Hmm.... Issues with DX engine

[haddock_n_chips]

Hi All,

Apologies in advance for the length of the post! But im banging my head a little here

Ok so the car is 1991 DX engine scala (Fuel injection)

The initial problem was camshaft oil seal

This went and it puked all the oil down the side of the block

Cue a house move and inevitable faffing around and this all went on the back burner, the car was tucked away until i had time to fix it

So finally got time to fix the bugger recently

Off came all the bits required to change cam shaft seal

As the cambelt was contaminated with oil this needed replacing too

Cue me remembering many moons ago when i had a new clutch the flywheel was replaced too as it was cracked... you'll see why this is a problem in a moment.

So got engine all lined up: (pics taken from google not my own)

Camshaft as follows: (also checked and valves in correct position as per Haynes)



Intermediate shaft Lined up OK with Crank pulley (put crank pulley back on temporarily) and also dizzy lined up OK with notch:



Flywheel.......

It should be like this:



However!!

My replacement flywheel does NOT have the TDC OR 6 Degrees marks!!

It has the two triangle lugs, which are for flywheel fitment(?)

But literally nothing else

So i went off where the TDC marker should be

I know someone is gunna say the marks are probably worn/rusty, but the flywheel is only about 5/6 years old and i looked and looked and looked and there are no bloody marks!

Car fired up, bit lumpy and timing seemed like it was out.....

Strange as everything should be back as it was.

Thought i must have got a tooth out on cambelt,

so off it all came again (even though all looked lined up OK)

All back together and car fired up, still seemed as if timing was out.

So re-timed to 6 degrees BTDC using timing gun (with Degrees setting)

Again not the easiest of jobs as prefer to time off Gearbox hole and no timing mark on bloody flywheel!

But got it running better

Quick spin and all seemed OK, drove OK, pulled OK Job done?!

Or not as the case may be!

Let the car warm up with a spirited drive and sat idling for over 40 mins so nice and warm (didnt overheat, sat nicely about half way on temp gauge)

I even got the gas analyser out and did the CO setting too! All set lovely and seemed like job done!

However!........

Come back to the car later/next morning so it was proper cold again and.......

coughing to start and backfiring slightly!

The car still started and idled but just touching the throttle it was coughing dropping all revs (nearly stalling) and backfiring.

Timing is still correct.....

So thought must now be fuelling issues?!

Once warm the car is fine will rev and doesn't seem bothered!

So popped out injector 1 - crap flow....
Injector 2 - Crap flow
Injector 3 - Nice clean cone flow (OK)
Injector 4 - crap flow

Previously i had a small issue of a stutter at low revs (800-2000rpm)

I put this down to

A. worn injectors and
B. Previous fuel neck rust issues

So popped the fuel filter off (stripping the thread in the process! DOH!) to check if the fuel was dirty/discoloured (as per when i had fuel neck rust issues)

But this was clean as a whistle, so fitted new fuel filter back on.

So swapped over the metering head and fuel lines for a known decent set

Injectors still getting crap flow as before and same symptoms when car is cold (backfiring, revvs drop to nearly stalling when throttle is touched)

So this is where i am at!

Should i look at 5th injector?

WUR? (how do you get the bloody thing off? its a squeeze down there and the banjo unions too close together to get socket or ring spanner on!)

Some new injectors are on the way anyway as 3 of them seem fubar

Anyone else any ideas?

Cambelt tooth out?

WUR Faulty/Blocked/Damaged

5th Injector faulty?

Ive got no equipment to test fuel pressure as this could also be a problem

Car has the Audi throttle body fitted (from 2.3 quattro) and previously ran fine right through the rev range using the 8v WUR

I do have a 16v WUR, but i believe this runs at different pressure to 8v? And struggling to get the blooming WUR off anyway!

Also just to throw a spanner in the works I'm due into hospital week on Thursday for an albeit minor operation, but will be out of action for a few weeks!

Can anyone help?! At least give me some ideas where to start?!

Aaaaagh!!

Cheers for reading this far

WiLL.....

[mark1gls]

If it's starting lumpy when cold try unplugging the blue electrical connector to the 5th injector and see if that helps? My car has leaking injectors and unplugging the 5th injector has helped as it was just adding more petrol in.

You may be right about no marks on the fly wheel as I'm rebuilding an DX engine at the moment and when I removed the gear box you can see there is no marks on the fly wheel.

In the picture the timing is all set and the marks should be around the top (may of moved a little when pulling box off)



Try advancing the timing on the dissy till it "pinks" under load then retard it a little so it stops "pinking", you will need to drive the car and keep stopping so find a quite road and a 13mm spanner for the dissy camp.
What type of fuel are you using, Super or normal unleaded?

[haddock_n_chips]

Hmm

Thanks for the reply Mark

The flywheel looks identical to the one i posted above but just without any timing marks on it!

Your one at least looks different!

I'll try without the 5th injector and see what happens

Dan (AKA Birdy) has suggested to look at the lift pump too, i have a spare one in the garage that i can swap out so i'll try that too

Fuel is standard 95 octane, car has done 150k, so last time i tuned it up i set it so it ran OK on the lower octane.

[fonzooorooo]

the 6 deg BTDC quoted in the book is assuming super unleaded, hence won't be ideal for regular fuel.

Can you TEST the fuel pressure?

what CO analyser are you using? My Gunson one used to read wildly different numbers each time I used it (and NEVER agreed with the one at the MOT station!)

[haddock_n_chips]

Im gunna get some fresh Super Unleaded in jerry cans and top up what is in the tank

Had a chat with our workshop and they think it could be fuelling issues, when opening the throttle you are allowing a large/larger amount of air in and if the fuel pressure or injectors not doing their job then engine is not getting enough fuel compared to air mix, so its coughing and farting away.

Once warm it can handle this problem easier, parts are warm and injectors probably opened up a little so the engine is just about managing to cope.

I did use my Gunson CO analyser, set it up as normal and set co using that. Its not as good as the one in our workshop but its all i have at home! :)

[haddock_n_chips]

Ive not got any fuel pressure testing equipment

[mark1gls]

The camshaft timing Mark is inline with the top of the head not the top of the rocker cover so check that mark.

[haddock_n_chips]

I'm sure I checked that. photos above are just stock pic's from google

[Chris M]

Not sure if anyone else has mentioned this but there should also be a TDC mark on the crank pulley that lines up with a little arrow on the plastic case behind it. If the pulley has been fitted for a few years you may need to clean it in order to see it. If aiming to set timing at around 6 degrees before TDC you can use this mark as a guide. On my DX the timing mark is set to about about a 1cm before TDC on the cover which is around 6 degrees. Hope that this helps.

[haddock_n_chips]

Hi Chris,

Thanks for the reply.

My engine doesnt have this part fitted.

A lot of the DX engines i've seen in the Roccos dont have it either

I know a lot of the Golfs had this, and it would be bloomin useful to have! But i've not got it

Injectors arrived today! so will pop them in tonight :)

[Tim_R]

Hi Will, I've got Kjet pressure test kit and can lend a hand if you need it, you aren't far away down the A14. It sounds more like an ignition timing thing to me though, especially if it's backfiring. I'd double check everything is still timed up where it should be and that the cambelt hasn't jumped a tooth.

[haddock_n_chips]

Tim you could well be my saviour!

Let me see how I get on with the new injectors and a tune up and I'll let you know

See this is why I'm more than happy to help support this club in my free time as there is always someone with an idea or offer to lend a hand!

[Tim_R]

No worries, let me know.

[haddock_n_chips]

So... Tim when are you free?!

Still struggling briefly when cold. As soon as i touch the throttle it either dies or nearly dies. 30secs later it's fine?!

Once warm timing seems OK and not pinking

[Tim_R]

Wednesday onward at the moment fella, away in Yorkshire until Tuesday evening.