Another misfire mystery.

[Kiewiet]

Hi,
I've bought a 2003 Jazz 1.4 i-DSi CVT with 105000 km a while back, with a misfire and can not get the misfire sorted. When it is idling there is no misfire, but as soon as you touch the petrol, it misfire whether in neutral or drive.
When pulling away from a stop, it misfire and hesitate, but from about 1500 Rpm the misfire seems to clear.
Fuel economy seems ok, 6,9 l/100 km around town and 5,3 L/100 km on the open road.

What was done since I bought it:
1. CVT service
2. Engine service (oil, filters and 8 new plugs)
3. 8 New coil packs
4. New petrol filter
5. Valve clearances adjusted
6. Injectors checked and professionally cleaned
7. Fuel pump delivery and pressure checked
8. Compression checked (Good)
9. Scanned for fault codes, none
10. EGR valve cleaned

Is there anything that I am missing?
Can anybody point me in a way to proceed?
I really like the little Honda, but it is driving me nuts, and I can not pass it on to someone with the problem.

 

[olduser1]

You need to access the fault codes if any by using OBD11 reader or find a local car electronic expert.
Once the codes obtained come back to the forum.

[CRC]

Clean the egr valve?

[madasafish]

No fault codes suggests the cause is :
MAF sensor needs to be cleaned.

[Major clanger]

But cleaned with what?  (I know, there is a MAF cleaner spray) Fact is you are more likely to damage it than clean it.

Before you attempt to "clean it", unplug it.  The ECU should default to a base map setting and if the MAF is dirty/faulty the car will run OK but be down on power by about 10-15%.  If no change its not the MAF.

[Jocko]

Check the small bore hoses around the inlet manifold for leaks.

[Westy36]

You've certainly spent the £ and replaced a lot of parts. I would be very frustated too.

Has anyone changed the coils about? Just because they are new, doesn't mean they're good. Could still be an issue.

Not sure how the car is driven, but a shot of Redex and a decent italian tune up could work wonders if the cars spends its life pootling around town at low revs.

[FBogdan]

Hi!
There is a similar technical issue on another post here.
See the link below, this might solve the problem. I'm having the same issue with a similar CVT jazz and I tried as you did to change or clean every part which might cause this misfire or idle rpms unstable.
This link was provided by another member so he should have our gratitude.
https://www.springbokphotography.com/autoelectrical/2019/7/15/honda-fitjazz-crank-sensor-interference