Starting problems with diesel Octy 1

[andy-fisher]

Does anyone have any ideas why my 1.9 diesel octavia (1998) only likes to start easily if the climate and engine condition meet very stringent requirements? If it's too cold then it takes alot of cranking to get going. If the engine is fully warm then it requires even more cranking but if it's a slightly cool morning and the engine is cold it fires up straight away. I was wondering if it was an air mass meter problem or a coolant sensor problem. I recently had a new battery as it was on it's way out but this has made no difference to this particular problem.

[trundlenut]

Could be a number of things:

1. Timing - too retarded makes for problems when cold

2. 109 Relay, causes all sorts of odd problems

3. Coolant temp sensor - generally fast idle when warm

4. MAF - normally problems when running

5. EGR/Anti Shudder valve - causes hot start problems.

6. knackered glow plugs - causes cold start problems.

You could do with getting the car checked for error codes, where are you located?

[andy-fisher]

Im near Ipswich in Suffolk. Its had the 109 relay done and it's had a cam belt change during this endless problem but appart from that, I guess I should start working through the list. As an aside, does everybody have problems with the electric windows? I've replaced the mechanisms in every door once now and the drivers one twice. Is it a common fault? Other than that it's been a very good car. On a little trip to Great Yarmouth I averaged 71mpg according to the computer, a bit optimistic I feel but the fuel gauge hardly moved a millimeter.

[trundlenut]

have a look in the vag com / diagnostics forum and see if there is anyone near you with vagcom who could check the codes for you.

[andy-fisher]

Just a little update on my never ending saga. I have had a guy look at it and check it with VAG COM. I was a little suprised to find out that there were no fault codes found. The only thing it showed was that the fuel pump was a little retarded so he adjusted the timing of the pump and hey presto, it seems to tick over smoother and may be marginally easier to start but not the desired result. It has got him a little confused aswell I think. I can't grumble at the service provided though, 2 1/2 hours work and he refused to take any money. I guess there is method in his madness as I feel obliged to return to him when it's next due servicing. He did say (but pointed out he is clutching at straws now) that it could be the thermostat, not causing the problem but not helping it, as it takes an exceptionally long time to warm up.

[ExAudiSi]

If it takes a long time to warm up, the stat could be faulty, mine warms up very quickly for a diesel.

Incidentally, how did your man adjust the fuel pump timing?

Is is done mechanically or with Vagcom?

[trundlenut]

If it takes a long time to warm up, the stat could be faulty, mine warms up very quickly for a diesel.

Incidentally, how did your man adjust the fuel pump timing?

Is is done mechanically or with Vagcom?

It's done mechanically. You loosen off three bolts and then you can move the pulley on the injection pump to advance or retard the timing. The pulley has elongated holes to allow for adjustment. Bit of a pain to get at though as the pipe from the intercooler to the inlet manifold gets in the way.

You only need to get it approximately correct then the ECU can adjust it within certain limits. My was far too retarded for the ECU to get it anywhere near right.

[KenONeill]

Iffy hot starting is usually down to the engine temperature sensor.

Ref the warm up, how long is "exceptionally"? Mine takes 4 or 5 miles, or 10 minutes, whichever is longer.

[andy-fisher]

Sorry for the delayed response, busy working. My car takes about 20-25 min to reach operating temperature. By the time I get to work which is 10 miles, it's nearly warmed up. I've ordered a new thermostat anyway and will fit this weekend if it arrives in time. I have noticed that the cold starting is much better now the fuel pump timing has been adjused. As trundlenut pointed out, it is done mechanically. It wasn't out of limits according to the graph on the computer but it was only just in which may not have been helping the situation. It is more than likely a combination of things rather than a single fault causing this problem. I may not be able to resolve the staring issue soon as I have noticed a loud clunking noise when I open and close my window so maybe a third mechanism for that door is comming up soon. At least my car eventually starts but I can't have a window held up with wedges again. That will make it six new mechanisms for the car in total!! It is getting quite annoying. I will have the door appart at the weekend for a quick look. Maybe the coolant temp sensor next if its still the same (for the starting, not the window. Unless I use the old one to hold the window up). I will update on progress if any.

Edited 23 April, 2009 by andy-fisher

[KenONeill]

Yeah Andy, that looks very much like thermostat stuck open and/or engine temperature sensor.

[andy-fisher]

thermostat not here yet so unless it arrives in the morning it will be 2, or even 3 weeks before it gets fitted... Working quite a bit for the next few months. I shall find the time and see how it goes. I was considering doing the CCV mod this weekend if the thermostat does not arrive. I guess it won't hurt to do it.

[trundlenut]

thermostat not here yet so unless it arrives in the morning it will be 2, or even 3 weeks before it gets fitted... Working quite a bit for the next few months. I shall find the time and see how it goes. I was considering doing the CCV mod this weekend if the thermostat does not arrive. I guess it won't hurt to do it.

Before you do the CCV mod take off the hose from the intercooler where it goes into the EGR valve and have a look at the state of the EGR valve then you will definitely want to do the mod...

[andy-fisher]

Did not get around to either the thermostat or the CCV mod today. I did get the time to have a look at the CCV mod and took the pipe off from the breather to the intake and decided there was no need to go any further before deciding to do it. The ammount of gunk in just that pipe was amazing, although my car has done 137,500 miles of dumping oil vapour into the intake so I don't want to know what the rest of the system looks like. However, as it was a nice day it was a chance to mow the lawn and get the bouncy castle out for the kids. Bouncy castle now broken so will now be taking that back to the shop tomorrow. If only I had won the euro millions last night then I would just buy a new car and bouncy castle. At least going into town will give me the chance to buy some nice shiney bits to do the CCV mod. Going to try and make it look OE rather than a mod.

[andy-fisher]

Finally did the CCV elephant hose mod last night, 9,000 miles after I first thought of doing it. I think it was more coincidence than anything else but it started no problem at all this morning. I did a pikey version using my old washing machine waste pipe and a rubber foot off one of our many unused exercise machines, I don't think SWMBO will even notice I took it. It's just vented to atmos at the moment but I am looking into getting a catch can. Maybe another year before I get around to that.