Integra Type R - revs dipping below idle

Got a problem with my 99 Integra Type R. When driving the car in town,
i.e. stopping and starting a lot I've noticed that if the engine is not

up to running temp the revs tend to drop below the idle speed when the
car is stationary and almost cuts out, battery light flickers and I
need to give it some revs to avoid stalling. Fine when up to running
temp. Its had a recent timing belt change but I've had it checked twice

and the garage says its fine! I thought that maybe one of the spark
plugs may have been loose but car is fine at speed and no hesitation in

any gear.

Any suggesstions?

 

didn't you post this before? did you take it back to the same place
that did the timing belt, or did you go get a second opinion from
someone else? iirc, you had the belt changed, and the problem appeared
shortly thereafter. if the original people got it wrong, and they're no
good, they may not fess up and not do anything. it's worth a second
opinion from a second different shop to be 100% certain.

here's what to do:
rough checks...

first, check for "gotchas" like plugs, leads, distributor cap, etc.

next, check ignition timing [with service connector in place] - if ok,
check position of distributor - if centered, ok. if not centered, the
rear cam is out, and the belt dudes fudged timing to compensate. for
the front cam, you can only check by inspection with the rocker cover
off iirc.

next, with the motor running and fully warm, disconnect the iacv, idle
air control valve. it should still idle ok. you should hear it
clicking when you connect and disconnect. if it dies when disconnected,
adjust the idle on the throttle body so it runs at the correct rpms.
then reconnect. /only/ do this if everything else checks out ok.

if none of the above produce the desired result, report back and we can
go through a more methodical in diagnosis.

 

====================================

Look at the adjustment slots on your distributor. If it's the same as a
CR-V (I think it would be), you should see it's sitting in the middle of
it's 'range'. If it's torqued over to one end, it may mean the person
who changed the TB did it wrong, then wacked the distributor to the
extreme end of it's range to compensate. The cam timing would still be
WRONG and that would show up in idle speed, poorer fuel mileage, and
possibly overheating. Tegger would know if I'm right.

Before you jump to any conclusions, fill your rad and fill the coolant
reservoir to the MAX mark. See if everything changes.

'Curly'

 

Yeah posted this before at the end of Nov. Thought I had it fixed as I
had the idle adjusted and it seemed ok. I go through the list of
checks you gave me this weekend and post back once I've found what it
is.

Thanks for the advice again.

 

like tegger says, check the coolant level too.

regarding the additional info you just supplied, if the idle was
adjusted, ok, then it's bad again, that makes it look even more like the
timing belt than before. the thing is, when servicing the timing belt,
tension is provided by a small spring on the idler pulley. it's not
strong enough to overcome friction of two cams and a crank, so left to
it's own devices, it produces a slack belt that will jump. seriously,
it's unbelievably common - junk yards are /full/ of hondas with slack
belts. to tension it properly, and this is specified in the honda
workshop manual, fit the belt, time it, rotate the crank [counter
clockwise, NEVER clockwise] so the cam moves 3 teeth, and retaining this
crank tension, tighten the idler pulley. with hand tension between the
crank and the cams, /now/ the idler spring can do its job, so adjust and
tighten. then rotate the crank so the belt rotates 3 full times, then
re-tighten the idler one more time as before. this ensures there are no
slack points, no mis-positions, no friction when the belt is finally
tightened. and that it's not over-tight. yes, this is a pita, but it's
essential process to get it right. /now/ check the cam timing. both
cam and the crank pulley will align /exactly/ per the book if everything
was done right. if not, re-time the belt and start over.

you don't need to do all this just to /check/ timing obviously, but you
/do/ need to remove the rocker cover - unless you have aftermarket cam
pulleys and have modified the cover accordingly.

 

Sounds like an idle air control valve problem.

 

First of all, what engine have you got? VTEC or no VTEC?

Secondly, has the idle been CORRECTLY adjusted? This vehicle requires the
IAC and the EVAP purge solenoid to be disconnected when the idle is
adjusted. The VTEC engine needs the idle to be at 550rpm fully warm and
IAC/EVAP disconnected.

If the idle is incorrectly set, the car will stall or run badly at idle
when cold.

Is the throttle body squeaky clean?

Like the others, I'm kinda suspicious about the timing belt alignment. The
only real way to check is to pull the valve cover. Crank the engine over by
hand until the holes in the cams line up with the holes in the tops of the
bearing caps, then check the crank pulley. It ought to be at TDC when the
holes line up. If one cam is out, the cam hole won't even be close.

 

Correction: MAY stall or run badly, depending on how far it's out.

And make sure the IAC is operating at all. At any engine temperature,
disconnection of the IAC should result in an rpm drop of about 200.

 

Thanks for all the info guys.

I'm now covinced its the idle air control valve thats out and that the
idle may be set wrong. Its a vtec type R engine, 1.8. Its not happy
idling at 550rpm, it just burbles and chokes, been like that since new,
about 850rpm and it sits happy. Other owners have said the same. When I
got the car back initially it was idling at 700rpm roughly and was
constantly stalling and hesitating in 1st gear when pulling away. I had
it adjusted to 850rpm and it is much better than before but still dips
below idle when cold and nearly stalls. I haven't checked the idle
speed myself to confirm it is at 850 but I'm taking it to a Honda
dealer next month and will get it checked out then.

I'll get them to check everything you guys mentioned.

Thanks to everyone as I now know where to look for the problem and will
post back when fixed

 

p.s. this is whats happening, drops by about 200rpm

 

Then the IAC is probably fine.

Don't assume anything here! Your garages have been doing a poor job of
helping you here.

The 550rpm I mentioned is only with the IAC *and* the EVAP disconnected.
Once those are hooked up again, the IAC will adjust idle up to the
specified rpm for your engine (anywhere between 750 and 850, depending on
engine model).

You ALSO have one of those Fast Idle Thermo Valves under the throttle body.
That valve is designed to provide extra air when cold. These go bad all the
time, especially when the cooling system is neglected. If that happens, the
engine can stall or run badly when cold.

With the engine *cold or part-warm* and idling at whatever abnormally low
speed, remove the air pipe from the throttle body. Is there suction at the
lower port just in front of the throttle plate? If there is no suction,
then the Fast Idle Valve is stuck shut.

 

If you have an automatic, that is...