1st start is hard some times

[Martin Cox]

Let's think a little about the figures you're getting from fcr and from itp-obd2.

Firstly they agree which suggests that both units are probably giving valid readings, or they're both wrong by the same amount which I would have thought would be less likely.

Secondly, let's take a look at the actual figures you're getting; 600 degrees and 650 degrees.

600 degrees is one and two thirds turns and this is a spectacular amount for the timing to be out.(it's the same as -120 degrees) You'd miss the compression stroke altogether and there's no way the engine would ever start, let alone run.

However, the engine is starting and pretty well too most of the time, so those figures cannot be right.

But suppose we move the decimal point two places to the left.

This would give 6 degrees and 6.5 degrees and these figures are entirely believable. A half degree difference between different days is also believable and probably not worth worrying about.

There are two ways of adjusting the pump timing. You can adjust the positions of the injection pump belt tensioner and idler and I believe this will allow a total adjustment range of about 6 degrees. This allows you to fine-tune the timing. if this isn't enough then it's a matter of slightly moving the camshaft pulley that drives the injector pump belt to bring it within range.

At 6 degrees out, the car will start and run although not as well as it should do. Mine did.

The problematic part is measuring the timing error and it sounds as though the equipment you have is doing the job. The actual adjustment is not that difficult.

Hope this is of some help

Martin

[PNuT]

Are these values being taken at idle or fast idle?

[Nullsleep]

Thank you, I had a feeling 600° and 650° was way out but I am only going by what these bits of software are telling me, 6° sounds more right to me. I will find out this weeknd when I pull it apart to see how far it is from the timing mark

[Nullsleep]

Originally Posted by PNuT

Are these values being taken at idle or fast idle?

This was at idle about 1100 rpm

[Martin Cox]

Before you go pulling it apart, the thing that causes most people problems with these engines is that there aren't any timing marks!

Well that's a bit of an overstatement but they aren't obvious. The two important ones are as follows.

A peg in the flywheel which lines up with a mark on the bellhousing when No 1 cylinder is at TDC. It's only visible from underneath the car when the rear undertray has been removed.

A slot in the end of the camshaft that's only visible when the pulley driving the injection pump has been removed. It should be horizontal, above the centre of the camshaft and parallel to the upper edge of the cylinder head when No 1 cylinder is at TDC. This is usually checked and set with the aid of a suitable metal plate and some feeler gauges if you don't have access to the official tool. When these conditions are met, the camshaft is correctly timed.

it is important to note that there are no markings on the camshaft pulleys since both pulleys can be fixed in any position relative to the camshaft. indeed this is necessary because of the way the cambelt is set up and tensioned.

There is a timing mark on the injection pump. it's not easily visible and is really only a guide to setting the timing from scratch: don't expect it to line up with anything meaningful when the timing is correct.

The absence of conventional timing marks is counter-intuitive but actually makes sense when you know how these engines are set up. I'm sure PnuT will explain it much better than I can.

Although somewhat long-winded, these videos ( https://www.youtube.com/watch?v=2AVg...RXN2NKcrgGharK ) give a good insight on how the timing is set up on the D5252t. I found them invaluable when repairing the aftermath of a cambelt failure.

One other thing is that these cars have a habit of growing on you. They are now getting quite rare and are beginning to be sought after. The Ph1 V70 is considered by many to be one of the best cars Volvo ever built. After 18 years of ownership I certainly have no intention of parting with mine.

Do let us know how you get on.

Martin

[Nullsleep]

So todays the day I got exploring. Well I found some kind sole has marked tdc on the pump with paint, so I barred the engine over to line them up, checked the marks on the pump and boom they line up, got under the engine and wow it lines up, easy.
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Well the tenchener looked a bit lose, not knowing when this belt was changed last I thought I could use it as a guide so I tightened up the lower pully a bit and nipped it up fired up the car and it started first time sounds a little quieter, so plugged in my obd and fired up 850-obd2(don't have fcr right now as that was a friends and he wanted it back) and I am still at 650°..... nothing has changed, uploaded a screenshot to show you what I see
Screenshot_20200823-133810_850 OBD-II_compress16.jpg

So no idea what's going on? What does the software use to sense the timing? Maybe that sensor is broken?

[Martin Cox]

Well, there's no mistaking that reading is there!

Your picture shows the flywheel in exactly the right place for No 1 piston at TDC. There's no camshaft position sensor on these engines.

I'm no expert on where the software gets its information on the timing but imagine it uses a crankshaft position sensor and a signal from the injector pump. One of the injectors, either no 3 or 4 (I can't remember which at the moment) has a needle lift sensor giving a signal when the injector opens. It's possible the software may compare these two signals and thus derive the actual timing. This is pure conjecture on my part though.

I'd agree that the fact you've made a slight change to the timing and this has had no effect on the software readout, does suggest an elecrical issue. It can do no harm to check the connections to the injector pump and the injector with the needle lift sensor.

Martin

[Nullsleep]

Injecter 4 does have a wire going to it while the others don't so will chase that back once I have finished soldering the abs module

[Nullsleep]

right abs all sorted and done, so followed the wire from injector 4 and its only a short run no breaks I can see of, might phone up some marine diesel places, there is loads around here so no idea if they will even look at my car, I have figured it might be worth spending on now.

Car: £0.00 yes free
Intercooler : £25 scrappys
Passanger drivesharft : £5 scrappys ( This was snapped when I got it)
Driver side cv joint : £10 but nut is rusted on
Abs : fixed for free
boot gas struts : unknown haven't looked yet
Cold start prob : ongoing

[Martin Cox]

As I'm sure you are well aware, the Volvo D5252T engine was sourced from Audi. Volvo made a few modifications to increase the power and reliability and to use it as a transverse engine.

Its closest relative is the Audi AEL which turned up in the Audi A6 and in some of its other guises in the VW transporter.

Hence it can be well worth searching some of the Audi and VW forums for relevant information. A diesel specialist who is familiar with VW / Audi version may well be able to help with the Volvo.

Despite the work you've had to put in the car, it does sound as though you have got yourself a bargain. I hope you get it sorted. Although perhaps the engine is a bit agricultural by modern standards, they are nice when right.

Martin