High idle and loss of power.. Suggestions?

[pillapow]

miles away from me so im not much help. judging by what your discribing i very much doubt its the maf. how dose the car rev underload. ie on the road. if theres no fault codes except for when you disconected the maf id say your looking at a mechanical issue but the generic code readers arnt always the best for picking up all codes. id check everything you can thats easy and free. is your turbo healthy. all boost pipes in good condition. youd prob get a code if one blew off. i did on mine. is there a blockage in the exhaust somewear. i once had a issue like that on a astra. it sounded like it was hissing when reved. once i loosened the bolts on the manifold to exhaust it reved normaly. these are just suggestions and i could be miles away. its hard to diagnose issues with out having the car infront of me. wrap up warm tomora and get stuck into it

Under load when fully warm it feels like there is the tiniest amount of boost, the "kick" isnt there anymore, normally, at about 25% throttle it will start to boost at 1800rpm and will start to pull there, then theres the hard kick at around 3500rpm, all of that is completely gone, its just one laggy powerband now with nothing of note, the exhaust is pretty much brand new, its a custom system with 200 cell cat. If weather is ok tomorrow, I'll get into it, I want to remove the intercooler aswell to inspect it, would the easiest way be to remove the slam panel?

[graemewelch]

if the intercooler is shot youll noticed its bowed and is oily at the bottom. very hard to miss. its a bumper off job to remove the intercooler. my first job would be checking all the accessable parts.

[pillapow]

Evening folks, spent 6 hours on the motor today, removed all boost pipes, removed etm, checked everything, checked all vacuum lines, pretty much gave it a good going over, cleaned and refitted the etm, (could do with a new gasket tbh, will do that asap. Cleaned all mating surfaces etc and put everything back together, tried to remove intercooler, got rad loose etc, fan out and realised its connected to the air con pipes, so didnt go further than that.

3 things i noticed, one was some carbon/oily residue around the outside of the turbo, same with the etm to intercooler joint at the intercooler side, lastly, i think this is the map sensor/ unsure? the one pictured, there is a split in the housing and there was some sort of putty around it, i removed the putty to investigate. I have taken pictures of what i thought could be the culprit for my problems.

Didnt manage to get a video of the idle as i started on it early and didnt want to be working on a hot engine.

After refitting etc, double checking everything was secure and connected, car fired up fine, ran brilliant, gave me full power, did some hard runs, felt like the problem had re-appeared albeit not as bad.. Let the car cool for two hours as i was replacing brakes on a fiesta for a family member, (oh how easy) lol.

Fired it up, drove home, plenty of kick, feels like full power. So again, its got me stumped.

Its definitely running better however its still raising the idle to 1000rpm when the engine is fully warmed up, seems to run better when the engine is cooler.

Any suggestions guys? Thanks in advance. (Here are the pics)

[Harvey]

Just looking at the turbo compressor wheel there looks like a dull area where the blades line up to the outer housing, have you checked if there's any play in the turboshaft as it looks like it could be rubbing the outer housing ?.

[M-R-P]

That's not the MAP sensor, that's the PTC nipple and nothing to worry about in this instance.
The sticky tar around the connection to the intercooler is a sign of a boost leak at some point.
I wonder if the actuator needs looking-at, it looks like a well used turbo so the actuator should really be checked.

At least you've made some progress

[pillapow]

Evening fellas, how you all doing.

Have realised something what the car is doing, i think it could be whats causing the loss of power.

Just to recap first, when the engine is cold, in the mornings for instance, its lively, it sounds good (and even though i dont use the boost while cold, i have been doing so slightly to see if this fault is happening whilst cold)

It drives perfect when cold, now when it gets upto temp, right upto temp, it starts idling high, its at 1000rpm now idling when warm, 800-850rpm when cold.

When cold, on initial startup, the cold start mechanism works fine, then i can hear a relay click and the idle drops to normal (850rpm)

What i noticed today, when the engine is hot, is upon startup, the car starts, approx 1200rpm, revs drop as normal and then i hear the "click", engine idles at 800rpm which is what it used to do and which is normal, however, approx 2 seconds later, (only when the engine is warm) it "clicks" again, which takes the idle to 1000rpm and it stays there, then the poor throttle response and the boomy exhaust ensues.

It doesnt do this when cold, so i am assuming there is a fault with a fuel relay of some sort which is giving it a rich mix when the engine is hot, also i noticed my fan stayed on for 30 seconds today too after stopping the engine and my consumption is poor, which all points to a rich mix.

This is what i think is wrong with it but i dont know how to go about rectifying the issue, On my previous T-5R, i had a fuel pump relay fault and had to bridge it, so i am assuming maybe another faulty relay or faulty sensor?

I have attached a video of a hot start and if you listen closely you can hear the initial click and then the second click.

Hope this is clear enough for you guys, hope i can get this fault fixed, had the chance to put a Masseratti to shame yesterday and had to refrain, haha. Thanks guys.

PS: Also note the little rev at 1500rpm on the comedown, it does this on its own (only on a hot engine)

[M-R-P]

I'm now thinking the temp sensor might be wonky....
If that's sending the wrong signals, the car will be overfueling in an effort to warm things up.

Your revs (from cold) should go to 1000-1200 revs straight away and over about 5 minutes, drop, in stages, to about 650-700 rpm.

When warm, it should go straight to 850 (ish) and drop to 650-700 quite quickly.

[pillapow]

I'm now thinking the temp sensor might be wonky....
If that's sending the wrong signals, the car will be overfueling in an effort to warm things up.

Your revs (from cold) should go to 1000-1200 revs straight away and over about 5 minutes, drop, in stages, to about 650-700 rpm.

When warm, it should go straight to 850 (ish) and drop to 650-700 quite quickly.

It is the temp sensor, did a ten minute run this morning, once warm car was immediately running like crap, boomy and nasty. Shut it off, unplugged the temp sensor next to the T-stat, started her up, revs were a little high but they soon settled to 900rpm (without any clicking)! they settled naturally, instantly i knew it was working ok as there was no boominess when revving, i wasnt expecting what came next though.

Ever heard a Supra twin turbo on full boost, yes, theres one under my bonnet i think, my god, its immense.
The boost is unreal, its a monster, i thought it was fast before but you couldnt hear the boost, just felt the pull, I replugged the temp sensor back in whilst running the car and did another run, still the same, so shut her off as my tyres were losing tread like a cheap pair of trainers, haha, Hope its ok when i restart.

What do you think M-R-P? A new coolant sensor and take battery off for half hour? Let things reset?

Many thanks.

[M-R-P]

Make sure the engine's been off for about half an hour, then pull the negative lead. Leave it at least an hour, then with the key in position 2, reconnect the negative in one hit - don't let it spark as you could annoy something electrical.

Deffo go for a new sensor

[pillapow]

Make sure the engine's been off for about half an hour, then pull the negative lead. Leave it at least an hour, then with the key in position 2, reconnect the negative in one hit - don't let it spark as you could annoy something electrical.

Deffo go for a new sensor

Im about to do that now re: leave battery off for an hour.

Seems that my temp sensor has failed altogether now, with it connected, the temp gauge doesnt even move, this has only occured after todays fiddling, im going to trace the wire on it and see if there is any kind of break of fraying.

Furthermore, the fan wants to stay on for a while when shutting off the engine now and runs constantly when engine is running, i have disconnected the fan power lead on top of the rad as my battery isnt too good.

Engine isnt getting overly hot, slam panel is cool and just a slight amount of pressure when loosening the rad cap, just a tiny quick "hiss" when doing so.

Do you think it will be ok to run it like this until i get a new coolant sensor? Im afraid of the boost level being too high?

Cheers.

[M-R-P]

Can't help much with the boost I'm afraid (unless you live down south and I can do some live logging on the thing)

The fan running is normal when something's not right, just don't sit in stationary traffic with the fan unplugged.

It's possible that the ECU has given up on the sensor after you unplugged it with the engine running and won't accept it being reconnected. Resetting the ecu might fix that "might".

Are you sure you have the right temp sensor? I believe there's 2 or more.

[M-R-P]

Looks like there's only one... (unless there's only one you can buy from eurocarparts)

[graemewelch]

i wouldnt even disconnect the battery. only ever do it when removing seats with airbags otherwise i just crack on. hope it is the sensor.

[pillapow]

No, im in the northwest, the car was mapped by kalmar union 6 months ago, unsure what settings/boost pressure he runs, its a claimed 300hp so obviously a bit more than stock.

The sensor is a genuine Volvo one, there is some breakage in one of the wires that parts from the alternator wire, that leads upto the sensor connector, the copper cable is intact but it is exposed a bit.

I read somewhere there was two, a coolant temp sensor and an engine temp sensor but looking around there only seems to be one type, So when its plugged in, car runs horrible, unplug it and the car flies, but having it unplugged causes me to lose the temp gauge and fan wants to run, I have removed the ground wire from the battery and will see what its like in half hour, see if the sensor comes alive again or if its still the same.

Thanks guys.

[deathrider311271]

the temp sensor on the ME7 models does more than you think, it talks to the MAF, Lambda, ECU and measures the temp obviously. The temp sensor partially controls fueling ie cold to hot so needs to be working correctly. If this sensor isnt working properly it goes into a safe mode limits the boost. So looks like you have found the problem. Also on a side note are you running a gen Bosch MAF sensor?

[M-R-P]

If it's mapped with no other mods then it won't be anywhere near 300bhp, 270 to 280 at best and in safe mode, it'll make nowhere near that.

get that exposed wire insulated or replaced and chuck a new sensor in there (less than a tenner) and go play

[pillapow]

Cheers guys, I am running a Bosch maf, its around a year old, I looked at it yesterday aswell and its very clean inside.

Put all back together, (temp sensor connected) fitted battery lead with key in position 2, after some high idle, it settled and idled ok, still around the 950rpm mark.

Took it for a run, marginally better running from previous days, can feel it holding back, especially in 3rd gear, so still not running right, wanted to leave it like this until i get the new sensor but curiosity got the better of me.

Shut engine off, unplugged coolant sensor and restarted, took it for a run, i blew an intercooler hose off! Luckily i was on the industrial estate and had a screwdriver with me and two kids in tow, yes!

After fixing, gave it some, same as today, sounds like a supra twin turbo, only this time the CEL came on.

Cheap OBD2 reader gave me a P0181, if i clear that code, the revs increase to about 2000rpm whilst idling and takes a few minutes to die down, so after fettling about a bit more, P0181 is back but the idle is 950rpm and the temp sensor is unplugged.

Re: Deathrider. If the coolant sensor goes into a failsafe mode when faulty, why is it vastly limiting boost when connected but allowing (what i can summise) maximum boost when unplugged?

Shouldnt it be the other way round?

M-R-P: Wouldnt a genuine Volvo sensor be better or doesnt it really matter? Thanks.

[Harvey]

When I get home I can tell what the resistance of the sensor should be at certain temperatures to see if it's faulty.

[M-R-P]

Something like a temp sensor, at that price, would it matter I'd you had to replace it every year?

[Harvey]

Just thinking doesn't the outside temp have some say as well in the door mirror. (or am I just day dreaming).