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Discussion Starter #1
Hi!

I don't know where else to turn to, but my FN2 has been slowly driving me insane...

I have the car since January this year, but the issues just keep piling up.

About the car and what was tried so far:

2007 FN2, about 160k miles (255000km) on the odo

- car had lpg fitted with the valve lubrication addon (whole system removed)
- valves have been adjusted
- spark plugs have been replaced with proper NGK ones (had some crappy lpg plugs fitted)
- Compression on all 4 cylinders is about 12bar
- intake manifold was cleaned (due to large amount of "valve saver" oil buildup) and lpg fittings removed and sealed off
- throttle valve cleaned
- ecu remapped by a honda specialist (no idea what the map is called), vtec now at 4500rpm, second O2 sensor disabled due to de-cat pipe - afr at 14.5 via honda hds reading - this greatly improved the throttle response and some feeling of power
- rear muffler removed due do things rattling inside, 2.5inch "tractor muffler" fitted (no obstruction, almost like a straight pipe with some muffling)
- car was serviced regularly and i also reinstalled the intake resonant box so the intake is completely stock

Even after all that, i get about 23mpg regardless of how i drive (did once manage 26mpg granny driving - mostly under vtec engagement) and the top speed caps at 127mph in 6th gear, pedal on floor the issue is kinda similar to the one in a post from BlackTazz82, engine without topspeed, can u see the problem (can't post links yet, sry)

I don't have a flashpro, so i can't post any readouts, only thing i have is the HDS diagnostic software if that helps in any way

Now i don't know much about the FN2, but reading the forum it seems that something is not quite right with my car. I'm running out of ideas so any help would be greatly appreciated :crying:
 

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Just for clarity, was the map done after all the changes had been made? As the AFR is about right so would rule out running lean or flooding.
Having said that, 23MPG average is very good for a FN2 so could be running on the lean side if the AFR reading is not correct. And may explain not being able to get full power at speed.
 

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Discussion Starter #4 (Edited)
Yes the remap was after everything else was already made. The remap was a last ditch effort. Tho the dude doing the remap told me that the lpg ecu did break the oem map.
Forgot to add, i had to repair the injector wiring harness when i removed the lpg loom which was spliced in.

Yea LPG on a FN2, and a crappy one i'm affraid. I tried it, when i bought the car, but there was a huge power loss and it switched to petrol as soon as vtec engaged. And it weighted down the car about 60kg's in-place of the spare tire...

Edit: Also standing behind the car while running gives a very potent fuel smell, but that may be due to the decat. She does like her oil tho, the exhaust is almost always black and i had to top up twice in the last 10k km, totaling about 1.5L. Am runing castrol edge 5w30.
 

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Forgot to add, i had to repair the injector wiring harness when i removed the lpg loom which was spliced in.
OK, so how did this repair get done, was the original wires soldered back together and not done using connectors?

Again to clarify, the ecu is the original one that came from the factory from new, not a replacement one to be able to fit the lpg??
 

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Discussion Starter #6 (Edited)
OK, so how did this repair get done, was the original wires soldered back together and not done using connectors?

Again to clarify, the ecu is the original one that came from the factory from new, not a replacement one to be able to fit the lpg??
Yes i had to cut out the lpg splices and have resoldered the original wires back together.
The LPG system has its own ECU and wiring loom which was, as far as i could find, spliced to the oem only at the injectors, everything else was separate.
The ECU which was remapped is the oem honda one that the car came with.
The LPG ecu is a Zenit PRO agcentrum.pl (says the sticker on it)
 

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So, if the system is removed, is the LPG ECU still in place.
Sorry for the questions, just trying to get a clear picture.
 

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Discussion Starter #8
No worries, I'll gladly answer any questions, thanks for taking the time to try and help ?
No the lpg ecm was removed, everything that was part of the lsystem was removed. Only the copper connection pipes that connected the lpg tank to the lpg valve in the engine bay are still left, because i have to get the car on a lift to remove them
 

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OK, so fully back to original OEM set up.

So, has this problem been a problem since you returned it back to OEM and had the ecu remapped or has it only just started?
Also, if I'm reading right. The ecu has been programmed but it wasn't done with a Flashpro so a fixed map overwritten the original map on the ecu?
 

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Discussion Starter #10
Yup back to oem.

Well the problem was a problem since i bought the car. With and without the lpg system. The overall feel of the car is better now after the remap, but the main issue is still here.
I tried everything, returned the car to stock with even the oem cat on. No dice.
Fitted the decat with the oem back box, still no dice.
Remapped the car, after that there was an increase in pull strength and about 5kmh in top speed. Found out that the back box was rattling, so i removed it, made no difference.

Yes the remap overwrote the oem map, the dude used some kind of obd pc interface which also worked with HDS software. The guy is widely regarded as a good tuner around here (Slovenia and Croatia - he's Croatian). Only thing about the map i know is what he told me, that this map is the best for a totally stock decatted FN2, lowered vtec @4500, improved throttle response

After consulting my mechanic, he wants me to replace the maf, manifold pressure sensor and possibly the wideband sensor, but that's like 500+ euro on a maybe that it may fix it...
The only way i can get a Flashpro is by ordering one from Tegiwa, but that's a hefty 700eur
 

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Personally, unless it's a faulty sensor which should come up on a diagnostics then I would be tempted to try and get a Flashpro and have it put on a Dyno and have a custom map wrote for your car. If there are any issues, the Dyno operator should pick these up and be able to tell you what the issue is, if there is one and it's not just in need of a good custom map.
 

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I take it all the filters are clean and have you check the fuel pump? It could be braking down under load, but a dyno run would show that up due to lack of fuel being drawn.
 

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Discussion Starter #13
Cool.

Maybe i should consider investing in a Flashpro. I do hear nothing but good about it everywhere.

The only problem with dynos is, that there are maybe 2 in the whole country, i know of one, but the guy that has it is a bit special. He does dynos, but does not remap or touch anything that doesen't have a Haltech ecu. I could maybe get him to dyno my car, if i get the guy on a good day if not i'm screwed.

Filters were changed, but the fuel pump was not checked, which made me think that you could be on to something. I forgot to mention, if i push the car hard (high revs, spirited driving), if the window is down, there's a faint burning smell, but not of oil, a bit hard to describe, but kinda gas-smoldering plastic almost like a clutch. The clutch tho is ok, but will check into that further when i remove the delay valve (which drives me nuts in traffic).
i'll get to the pump tomorrow as we have a holiday, will post findings. Just in case, can the pump filter be cleaned or only replaced?
 

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Not sure on pump filter, but everything can usually be cleaned.
All the manifolds (inlet at exhaust) and all pipework clamped up correctly (no air leaks)
What is this delay valve?
 

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Discussion Starter #15

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Fingers crossed you get it sorted, I'm sure others will be able to offer help too.
Have a good holiday tomorrow whatever though, messing with the car by the sounds of it.
 
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Calipers all OK? Could be dragging the brakes causing the smell, making the car feel slow and ruining mpg.

FN2s run around 25-30mpg depending on driving style, anymore and you're lucky.
Mine was averaging 22mpg until I got RDX injectors and it went up to 28-30mpg.

Compression is on the low side but normal from age at that mileage but could be why it's burning oil too.
 
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Discussion Starter #19
An update on current developments:

I did not manage to disassemble the pump due to rain :p
I did however manage to record AFR live data (via HDS and screen recording software), but just 120seconds due to trial limitations of the capture sw. From an intersection at idle to WOT while merging to the highway the values jumped all over the place, going from 11 to 29 at times on WOT. But 120 sec seems a bit short, so i'll try and record the whole trip from work, for a clearer picture.

Regarding the calipers, we checked the brakes about a month ago when i replaced the lines with braided ones and everything seemed ok - but i'll check to be sure.

I've went to my mechanic again today and we discussed the possibility of the AFR malfunctioning. I know from past honda ownerships that the cars really throw a tantrum if the O2 sensor is faulty.
I'm thinking that the lpg system could have damaged the afr.

On a side note, i remembered that, when i bought the car it already had the decat pipe fitted, but i then refitted the oem cat for about a month (in hopes of improving the fuel economy). As nothing improved, the guy that did the remap told me that it would be better for the car (and the map) if i fit the decat pipe before i come for the remap. So i did. When removing the cat, we found that it had cracked in the month i had it fitted (it had no damage before i fitted it). It's still kinda good for mot purposes, but not really recommended for long term running as it may shatter and clog the exhaust.

Quick question regarding the afr sensor. If i disconnect it, would the car still run or go in some limp mode? I'm certain it will throw a check engine lamp, but i'm curious if there would be any difference.

Sorry for the long post
 
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