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1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 12:03
by PeteandNikki
I have an early 1.9Dg running what I’m guessing is the original engine (showing 50 thousand on the clock so probably 150 or could be 250!)

It was low on power and wouldn’t tick over well when I first had it, so I changed all the suspect service items first thing.( plugs, leads dist’ cap, rotor arm, air filter, coil) this didn’t help much other than the fact that I found that some previous owner had rammed a rag into the normal air intake side of the air filter so as soon as the engine was warm and the flap closed to the warmed air inlet then engine was trying to breath through the rag! Removing this a couple of years ago made a huge difference but I was always convinced something was still not good as I could never get tickover consistent. The next step was to replace the carb with a brosol item. Things got a bit better but I had no way of knowing if it was set-up correctly until recently when I purchased a gunson analyser and set up the CO2 levels and tickover speed accurately. Also fitted a new fuel pump and rod to eliminate that!

At this point everything seemed much better and last weekend we set off for a week touring Brittany. Driving was much smoother and tickover fine until about 500 miles later when, as soon as the choke came off then it wouldn’t tick over without constant tickling the throttle. Once on the road everything seemed fine when warmed up other than a bit underpowered and the exhaust note a bit ‘raspy’, tick over at Rd junctions was ok but if the engine was turned off and re-started for even a couple of seconds then it wouldn’t idle. Anyway, after an interesting and embarrassing time loading on to the ferry, either heel-and-toeing the throttle or constant re-starting in the queue, we made it home.

I’ve now rechecked everything I can and still the symptoms are the same. It will start ok and then you need constant throttle to keep it idling. Take it for a drive and carefully pull to a stand still and it’ll tickover. Stop the engine and re-start then it won’t. The timing is 5deg btdc at tickover and the CO2 about 1.85%. If you remove the vac advance and retard to the dizzy then the engine stops dead though.the exhaust note does seem a bit ‘poppy’ and the engine is not idling smoothly.

Sorry if all that seemed a bit lengthy but I thought the whole story may eliminate the need to ask some questions.

What do I try next?!!

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 13:20
by CovKid
Before you do anymore, do a compression check so you can at least eliminate that. Without good compression you don't get a good vacuum either and that impacts the idling.

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 14:04
by george2490
Sounds like an air leak to me.

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Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 15:04
by Cobra88
Agree on air leak
Check vacuum hoses are all still on

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 15:10
by PeteandNikki
Compression test done- 140 on 1,3&4 145 on 2.
I suspected air leak myself at the first but every looks sound.i see the WD40 test mentioned in another thread, not sure how that works? I assume that it’s sprayed around the suspect areas, but what is the indication of a leak?

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 15:47
by jrt
When the leak is found the engine will pick up and run smoother.
David.

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 16:05
by PeteandNikki
1/2 a small can of WD40 later and still no answer! Tried all the obvious points, carb to manifold, inlet manifold to head x2 all the vac pipes and junctions.

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 18:46
by 937carrera
A couple of suggestions if you are sure there isn't an air leak:

Bypass the idle stabilisation by connecting the plugs together, see if that makes a difference (probably won't)

Then check what the ignition timing is, vacuum hose connected, then vacuum hose disconnected.

It should be 5 degrees BTDC vac disconnected, you might need to move the idle screw a little to increase speed

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:29
by PeteandNikki
Ok so now I’m feeling really inadequate, I didn’t even know I had an idle stabilisation unit! Where do I find it and the plugs to bypass it?

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:32
by Cobra88
I havnt seen a stabilisation unit on my carbed 1.9 dg either
You sure your not talking anout inj model ?

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:38
by 937carrera
I think my DF/DG has an idle stabilisation unit, I know my CU has, perhaps it's me that's confused. Anyway if there's one it'll be the green box on the left hand side of the engine compartment, if there isn't, then one less thing that could be wrong,

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:46
by bigherb
937carrera wrote: perhaps it's me that's confused.
Yes you are.

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:48
by PeteandNikki
Just checked, there definitely isn’t one!

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:48
by Cobra88
Lol

Re: 1.9Dg was fine now very temperamental!

Posted: 03 Jun 2018, 19:52
by bigherb
PeteandNikki wrote: If you remove the vac advance and retard to the dizzy then the engine stops dead though.the exhaust note does seem a bit ‘poppy’ and the engine is not idling smoothly.

Sorry if all that seemed a bit lengthy but I thought the whole story may eliminate the need to ask some questions.

What do I try next?!!
What speed have you set the idle it should be 900 +or-50 RPM
When you disconnect the vac advance only, does the engine idle speed change?