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156 V6 temp. and idle problem

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idle temp
9K views 109 replies 14 participants last post by  Pud237 
G
#1 · (Edited)
Temp problem sorted but

Secondly when my car is idling it is wavering slightly sounds a little spluttery, when I come up to a junction and change down through the gears and come to a stop as I clutch the car from second gear to stop, the revs drop right off all most stalling then the revs come back on,? Also does it if your sat at idle and rev the car the revs drop right off on their way down before recovering

I now have intermittent loss of power when trying to accelerate the car, the cars judders then takes off, does this randomly. Feels very much like when my previous peugeots coil pack packed in. Absolutely shocking MPG too.

Help me please:cry:
 
#2 ·
Hi guys as you may know I picked up a 1998 156 V6 today full leather brilliant paintwork every service, every reciept etc. I drove it back and have found my temperature gauge reads 50 doing 70-80mph on motorway not good engine temp. is not coming up. Definately not the gauge as when going slow temp. comes up. I am guessing thermostat anybody agree?

Secondly when my car is idling it is wavering slightly sounds a little spluttery, when I come up to a junction and change down through the gears and come to a stop as I clutch the car from second gear to stop, the revs drop right off all most stalling then the revs come back on, Any ides could it be because of the cold engine due to the thermostat or any other ideas? Also does it if your sat at idle and rev the car the revs drop right off on their way down before recovering?

Help me please:cry:
Definately the thermostat at fault there.

As for the idling, try disconnecting the maf and see if it runs any better - if it does then your maf is fecked.
 
#4 ·
Bear in mind V6s don't run well without their MAF meters. You could have a throttle position sensor fault. I would suggest leaving the MAF in, but removing the front battery lead for 20 minutes and then performing the throttle reset procedure.

1) Turn key to the 'MAR' position and leave for 90 seconds.
2) Turn key back to off and leave for 90 seconds.
3) Start car and let it idle for 15 minutes.

Do not touch the throttle while doing any of this, even starting.

4) Take it for a good thrash for a few miles, see if it feels any better.
 
#6 ·
Other reason's why it could be running rough is worn out spark plugs, failed/failing lambda sensors, or it could be the MAF afterall. Also a hold in the inlet piping will cause your sensors to go loopy..

Has it ever shown a red injector light next to the red-line on the rev counter? This indicates an error code present in the ECU..

Also, if you give the throttle a quick, hard stab does it rev up straight away or seem hesitant to rev? When your driving it does it sometimes feel like there's turbo lag, it doesn't responde to the accelerator for about a second then the revs start to rise and the power gets better and better as the revs go up?
 
G
#7 ·
it is reving allot better now, does not seem to hesitate and is not dropping like it was. I do have quite a strong smell of petrol which says to me my air/fuel ratio isn't right or that my ecu is compensating either for the thermostat (trying to bring eng temp up) or its compensating for the dodgy revs
 
#8 ·
But if its not getting up to temperature it will be running a little rich, cause thats what they do under cold conditions. That might explain the petrol smell, but then again it might be down to either a failed/failing MAF or O2 (lambda) sensors..

If I were you I'd get your thermostat changed before doing anymore diagnosis on any remaining throttle problems.

And you never mentioned before whether or not you ever got the "red injector light" on, normally a throttle position problem will trigger this light to come on, but usually a MAF problem won't..

Glad to hear that its at least a little bit better :)
 
G
#9 ·
Hi sorry no red lights at all. I am crap at diagnostics lol I think the choke was responsible for idiling my car better because when it was driven around town and the temp came up a very little bit it started wandering when trying to idle around 800 and dropping drastically when reved and allowed to come back down. No noticable losses in power or reaction.

I will leave the car alone untill I fix the thermostat getting it Thursday probably fit it saturday and give the MAF a clean, and do the reset as you said earlier in the thread and see how that goes will be back on this thread on Saturday/Sunday Thanks for the good advice
 
#10 ·
I'd not bother cleaning the MAF at the same time, just stick with the thermostat. Its good practice when diagnosing a fault to only change one thing at a time, isolating the component you think might be causing the fault.

I reckon you should leave the MAF alone, change the thermostat and then see how she feels, if there's still a problem, hopefully there's someone on here in South Wales with a 156 2.5 V6 who will lend you a working MAF for half an hour to test, then you will know finally one way or another whether it is MAF or something else..
 
G
#12 ·
Replaced the Thermostat today engine temp. seems ok unsuure if the fans are kicking in properly as temp. did push above 90 but will see how it goes. I carried out the reset and I am still having problems at idle. I have been assured that the car has had a new lambada and maf recently. I really need ideas as to why the car revs are wavering at idle, and why the car when coming down in revs doesn't seem to be able to find idle speed without all most stalling first. There are no ecu lights or any other lights present on dash. Car picks up fine once at 1000 rpm and above I even took it right up to 6000 rpm today don't seem to have power loss, however its a new car so I might not know what it is supposed to feel like.

Please help any ideas before I have to take her in to a garage
 
#17 ·
IMO: In my opinion

IIRC: If I remember correctly

AFAIK: As far as I know

Forum/txt shorthand ... ;)
 
G
#19 ·
Does anybody else agree with this.
Check air leaks on induction.
Try Another reset.
If that don't work get some Carb. cleaner and clean it up see how that goes (how long does it take to settle?)
If that don't work try swapping MAF with someone see how that goes.
If that don't work Throttle Body needing changed?
 
#22 ·
Yeah, the throttle body could be a bit stiff in its operation, carb cleaner would help here. You could always remove the induction pipe and have someone rev it to see if the throttle butterfly is moving smoothly or is stuttery. Don't move it manually though, it can knacker the gears and also throw out the alignment.

If you're going to try that, unplug the MAF first.
 
G
#26 ·
Update I have just come back from cleaning the throttle body here is what I have done so far.
I disconnected the Battery
took off the throttle body cleaned gently, didn't try to open it.
Put it back on.
Waited a while longer, reconnected the battery.
Turned my key to MAR left if for about five minutes
Turned it to off
Turned it back on started the car and let it run for about five minutes or so.
When the car warmed up it started doing it again drove around the block and if anything the car is worse, when clutching it now drops off to all most nothing, I can't get her out for a good thrash till tomorrow. Do you get any immediate effects or does it take time?
:confused:
Also when I was doing the throttle reset when the key was in the MAR position I could hear a constant whirring noise from the throttle body (is this normal) it also clicked once or twice.:confused:
Further to this lot. When the car has warmed up a clicking noise starts seems to be coming from behind the engine drivers side?
strange, and I also get allmost like a wheel bearing failure noise except it is not the wheel because the noise decreases, increase with engine rpm and not car speed. :confused:
Anyone have a magic wand handy?:)
 
G
#28 ·
Me again:cheese: I keep hearing about getting the diagnostics reset, what is this about and how would I get it done and what sort of money am I looking at to do that.

Also I have heard of some people who have their own diagnostic kits how do you get these, how much we talking and what can you do with them other than fault codes
 
#29 · (Edited)
you need an OBD cable - get one off ebay, preferably 9 way serial type to OBD connector.

If ur laptop doesn't have a serial connector then you can use a few USB - OBD cables - make sure it has the FTDI 2xxx chipset USB Serial port hardware.

Like this one (not me selling this!) VAG COM 409.1 KKL USB Diagnostics Cable UK Seller on eBay, also, Diagnostic Tools Equipment, Garage Equipment Tools, Cars, Parts Vehicles (end time 08-Mar-08 20:11:18 GMT)

You're looking for one that works with VAG com (Volks / Audi software made by Ross Tech)

Once you've got that - you need the alfa diag software - a license is about 50 quid.

You could pay a main dealer to do it but I'd bet they'd charge a full hours worth of labour - which has got to be about 90 quid I reckon these days.

That said I'm sure somebody closer to you from these forums will gladly reset it for you with their software and cable.

If ever you're up in Yorkshire I'll do it!

Incidentally - my missus v6 156 did this a few times (stalling at low revs) - the batt was virtually dead due to cold snap and the wifes rediculously short journeys (6 engine starts in a trip of 12 miles return - home, mothers, shop, other shop, mothers) - after a full charge it stopped doing it. Presume on hers at idle the Alternator / Voltage regulator just couldn't cope - they prob need a recondition anyway....

Most likely this isn't what's going on - but rule it out either way.
 
#31 ·
From the start...

The thermostat will be stuck open, this is why temps remain low whilst mobile and rise slightly when stoped.

Because of this low temp the ECU is keeping the engine in an overfueled state this explains the lacking performance and most probable horrific mpg.

Best engineerin practise is to fix one thing at a time as this may cure other so-called problems induced by the replaced component. Mafs are often replaced in error on an engine that is running cold because of a sticking thermostat or faulty temp sender.
 
G
#32 ·
cool thanks for that just to say I have changed the thermostat and it was stuck open engine temp. has setlled out nicely only moving a little less than 90 or a little more. MPG has sorted itself and no more fuel smell. I only got to sort the idle problem now which at the moment is a pain, it does seem to be finding it a little better since the clean it has a few jumps around but finds it still wavers though
 
G
#33 ·
I now have the cleanest throttle body known to man unless you buy a new one of course.

Anyway still doing it, I unplugged the MAF today no change still doing the exact same thing, so to me that syays the MAF is not working because it didn't change the engine when I unplugged it, on closer inspection I have found that the top of my filter box only has one bolt holding it in place, great a nice little entry for unfiltered warm air to get in :mad: So I now need a new filter box where is the best place to track one down, also does what I said about the MAF sound about right. I am now going to send a e mail to the bloke who sold me the car:tut:
 
#34 ·
I'd say there's nowt wrong with the MAF - if unplugging it made no difference then I doubt it's at fault. Without the MAF the engine will use rough calculations to work out air flow and as such should run better than with a faulty MAF - as urs isn't then we can rule that out.

I'd get an airbox from a scrappers - there's a load of V6's being broken on ebay right now - give any one of em a call and ask.

In the mean time - try sealiing that leak up in the box with say some gaffer / masking tape - then you'll know if that leak makes a difference or not - it'll have some effect but I'm not sure how much.

I'm beginning to think that it may be an ignition problem. Maybe a plug / coilpack isn't playing ball?
 
#38 ·
Does it idle fine when you start it up first thing, and only starts playing up once it gets warm? That would hint lambda..

The throttle reset procedure is a pretty accurate procedure and you should really aim to get the timing right.

MAR for 90 seconds.
Off for 90 seconds.
Fire up.
Idle for 15 minutes - do not touch the throttle at any point during the above procedure.
Thrash.

Definitely as someone above suggested, best engineering practice is to fix one problem at a time. Sort the airbox first, then we'll see what happens. I'd say get an aftermarket filter, but you could get a airbox & lid assembly from a scrapper - but a lot of them will be in as bad shape as yours by now.
 
G
#39 ·
cheers mate really appreciate the constant advice.

As u mentioned there yes idles fine but as the car warms up and the car trys to lower the revs at below a 1000 then it starts to play up. also I have noticed that if i am driving and slow the revs right down to all most idle before i clutch it tends to stay there wavering only slightly. However if I clutch the car from quite high revs it drops off seriously low to all most a stall.

As people are saying I will sort the air box do a well timed reset procedure then I will see what happens but it looks like I need Alfa diag or a garage
 
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