jguerdat

Been struggling with this for the past couple of weeks. It doesn't happen all the time but seems to rear it's ugly head when the temps drop to around 30 degrees F. An attempt to start the car when cold immediately trips the CEL and the car runs very rough and smells like it's running very rich (haven't gone back to check the tail pipes to see if it's black). Resetting the ECU by pulling the backup fuse (7.5 amp) doesn't seem to help. If i _also_ give the MAP sensor a whack and reset the ECU, it seems to start and run fine. So, I bought a new MAP sensor at Advance Auto and installed it with the new O-ring. No problem while it was warm or cold starts when the temps were above 40 but this morning, with temps around 32-34, the same problem popped - CEL and poor running. MAP whacks on the new sensor and ECU resets did nothing. Put the old MAP sensor in, whacked it and reset the ECU and it started right up. I was able to return the new sensor to Advance for a full refund.

The car runs fine once I can get it started with no CEL and all warm starts as well as cold starts that aren't too cold (40-50 degrees F) have been fine. It appears to only be when below 40 or, at least, close to 30.

I tried to pull any code before resetting the ECU using a jumper as described on Modifry's site but the only blinks I get are from the ABS and EPS systems, not the CEL (no, I didn't count those since I ass-u-me-d that they were of no importance).

Suggestions? Is there something special to the Honda MAP sensor that isn't duplicated with an aftermarket one?

Siepel

Just for consideration, I had similar symptoms (running rough during startup) and it came down a dirty injector (stuck closed due to it being gummed). A bottle of injector cleaner in the tank simply did the trick.

If you're somewhat mechanically inclined, you can 'listen' to the injector clicking when the engine is running badly (put large screwdriver flat bit on the injector surface and your ear against the handle). Listen to the clicking of all injectors to see if you find one that does not click.

Good luck!

Siepel

jguerdat

I can give this a try but it seems like the ability to reset the ECU (and possibly whack the MAP) wouldn't fix a stuck injector.

Something that may be of use - I recently had a CEL with a code of P1456 or P1457 (don't remember which for sure but it was the EVAP control system) which ended up with a $400+ repair bill at the dealer for a solenoid and something else, both related. It's possible, I suppose, that all of this is related but the ability to pull a code with the EVAP issue but not this one is a problem. I'll run down to the local Advance Auto and have them try to read the code next time it happens.

jguerdat

New info! I was finally able to read the code and it's a P1607 - ECU. I also tried letting the car warm up slightly (idled for 2-3 minutes - no extra bars on the temp gauge), shut it down and was able to reset the code. So, it's a cold start only and a little heat clears it.

Please, please, please, can someone suggest a cure? The Helms manual says to replace the ECU (I did the troubleshooting section and it fails immediately) but somehow the problem seems to be only cold related. Is there something else that could cause this?

w00t692

When you order your new ECU

GOGO 2003 ecu

jguerdat

It's looking that way. Found an '03 on eBay for $200...

Ralleh

Do 03 ecus run leaner or something?

jguerdat

FWIW, I bought a used ECU and installed it yesterday. Last night got cold enough to trip the failure mechanism so I was anxious about the result this morning. Started right up with no problems whatsoever.

Thanks to milkman2089 for the ECU!

Testut

Congratulations, Jeff! Now get back to work on the 850...

jguerdat

No steenkin' computer in the 850. At least when the engine doesn't run it's easy to figure out why (and cheaper, too)... Maybe the S will be my next 40 year old car...