light on the dash, but on Drive no light. Car revs but does not move. Immobilizer light continues to flash, CEL on, unable to communicate with ECU through obdII. I let it warm up try changing gears same jerking but no move. I turn car off wait a min or two and start again and all is ok. immobilizer light no longer blinking continuously, can communicate with ECU, smooth shifts through gears, car moves in drive, drive LED ON on dash.

I was thinking Immobilizer but I though that would prevent car from starting.

CraigW

iTrader: (1)

Search this site, if the alternator is not correctly installed back in 01-05s it can cause damage to electronics.

ezone

Most common cause: The alternator BOLTS were left loose when the timing belt job was done.


Now I bet they are still loose, and you will continue to burn up computers until this root cause is corrected.

Hopefully you can fix the root cause before this current computer burns out completely.


Not sure what to say about the trans issue, if it's an issue at all, but it sure needs the PCM to be working correctly first.

opac

I didnt have a battery indicator light to indicate issue with alternator. When I was having the issue, before starting car battery was 12.59v . 14.7V with car stated. 14.5V with car stated at the time I didnt have the issue.

I took out the power steering pump and checked the alternator bolts. upper and lower bolts were tight, and so was the tensioning wing nut. There was tension on the belt as well.

I couldnt figure out how to remove the black little enclosure going to the alternator. I was able to slightly pull up the rubber boot on the upper wire going to the alternator and it seemed tight and the lower connector wire seemed snug in there as well. Any electrical connections I should check or readings I should take such as ones going to ECU?

I'm going to put the power steering pump back in and do some more testing. From what I recall, When the issue is present, the imobilizer light was flashing (more than the initial 2 seconds) with the key just in the ON position. When this happens, no communication through obdII either.

ezone

From what I've seen, the light doesn't come on while it's trashing the PCM.

Hell, half the time it doesn't even come on when the alternator goes bad.


From what I've seen, most of what you can see in and on the car is not affected.
The problem apparently lies between the alternator which lost its ground, and the PCM which has the control of the voltage regulator but can't determine the actual charging voltage, so it keeps trying to increase.

Large bolt on top (14mm wrench): 33 ft-lb --- IF the threads aren't damaged in the bracket. Look closely at the head and washers, are they mashed flat or do they look like there's clearance?

Small bolt (12mm wrench) 17 ft-lb,
and I don't care about the wingbolt, it's only for adjustment.

Lower alt bracket where it attaches to the block, 14mm wrench, 33ft-lb




Here's another thing: The bulletin I'm thinking of refers to Civics, not the EL. I'm in the US, we don't have any EL here but since it's pretty much the same car I assume it can have the same issues.

Bulletin link: http://www.underhoodservice.com/tech...ernator-bolts/

Most of your descriptions in the first post made me think of the PCM going brain dead and limp mode, that's what happens when the PCM burns out from the alt loose bolt problem. ALso, gauges and warning lights can go haywire since most of those operate using data from the PCM.

Oh, I hate those things.

There's a bunch of troubleshooting info for the charging systems in the service manuals.

Engine is NOT running when this happens?

Hmmm. That would change things a bit.

I'd probably want to seriously consult with a wiring schematic for the PCM.....Monitor each of the power inputs and grounds right at the computer, see if any of them have dropped out when the problem arises.



Check the ground wires on the thermostat housing, clean the ring terminals, bolts, and the aluminum casting to shiny metal?

opac

It seems my issue was related to an intake air temperature sensor that had gotten burnt somehow and was intermittently shorting causing ECU to crash.
Thanks for your help!

CraigW

iTrader: (1)

Thanks for updating thread.

ezone

Well that certainly wasn't a usual issue, but it certainly does explain why the PCM would shut down. Thank you for the update!