Alfa Pages

[BigAl]

Quick question
Will disconnecting the lambda sensor and telling the ecu that there is no lambda sensor, by removing the jumper and resetting the ecu, damage the cat?

I am trying to eliminate the lambda sensor as a possible fault.

Long explanation
Since getting the car running again, it is using twice as much fuel as it used to. The only difference from before are the following.
1. leaking manifold cat gasket
2. possible jammed open injector
3. running shell v-power
4. car first started with no 2 and 4 ht lead on incorrectly
5. using 20w 50 engine oil
6. possible faulty thermostat

1
The manifold/cat gasket nut and bolts are not the original ones and were as tight as I could get them but still leaked. I haven’t had a chance to fit new bolts yet, due to being busy and our lovely weather.

2
When refitting the injectors I had to remove and replace the injectors a few times, as I thought the metal u clip wasn’t holding the injectors in the correct position. I used white grease to aid in their re-seating and noticed that the top o-ring had a small chunk taken out of it but doesn’t leak. I looked for the missing piece and thought on the previous application it could have gone in the fuel rail, leading to a stuck open injector?

3
When the car was first used I used all my old fuel, as it had been sitting there for 7 months and started to use shell v-power. It maybe a coincidence that fuel consumption started to get worse.

4
I first started the car with no lambda probe connected and the pins not shorted to tell the ecu there was no cat and the cat not connected, so not to blow any crap into the cat. I incorrectly had ht leads 2 and 4 inverted, however on the very first attempt to start the car it ran ok for about 10 – 20 secs then died. After trying to restart the engine it backfired and I knew what I had done wrong and reverted the ht leads, made sure it ran, connected the cat, lambda probe and shorted out the pins to tell the ecu the cat and lambda probe is there. Should I have reset the ecu?

6
Still not had a chance to find out if the dashboard temp sensor is faulty or if it’s the thermostat. The dash temp sensor either shows no temp or gives a sporadic reading. Heater seems ok, but not as hot as it used to be. I did a test before cam belt gave up and I think it took 15 – 20 minutes from cold for the radiator fan to cut in on tick over.
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[lee16v]

Hi Al,
Not sure about how that will damage the cat by disconnecting the lambda but I can say that I changed my lambda sensor because I had crap fuel economy (the exhaust gases were smelling of unburnt fuel) and the difference was huge. I drove to Johnboys house in Margate which is a 275 mile journey and had a 40 mpg return which I thought was quite good seeing as the car was sitting at 4-4.5 rpm.

[Ben_nz]

40mpg at 4000rpm? Looks like fuel-injected 33s must be much better on the fuel. =|
These days I average around 26mpg from my 1.7QV, and I've never got 40mpg even on 100% open road runs (3300rpm?). I'd almost say it's not physically possible.

Can anyone tell me which uses less fuel in a carby 33:
a.) coasting down a hill with the car in gear and my foot off the throttle (I'm guessing fuel is still used for the important purpose of producing burbling and popping exhaust noises), or
b.) coasting down the same hill with my foot on the clutch or the car in neutral (fuel is still used because the engine is idling).

I know from a modern rental Corolla that under certain conditions, 'a' uses zero fuel while 'b' will always use some fuel.
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"Now, all that is left to do ... is wait that something else brokens, to fix up again!"

[lee16v]

Hi Ben,
Sounds unreal I know but I filled up before I left home And filled up again at Margate and it cost me £34 and it's roughly £5 a gallon here.

[BigAl]

There is nothing wrong with my fuel consumption, just my bad memory due to not driving my car for ages For some reason I had 70 miles for 5 litres from empty, instead of 25 - 30 My apologies
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[greencloverleaf pat]

fuel has gone up since a bit since last time your alfa was on the road
p.s i was working near cockshot hill in reigate last week and saw a silver 33 go by quite quick maybe you should not have such a heavy right foot al and then the fuel will last longer.

[Oggie]

ahh Pat, fuel is going out of fashion and Al was making up for lost time .
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PHAT 33

[BigAl]

it wasnt me i tell you, there must be someone else with a silver 33 in reigate
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[Oggie]

sleep driving al
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PHAT 33

[Admin]

Hi

Fueling will probably be out a bit which is likely to shorten the life of the cat.

The 1.3 carbed car would manage 39mpg sitting at about 90, but barely over 20 on short journies around town.

As to going down the hill, would think it would use slightly more in gear with the revs higher than with the clutch down at idle.

All the best

Keith
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[paulhide]

The original road tests of series 1 1.5s brought in touring mpg figures of 38.2 (autocar 11-6-83), 36.9 (The Motor 11-6-83) and of the 1.7 of 33.3 (The Motor 18-8-84) and 42! (What Car, Dec 1984)
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[Ben_nz]

A range of 33 to 42? That shows excellent consistency.
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"Now, all that is left to do ... is wait that something else brokens, to fix up again!"

[paulhide]

There is no doubt that there was a lot of varability from one engine to the next, but I would imagine carb tuning would make a large difference also.
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[BigAl]

I tried for a while with the ecu set to 97 ron and saying there is no cat when there was and disconnecting the lambda sensor.
Thinking about this, some cars with carbs have cats but no lambda sensors and cant auto adjust the mixture, this works fine all be it not very efficient, so should be ok ???
You can notice a big difference in low down torque and top end pulling. This might be just due to the timing being advanced, this is using shell V-power btw, better to do this with a higher octain rating fuel than just using normal 95, as it might pink.
I wish there was a way to tell the ecu that its running on 97 ron with a cat, for lambda correction and advance the timing, when not on full throttle!!! Wish we had knock sensors on our ecu and it would auto adjust the timing.
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203