John Halliday

Hello all,

I recently bought a Roger clarke motorsport parallel fuel rail kit and installed it on my 2006 STi which is already highly modified.

Prior to the mod, the engine was fine and running flat out with no issues. I then removed manifold, wiring loom etc and installed the rails and original injectors along with new O Rings and manifold gaskets. After checking for leaks, I fired the engine and it revs higher and there is an awful intermittent banging/mechanical noise which comes and goes.. Now nothing mechanical has been touched in the way of heads/bottom end and I have checked all connections and checked that the fuel pressure on the new RCM regulator was about 3bar. I also checked all wiring loom connection in case one was loose on an injector or HT coil pack.

My main question is, could the noise be down to knocking from too much fuel getting fired in now? Even though the injectors aren't changed, I guess the thicker delivery pipes would cause this.

Am I correct in thinking that it basically needs remapped to account for the changes in pressure and line thickness etc? If not....something else more expensive could be the problem.

Thanks for the help,
John

bludgod

iTrader: (3)

I'm still going with too much fuel getting injected - scale needs adjusting in the map.

Checking the A/F corrections with the logger should show if that's right or not.


Any chance you could post a video of the sound - might help some people recognise it just.

John Halliday

Thanks for the advice yes I'll try as get a video tomorrow as te car is pretty loud and the neighbours don't appreciate the gurgle!!
I'll upload it to you tube and post the link!

John Halliday

Hey,
Here is the YouTube link from earlier today: it sounds different due to the iPhone microphone but hope to get the idea:
http://youtu.be/LbyTSZJRUfA

gazney101

iTrader: (5)

Omg, that sound bad.

Is certainly a strange one

John Halliday

Yeah!

The engine was fine until now..... Think Ill take the manifold off again tomorrow just for a look, haven't a clue what it could be now!

Bob Rawle

I think you have dropped something into it !!

by the way the std fuel pressure is not 3 bar atmospheric on the hawked, did you wait for the fuel pump controller to drop the pump duty from 100% to 33 % at idle before checking, did you check the original pressure?

If not then it won't be correct now. So be wary

bob

John Halliday

I basically disconnected the fuel pump relay and cranked the engine over on the starter motor with oil pressure only and the engine sounded perfect....just like normal except it didn't start. That rules out any mechanical problems as far as the engine actually spinning or there being something trapped inside there. Its only noisy when run on fuel. Got the car booked for a good mapping after Christmas now so I guess Ill just have to leave it in the garage for now!

ALi-B

iTrader: (1)

As Bob says that sound like debris bouncing around...stop and strip and inspect before it gets worse. Hopefully its something just bouncing off the back of a inlet valve (injector pintle cap?), and not entered a cylinder.

That sounds exactly like a Fiat Punto I drove where a screw had got into the intake. Sometimes the screw would stick on the piston crown (or head) so it'd stop, only for it top become loose again and start rattling.

Info here:

https://www.scoobynet.com/non-scooby...engine+screwed


The damage in the pics is from about 30 seconds of engine running. I shut it off within three second of hearing it, but after hand cranking and not feeling anything ( screw had stuck to piston), we fired it up again, and it was quiet for about 25 seconds, then the screw become free and rattled again.

John Halliday

Oh no!!! Ill rip the manifold off tomorrow then.....

scooblet

iTrader: (5)

Yeah defo sounds like a bolt or something been dropped in there.

John Halliday

Hi guys,

Firstly; Merry Christmas!

Secondly, thanks for all the help and advice over the last couple of days....especially Pete.

I just wanted to update you as I managed to sort the problem and just wanted to share the info. The more we learn from other people mistakes, the easier life is!

Basically I tackled the problem again and totally removed everything from manifold down to the rails and wiring loom. I disconnected everything and then manually cranked the engine over by hand with a ratchet on the crank pulley. All sounded good....
So, I then inspected each cylinder by cranking over by hand and using a decent torch to peer in between the valve seats as the valves opened. Not much room to see, but all cylinders looked clean and no signs of damage initially.

I then reconnected the wiring loom and got the manifold back on. I did notice that one of the wiring clips to the passenger side rear injector wasnt in great condition so I made sure it seated and had a good connection to the injector body. I then re-attached everything else and got the engine back together. After a quick finally check, I cranked the engine by hand again then disconneted the fuel pump relay and and cranked it on oil pressure on the starter motor. STILL GOOD!

So, I then took the plunge and connected the fuel pump and fired it. I heard one or two bangs and just before I could kill the ignition, everything "smoothed" out after a few seconds of rough idle. The engine sounds great and idles rather high, but well. I then did a quick visual check for leaks and that was it. The engine definitely needs a map, but at least now, all is well.

Thanks again to everyone here for offering the advice and I appreciate it :-) I don't know if it was changing the position of the fuel pipes or perhaps the main reason could be the fuel injector wiring clip being suspect, but wither way, at least its another couple of potential things to add to your future trouble shooting, should you be unlucky enough to have this problem!!