Having had the head off the Audi 80 TDI a few weeks ago, for a bit of DIY porting and top end rebuild, I finally got round to re-checking the injection pump timing in VAG COM last night, and it looks a bit retarded, although the engine wasn't getting warm enough due to the cold weather... I suspect that means it's even more retarded than VAG COM is telling me, as if anything I'd expect it to run more advance when cold (although maybe it's not that sophisticated). This ties in with what I suspected, because the car feels a little bit sluggish, and the fuel economy is a bit off from what it was, at around 42mpg (EDITED - re-did the sums and it was 41-42) , driving sensibly. I had a look at the manual (I've got a Haynes for an Audi 100/early A6 that covers the 1Z TDI) it says 'slacken the adjustment bolts and adjust the pump), without anything so helpful as a diagram or marked up picture of where the adjustment bolts are. I guess it's meant to be obvious then! I've had a look on the TDI Club forums, but can't find a guide for the 1Z. Some of the later models seem to have a vernier type pulley on the injection pump, but from memory of taking it off to do the head, there's just one bolt in the pulley on mine. Any top tips and pointers gratefully received, on 1. Where do I find these adjustment bolts 2. Which direction of adjustment to advance the timing? 3. Any other top tips?? BTW, if anyone local to me wants their pump timing checked, then drop me a PM and I can easily do it in VAG COM - takes 5 mins on a warm engine. Adjustment *may* take a little longer
Not a 1Z, but this is the guide I used to adjust my AHU, which does not have a vernier pulley. http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#k took me 3-4 attempts to hit the sweet spot Grant
The 3 mounting bolts on the pump, that fix it to the mounting backet. Turn anti - clockwise if its high mileage put a couple more degree's advance on it to compensate for a worn pump 1Z Engine in a T4 (Danster would like this pic) get it running on veggie oil
I want to get it running 100% on normal diesel before I move it to Bio, and I know a guy who used to make his own biodiesel, who reckons it'll clean all the gunk out of the fuel lines and block the filter with it, so I'm not really in a hurry at the minute, especially in winter... Does 158k count as high mileage on one of these? I was thinking the injector timing signal in VAG COM would have already compensated for any wear - isn't it the 'actual' injector opening time from the 3rd injector, or does the signal come from the pump itself? Thanks in advance for any further explanations!
Signal from 3rd injector the signal from the pump is the pump speed etc Bosch VE Pump Manual - http://gnarlodious.com/Vanagon/Bosch_Pump/Bosch_VE_Pumps.pdf
Thanks for the tips guys. Got the adjustment done today - adjusted it to the more advanced end of the 'in spec' range. It feels a lot stronger. Hopefully it'll be more economical too. Going on a long run tomorrow, so we'll see. I was wondering if the cold weather will be hurting economy as well. The car doesn't get near 'normal' temp, and the fuel pump timing was maybe compromised because I couldn't get the car warm enough. I'm not sure how the engine temp would affect the pump timing. It's also difficult to get an accurate reading because the car is hunting on idle, so I took the average of where the timing was jumping around.
If the engine isn't reaching normal temp you probably have a duff temp sensor or a duff thermostat. YOu can check the temp sensor by reading the measuring block for water temp when the car is cold and compare to the intake air temp.
I was thinking it was because of the weather but I guess that's worth a look too. Any idea which measuring block it is?
My 1z in my golf takes a fair while to warm up mike...have a play with the measuring blocks until you get the right temp readings Electronically delete the egr through adaptions, makes the car pull more cleanly off boost at light throttle angles and stops the inlet manifold clogging up....I haven't got the info to hand but will add it later if interested?
The EGR is physically blanked off. There's no direct electronic connection to it, so I'd think it's only vacuum controlled, unless it's via the solenoid that controls it via vacuum. If you have any more info on that, I'd be happy to read it.
My housemates a4 tdi get's to a stable 90c in this weather no problems. Does take about 5 minutes to get there when driven gently though. Even in -5c my ibiza used to hit 90c most of the time. Not entirely sure right now. But just go in and click up through the blocks and it's not too many clicks and you'll see it.
I had a look on the laptop tonight. On a 12 mile run home via A and B roads, the temp never got much over 50*C. I opened the bonnet and 'grabbed some hose'... top and bottom hoses both warm but not hot. Initial diagnosis is a faulty thermostat - stuck open. Can't be helping the fuel economy if the engine isn't getting up to proper operating temperature. I also noticed a couple of things looking at the measuring blocks. There are two of them which give engine RPM, and I'm getting a different reading on each. Any idea what the source of each signal is?? The engine doesn't have a crank sensor hole, so I guess it's driven by the fuel pump, or?? Also the injector idle quantity jumps around a lot - needs more investigation.
I'd go with the thermostat being stuck open too with that diagnosis. Your engine does have a crank sensor though I believe...... Are the both engine rpm readings different at idle too? I only ask as sometimes when logging multiple blocks vag-com can lag a bit so you see different values but in reality it is the same. I believe the only two ways the ecu can pick up engine speed are the crank sensor and the third injector pulse. I have never seen a difference in the two rpm values shown before though and am not quite sure where they both come from.
Oh hang on... I'm getting my engine codes mixed up... it's the 1Y that doesn't have a crank sensor, not the 1Z. I shall have another look. Sometimes the rpm readings are the same at idle, sometimes not. I've still got a rough idle, so I guess it could be the signal from one or other source dropping out. I'll disconnect the third injector and see if one of them disappears. I only got a chance to do the diagnostic bit at 11pm, so there wasn't much time (or light) to play around and try things.
Update: Changed the thermostat and the temp gauge now gets up to 90* on the run home. I had to turn the heater down for once Bit of a schoolboy error really - I should have spotted the dodgy stat a bit sooner. More interesting than that, the car drives a lot smoother now - the judder I've had on light throttle is a lot better, although not completely gone, and the car pulls a lot smoother at heavier throttle openings. So that would seem to explain why the fuel economy has been getting worse as the weather got colder, although with all the other fun and games with skipped cam belts and head rebuilds, there's been a lot else going on
Sorting the thermostat should help your economy to a reasonable extent. Although the odd different rpm figures might be worth a search on the tdiclub forums for a similar problem.
Yep - need to do a bit more diagnosis on that - starting by pulling the plug on the 3rd injector... haven't had a chance yet.
Did some more investigation on this.... pulling the plug on the 3rd injector makes no difference to the two idle speed readings. Also, now that the car is running at the correct temperature, the timing seems slightly less advanced than it was, although it's still on the advanced side of the middle mark, but within spec. I don't think the MPG on this tank is any better than the last one, based on having used about 40% of it.
