[Heppy]

Hello I have a 8th generation 1.8 vtec civic and having issues with it.. Just replaced the engine and keep getting random misfire. It will start and run fine at idle for about 5mins then goes off a cylinder. I have checked resistance on injectors and also coils and plugs are fine. Could it be possible that the ecu doesn't like the engine change? 🤔

 

[stivbox]

after the 5 mins then you loose a cylinder, if you turn it off and on do you get another 5mins or is that way till the engine has cooled again ? I am not a mechanic or anything but from what you've said so far i'm thinking heat. If it restarts and you get another 5 mins then it may be something like sensor/fuel pump/fuel injectors /electric. If it's the cylinder close to the egr valve(which may be dirty) as that has led to your symptoms for others. I'm sure the experts will be along soon to help you further.

 

[p7jox]

Hello I have a 8th generation 1.8 vtec civic and having issues with it.. Just replaced the engine and keep getting random misfire. It will start and run fine at idle for about 5mins then goes off a cylinder. I have checked resistance on injectors and also coils and plugs are fine. Could it be possible that the ecu doesn't like the engine change? 🤔

hi heppy have you pluged a obd code reader in to the car to see what fault codes are logged
if so what codes are showing?

 

[Heppy]

Hi I have plugged a reader in and faults are p0304 and p0303 nothing else. You are probably right about the heat, seems if you start it from cold it does run ok for 5 mins 😏

 

[p7jox]

hi heppy p0303 and p0304 refers to cylinder 3 and 4 misfire the first thing I would try is to swap the coil packs and plugs from cylenders 1 and 2 in to 3 and 4 and see if the misfire changes to the other cylenders if it stays on 3 and 4 then the coils and plugs are ok
you could also try swaping the injectors around just to rule them out aswell
I would also check the cylinder compresions just to rule that out (but as it runs ok for 5 mins I don't think that's the problem)
next thing to check is for any air leaks at the inlet manifold expecialy at the inlet ports for cyls 3 and 4
another thing what make are the plugs as the r18 engine can be problematic when not using ngk plugs


when the engine is missfireing if you restart the car does it misfire strait away or does it run ok for a while then misfire?


hope this helps jox

 

[Heppy]

Hi again a little update I sent the ecu away to (ecu Testing) to get tested but they said there wasn't anything wrong with it and if I exchanged it would 90% fix the problem as it was common.... Well gues what it hasn't 😬.

When I fitted it it was idling fine for about 15mins but soon as I was away to take it a run it went straight off a few cyclinders. The coils have been swapped and checked along with injectors and it ain't that and plugs are ngk.

I am getting rather peed off with it now 😢