T5 power loss under acceleration

[zodski]

Hi, I'm new here, but have been using the forum for sometime as a great source of info about maintaining my '96 850 T5. However, I'm now faced with a problem that is causing me some grief. Sorry about the length of the post.

Symptoms:
1. Recently, the car has taken about 20 turns of the engine to start, rather than the normal 3 to 4.
2. When pulling away from a stop, it has paused significantly, and then accelerated slowly to 30mph (I have to look for big gaps in the traffic - not good!)
3. When getting on to the local bypass, I have tried to accelerate, but as the engine rev counter passes approx 3000rpm, the engine dies on me (drops back to about 2000rpm, and seems to wait for the car to catch up, speed wise, before revving up again). This means no overtaking, as the car feels like a Trabant (I imagine!). The turbo boost moves about 2mm into the white section (very slight positive pressure??). Given time and distance, the car can make 80 mph.
4. The car refuses to start until it has cooled down.
5. The Lambda light has illuminated, and fuel consumption is around 8mpg local, 14 mpg open road.
6. This all started very suddenly (except item 1 - this has been happening for about 2 weeks, and I thought a weak battery, to be replaced on pay day) last Thursday, during the very hot weather.
7. The turbo hasn't exploded, there is no unusual noise from it, there is no smoke in the exhaust, and it spins freely.
8. I can get to about 4000 rpm in neautral, but whem I apply the brakes and select Drive, I can only get 2000 rpm.

Actions:
I've researched the forums, and had a good look at all the pipes from the turbo inlets, manifolds, breather and intercooler. I have found some cracked rubber joins, but cannot get to the manifold inlet yet to check that. Curing the most obvious faults (temporarily at best) has caused the car to accelerate from stop a lot better, whilst cold. It still pauses when hot. I have found the solid pipe from the engine block to the turbo inlet side has broken, and want to replace that, but I don't see how this affects performance. Also, how do you replace it? Does the inlet manifold need to be removed?
I have seen comments about the wastegate sticking. Where is this (on the turbo, but where?) and how can I check it?
Other possible faults I have seen are the Bleed valve, possibly the thermostat, or possibly the MAF. Are there any other sensors that might cause this problem?
I accept that an ideal post will include the fault codes, but my local independent dealer has written himself off for a couple of weeks following an accident, and I NEED to use the car for work and ferrying my daughter to hospital. I have sent off for the parts to make a 'flash' reader as instructed else where on the forums, and would hope to have the appropriate codes within a couple of days. I need to try and solve as much as possible as soon as possible. Also, I am missing the performance!!
Can anyone help? Can I provide any more information at the moment?
And finally, can anyone recommend a good on line seller of all the elbow joints, tubes and pipes for the vacuum and intercooler system?
Sorry about the length of the post, but I ain't rich, so cannot really afford unneccessary garage work - besides. I love working on the car.

[bobcat]

wait for the codes, but i think maybe an air leak. hopefully the codes you pull will be along the lines of the maf sensor.

when i crawled home with my top hose blown of the car ran extremely rich and had to be given many revs to keep it going.

if your boost guage isnt goin over 2/3 max then i would rule out the wastegate.

the fact that you running rich (low mpg) shows (i think) that your getting the fuel.

In the mean time, check every air hose, the main ic\throttle ones and all the little ones. other things include a leaky intercooler. to test for this you could bypass it.

for all the elbows best to go to volvo or nordic as they arnt that expensive. for the vac hose (wastegate\bcs etc) just take of a bit and go to any hose shop and get some industrial rubber hose. i use some 20bar thick stuff that wont perish and i can get a jubilee clip around.
im sure others will chip in with more tips.

[zodski]

Thanks for the advice. Sorry about the delay in replying, but I've been trying to pull the codes from the OBDC using the LED and switch as described elsewhere on the forum - without any success. I get absolutely nothing. Any tips?

I've checked all the hoses, and replaced the elbow on the line from the turbo to the inlet manifold at the turbo end. This was severely bust. All other pipes and hoses are Ok, or appear so. I cannot reach the inlet manifold end of the above tube, but assume all is ok with it, as when I put my thumb over the turbo end, I can feel a steady vacuum with the engine running. The only other really bust pipe is the crankcase breather pipe from the oil trap to the turbo inlet. This has snapped in two places (that I can feel), and I am looking to get a replacement (Nordic don't appear to sell them - any idea where can I get replacements, as I am finding it hard to find a part number?). As an aside to my main problem, do I have to remove the inlet manifod to replace this pipe, and if so, is this the time to change the oil trap?

At the moment, the car starts on the second start attempt. It seems like I am priming the system first time round, and then doing a reset to start second time. The Lamda light is on all of the time. I can accelerate the engine to 3000+ rpm when cool, but the auto won't shift until I drop the revs back, and let the speed build up a bit. The turbo indicates about 2mm into the white when doing this, so I assume not enough torque is being developed to allow acceleration and gear change. When warm, or in hot weather, the car is susceptable to stalling if left to idle at traffic lights, and will definitely stall if queued in traffic for a long time. With nursing, it will easily reach 80mph, and runs beautifully at this speed. Trouble starts when it comes back to 30mph (starts to very slightly stutter) or is brought to a stop, when the engine drops to 300 - 500 rpm, and I have to pause on the accelerator to allow idle to recover before pulling away again. Fuel consumption is slowly creeping upwards (was 13 mpg, now 15.2 mpg 2 weeks later)

Has anyone any ideas about what is happening? I cannot, at the moment, afford to put the ol' girl in the garage, but still MUST use it to get to and from work. It is depressing me, because I know I am doing damage. Its like I'm slowly killing a much loved pet. I've got one more week to go before the school holidays, and then I'll be able to have a good go at the problem, but until / if I get a loan, the work will have to be my own. So any one - any clues or advice? Thanks in advance.

[Chris_Rogers]

Did you make the LED and switch correctly?

Did you have the ignition key at position II?

Does the led light when you press the button?

If not check the circuit you have made and for +12V at pin 16 of the socket. You should see about 10V at pin 3(0V when the switch is pressed) and 0V at pins 4&5.

Other queries:

The only source I know of for breather system parts is the Volvo dealer network. The parts are not that expensive. Plan to remove the inlet manifold and replace all the breather rubber parts and the oil trap.

Your poor running is, I'm sure, due to the air leaks you have.
It may pay to clean the throttle body, idle air valve and turbo control valve while you're at it.

[sholtby]

First priority is to be 100% certain all your hoses and vacume pipes are leak free.

Simon

[warthog]

Hi,

I concur with the general trend that you still have an airleak somewhere, although with the engine check light on, I wonder if the ECU isn't in 'get you home' mode as well due to another fault possibly caused by the excessively rich mixture in the past.

Regarding the small rubber elbows. I wouldn't bother buying new Volvo ones. Your local car accessory shop may have small bore silicone rubber hose. Use this to completely replace the original rubber pipes between the inlet manifold tree, turbo, inlet manifold and the various sensors. Not only will the pipe probably outlast the car but you'll eliminate any possible break in the hard plastic pipes where you can't see it. Unless you've replaced the rubber pipes from the turbo actuators to the sensor mounted on the airbox, you will almost certainly have an air leak there as these pipes perish with the heat and go porous.

[zodski]

Thanks for the help so far. I've been away a recently, and so work has fallen behind.

First - a bit of boneheadedness from me. All the pipes that I can reach have been replaced, with no discernable improvement. So I went back to trying to get the LED and push button to work. After many days of re-reading the instructions, and re-wiring and re-checking, I could still not get a flash code, and could only get a dimly lit LED.

Now the bonehead bit - I noticed that the courtesy lights were not illuminating (summer time - who sees them?) and realised that the fuse had blown. On this circuit is also the OBDC supply. Replaced the fuse, and voila, a set of flash codes! So a warning to other novices - check the electrics.

I mangaged to get the codes 1-2-1 and 2-3-1, which I understand are to do with the MAF sensor - ie its failed. Is this correct? Reading up on how the ECU uses this input to control the turbo as well as the gear changes on the auto would explain my problems, but am I jumping the gun?

Any help is obviously appreciated.

[bobcat]

yep as i said above i think it points to the maf.

1-2-1 is a missing or faulty maf signal.

try taking the connector of to the maf, giving it a clean inside with electrical cleaner and putting it back on. all repeat taking it off and putting it on to clean it further.

having a faulty maf is the same as having a major air leak, and you symtoms are the same as i had when i blew a hose.

for the maf check ebay and breakers for a cheap one to try or give one of the resident volvo tuners a call as im sure they carry mafs for test purposes.

[zodski]

Thanks for that.

I've got a new MAF installed, but still have mainly the main symptoms ie the turbo won't kick in. The engine will now rev to 5000rpm plus, but when I try to do this on the local dual carriageway, all that happens is that the engine revs, the gear stays in 2nd (or drops to 2nd), the turbo boost indicator shows about 2mm in the white (I take it this means slight positive pressure at the intake manifold), and the car starts to slow down from 50mph. If I drop the revs back to 3500, the gear goes up one, there's a slight kick, and the car starts a pedestrian acceleration. It'll get to 70+, but takes time, and if I let the revs go anywhere near 4000rpm, the engine pauses. Its almost as if the turbo is totally bypassed (the indicator hardly moves from the 2mm position).

The turbo spins, and I can here what I always think of as a jet engine type whine when the car is accelerated (I've always had this sound - its not loud, and I have to point it out to my wife so she can hear it) which I have always assumed is the turbo spinning. I've had the bonnet up, nudged the throttle to get some acceleration on the engine, and listened - and, apart from the slight knocks and rattles that I would expect from a 150,000mile engine, I hear nothing unusual, certainly no wooshing as if there is a leak. What would a leak sound like? Is it loud?

I've replaced all the hoses from the turbo inlet to all the sensors with new tubing. My only worry is that it isn't the same strong thick walled piping as the original, but a 3mm ish walled Neoprene piping, suitable for temperatures to 100C. Is the vacuum in the line when accelerating likely to collapse the pipe, and thus cause this loss of turbo? Should I go for a reinforced type of pipe?

Any other ideas?

Thanks for all your help. I am enjoying working on this problem, if not a little concerned about the state of the engine!

Have you checked the hoses under the throttle cover? Have you checked the hoses connected right after the MAF sensor at the top of the turbo inlet pipe?

Adam.