Hi,

 

My OH's SDI has developed a problem and I could do wth a little help diagnosing the problem.

 

Symptoms...... down on power heavily. Will do 70mph flat out on an even road. Sounds very diesel chattery. From half throttle to full throttle seems to make very little difference to engine tone or performance. The engine chatters loudest after a period of coasting in gear or slowing down. When the throttle is then depressed it chatters very loudly for a second or two before easing off. It fires first touch of the key and idles perfectly albeit a smidgeon louder than it should and revs freely but again a litlte louder than it should.  No other knocks or rattles from the engine at all.

 

One thing I did notice last  night was the instantaneous fuel consumption readng seemed wrong flat out. Cruising along at 50mph it was showing 62 ish which is about right but floor it in top and keep it floored and it would read no lower than 46 even at 70mph with the throttle buried in the carpet. IIRC in such a situation it should be readig in the 20's?

 

Another point to note but dont think its related but will mention it anyway. Her car was just above the red and showing an estimated fuel range of 75 miles. I then put in 10 litres of SVO so it was running about two thirds SVO. Its run this many times with no issues over the past couple of years so shouldnt be a factor but worth mentioning just in case. It has since been run down to the red again and £35 of diesel added and no change.

 

It was dark last night when I drove it so cant coment on smoke but OH says she did look when driving and wasnt aware of any smoke but I'l check that and report on here when she is home from work this evening.

 

Will it cause any damage if I use the car like this for perhaps 500 miles until I can organise scans and repairs etc?

 

Just taken it out again and noticed the problem is slightly intermittent. Although chattery it just pulled quite strong and flat out the instantaneous MPG was showing 29.6 which looks about right. After a couple of miles I turned to head back. All was good at first then I noted the engine floored seemed to instantly lose some power and flat out the MPG was back to 46 again.

 

It appears not to smoke at all. I've had a look around the engine bay and all appears to be in order, no loose wires etc.

 

many thanks in advance.

In all honesty, I'd run it until empty and do a fill of v power diesel

or similar 'super grade' diesel. I think if you are running SVO with any regularity

I believe it's good practice to flush through with a tank full of the very good stuff

once or twice a year. Mostly for the detergent properties than the higher octane.

Hows your air filter? Has it been a while since changing that?

After doing the fuel and airfilter thing I'd be looking at the MAF next

if it was me.

Hi, thanks for the reply.

 

I run mine a lot on veg and do exactly as you say every 3rd tank or so as my car develops what sounds like a hydraulic cam follower tic (but surely cant be) runnig veg which gets awfully loud and horrid. A few hundred miles on v-power and it goes quiet again! Never managed to find out what it actually is. Currently it seems fairly happy running 25% veg with only a slight tic which isnt getting worse.

 

The OH though doesnt run veg very often and it hadnt had any in a while so doubt that is the cause but yes once the tank is empty it will be filled with derv.

 

Would the air filter go from running perfectly fine to so bad in just a few miles?

 

Where is he MAF sensor? Is it the one that pushes into the side of the airbox? How do I check it?

 I would first check the valve [cam belt] timing. Given that it starts and idles well it's probably ok, but I'd check it all the same. If the timing has slipped a tooth it'd be best to find out now rather than if it slips further and causes bent valves.

 

Secondly, and IMO a more likely cause of your car's symptoms, I would check for a collapsed/blocked catalytic converter/exhaust.

Thanks I did pop the cover off the top of the belt today and its still nice and tight so doubt its the belt. Also wouldnt explain why it changes and sometimes does have power would it? The fact it reports the instantaneous MPG at sustained full throttle so wrong is hinting to me at some kind of fueling issue. I was leaning towards the fuel pressure regulator valve but not tottally sure of the symptoms of that one.

Fuel filter? Running veg and diesel tends to deposit different erm... deposits! Try whacking a new filter in.

OH has gone to get a set of filters. Its overdue a service so best to eliminate the obvious. Will report back later. Oh I got her to give it a few healthy revs starting it from cold. Not a hint of smoke at all. Exhaust fumes were clean as whistle.

I had a problem with the wife's SDI running on major concentrations of sunflower oil. Had problems starting and wouldn't pull properly under 2500 rpm. Fortunately, the tank was almost empty, filled up with diesel, back to normal. Never used a concentration of more than 50% after that till I got rid to buy a Citigo S. My other SDI has never misbehaved on any concentration of sunflower oil and is still going at 150,000.  

Hi peter. Her car doesnt often run veg but has run over 80% with no issues at all. She had her car before me and it was driving hers (including on veg) tha made me get mine.

 

Changed the diesel and air filters tonight and no change at all. Looks like i'll have to take her car home with me to birmingham tomorrow (from hunstanton) and get some error codes out of it and work it from there.

 

I'm thinking fuel pressure control valve. Symptoms sound about right. Cant seem to find one online or a price.

I got it scanned locally tonight. Well 40 miles each way was better than 140 each way to go home. £20 later and we have an error code.

 

17656 - Start of Injection Timing Regulation       P1248 - 35-10 - Control Deviation - Intermittent

 

Gonna go and have a google now!

Quite a bit of talk about the vernier bolts slipping on the pump. I'll check this of course but last night just once in the journey after I  left tesco it had almost normal power for 400 yds or so then I felt it just vanish again. I doubt it wuold do this if the timing had physically slipped. I'm really leaning toward the valve now. Any other ideas or thoughts?
 

Popped  pizza in the oven tonight and while it was cooking just checked the vernier bolts. All seemed tight but undid them anyway as the vernier was up to the one end of the elongated holes and shoved it as far as it'd go to the other end and tightened the bolts up again......

 

.......OH now has her flying machine SDI back again with a nice quiet engine.

 

Job done. Well almost done. Will get some new bolts and replace them on my next visit just to be sure they dont slip again.

 

Cheers for being a sounding board fellahs