This is not regarding a TL but since it's regarding timing belt replacement, symptoms probably are similar to most timing belt replacement issues across other makes and models.

My friend has a 1999 CR-V (b20z engine) 150k which recently had the timing belt service completed. The service included Dist cap/rotor, plugs/wires, fuel filter, cam/crank seal, and belt/tensioner/water pump/pcv valve replaces. The day he took it home it was fine, but the next day he started noticing start up idling issues.

Symptoms are as follows

cold start idle- initial start idle will jump to 1500 as normal but will immediately drops to around 500 rpm for a second and then back to 1500 and stay at 1500.

Warm start idle- initial start-idle will start at 700 and immediately drops to 200 then engine stalls or will jump back to 500-700 rpm.

The idle does not bounce continuously once running, just on start up it will drop then stall or settle between 500-700 rpm but does not bog or fluctuate. There are no engine codes and the check engine light does not flash and he states the car drives fine no loss of power or sputtering.

He took it back to where he had it serviced and they are blowing it off as the IAC valve, but that answer seems a little far fetched since the problem did not exist before the belt was replaced. They did not spend time testing to see if it was the IAC, so the IAC to me is just there assumption. I am thinking either the timing marks are off on cams or crank or the timing it self is off, but there defense is since there are no engine codes then the timing belt is not the issue and immediately point to the IAC.

Anyone with experience or thoughts? Is it possible that the cam and crank marks are not lined up even though it is not throwing a code?

I found other possible causes could be air in the cooling system or vacuum leak.

 

I would think a bad IAC (bad enough to cause those symptoms) would definitely through a code/MIL...So I kind of doubt it's the IAC.

The belt could certainly be off, or the TB tensioner could have been mis-installed or could have gone bad (did they install a new one) and the belt skipped after the first run.

Does that model have a crankshaft position sensor learning procedure? The TL FSM calls for it to be done after a TB change, but several of us TB DIYers have had no issues without it.

 

if the shop wont touch it without getting paid, you can take off the valve cover and check the timing yourself.

though honestly the shop sucks for not wanting to following up the next day.

i have heard about air in the cooling system causing weird idles as well. IACV controls idle and can influence start up though, it was a common annoyance with the B18 based Integra. But it's hard to say that it suddenly started acting up on its own after this major service.

edit: the FITV controls fast cold idle.

 

I would also check for vacuum leaks then clean the IACV. Timing belt won't cause those kinds of problems. You will get more constant issues such as poor or rough idle (constant, not going up and down), hard starts, poor acceleration, bad gas mileage.

 

^ +1, I once got the timing belt off by one tooth on a 89 Civic after I replaced it. It ran and idled awful (misfire and rough), it was very obvious. It was also a constant problem, nothing like a idle rising and falling.

 

'99 CR-V, might not be sophisticated enough to throw a code for IAC. Sounds like an intake / throttle body issue. I would clean / check / replace IACV, TPS and MAF sensors. If the intake side checks out. I'd follow-up with valve job.

Doesn't sound like a timing issue to me, but it certainly wouldn't hurt to check marks and belt.