Misfiring & running lean

[jameso89]

Hi guys,

I wonder if someone could help me with an issue I have been having. It’s stumped quite a few people.
Honda Civic Type R EP3 2004 (UK), Rotrex supercharger C30-94 (FMIC), RC750 injectors, 3” exhaust, de-cat manifold, RBC, 74mm BC throttle body ported to RBC, built engine (10.5:1 compression, FD2 cams, uprated pistons), running 430bhp.

Had the Kpro for 3 years, bought it 2nd hand, never had any issues with various maps prepared on it.

I will upload a data log of the issue as soon as I can, along with the map itself and serial and ECU part number.

The problem: I had the car mapped about 3 months ago and have had problems ever since. Straight away I had some issues with the car cutting out at WOT and going around corners, however, this was fixed by changing the fuel pump hoses and connectors. My new issue is that the car is misfiring like mad. The car idles fine although rather high at first 1800rpm reducing to 900rpm when warm. When driving the car, the AFR gauge shows the car is running majorly LEAN, and the car flutters and hesitates. I had the exact same issue about a month ago, after a long drive on the motorway the car started running lean, misfiring and lacking any power, it got so bad I had to pull over on the motorway and get recovered. When this issue previously occurred I did manage fix it for a period of 2 weeks (car literally ran mint in these two weeks) by changing the plugs for new ones (NGK heat range 8) and the injectors (identical RC 750’s). The old plugs were majorly black and sooty. However, after two weeks of hassle free driving with the new plugs and injectors another trip down the motorway started to see the car run lean again (after doing 80 miles on the motorway). It has not started misfiring yet but the conditions are the same and the power is down. I can feel the car is just on the tipping point of starting to misfire and do exactly as it did last time. I have checked compression and all is good, I also have the battery relocated to the boot and the car takes quite a few cranks to chime up...

My gut feeling is telling me it is burning plugs out or a heat related issue (linked to motorway driving), however, I have not had chance to take them out and check them yet. If the plugs are burnt out after only 200 miles then why could this be happening? Anyone shine any light on this for me?
Also, probably not linked by my ABS light is on, possibly caused by teeing the AFR gauge wire into the ABS wire in Kpro by accident, then realising and teeing it into the correct wire in the next pin along.

Thanks in advance,
James

[Hondata]

Two different things I think.
black plugs = a combination of tuning and injector spray pattern. Even with RC750s the plugs should be clean after many thousands of miles.
lean = fuel system or electrics. I would put a fuel pressure gauge in.

[jameso89]

Two different things I think.
black plugs = a combination of tuning and injector spray pattern. Even with RC750s the plugs should be clean after many thousands of miles.
lean = fuel system or electrics. I would put a fuel pressure gauge in.

Thank you for your reply. i do have a fuel pressure gauge in on my fpr. it reads 58psi at idle (this is what is was mapped at).

would you advise me to do a datalog and post it up on here or trailer it to a tuner?

[Hondata]

But what does the fuel pressure do at full load when the car is hot?

[jameso89]

But what does the fuel pressure do at full load when the car is hot?

Would you possibly set a go-pro or something up in the bay to check this?

[jameso89]

Just for information:

The car isnt throwing any codes and kpro isnt showing any either. I have a picture of my old spark plugs when I changed them over, I will upload that now.

I will upload a datalog as soon as I can, it might be tonight be more realistically tomorrow evening.

Nothing has been upgraded in my ignition system.

Thanks for your reply. Here are my old plugs:

[Spunkster]

I believe these are non-resistor plugs and should not be used. You must use resistor type plugs.

http://www.hondata.com/techksparkplugs.html

[jameso89]

I believe these are non-resistor plugs and should not be used. You must use resistor type plugs.

http://www.hondata.com/techksparkplugs.html

wow thanks for this mate. These are my old ones that I took out about a month ago. i replaced with ngk heat series 8... are they ok?

[Spunkster]

You will need to check your part numbers.

[jameso89]

Ok, So I checked the plugs and did a compression test this evening. Plugs were slightly black/Compression test read the following (10.5:1 compression)
Cylinder 1 - 171
Cylinder 2 - 172
Cylinder 3 - 161
Cylinder 4 - 170

I believe these to be ok. I also took the injectors out and made sure they were ok, no damage to O-rings and put them back in.

I then took the car out for a drive, it still showed to be running a little lean at certain rpm but overall it felt much better. I have datalogs but for some reason it wont let me upload them? Anyone tell me how to upload or I can email them?

Thanks,

James