1.5 diesel,revs then slow to/wont return to idle

[imported_brackie]

Go on... We'd love you to. The bottom bolt on the the injection pump is a bitch to get at. What's the trick?

[peter_j_g]

I'd like to hear how you do it with the engine running too! Mine would be a challenge exercise as it has airconditioning, so there are brackets for the compressor and the alternator covering the injector pump mounting bolts...

[gldgti]

i'm not sure about the air conditioning, since i've never had a good look at that setup - only once and briefly.

NOTE: OBVIOUSLY, I ACCEPT NO RESPONSIBILITY FOR ANY DAMAGES INCURRED SHOULD ANY OF THE FOLLOWING ADVICE BE FOLLOWED. IN READING THE FOLLOWING YOU ACCEPT YOUR OWN RESPONSIBILITY IN ANY MODIFICATIONS YOU MAKE TO YOUR VEHICLE OR OTHERWISE.

now that that is out of the way...

basically, you loosen all the pump bolts (dont forget the one at the back of the pump under the outlets). the bottom one is a big problem, yes, but can be accessed with some unorthodox methods. this involves buying a cheap 13mm spanner and putting two 45deg bends in it so that the open end ends up being at 90deg to the ring end, and each bend is approximately 15mm from the either end of the shaft of the spanner. this should allow you access to the lower bolt. remember you only need to loosen it to allow the pump to turn.

note: your new spanner can now be named "VW tool #XXXX-XXXXXXX" and placed on the shelf with all the others, like the tube for holding the pump srocket in place, the bar for holding the camshaft in place etc etc

mark the position of your pump before you move it, so you can go back to where you were before should anything not work properly.

with the engine warm and the cold start out, start the car, then loosen the top bolt so you can rotate the pump. take note of where the pump is, then rotate the pump in the ADVANCE direction (top towards camshaft cover) until you hear the idle revs begin to drop off. you will notice as you advance the pump, the dieselling noise will get louder. this is expected. NOTE: you are listening for a very small decrease in revs. at this point, note the position of the pump (getting somone else to mark this is handy). Now, retard the pump by between 0.5 and 1mm, and snug down the top pump bolt. take note of the new position of your pump.

listen carefully to the engine. ideally, it should be rattling away happily, and if you have advanced it from previous position, it will be louder. you may notice less smoke from the exhaust. take it for a drive and see if you have any more power etc. you are likely to notice the increase at all rpm's.

it may turn out that in this process, you retard the timing, if your timing is already well advanced. in this case if you experience an increase in power, then you have probably saved your engine a bit of stress and prolonged its life. hence, be mindful of advancing the timing too far. at the same time, my 1.5 has had its timing advanced significantly from previous setting for a year now, and is running better than ever.

note that if the engine revs begin to drop immediately as you turn the pump to advance it, then you are already advanced too far, and do not advance it any more.

you are aiming for a point 'just' retarded from where revs begin to drop off when the pump is advanced. note, the engine should rev most at this point, because everything is optimal. listen carfully to your engine during this process and you cant go wrong.

remember to tighten all the bolts back up, and please remember to do all adjustments with the cold start cable out.

if everyhitng goes well, you should experience and increase in mpg, power and better cold starting. I have successfully performed his operation on my own car, and so has my dad on his, and have even ported a similar method accross to my friends '91 diesel cressida import, all with great results.

good luck

aydan

[peter_j_g]

Thanks for the detailed description!

Have you checked what the setting you end up with is with a dial indicator? Is is more/less/same as the recommended lift of .88 to .92mm?

Regards, Peter

[imported_brackie]

Yeah, Aydan... Good description. A lot depends upon your "ear" but anybody who knows diesels should be able to do it. Is it possible for a pic of the spanner you made up and the angles you used? I reckon we should all have one of those! Also, we diesel owners should get together and buy a timing set that we can share as needed. What do you reckon, Dieselers?

Peter, I had a diesel with aircon back in WA and it was hard to get at anything on the front of the motor. Somebody had fitted a device that cut out the compressor when the car was under acceleration. I never got to have a good look at how it worked before the old girl died but it was excellent as the compressor only cut in when cruising or decelerating.

[peter_j_g]

Hi,

My aircon has the rotary type compressor, so there is very little drag when it is on, unlike a petrol golf I once had which slowed dramatically when the compressor cut in, then jumped forward when it cut out! (It had a piston type compressor)

I have throught about a cutout at full load, it would be easy to do with a switch on top of the injector pump, or even an automatic transmission kick down switch under the accellerator pedal.

However at the moment I have a slowly leaking seal on the compressor so it doesn't hold gas for long, and it's the old style gas which you can't get anymore.... so I need to convert it to R13A.

Cheers!

[gldgti]

unfortunately, i've never checked with a dial guage what setting i have ended up with, suffice to say becasue we dont own one... (tho i have access, never had one handy when i've had it all set up and ready...

as to a pic.... i'd love to ablige, but it'll be one of those get round to it thingies. might be a while... sorry

i might upload some more pics to my website now...

[hill billy]

while doing the head gasket I droped a bolt from the water transfer on the end of the head, just thought it had fallen into the grass and gavel below never to be seen again. How wrong was I, it had gone into the bell housing, making itself present, about a week later, by knocking a small hole in the gear box and liberating all the gear oil. Still managed to drive it home 35k's and then back into work 50k's to swap in the spare. All's well now.

Although I still have the slow return to idle issue

At start up it will intermitently blow puffs of white smoke and miss fires, I think it could be a leaky injector.

Steve

[Golf Loon]

Good Work driving 75kms with a hole in the gearbox. I love VW`s