just not running rite

[mdm]

so, good evening folks, i need you help,

rite so the car (aby with 156,000miles with mrc remap) is rather lumpy when you floor it. it like a pulsing sort of sensation, it just doesn't feel smooth, also it hits what i would call fuel cut, (it boosting about 1.3bar when it hits it)

so i pulled the codes and i got 4444 first time (that's injector number 1) know i don't think that thats the problem. so i reset the codes and took it for a drive. got back and pulled the codes again and this time i got 2111.

so 2111 is the engine speed sensor, now bare in mind i had the engine off so i turned it on and still got the code, i didn't reset the ecu,

also the car runs smoothly off boost.

so my bets on the maf, i cleaned it about 2 weeks ago (with wd40) to see if that would fix it, seem to fix it for a week or so.

so has any body got any ideas

[BRY]

boost leak
"fuel cut" is overboost protection - search for it

[shark_90]

If your injector code hasn't come back, then it's something the ECU doesn't know about, so it thinks it's doing it's job properly.

I had exactly the same symptoms as you. Can you smell fuel when it pulses? Do you think it's missing?

I ended up changing all my coil packs, and it was money very well spent. Car goes like feckery now!

[mdm]

a boost leak is in the back of my mind, before i chipped it the boost would tail off to 0.5 bar at the redline, now it doesn't happen so much. only thing is that the boost dosn't go above 1.3 bar.

also last night when i was coming home i got what i would think of as a misfire, well sort of like a cough followed by a puff of black smoke, (my friend was following me), that made me think it is an ignition fault. today it's got a bit worse. as far as i can remember it only happens when the engine is warm (at 90, o and i've just changed the thermostat), the also car runs smooth when it's heating up.

i can't say that i smell fuel, any were round the engine.

[shark_90]

I mean when you're booting it, and you get the "cough" can you smell fuel? I found with mine (which was quite pronounced) about 3-4 seconds after it had been missing, I could smell fuel.

[mdm]

can say i do, but i have noticed that it only happens when the car is warmed up, plus it's starting to get worse.

so time for the 1.8t conversion, i think, or has any body got any other ideas?

thanks

Mark

[ericd]

Still sounds like you've got a boost leak, check all the hoses (boost & vacuum), tighten the clamps if applicable when you're there, also have a look at the MAF multiplug, worth a quick abrasion/clean with something, as Bry indicated there's many threads describing various ways certain items will cause behaviour your describing, if you can borrow/buy a boost leak kit from somebody may well help you out...

HTH

[mdm]

but would a boost leak only appear when the car is heated up, that what gets me.the plug on the maf is as clean as a whistle, i have even had the maf out to clean it.

if it was a boost leak and the ecu was going in to over boost protection mode ( momentarily killing the fuel, ie fuel cut) then in theory it would come up in the error codes, but it doesn't, which bring me back to the ignition system, if there was a fault with a coil then the ecu isn't going to pick this up hence the lack of error codes, the only other option i can see is a fault maf, but as i said before the maf plug is clean and i have also cleaned the maf it's self.

[merlin's S4]

The ecu won't store a code for overboost protection. A boost leak is the most likely cause of overboost protection. Could well be ignition related. Check coilpack wiring and rubber spark plug boots. If it's definately heat related then it could be a POS.

[Knight Rider S4]

I would go for POS

http://www.sjmautotechnik.com/trouble_shooting/S4_Ignition.htm

[mdm]

if a pos had gone then it would be rough at idle would it not, but it idles perfectly

the thing is that it doesn't really feel like overboost protection, i had that about 2 weeks ago and it was violent enough to know the car out of gear, so i cleaned the maf and it was ok.

but what it's doning know isn't as violent. but it feels lumpy when the boost starts to build. which it didn't when it was hitting overboost.

the boot's look ok, on the coil closed to the windscreen the insulation has started to beak away from one of the wires.

[ericd]

if a pos had gone then it would be rough at idle would it not, but it idles perfectly

the thing is that it doesn't really feel like overboost protection, i had that about 2 weeks ago and it was violent enough to know the car out of gear, so i cleaned the maf and it was ok.

but what it's doning know isn't as violent. but it feels lumpy when the boost starts to build. which it didn't when it was hitting overboost.

the boot's look ok, on the coil closed to the windscreen the insulation has started to beak away from one of the wires.

I would still visibly check everything , even it means a couple of hours working from the turbo up to the TB , If you could source the temporary loan of a MAF also might be a way forward.

[mdm]

tried to do a leak test to do, and i found one,



the leak is coming from the Pressure regulating valve, (were the jubilee clip is)

thing is it's not a big leak, it holding pressure, just bleading away,

so i'm going to try and get a proper jubilee clip or two to see if it will stop the leak, thing is the one i have on at the minute is quite good but it still leaks.

also i pulled the biggest lump of copper wire from the same hose, don't know what that was about.

[ericd]

Think you'll find the clump of copper wire was the remnants of the flame trap that lives around there

[T2Andy]

would that valve have anything to do with boost pressure