hesitation/stutter at light throttle

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.

No one has any idea?

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

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

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.

Check your TPS to make sure it is adjusted properly

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!

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

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

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.

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.

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!

Sounds like your car went through exact same symptoms (stutter at light throttle, VTEC is still working, slammed accelerator and hestitates then travels fine at mid-high rpms) as mine except I was NA. I had checked all the above items (TPS, electrical, ignition, ICM, dizzy, leads, plugs, etc.) and you guys are correct in checking for those items first (same I did) and could not find the culprit until 4-5 weeks later after searching/diagnosing the problem etc. I finally decided to change my injectors as it was worth buying new ones then carrying out cleaning them professionally.

Could have been your injectors are blocked where rust particles travelled through your fuel pump, fuel line, past fuel filter and into the injectors. This happened to me as moisture built up in the fuel tank and was filled with rust. However I changed to a 2nd hand fuel tan. You would like to change/check fuel pump then the replace with OEM fuel filter and if the problem is still there, then its your injectors.

If changing injectors, be sure to flush out all excess fuel from the fuel lines, then reconnect fuel pump, fuel filter and injectors. This way. you can be sure anything still stuck in your fuel lines all came out.

Hope my experience is useful to you.

Quote:

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Originally Posted by zropts

Sounds like your car went through exact same symptoms (stutter at light throttle, VTEC is still working, slammed accelerator and hestitates then travels fine at mid-high rpms) as mine except I was NA. I had checked all the above items (TPS, electrical, ignition, ICM, dizzy, leads, plugs, etc.) and you guys are correct in checking for those items first (same I did) and could not find the culprit until 4-5 weeks later after searching/diagnosing the problem etc. I finally decided to change my injectors as it was worth buying new ones then carrying out cleaning them professionally.

Could have been your injectors are blocked where rust particles travelled through your fuel pump, fuel line, past fuel filter and into the injectors. This happened to me as moisture built up in the fuel tank and was filled with rust. However I changed to a 2nd hand fuel tan. You would like to change/check fuel pump then the replace with OEM fuel filter and if the problem is still there, then its your injectors.

If changing injectors, be sure to flush out all excess fuel from the fuel lines, then reconnect fuel pump, fuel filter and injectors. This way. you can be sure anything still stuck in your fuel lines all came out.

Hope my experience is useful to you.

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so you said you changed the injectors.. what did you change it to? and how much?

i have a similar problem and considering cleaning the injectors, but since you changed yours, might be a better option...

anyone know how much to clean injectors?

thanks

RC 240CC at roughly $300 I think... Cleaning the injectors professionally will cost around $100-$200

Quote:

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Originally Posted by zropts

RC 240CC at roughly $300 I think... Cleaning the injectors professionally will cost around $100-$200

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hey thanks.

taking out the injectors.. how long you think time wise?
anything i should watch out for?

Quote:

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Originally Posted by zropts

RC 240CC at roughly $300 I think... Cleaning the injectors professionally will cost around $100-$200

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regarding the rc injectors? did you buy from america or someone locally? what type of injector? peak/hold or saturated?

for that price, might as well buy new ones unless someone can comment on the flow pattern between stock vs RC..

what engine was the injectors for?

thanks again

Quote:

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Originally Posted by nugget

hey thanks.

taking out the injectors.. how long you think time wise?
anything i should watch out for?

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Not much, pretty basic, a few bolts and the fuel rail & injectors will come off. You will leak a little fuel. All took 30mins out and new ones in.

Quote:

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Originally Posted by nugget

regarding the rc injectors? did you buy from america or someone locally? what type of injector? peak/hold or saturated?

for that price, might as well buy new ones unless someone can comment on the flow pattern between stock vs RC..

what engine was the injectors for?

thanks again

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Because I'm N/A, I got saturated. I just wanted stock replacement injectors so I bought it from America with the clips to suit my B18C. Im sure you'll be able to find threads on the stock vs RC vs saturated/peak injectors.

Quote:

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Originally Posted by zropts

Because I'm N/A, I got saturated. I just wanted stock replacement injectors so I bought it from America with the clips to suit my B18C. Im sure you'll be able to find threads on the stock vs RC vs saturated/peak injectors.

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greatly appreciated..
im NA as well. B18c7. so stock injectors are saturated then...and 240cc.

thanks for the info.

i dont think injectors are the problem mooshie is having.
In the first post he states that

Quote:

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Originally Posted by mooshie

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.

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if it was a fueling injector problem at very light throttle the oxygen sensor would make the correction and it would behave the same at wide open throttle as it would be lean.

maybe the problem is with tuning of his Autronic SM4.

It might be worth running some upper engine cleaner through,it will help 'smooth things out'...

The fuel filter would be the next thing i would swap.

And I recommend to check the timing is set correct.

Quote:

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Originally Posted by beeza

It might be worth running some upper engine cleaner through,it will help 'smooth things out'...

The fuel filter would be the next thing i would swap.

And I recommend to check the timing is set correct.

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when you say using engine cleaner, h ow do yopu use it?

just spray in the throttle and let the engine burn it?

cheers

Got a similar problem too but my engine light comes on and off. Will be replacing my ignition coil to see if it fixes issue.

update:
igntion coil replaced.

car fires better and takes off smooter/better
the hesitation is still there but not as harsh. engline light comes on after i vtec.

while changing coil i noticed the distributor cap was coroded, i sanded as much off as i could.
also the distributor rotor was abit rusty and sanded that off back to bare metal.

will be replacing these 2 items soon and getting new oem ignition leads.
im running brand new ngk platinum spark plugs too!

Remember to clean the carbon off the 4 points in the dizzy.

An new 02 sensor for $100 is always a good buy too.This can cause your car to run rough as an old/faulty one sends an incorrect reading to the ECU.

Many people including mechanics underestimate the importance of a properly working 02 sensor on Honda's.

Quote:

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Originally Posted by beeza

Remember to clean the carbon off the 4 points in the dizzy.

An new 02 sensor for $100 is always a good buy too.This can cause your car to run rough as an old/faulty one sends an incorrect reading to the ECU.

Many people including mechanics underestimate the importance of a properly working 02 sensor on Honda's.

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yeah i sanded the corrosion off the 4 points in the dizzy but couldnt get rid of them back to bare metal.
is the 02 sensor easy to install? where to get the part from?

Quote:

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Originally Posted by kriZy

yeah i sanded the corrosion off the 4 points in the dizzy but couldnt get rid of them back to bare metal.
is the 02 sensor easy to install? where to get the part from?

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The carbon should come off real easy.I'm on my second dizzy cap cause I was taking too much off those 4 points..the metal comes off quite easy too..

I use a flat head screw driver and chip /scrape it off,it takes 45 seconds for each one,anymore and more than likely you are taking the metal off.It's just easy to do..

The 02 sensor is easy to install,just gotta make sure it's installed on the 1 pipe on the headers i.e. where the 4 meets the 2 then meets the 1,there,that way the reading will be correct as it will be reading all 4 cylinders.If it isn't there it should be moved there,if a bung isn't already there it can be made easily and the other bung plug up with a short bolt,so it dosen't stick through into the pipe.The 02 sensor wire will need to be extended.

Also make sure U are ordering the correct 02 sensor,can order a bosch one from global spares or the likes.

If your engine is stock, why not try a stock ecu and see how you run with that.

well I swapped the coil today and to no effect, still had the hesitation after about 20 mins of driving when it got hot.

So fk it, now the car is going up on stands to swap turbo, radiator and traction bar install cos I go on leave in a weeks time. see if a retune fixes the problem when the turbo is installed.

kriZy if you want to try an o2 sensor to see if that fixes your problem I have a spare that made no difference to my issue so I assume it is all working correctly, will let you have it for a bit less than I paid if you like. shoot me a PM if you are interested.

any updates?

cheers

Hi
Is this a common problem for dc2's I have just brought one, and I am having the
Samee problem aswell but mine is N/A

I ended up installing the new turbo etc and took it down for a retune and that fixed the issue, never did know what was actually causing it.