hesitation/stutter at light throttle

**mooshie** · 22-01-2011 10:30 AM

Ok, I have had this problem for a while and thought it was the sparkplugs which were a bit fouled, on TodaAU's advice I swapped them out for some BKR6E (they were 7's previously- turbo) and this alleviated the problem a little bit but now that we are having hotter weather the hesitation is back. Sparkplugs, cap, rotor, leads are fine (all checked and/or swapped) so I though that it might be the Ignition Control Module.

Anyone know what ICMs are compatible across Honda engines? I have a spare Concerto distributor (it was on my wreck DA9! held on by the top bolt only yet it still ran fine) which I know is working and I have removed the ICM.

In the service manual the B18C and the B18B have the same distributors but when I looked up parts on the Supercheap website they have a different ICM part number listed for the C and B? the B18B has the same part number as the D16A8, D15Z1, D16Y1, B18A and costs around $70-$110 but the B18C part is over $250!

So can I just use the Concerto ICM? will it screw anything up if I just test it? Visually it looks like it will fit, although I haven't taken out the ICM in the B18C yet.

The car ins't stalling at all and it starts fine, just a very slight misfire on very light throttle like cruising on a flat road. Speed makes no difference and it is fine when I apply a heavier load to the engine such as going up a hill or accelerating, seems to be worse on a hot day and it doesn't happen when the engine is cold, although my engine warms up very quickly compared to stock due to the turbo.

**mooshie** · 25-01-2011 06:45 PM

No one has any idea?

**ECU-MAN** · 27-01-2011 09:23 AM

if the concerto ICM is from an OBDI engine, then it will work

the heatsink on the ICM may be different and ban be swapped.

Id be inclined to change the coil first though

**mooshie** · 27-01-2011 08:56 PM

Thanks. unfortunately the ICM is from an OBD0 engine. I still cannot understand why there is such a price disparity with different modules?

I have seen modules for the Type R priced from $96-$386 and the same for the B18B but it seems that the B18C is always priced around $250.

I will replace the coil. I was under the impression that when the coil goes it simply wont work, ie- you cant start the car, but after a bit more searching, they can tend to slowly go out resulting in the same poor performance that I am experiencing

**mooshie** · 29-01-2011 11:28 AM

Well I swapped out the oxygen sensor today as I got hold of a spare just to eliminate that as potential cause of the issue.

Took her for a drive and all went very smoothly until after about 40km all through the hills I got down to the plains and it started again although not as bad as the last time, still very annoying.

**chongy** · 30-01-2011 11:21 PM

Check your TPS to make sure it is adjusted properly

**drgtr** · 31-01-2011 08:47 PM

I have the same problem in my EG civic with B18c7. Only when engine is cold. Light throttle. It slight misfire but hesistate and stutter. Put the pedal down and it smooths up!

**mooshie** · 01-02-2011 08:57 PM

thats the opposite of mine! mine only does it when hot.

Chongy- TPS is top of my list of things to try when iI actually get some time to problem solve this, then it is on to distributor internals

**chongy** · 01-02-2011 09:36 PM

do the simple checks first.
put checking your plug wires on that list too.
you could check them if you had a meter and measure the resistance for the wires.
if i remember correctly you should get approximately
12kohm for #1 wire
10kohm for #2
8kohm for #3
5kohm for #4

**MM89** · 01-02-2011 09:57 PM

Are you running hondata ecu?
If so, perhaps avoid "adjusting" TPS manually. You can do that through the TPS parameter - There's a minimum and maximum reading and I believe it allows for slight variations. If the values are something like >20% out of whack you may need to replace it all together.
However, I doubt your TPS is causing you this problem.

I too am looking forward to a solution to your issue as I'm experiencing the EXACT same problem. Leaning towards the leads, rotor, ICM or coil atm..

Keep us posted.

**chongy** · 01-02-2011 10:57 PM

well if he has hondata the best thing would be to get a wide band and record a datalog session and then review the log and see what is not normal.
It could be a number of things ...even incorrect fueling or timing issue.

**mooshie** · 02-02-2011 08:30 PM

Not using Hondata, I have an Autronic SM4. I have been looking at wideband sensors but there is a bit of debate whether an ordinary one with a gauge such as the LM-1 etc will work well with the Autronic. Anyone have any good sensor/gauge suggestions?

I replaced the leads with another 2 sets that I have and no difference, feeling the pressure now.. I have no time to work on this thing during the week and only sometimes get a chance on the weekend please be patient!