Mk3 Astra 1.7td gm engine problems

[nobbysnova]

Hi guys been having some problems with my bros mk3 1.7td gm engine. All has been fine until he went to start it yday morning and it will idle and not rev and blue smokes when it doesnt rev but stops smoking when it revs, i have messed with the vacuum pipes and it has revved cleanly and drove fine x2 but then when he stops and leave it for an hour os so it wont rev again i have checked -


1. Turbo is fine no play in shafts and if you grab the boost pipe you can feel the pressure.
2. Im unsure what the round thing is on the top of the inlet see pic

as that seems to be where the vacuum starts? if we take the boost hose off the inlet its the same as when its on so clearley its not seeing any boost? we took the pipe off last night and blew and sucked it and it revved fine and he went out in it now hes done the same this morning and it wont rev? Howver he has lately ran it on abit of veg oil, is it possibly fuel filter blocked? anyone came across this before??



this is the vacuum thing



any help appreciated!!

[paul.spencer]

Hi there,

Same engine as mine. That round thing is the EGR valve. The vacuum line goes to it from the vacuum pump on the right side of the engine. Some people just plug the vacuum line so the EGR is disabled.

If you remove the EGR valve you will see how cruddy it is is and how oily/cruddy the inside of the intake manifold is as well. One day you may want to remove the intake manifold and clean it out, but on the GM engine you have to remove the trurbo in order to remove the intake manifold.

I ran mine on biodiesel for the last couple of years no problem but have heard of issues with veg oil. Whatever - probably a good time to install a new fuel filter. When you do just fill the new filter with diesel to make starting easier (and make sure you reinstall those copper washers correctly, one each side of the banjo bolts).

Cheers, Paul

[nobbysnova]

hi mate thanks for the reply i have just changed the filter today to no success someone mentioned that the diagpram inside the egr could be at fault?

[paul.spencer]

Remove the EGR valve and clean it well with carb cleaner. Some people say after carb cleaner you can even soak it in petrol for a time and get more crud out. Dry it completely and test for action by applying a vacuum to it. Its probably OK just crudded up with oily sooty crap. If it does appear to be faulty you could just reintall it, stick a plug into the vacuum line, connect it up and it is disabled. They run fine that way - probably better in fact. It normally just allows some exhaust gases back through the intake when up to temp.

I think there must be other problems. It was good to replace the fuel filter anyway as that is a common source of running problems. If you have ruled out fual filter and EGR valve I would consider the injectors. You can get probably get them properly cleaned and serviced, spray pattern checked by a diesel mechanic with a proper spray booth for around 25-35 quid per injector. Well worth doing on an older diesel.

[paddy>gsi/turbo]

its the bio diesel your injectors are clogged up. pauls right fuel filter need to change every few months on bio diesel

dont think your egr is at fault

pour some injector cleaner in to diesel filter. norm works as goes straight to injectors knocks the **** out off them

[romy_chennai]

i have the same engine in my opela astra 1998 model..... but its giving very poor mileage... eventhough the engine start up and everything is normal but its not giving good mileage....

[paul.spencer]

i have the same engine in my opela astra 1998 model..... but its giving very poor mileage... eventhough the engine start up and everything is normal but its not giving good mileage....

Hi romy,

You could have started your own thread, but doesn't matter I saw your post.

Anyway, have you taken care of all the usual maintenance items? Definitely worth doing all the basics first - new air filter, new fuel filter, change oil and oil filter, clean out your EGR valve (and consider just plugging it off).

I mentioned the air filter as max air flow is important. Having said that though, it reminds me that your intake manifold is likely fouled up with sooty crap which restricts flow. You can see it in there if you remove the EGR for cleaning. One day you could consider removing the intake manifold for thorough cleanig. Its a little more work to get it off because you have to remove the turbo first.

Lots of people recommend injector cleaner products (like poured directly into new fule filter when changing it) but frankly I would consider having the injectors properly serviced by a diesel specialist with all the buits and pieces (new nozzles, shims or whatever) and a proper spray booth to check spray pattern.

I know you say it starts up well but i was just thinking that "Start of fuel feed adjustment" which must be done on the injector pump after cambelt fitting greatly effects start-up but maybe also fuel efficiency.

I suddenly had to do the cambelt job myself (no choice) and the timing is slightly out. Its OK but it has effected fuel efficiency and I hope to reset timing again in the near future. Just trying to make room and set aside the time for it.

So if its getting close to time for the camblet belt, consider having that done, maybe that will make a difference. And if you do get the cambelt job done (including tensioner and roller), make sure to get them to replace the water pump at the same time - its not much more work at the time.

Cheers, paul

[romy_chennai]

thank u for ur valuable advice paul.. ill try that and let u know... already cleaned the egr valve... have to reset the cambelt timing.....

[romy_chennai]

hello paul.. pls tell me how to do fuel feed adjustment in the injector pump... .any adjustment screw there in the injector pump?

[paul.spencer]

Hi again,

I just sent you an email so if you reply to that I will have your email address and can send you a file describing how to do the start of fuel feed adjustment.

Its not an adjustment screw - for this you need to undo the center bolt between the 4 injector pipes on the pump head. Then a dial gauge adapter it attached with a metal rod that goes down into the pump. A dial gauge is used to accurately measure the pump position at TDC.

You can buy a kit with adapter and dial gauge but it can be a bit expensive. Here's a pic of my home-made adapter made using a green plastic garden hose connector, a few bits of brass from old kerosene lamps, plunger rod from a spare bit of stainless steel, and a dial gauge I bought of the internet



Adjustment is made by loosening the injector pump pulley and carefully rotating (eg. lightly tapping the wrench) then tightening the 3bolts:



Cheers, Paul