745TD more trouble..

[740-estate-nut]

hi there... I am at my wits end... If I had hair to pull, I'd be bald...
right.. here's the deal..
(1) The car is REALLY sluggish.... won't rev over 3000rpm and feels like I'm bearly toutching the accelerator... (In saying that, I did replace the fuel filter, now it revs freely and cleanly).. KEEP READING...
(2) The car takes an age to start... Cold or hot... if it's cold, I leave the glowplugs to their jobs, then wait for the wee clunk from the fuel tank, then try to start the car.. now usually it just turns over once then she's alive, but now, it's "wugga wugga wugga wugga" for about 20 or thirty seconds, and as it's firing up, it seems to fire up each cylinder individually.. Am I making any sense?? Like 1, then 1,2.. then 1,2,3 etc.......
(3) I was on the motorway, and I disengaged overdrive and planted the right foot to pass a truck... flew like sh** off a shovel... but when I took my foot of the pedal to cam the speed down, it kept accelerating.. I turned the key off, to try to kill the engine, but it kept going, and at full speed... I had to hit the brakes and handbrake together to stop the car and engine...

THERES MORE...

I got home and I sweared a bit out loud... and had a cup of tea and a smoke.. once that was done, I decided to go out and start up the car... it eventually started... Idle ok, just below 1000rpm... gave it a rev, turbo spun up then calmed down... ok... turned the key to turn the engine off, and it didn't turn off... tried to floor the accelerator, to try to flood it.. but it didn't.. it didn't rev higher, or stall.. so I had to put it in fourth, brake on and release the clutch...

Now, I hope you enjoyed my little story on my stupid f****** piece of sh** of a tank, but can anyone help?? Is it an easy fix, or an I looking at a fortune to fix it...

All help aprecieated..(I think that's how ya spell it, but you know what I mean)

Simon

[Ben O Brien]

Hi,

I would put money on you having a knackered diesel pump, are these mechanical injection or fly by wire?? I assume mechanical, it sounds like a problem with its accelerator linkage,

another thing is how is the oil level?? If diesels are overfilled with oil they will keep revving until it either burns the excess oil, runs out of diesel or blows up as they are a purely compression engine so when you turn off the key it doesnt matter it will still go,

Try both of these suggestions and come back, i hope for your wallet's sake its option two!!

Ben

[Peter Milnes]

Simon, sounds like you have a small wiring problem. The fuel solenoid is mounted at the front of the pump and has one wire going to it's spade terminal, earthing through the pump body. Two ways to stop the engine - pull the wire off the solenoid and if your car has automatic gearbox there is a lever on the side of the pump which will also stop the engine. Do you have a handbook for your car? That will have the information and a picture of the lever. Haynes does not cover the diesel versions and Chilton has the diesel information in the earlier manual (number 72300).

Check that the 12Volts dissappears from the solenoid terminal when you turn the ignition "off" with engine running. I would also guess that there is something wrong with the accelerator cable and/or the quadrant. Possibly the kick-down cable may be binding in it's outer casing stopping the throttle from returning to zero. I assume that your car only has the turbo without an intercooler. If it has EGR fitted it would be better to remove all traces of the EGR equipment (I can let you know how to go about it). This means that the inlet and exhaust manifolds need removing, the inlet in particular as with EGR it gets very sooted up. My old 760 GLE Turbodiesel was like this. My 945 has had the EGR removed and also runs on 100% Biodiesel (recycled chip oil).

All the best and keep me in touch with your progress, Peter.

[740-estate-nut]

hi guys,
here's my findings so far...
I have totally bypassed the fuel filter, just to try to eliminate things.. so the pipe from the fuel tank is going directly into the fuel pump...
That didn't work... same problem... but c'mere, there's more..
i got the car started with the aid of a tow.. because I ran the battery flat trying to get her started.. Once she fired up, I thought things were ok, I was letting her idle while i took the towrope from my mates car and my own, sounded ok.. but as soon as I put my foot down to accelerate away, nothing.. I mean, she was still idling, but my foot was planted... then it started to drop cylinders.. 6, then down to four, then three, but then it reved up nice and freely...
Anyways, I let her tick over outside the house, to charge the battery.. grand... but I came out a few times, and it sounded like it was losing cylinders again... so I got in, and reved it up.. held it at around 3,000rpm... Couldn't keep it at exactly 3,000. it kept fading down, then picking up again, but only about 100rpm in the difference either way.. once I let go of the throttle, the revs dropped to idle, about 650rpm... then it started to lose cylinders again.. but the wierd thing is, when it was running on less than 6 cylinders and trying to die out, there was smoke coming from the exhaust... I mean, it was like I lit a small bonfire under the car.... but once I kept my foot down to clear it out, it got a bit smokier, but then it was nice and smooth, the way I am used to..

Oh, Peter, I checked the wire on the fuel pump.. I had her running, then pulled the wire from the top of the pump, she died instantly.. I am thinking it may be an intermitently bad relay, perhaps?? But where is the relay for the fuel pump?? Is there one, or is it purely mechanical??

so, any ideas?

[740-estate-nut]

more news...
If I keep the turbo spinning, from 2250rpm and up, it'll rev freely like a jet engine.. really sweet... but if I let the revs drop below 2000rpm, the revs will drop to between 500 and 600 rpm, and no matter how much flooring of the accelerator I do, it won't catch.. I just have to let it sort itself out, then the revs will rise again to about 750rpm, then I can floor it, but it takes about 4 or so seconds before the revs will rise up to 2000rpm, then it'll fly sweet again...

i hope someone can help me.. Do I need a new fuel pump, or injectors or what...

[Inverted]

Hi Simon,

I just re-read your post. As Peter mentioned, the first thing to check would be the fuel solenoid on the injector pump. ( I used to work at a volvo parts dept, and we sold quite a few.) Another thing to check is the glow plug relay, which can sometimes fail, though not as often. It certainly sounds more like an electrical problem, as it seems to be intermittent from your symptoms/description.

Does the problem go away when the engine is at normal operating temp? Or is it just random?

Let us know how you get on,
Regards,
Chas

[740-estate-nut]

hi de ho peeps...
Well, I found my problem... It's technical, so follow carefully...

On the turbo, where the air comes in from the filter, theres a pipe.. The EGR pipe... Now, there's copious amounts of oil all around this small port... This, I am guessing is a no no, because if oil gets in the airway, it'll burn it in the cylinders.. BTW, the air intake manifold was gunged up too...

So, does anyone out there in the heavy fuel brigade... (Diesels) know of a way to disable/remove the EGR??

Many thanks for all your help...
Thanks
Simon

If you are getting excessive oil in the intake, that would be from the crancase breather tube, from excess blowby. That combined with the runaway condition and the hard starting makes me think it's time to run a compression test on the thing ( that having to start on a chain is a dead giveaway )
With worn rings , blowby increaes, takes more oil with it right back into the intake.
you can rig an oil trap in the breather line to catch the excess oil to keep from crashing, but it won't help the hard starting.

---------Robert

[ivor940]

Hi Simon. As the 6 cyl Volvo diesel is based on the 1.6 VW 4 cyl diesel, check on the VW Golf Diesel websites. In the 1980s, there were cases of Golf 1.6 diesels accelerating without driver input. A guy in work had this happen and it was a fight between the brakes and the engine before he stopped the car ( without hitting anything). I think there was a mod to prevent engine oil getting into the cylinders or inlet manifold. Unfortunately I have no further info on this.

ivor940

Originally Posted by ivor940

Hi Simon. As the 6 cyl Volvo diesel is based on the 1.6 VW 4 cyl diesel, check on the VW Golf Diesel websites. In the 1980s, there were cases of Golf 1.6 diesels accelerating without driver input. A guy in work had this happen and it was a fight between the brakes and the engine before he stopped the car ( without hitting anything). I think there was a mod to prevent engine oil getting into the cylinders or inlet manifold. Unfortunately I have no further info on this.

ivor940

I believe you are talking about one of these : http://www.greaseworks.org/index.php...view&ItemID=10

I don't know how much good one would do as the d24t already has an internal baffel and the rudimentry oil trap attached to the valve cover as opposed to the straight tube on the d24. And the bolt spacing is likely diferent as well.

On one that was really belching oil from blowby, I grabbed an oil trap off an Isuzu NPR delivery truck and modified it to fit with an oil return tapped into the dipstick tube. It worked rather well.
Or you could fit one of these things http://www.maesco.com/products/racor...ccv_intro.html
but they are pretty expensive and the money would be better spent on new rings.

----------Robert