Engine Surging After Timing Belt Job w/No Codes

lothian

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2000 Honda Accord
~119k miles

I completed a timing belt replacement job (all three belts & both pulleys, TB auto-tensioner, water pump & front eng. mount--all OEM Honda parts). I quadruple-checked timing marks before and after TB removal and replacement, and I manually turned over the engine a dozen times to seat the belt, check for interference, and TDC at all pulleys--absolutely no problems there. Once finished, I topped off the coolant. Then I started the engine...

- Cold engine turns over fine, but idles high at ~1700 (per scanner; engine temp is 61°). After ~5 secs the engine surges cyclically between ~1600 to ~1700;
- I can hold idle steady with the throttle or by shifting into gear, although load idle remains high;
- I held idle at ~2500 for ~5 min, then drove it around my neighborhood for ~2 miles (~10 mins at <30mph);
- I drove it through each gear: idle is steady (though high) thru 2,3,4, but engine surges in first gear;
- Surging resumes after I shift to park (or neutral); engine temp levels at 174°;
- There is no check engine light, and no codes on the scanner;
- I found no obvious vacuum leaks or loose electrical connections.

I have not purged the coolant system of air per procedure because I simply cannot locate the bleeder valve on this engine, even with shop manual and flashlight in hand!

I followed the procedure in the shop manual, and noted my progress on paper as I worked. I found no loose vacuum lines in the vicinity, nor any loose electrical connectors. Could I have possibly missed something, or pulled something loose? Could replacing a TB induce high idle/engine surge, yet with no codes? ...or is this merely coincidental, unrelated problem.
 
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RawCarnage

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Purge the air from the system first, the bleeder is located to the left(passenger side) on top of the thermostat i believe its called. It could be as something simple as that. If you still cant find the bleeder valve use the other method of bleeding by taking off rad cap and letting the engine get to temp you will see alot of bubbles, as the coolant gets lower from air escaping just keep filling it back up till there is no bubbles or you feel there is no more air in the system. I usually squeeze the rad (top and bottom) hoses to get any trapped bubbles of air. But to me that(the jumping revving) is what it could be.

Edit: dont forget to put heat on full blast. also revving it a little will help the process go much faster.
 
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xci.ed6

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I use a 'funnel' that has a radiator fitting on the bottom:

IMG_2127.jpg


keep 1/2 full!

let fan turn on twice!

Has plug to remove when done.

Also, check timing belt timing, sounds like you may be off a tooth or two.

Finally, whatcha got for obd2 testing? I recommend bluetooth adapter w/ your phone and Torque (program)
 

lothian

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Success.

It turns out there is no coolant bleeder valve on a 2000 Accord V6 (there is a coolant drain valve on the block, however).

The problem was a faulty idle air control valve (IACV). I replaced the IACV (Honda p/n:16022-P8A-A03; ~$163 from hondapartsnow.com as of 01/2015) after the cleaned-up original 15yo part did not fix the idle problem. And just like that, the engine idles normally.

For those of you who find this thread after searching the many, many variants of "engine surging", check your IACV!
 
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