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RFlower · Posted: Wed Aug 26, 2009 11:00 am Post subject: Imola not running right!

Hi,
I finally got the Imola back together yesterday, with new lifters, 2 near-new camshafts and the injectors ultrasonically cleaned and tested.

It now starts reasonably quickly, idles smoothly at 800rpm once it reaches temperature, and the tappets are quiet, but it has no power over 2000 rpm, backfires through the intake if I press the accelerator more than very gently, and I have to change down on hills to maintain speed and stop it backfiring.

It feels as if the ignition timing is too far advanced and/or the acceleration mixture is too weak, or has an air leak on the inlet system. The lower manifold gaskets were replaced with a smear of non setting cement on both sides, so I'm pretty sure they are OK, and the injectors have new "O"-rings, which I greased lightly before fitting. I renewed the small hoses to the manifold from the fuel pressure regulator and the oil filler neck (this one was broken off at the manifold end) and inspected all the other hoses. I just rechecked them all again.

I sort of suspect the throttle position sensor, as this also provides a signal of opening rate, but as an engineer I try to look for the simple things first, as being the most likely, and will look for wires which could have broken when they were moved. A fault code reader would probably speed up that task.

I imagine the backfiring could have ruined the MAP sensor by now.

The injection system is Weber Marelli IAW.

The battery was disconnected the whole time I worked on the car. I simply unplugged the sensors and put the components on a table while I worked on the engine. None were removed except the air temperature sensor, which I unscrewed, looked at, and replaced, and the lambda probe, which I had to unscrew to work on the exhaust. I brushed the soot off the outside of this with a brass wire brush.

This morning I washed the car (you never know) and took it for another short run. It seemed to run better until it got to working temperature, but the lack of power and backfiring is still the same.

I have hunted the Web for information or a source for the appropriate fault code reader, but mostly found references to zp's site, so maybe he can help?

Any ideas anyone????

I have to go to Spain today, daren't take the Imola, the VW has a clicking cv joint which I have to look at, and the inside of the Sprint is still stripped out waiting for rustworm treatment, so we're going in the (1973) Ro80. With twin SU carbs and a relatively simple Mazda ignition system it's probably the most reliable car I have, certainly the fastest and most comfortable. Pity it only does 25 mpg, which is good for a Ro80, but still expensive these days.

Though I still wonder if the Imola saves enough petrol to justify the parts and time it uses up.

Dick
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

ZeNiTh-PbArM · Posted: Wed Aug 26, 2009 11:10 pm Post subject:

hi,

RFlower · Posted: Fri Aug 28, 2009 9:35 pm Post subject:

RFlower · Posted: Tue Sep 08, 2009 7:14 pm Post subject:

Hi,
I've done nothing at all to the engine, but it runs better every day. Now it has more power than it had before the work and only a very occasional backfire on the overrun going downhill.
It seems the ECU is "re-learning" after the battery was reconnected.
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

gloom · Alfa Arna Joined: 09 Sep 2009 Posts: 3 Location: Greece

Hi, most probably the EGR valve is either malfunctioning or not functioning at all.

According to manual the ECU(marreli) is not "re-learning" after the battery is reconnected but after 5 journeys that last more than 20 mins each and ,also, there is a stop interval of at least 2 minutes in between them!

RFlower · Posted: Wed Sep 09, 2009 1:38 pm Post subject:

Hi gloom,

As far as I can see there is no EGR valve on the Imola, unless it is really well hidden. I certainly didn't see one when the inlet manifold, exhaust system and heads were off.

Thinking back, I have probably just about made five journeys of more than 20 minutes each, the last one being yesterday. I remarked to my wife that it seemed even better.

Dick
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

gloom · Alfa Arna Joined: 09 Sep 2009 Posts: 3 Location: Greece

There is a hose from the manifold that leads directly to the EGR valve. The EGR is situated behind the front left wheel(it is hidden there, so the wheel has to be removed first, together with the cover). The EGR valve can't be reached otherwise.

RFlower · Posted: Wed Sep 09, 2009 4:22 pm Post subject:

Hi gloom,

EGR is Exhaust Gas Recirculating valve, which feeds some exhaust gas back to the intake manifold. Not fitted on my Alfas.

The items in the wheel arch are the vapour canister and its purge valve. The canister collects fuel vapours and the valve allows them to be fed into the engine as decided by the ECU. I don't know the short term for this - VCPV?

Maybe something amiss with translation...

I have already checked for air leaks on this pipe - removing it and blanking off the manifold connection makes no difference to the running.

I intend to remove the wheel and cover and visually check the canister when I have the time. My time and my work space is occupied with my VW having its front suspension and drive shafts rebuilt at the moment.

Dick
_________________
Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

gloom · Alfa Arna Joined: 09 Sep 2009 Posts: 3 Location: Greece

You're right, I have referred to the solenoid valve connected to the fuel vapor filter(canister).
The one end of oil vapor breather pipe is connected to the oil filler and then to the intake manifold. The other end of the pipe is where the plastic EGR valve is(it is located inside the corrugated sleeve).