Worsening Misfire

[SargeRX8]

Your compression is low man, that is a tired motor. did you do the test warm? That rich cylinder could be three things. Unlikely, but maybe all other five are not flowing. Maybe that one injector is worn out. But what I think is the injector o rings may be work and it's leaking fuel into that cylinder which may well and truly explain your start too issues, the cylinder might be flooding with fuel when your motor is off. You aren't misfiring when you turn your wheel, or on idle. That pop you hear is a lean pop and is very normal if you are running close to stoich fuel mixes.

[GH05T]

the car was not cold but had been sitting for about 15 mins.

the car does have starting issues usually when running before hand so a leaky injector may be present. the fouled plug wasnt on a low compression cylinder

also is it common to have 3 at exactly one compression and the following 3 to have identical lower compressions?

and no the car isnt misfiring when i turn the wheel (it does hiccup a tad on idle which an injector may explain?)

it missfires on boost when turning a corner, the harder the more evident (or just after turning, straighten up... hit boost... misfire ... get thrusted forward and back when it hits boost again, very unsatisfying)

the cornering thing realy confuses me, i was thinking something may be loose like the bosh 440?

[Adriano]

Cornering will most likely be a bad fuel pump install, Overfuelling in 1 cylinder cant be an injector oring, as its an rb20 running top feeds

[GH05T]

I don't know enough to check the install or reinstall of te fuel pump, if I take it to a shop will they be able to tell what's not right or is it going to be a headache?

[GH05T]

Adriano, would I ten suspect the actual injector or something else

[GH05T]

ok well i suppose i should start by checking the fuel pressure, where do i get the fitting for the fuel pressure tester (work will have the tester)

i need to chase this backwards to find the fault i guess? where should i start for easy or telltale signs? ie, injectors easy to test or fuel pump easy to check out? a bit lost here sory guys but any help will be appreciated.

i will not be fixing this i will most probably get a shop to FIX things properly but i wanna cut down on time and money on diagnostics, but help is appreciated.

[GH05T]

Ok I have removed the boost controller.

Boost has gone from about .9bar to about .4-.5bar (quick spin around the block)

Will take it fr a decent drive tonight and see how she reacts now, see if any issue goes away.

Also f**kibg hatin the screamer pipe now that the wastegate opens so early

[GH05T]

Ok on the drive home the car is allot enter at the mug lower boost level. Even the weird cornering and high load miss fire is gone.

NOW I don't know if this is normal but it stays at a smudge under .5bar from 4000rpm - 6000rpm but then it pushes us to about .7bar on full throttle and I got a misfire at that level too.

Is the actuator/ wastegate failing?

Also I'm still suspecting a fuel pressure issue due to the higher boost levels cannot hold properly

With the black spark plug, idel misfire and trouble warm starting.... Should I be suspecting a valve problem perhaps?

Edited January 30, 2012 by GH05T

[Adriano]

The fact that one plug is black and you have a missfire, i would clean two plugs, swap the coils and see which one goes black then, im suspecting a dud coil

[GH05T]

Well theirs new plugs in their, will pull them out again soon and compare.

[WARLORD]

i had a similar problem for me it was the injectors,when you pull each cylinder coil out one at a time and put them back to see the idle change as a cylinder stops getting spark cylinder 4,5 where not working after testing everything it was the injectors,they worked but not properly for some weird reason and there newish i hope this might help.i replaced them and its 100%

Edited January 30, 2012 by WARLORD

[GH05T]

To be honest, I'm suspecting the head unfortunatly

It would explains te misfire, low comp (even though it's weird that 3 clys are on 130 exactly and three are on 112 exactly) the fouled plug, the hard start on warm especially.

So yeah mightn't be a quick fix

Edited February 2, 2012 by GH05T

[DVSTRK]

Try a new ignitor, my 26 had the same issue, turned out to be my ignitor. Found one second hand for about $70.

[GH05T]

Speaking of the igniter, this was interesting... I pulled the spark plugs out again recently to do a comp test but also to check their condition...(no1 plug black again the rest fine so that's not changed)

But I found what looks like a ground wire from the igniter, or at least loom which was broken and not grounded. I have re grounded it which unfortunately made no difference. But what would this be for? Igniter? Does it make a diff that is has not been connected?

[GH05T]

important?

[GTSBoy]

Well, yes, it is the earth for the igniter. But the igniter also earths through it's body, so if it was bolted down like it should be, then it was earthed anyway.

[GH05T]

Hmmm, well it defiantly hasn't bolted down or earthed properly until now. Dunno how long that wire has been broken for and how long it has been unearthed for.

Would this have caused some damage maby. Maby it really is time for a new ignitor.

Surprised that when I earthed it properly that their was no change,mor that being unearthed didn't cause more dramas.