View Full Version : Right...second day of ownership, problems :)
It's still working but hope you can help me with a few queries :D
Boost guage - is reading negative 0.5 at idle, then up to 0.0 at about 1500-2000rpm but no movement after.
Lift off and it drops to -1 and settles at -0.5 :?
Yesterday it settled at zero and dipped to -0.5 at anything over 2000k revs. But, today I found an air leak to the large brass fitting (electrovalve) behind the PS fluid container (what the hell is it?).
Repaired that and then found a disconnected/broken small bore pipe on the right hand side of the block...looked like it may go into the thermostat via a temp sensor but not sure as it looked like small bore boost piping again???
Also, whilst doing a bodge repair (black tape!) on the air intake pipe I removed the metal cylinder on the RHS of the block for access. This, and all the piping had loads of oil inside....is this bad? I'm wondering if the turbo is blowing oil :(
Now the air intake has been quietened I can hear some transmission whine at idle. Disappears when the clutch is depressed. :roll: Not too worried as I'll just drive it until it gets worse and the whining drowns the engine :lol: But, just checking it's not normal??? I'll check the gearbox and transmission oil asap.
Engine's a bit quieter today since I put about two litres in it :evil: (could this be linked to the turbo?).
Sorry for the long post....Q4s :roll: :lol:
wrinx
Steve Webb
07-04-07, 21:54
Boost guage - is reading negative 0.5 at idle, then up to 0.0 at about 1500-2000rpm but no movement after.
Lift off and it drops to -0.1 and settles at -0.5 :?
The readings for idle and low revs sounds about right, but sounds like the turbo isn't making boost, or the boost isn't getting to the inlet. Could be busted wastegate, split endcaps of the intercooler, or split hose in any of a number of places.
Yesterday it settled at zero and dipped to -0.5 at anything over 2000k revs. But, today I found an air leak to the large brass fitting (electrovalve) behind the PS fluid container (what the hell is it?).
Sorry, not sure what the large brass fitting is, can't say I've ever seen it.
Repaired that and then found a disconnected/broken small bore pipe on the right hand side of the block...looked like it may go into the thermostat via a temp sensor but not sure as it looked like small bore boost piping again???
Any chance of a pic of the offending items?
Also, whilst doing a bodge repair (black tape!) on the air intake pipe I removed the metal cylinder on the RHS of the block for access. This, and all the piping had loads of oil inside....is this bad? I'm wondering if the turbo is blowing oil :(
This is the engine breather canister, relieves pressure from the head, oil splash and vapour. Vapour goes back the the intake just after the airbox, any liquid oil should go back down to the sump via a pipe. This pipe might be blocked.
Now the air intake has been quietened I can hear some transmission whine at idle. Disappears when the clutch is depressed. :roll: Not too worried as I'll just drive it until it gets worse and the whining drowns the engine :lol: But, just checking it's not normal??? I'll check the gearbox and transmission oil asap.
Nope not normal, sounds like the clutch release bearing is on its way out, sorry.
Engine's a bit quieter today since I put about two litres in it (could this be linked to the turbo?).
Have you got much visible smoke out the back on overrun? If you aren't making smoke like a WW2 destroyer then chances are the turbo is still ok.
Your boost problems are more than likely wastegate stuck open at the turbo or a hose problem or an intercooler problem. The design of the intercooler is good but its got plastic endcaps which can crack, venting boost.
Steve
Wow...thanks Steve! Afraid turbo's are a new entity for me! I'm ok on NA engines but still have much to learn about turbines! :D
The transmission whine I think may be input shaft as it stops when I press the clutch, so it's not release bearing....which actually makes it worse as it's gearbox I think :roll: Hence I'll leave it 'til later ;)
Turbo wastegate....makes sense as I don't think the turbo is boosting properly, the car doesn't want to "go"....do I have to remove the turbo to check?
Would I hear any noise from split hoses?
Intercooler....err, radiator type thing??? :lol:
The electrovalve is right next to the Power Steering fluid reservoir. It looks like a rad fan switch and has two electrical connectors. Small bore piping leads from it to the inlet side.
Breather canister, that the small can at the back of the battery? Interesting, I'll check the little can isn't blocked as that may explain the oil anyway, but I was referring to the intake pipe, the long steel tube :D..in fact all the intake tubing :(
Thanks for your help so far :D
wrinx
Ok, found the wastegate...and intercooler, will check them later :D
From what little I've just read on the 'net it does sound like wastegate or perhaps actuator?
Worried about the oil in the inlet trunking though :( Does it sound lie the turbo is on the way out?
wrinx
Can't see any problems...is the 5mm steel rod supposed to move in and out of the wastegate or is it just a tube for pressure?
No turbo noise that I can hear.
Gauge still reading negative boost, checked all the piping I can see, seems ok. Can't see where the guage connects though :roll:
Another couple of potentially major problems have reared their heads :redcry:
Backfiring when restarting, after just being turned off...overfuelling????
May be using water....head gasket? :redcry:
What have I done....:lol:
wrinx
hmmmm, mine backfires a bit on startup, and pops a bit when driving at gear changes with mid revs - dont know what it is but I am getting a water temp sensor this week to see if it will cure it.
Any mayonnaise in water or oil caps?
Not that I can see...to be fair, the car had no water when I went to see it but no sign of overheating, or backfiring then. We topped it up and went for a spin, only today have I noticed the level has dropped, it could simply have settled and need topping again.
Backfiring is worrying me, it won't start until I stop cranking and then it fires..??? :lol:
*maintaining a sense of humour as I was warned about Q4s :lol:*
wrinx
hmmmm, mine backfires a bit on startup, and pops a bit when driving at gear changes with mid revs - dont know what it is but
When is the last time your valves are checked for clearance :?:
A couple of weeks ago I reported engine troubles, ticking sound in the head out of nowhere :shock: All kinds of strange things before, including huge after burning "explosions" in the exhaust :twisted: Difficult starting, loss of power (bhp) and bad fuel consumption :?
After a close look at my Alfa Specialist it became clear that the valves clearance was way out off specification :shock: Ranging from 0,42 up to 0,78 mm :roll: (keep the different settings for the in- and outlet in mind).
Last thursday I got my Q4 back and it drives like crazy :P The power is back and the engine sounds so fine (read, very very quiet). All the strange things/problems are gone know.
Greetings,
Marc
Steve Webb
08-04-07, 21:51
Ah, filling one of these up with water is a pain in the ass. Always takes me about 3-4 tries to get the level right. You fill it up to the level, go for a run, let it cool down and then fill it up again.
Just had a thought about the brass union you were on about before, Does your car have the factory waterspray? If so the brass thing might be the pressure switch for it.
Not sure about the backfiring, but I do know that mine pops and bangs on lazy gear changes, and on over runs. Sounds like overfueling in your case though. Does your oil smell like petrol?
On the turbo front, have you checked the pierburg valve (small cylinder on the right of the rad as you look at the car, 2 wires and 3 small bore hoses)
Also the recirc valve could be shot as the standard one is a crappy plastic diaphram one. This is buried under the piping from intercooler to inlet.
Oil in the inlet tract is a little worrying, but could be there due to wrong oil use. Give it a clean out, then check again in a week.
Steve
May be using water....head gasket? :redcry:
Easy to check. Look at the back at the color of the gases from the exhaust. Also a sweat smell is noticable.
Greetings,
Marc
Ah, filling one of these up with water is a pain in the ass. Always takes me about 3-4 tries to get the level right. You fill it up to the level, go for a run, let it cool down and then fill it up again.
Ahh, that's what I was hoping, will check again.
Just had a thought about the brass union you were on about before, Does your car have the factory waterspray? If so the brass thing might be the pressure switch for it.
Yup, Jack has confirmed that on 155org. I do have the water spray but it's not connected yet.
Not sure about the backfiring, but I do know that mine pops and bangs on lazy gear changes, and on over runs. Sounds like overfueling in your case though. Does your oil smell like petrol?
Don't think so, will keep an eye on it.
On the turbo front, have you checked the pierburg valve (small cylinder on the right of the rad as you look at the car, 2 wires and 3 small bore hoses)
Also the recirc valve could be shot as the standard one is a crappy plastic diaphram one. This is buried under the piping from intercooler to inlet.
How do I check these?
Oil in the inlet tract is a little worrying, but could be there due to wrong oil use. Give it a clean out, then check again in a week.
Yup, cleaned and eye being kept ;)
wrinx
Easy to check. Look at the back at the color of the gases from the exhaust. Also a sweat smell is noticable.
Exhaust seems fine...hopefully just the contents settling :D
wrinx
Exhaust seems fine...hopefully just the contents settling :D
Not the exhaust itself, I'm sure that's fine :D But look at the color of the gases that comes out of the exhaust ;) And also smell the gases, if it's a sweet smell you probably burning coolant (head hasket). You could also check the resevoir for bubles.
Greetings,
Marc
Yes, I understood but wasn't clear in my answer ;) Will check, but petrol cars can often smell sweet, like marzipan :D
wrinx
but petrol cars can often smell sweet, like marzipan :D
Your free to take a snif from mine any time, but I can guaranty it's not sweet lik marzipan :twisted: To much will kill you :roll:
Greetings,
Marc
Backfiring is worrying me, it won't start until I stop cranking and then it fires..??? :lol:
Mine doesnt do it too often but the engine seems to start as it fires :twisted:
Not sure about the backfiring, but I do know that mine pops and bangs on lazy gear changes, and on over runs.
Ah that sounds like mine, lazy gear changes etc.
Brul, they have never been checked, at least not be me, il get on to it :)
Can't see any problems...is the 5mm steel rod supposed to move in and out of the wastegate or is it just a tube for pressure?
Sorry, that should have read wastegate actuator :roll: Just been doing some reading, looks like the waste gate actuator rod should move 1-4mm, does that sound right, think mine is solid!
wrinx
they have never been checked, at least not be me, il get on to it :)
Service manual suggests a check every 20.000km :shock:
It was also a while for mine ;)
Greetings,
Marc
Had a play, wastegate actuator rod is moving so I guess that means the wastegate itself is moving.
Took it out for a spin and heard a chattering a couple of times but couldn't replicate it again...it happens when you lift off yes?
I'm now showing -0.5 at idle and +0.3 on boost, perhaps +0.4. Seems very low.
What's next To check?
Checked a few more pipes and there was some serious mayo to and from the oil seperator :(
Also, backfired when starting from cold this morning....head gasket or fuelling?
wrinx
0.4 boost is the base level my car was reading this and the problem was traced to the Piersburg valve. In my case the wires were just on the wrong way round, quick removal and move them around and boost was back up to 0.7.
I still don't get any overboost, so am currently planning to replace all the small boost pipes and if I can get one replace the Piersburg valve as well.
Juan AR155Q4
10-04-07, 22:39
Check the pierburg valve for bad conections. Other thing you could try, is to bypass it and connect the wastegate actuator directly to intake plenum. You should have base boost (0.4bar).
Also you could leave the wastegate actuator free to air, but be carefull because youŽll have FULL BOOST (more than 1.5 maybe). With this youŽll check if turbo is spinnig right.
About backfire, check fuel pressure. Also check if the FPR is connected with a little hose to intake plenun.
I plan to let the actuator loose with air by removing the bottom hose...also what's the FPR?
wrinx
Juan AR155Q4
10-04-07, 22:47
Be aware of high boost!!
FPR = fuel pressure regulator
ItŽs located behind throtle body, attached to intake plenum.
Ah, fuel pressure regulator?
wrinx
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