intermittent power problem

[cardboard 0]

i have a 2.0 16v and occasionally it randomly has no power. it ticks over fine and around 200o rpm it just starts to reduce to tick over. it doesnt stall or struggle or backfire, it sort of sputter slightly but its as if 3 of the injectors have stopped momentarily and the revs just come down slowly. if i turn the engine of it sometimes occurs again but normally turning the engine off 2 or 3 times sorts it and its fine?

is this an ecu issue or like a recirculating valve issue or sensor or what?

 

thanks

[staffs_til_i_die 0]

Anyone got any ideas? Mine does the same.... :(

[cardboard 0]

still got the problem

[olly elworthy 0]

lambda wiring

[staffs_til_i_die 0]

I've been trawling past posts again and have found these which might shed some light:

 

viewtopic.php?f=1&t=21068&p=221159&hilit=clean+MAF+valver#p221159

 

viewtopic.php?f=1&t=56281&st=0&sk=t&sd=a&hilit=ISV+clean

 

viewtopic.php?f=1&t=54574&p=645342&hilit=+MAF+clean+16v#p645342

 

viewtopic.php?f=1&t=54478&p=645295&hilit=+MAF+clean+16v#p645295

 

Lots of useful tips. I don't have enough technical knowledge to decipher much of this though (I've been reading books, surfing the net, etc. etc.) but still don't know enough to start pulling my engine to bits. I've stuck some photo's below. If anyone could point out where the ISV, MAF, etc. etc. are I would be really grateful. Also, what should I clean them with? Some people are saying contact cleaner, others brake cleaner. What's the best thing?

 

There also seems to be a few other people with similar problems. I've tried to link your threads to this one, so let us know if you sort it!

 

Cheers :D

[cardboard 0]

awsome work mate ill have a good read and play tomorrow and let you know if i get anywhere!!

[staffs_til_i_die 0]

Right! Had a tinker with a screw driver and have disconnected what I think is the ISV. Not sure though, and this doesn't look that dirty, or like it's something I can soak in contact cleaner. Is this the ISV? Anyone? Second photo shows the part of the engine I took it from.

 

 

 

Also, there appears to be quite a bit of oil (or general car grime) around this area. Any ideas?

 

 

Cheers!

[Toad 0]

Yeah ,that is the ISV. unplug the pipes from it and the inside needs cleaning.

 

The oil is leaking from the rocker cover gasket. I'd not worry too much... It's cosmetic mostly.

[cardboard 0]

whats the best way of cleaning it?

[Toad 0]

Carb cleaner from Halfords.. a few people have done it before.

 

Look in this list...

[mic_VR 3]

How are your plugs/leads looking. Recent run of wet/damp weather could be causing it to play up if the leads are not 100%.

 

As Toad says, ISV is the part you've taken off, get it off and soak it overnight in petrol or flush it through with carb cleaner, (only thing with carb cleaner on the older ISV's is that if you use it too many times it can degrade the internal seals) Dry it off and spray with WD40, replace and see how it goes, although I'd have thought that would show itself more at idle than at about 2000 rpm...

 

As for MAF, the 16V air flow meter sits on top of the airbox and it's more a mechanical valve than an actual sensor like of the VR's.

 

I've never worked on one myself but I'm thinking it might be a good idea to have a better look at it, see if it's got all crapped up or something.

 

Hope this helps.

[staffs_til_i_die 0]

Thanks for all the advice fellas - that was quick!

 

ISV is now soaking in cleaner. Will have a look at the MAF (if I can find it) Can I clean it with some contact cleaner as well or is it more complicated than that? I've also just noticed this down by the oil filter. It looks like some sort of connector that should be plugged into something, but I can't see anywhere to plug it. Any ideas anyone?

 

 

 

Thanks again for all the help...

[mic_VR 3]

I think the yellow wire is for the oil pressure switch, which has probably just got that extra connector on it as the same wiring is used on another model with a second switch.

It's probably never been connected to anything ever, don't worry I think everyone has a similar connector that appears it should go somewhere on their C. I've got one near the fan, has no purpose what-so-ever. :?

[gg7aph 0]

I have no idea how a 16v MAF wirks, but I can tell you that by removing mine and cleaning it I somehow knacked it. I had to get a whole new one - which cleared the problem.

I'm still a little unclear on your problem....your saying that at around 2000 rpm you loose power and the revs drop back down to idle?

[staffs_til_i_die 0]

Thanks again. It was Cardboard who was having the problems at 2000 revs. I've hijacked this post a bit as I was having similar troubles and two heads are better than one...

 

My car problems are also intermittent. The power just doesn't seem to be there as much. It revs quite high when I start it (1500 - 2000), but then settles down. It is eating fuel at the moment (I'm getting less than 300 miles on £50). And sometimes it stalls, often when I've slowed down (roundabouts, etc.) It's more of a complete loss of power than a stall. Everything just dies. the power steering also seems to be heavier. Have searched lots of posts, and there are lots of other people having similar problems, but there doesn't seem to be many solutions (or one's I can understand :oops: )

 

I've cleaned the ISV and I'll take it out for a spin in a bit. Any tips on the MAF would be great as I don't want to break it!

 

Here's some photo's with some arrows on showing where the ISV is on my valver. Don't know if one of the mods wants to put this in the wiki for other newbies like me?! If not, delete them.

 

 

 

 

[cardboard 0]

i think my problem sounds identicaly to yours actually maybe im just not as good with the old english language. mine used to stealthly stall like yours but hasnt dont that recently it just decides to have no power. i have taken my ISV off just now and left it soaking!

[CrazyDave 0]

Hi Staffs, got your PM.

 

I've just done a huge response to try and help and the forum died on me! So hears a quick summary.

 

The LE-Jetronic (well I think it is but not sure) fitted to the valver is pretty reliable as it's mostly mechanical. But it does have a few quirks.

 

The faults you guys have sound like a combination of the following:

 

Idle problems can be caused by a sticky ISV so it does need a clean, but also check that the throttle switch / throttle plate is closing. I've seen the cables goes sticky and stop the TB closing the switch properly. The engine won't idle if the switch doesn't operate, so check it does mechanically. Then check that it does electrically with a meter. Sometimes some oil worked down the cable does the trick if its tight.

 

The jetronic system has a flow metering head (like a MAF but mechanical). It's just a flap in a very precisely machined cone, air pushes the flap up and the shape of the cone sets how much fuel pressure, more air moves the flap up and give a higher fuel pressure to the injectors, so more fuel. Warming up or choke is done by regulating a resistance pressure to hold the flap down a bit to make it lean, or allowing it to rise more to make it richer. You can see the cone and flap by removing the rubber ribbed hose on the left of this pic. Be very very very carefull not to damage the cone or the flap, it should lift easliy if you pull the bolt in the middle. The cone should be clean, not oily.

 

 

I've seen problems with the cold start injector triggering whilst driving along, this will make the car drink loads of fuel and die like you all describe. To test this out, just pull the blue plug off the injector (it's on the end of the fuel rail in this pic, lower left). Drive it around for a few days and see how it goes. The car should start without this at the moment because its not that cold.

 

Air leaks are also a big problem for LE, make sure all the vac hoses are ok and that the breather hoses are clean.

 

Hope this helps?

 

Dave

[staffs_til_i_die 0]

Crazydave - MUCHOS GRACIAS! Really appreciate the help. Will get medieval on my car with a blow torch and a pair of pliers (or something like that) tomorrow... :onfire:

[wazza 0]

Hi Staffs, got your PM.

 

The faults you guys have sound like a combination of the following:

 

Idle problems can be caused by a sticky ISV .....

 

I've seen problems with the cold start injector triggering whilst driving along, this will make the car drink loads of fuel and die like you all describe. To test this out, just pull the blue plug off the injector......

 

 

Dave - i've got a similar problem which has only just started happening and only when the car is warm after long trips. The revs will either sit at just over 1000 or die completely. I cleaned out the MAF at the weekend and i'm sure I found some more power from it (which was nice!) but the problem persists. I'm going to have a go at cleaning the ISV this weekend and see what happens but could this be the same problem?

 

It may be coincidence but the problem did start after I changed my air filter to a piper-cross foam panel filter, which after doing so the car died a few times over a few days but was then fine, until this...

 

Any ideas?

 

Cheers

 

Waz

[CrazyDave 0]

Hi Waz,

Most VR idling problems are MAF or ISV. No cold start injector on a VR, ECU handles extra fuel for cold start. VR should idle at 750rpm and be pretty steady. Air leaks and broken hoses in the lnlet system are also a good bet, especially the breather and plastic noise damper box under near the ISV, prone to failing.

 

If you don't have any joy, pop round and I'll have a look.

[wazza 0]

Cheers Dave,

 

Will be having a look at the ISV tomorrow so will have a look around at the other bits while i'm doing that. It only seems to do it after a long run though, but i'll see what a clean ISV does to it.

 

Waz

[staffs_til_i_die 0]

Gave the flow metering head a clean today. This is what it looked like before and after:

 

 

 

It wasn't really that dirty, so I guess that it may not have been this causing the problem. Underneath was clean:

 

 

I know I keep posting lots of photo's but hopefully this may help others, or someone who knows what they're doing may be able to shed some more light on the problem...

[CrazyDave 0]

Have you unplugged the cold start injector yet, I have a feeling that may be causing most of your troubles?

[staffs_til_i_die 0]

I'm going to drive it tomorrow as normal to see if it was the thing I cleaned today. If not, then unplugging the cold start will be the next thing. If it runs ok with no cold start, what does that mean? What needs fixing/cleaning/replacing???

 

Cheers!

[vr6 storm auto 0]

Hi

I had a golf with the same problem as carbord decribed and it turned out to be fuel starvasion in my case it was a dogey fuel pump but it could also be the strainer inside the tank on the lift pump

 

hope this is some help

 

ross