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Dr A. 33 1.5IE · Posted: Wed May 13, 2009 2:32 pm Post subject: Major problem

Dear all,

I am desperate and I need your help. My 33 had recently been through a service which included a second hand Lambda sensor and a new thermostat (and new Golden Lodge's).

A few days later the car when it was just getting up to temperature around 45-55 degrees centigrade, the car under acceleration was cutting a bit and pushing the throttle down seemed to be a temporary measure. On idle the car was running heavily with a repeated fluctuation in revs, but as soon as the car got up to 65 degrees centigrade (the cruising temp) everything worked in order.

A few days ago the car all of a sudden run with two cylinders but didn't die and I 've managed to drive it to mechanic's place.

Since then the throttle switch has been changed along with the sparks cables and the sparks control modules. Different ECU's have been tried but it did not make any difference. Although the car now runs with its all four cylinders the problem of cutting down now occurs whenever the car is stopped for 10mins or more at any running temp and it does not run properly. Today the problem got worse and the car in the afternoon refused to run properly and by pressing the throttle the car bogged down and exploding sounds (misfires) were heard from the exhaust.

Alfistas I really need your help as the car is undriveable.

Thanks in advance
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

lee16v · Posted: Wed May 13, 2009 3:05 pm Post subject:

Are you sure the second hand lambda was ok?

Other than that you could check the resistance values on the coolant temp sensor as this had a big effect on the running of my car before it was up to running temp. Another thing that could cause the lumpy running is the balance of the throttle bodies, check they are all opening at the same time. (I'm assuming the throttles are operated the same way as the 16v by a bar? It's a long time since I owned one!)

Dr A. 33 1.5IE · Posted: Wed May 13, 2009 3:09 pm Post subject:

How to disconnect the lamda sensor to check if it is at fault?
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

lee16v · Posted: Wed May 13, 2009 4:58 pm Post subject:

Try this site, might have some useful info.

http://www.lambdapower.co.uk/technotes/techindex.asp

ZeNiTh-PbArM · Posted: Wed May 13, 2009 7:52 pm Post subject:

Hi,

difficult to tell according to your symptoms did your mechanic remove the inlet manifold to replace the termostat? If yes new gaskets are almost mandatory otherwise an air leak is likely to arise. The different behavior you mentioned between hot and cold running might be due to the fact that the air leak changes with the dilatation of the gasket. Misfires and flashbacks are typically due to a weak mixture which might indicate an air leak at the intake side as well
also you might want to test another spark plug set as i've already seen defective brand new plugs (especially lodges) ; here Golden Lodges are no more available, i've been using Bosch WR78 as a replacement without problems for more than 140 000kms now.
regards,
zp

Dr A. 33 1.5IE · Posted: Fri May 22, 2009 5:40 pm Post subject:

Since the last time I 've written this post this is what has been done.

The car as I said it had a used lambda sensor installed that helped it pass the MOT with flying colors. Since then though the car behaved like a nightmare. One afternoon just outside a shop the car started and then all of a sudden run with what it sounded to be three cylinders. I managed to get to the garage to find out that i was running on two cylinders.

So far both ignition coils along with spar cables have been changed with used ones, a new Bosch lambda was installed and another throttle switch has been tried making no difference at all.

The major problem has been fixed but not the car on idle shakes a bit, pulling from stand still and acceleration with half the throttle at any gear has a few hick ups that disappear with full throttle and the exhaust sounds a bit heavier.

What I mean hick ups the car sounds as if it pulls and then cuts a bit and then pulls again and so on, but the car does not run smoothly as it used to run.

What can I do to make it run better...?

Chears everyone for your feedbacks
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

Dr A. 33 1.5IE · Posted: Tue Jun 23, 2009 10:45 pm Post subject:

Dear all,

Once again I need your help. A lot of stuff has been done over the last couple of weeks... I just found out that the used lambda sensor that my mechanic installed fried up the new cat I had installed about 6 months ago ... not an original of course.

A used cat replaced the other one and readings are just perfect. The problem still remains that the car does not pull nice and gradually and the idle is not 100% stable... it fluctuates a bit!

I have replaced the idle valve with a couple of newish ones, i have replaced almost brand new sparks with new ones, newer spark plug wiring, newer ignition coils, throttle switch, non-return fuel valves and pressure regulator, crank sensor, checked fuel pump that is ok, newer air temp sensor, checked the blue switch (water temp sensor)... and still the problem is there!

Please please please what else can i do?

Chears
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

Guest · Posted: Wed Jun 24, 2009 6:56 am Post subject:

Hi,
hiccups at part throttle and no problem at full throttle are most of the time due to a vacuum leak on the intake side.
regards,
zp

Dr A. 33 1.5IE · Posted: Wed Jun 24, 2009 11:13 am Post subject:

What should I check zp...

The black tubing from the air filter to the intake manifold and what else...?

Under inspection the black tubing appear ok with no cracks just a few superficial cracks where the rings turn towards the throttle body...

What's next to check?
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

33bits · Posted: Wed Jun 24, 2009 6:54 pm Post subject:

i've come accross these symptoms before, the green gasket beneath the inlet manifold would be my 1st suspect, followed by the vacuum system although you said all is fine there. It could be somethin as simple as a slightly blocked fuel filter, or maybe blocked fuel lines. Is the tank in good condition?
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Dr A. 33 1.5IE · Posted: Wed Jun 24, 2009 7:16 pm Post subject:

Alex hello and thanks for your answer,

My mechanic checked the compression of each cylinder and found everything normal (that is an indication that there is no leak from the intake manifold). Also after changing the fuel pressure regulator and the non-return valve he also checked fuel pressure and he claimed all to be normal.

I do not know what else to look for....

About the vacuum tubing how can I check if there is a leak other than a visible crack?

Cheers once again!!!
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

Guest · Posted: Wed Jun 24, 2009 7:19 pm Post subject:

Dr A. 33 1.5IE · Posted: Wed Jun 24, 2009 7:27 pm Post subject:

ZP thanks,

Question: which one is the brake amplifier tubing and the vacuum sensor???

All the rest I am sure are already checked and appear alright (the fuel vapour canister was removed under the front left wing apron and cleaned as well ), the idle tubing checked, intake tubing ok and vacuum tubing under the intake manifold also checked!!!

Thanks a lot...
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

Guest · Posted: Wed Jun 24, 2009 9:57 pm Post subject:

Hi,

vacuum line to brake booster on the driver side under the manifold.
vacuum line to sensor doesn't exist if your car has an AFM

but did you renew the manifold gaskets? one on each side, under the manifold. New ones must be installed whenever the manifold is removed
And i guess your manifold has been removed for thermostat replacement.

regards,
zp

Dr A. 33 1.5IE · Posted: Wed Jun 24, 2009 10:10 pm Post subject:

I will I promise...
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

frenchy · Alfa Arna Joined: 22 Jun 2009 Posts: 23

you can check for air leaks in a few ways. the easiest way is to rev the car up from idle by pulling the throttle cable by hand and use a plant mister (them plastic bottles with the trigger on them) and spray a fine mist of water near joints. try no to soak everything while doing this.. it doesnt work on a windy day if you outside.

the water mist will get sucked into any air leaks.
have you tested the afm for resistance?
and i'd recheck the landa sensor too.

you could also check the engine loom (the wires) from the various sensors back to the ecu. this takes a while but if you have a borken wire or some poor contacts, this test will show it up.
i'd do this after checking the other stuff first.

by the way, a compression test does not test leaks from the intake manifold.. it just checks the pistons, rigns, valves, head gasket and head. sounds like you had a good result here anyway.

good luck.
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Dr A. 33 1.5IE · Posted: Thu Jun 25, 2009 8:19 pm Post subject:

Thanks for your reply frency...

I just got the car back from the garage and still the problem remains... the car pulls with some hiccups and not nice and straight...

The idle stability improved a lot but the exhaust gases come out the rear silencer not in a continuous stream of air!

Listen to that though, removing the one of the two lambda sensor connectors and the car pulls in a better manner with no judder at all. I did not remove the preheating wire of the sensor but I will try it tomorow so as check if things improve a bit.

So as the lambda sensor is a brand new one by Bosch could it be the wiring of the main loom ?

What is the best way to check the wiring?

Thanks a lot for your ideas
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

paulhide · Posted: Fri Jun 26, 2009 8:52 am Post subject:

Big Al bought a new Bosch lambda probe and it was faulty!
ECU?
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bobbber · Posted: Fri Jun 26, 2009 9:33 am Post subject:

Yes, I NEVER trust new things. These are just two real-world examples that happened to me :

Car wouldn't start, my NEW relay was mis-manufactured at the factory.

Car overheats, probably my NEW thermostat isn't working correctly.

I have many other examples, but these others are to do with NEW/FAULTY computer and electrical components. Also, as Paul said at SPA, a lot of parts for the 33, while "NEW" (i.e. unused) have probably been hanging around for years on some shelf somewhere.

B
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frenchy · Alfa Arna Joined: 22 Jun 2009 Posts: 23

the best way to check the loom is to get a wire diagram of the ecu plug and stick a multimeter in the relevet pin(s).

e.g. if you have a plug with 2 pins at the sensor end, join those 2 pins with wire or paperclip etc.. then test for continuity at the ecu plug end. if you get a good result then both wires are ok.
if not then you need to test each wire on it's own. you may have to extend one of the probes from the 'meter to reach the plug end of the wire.
i have some long (4m) single wires with mini crocodile clips on the ends that i use.

sometimes i test the resistance of the wires too, as continuity doesnt allways mean a strong signal.

on the example above, the test shouldn't take you more than 20mins for both wires.

testing the (resistance of the) sensor at the same time is a good idea and doing a resistance and or continuity test on any earth points is also a wise move.
you'll need the tech info to know if the sensor's readings are within range.

good luck.
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Dr A. 33 1.5IE · Posted: Wed Jul 01, 2009 12:07 am Post subject:

Dear all,

Thanks very much for your suggestions and your help that is mostly appreciated...

I am still searching to find the faulty bit that does not allow the car to run properly...

The idle is not stable but better than before, the car shakes on idle because you can feel that it cuts and stutters and of course while in gear and below 4000 rpm in any gear (in a lesser extent in 5th) the car pulls unevenly with sudden bursts of power and sudden cuts of power!!!

As i have mentioned before almost every electronic component has been replaced from another donor Alfa that run properly with no success.

My question now has to do with timing... could the car run with slightly not correct timing or it wouldn't run at all?

Also could a faulty steering wheel hydraulic pump cause such a problem and if so how can I check it?

Please any suggestion is always welcome

Thanks very much
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

paulhide · Posted: Wed Jul 01, 2009 8:47 am Post subject:

Yes a faulty power steering pump could definitely strain the engine. I had this once when the system developed a leak and there was hardly any fluid. The pump became noisy and the car kept stalling until I sorted it out.
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BigAl · P4 Joined: 06 May 2003 Posts: 2990 Location: U.K Surrey

To test for this, just remove the belt for the PS Pump, be prepaired for a work out when test driving Smile

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Dr A. 33 1.5IE · Posted: Fri Jul 03, 2009 11:16 am Post subject:

Hi everyone,

The steering pump works fine but I am a bit worried about the fuel pump.

With car running, sticking my ear on the rear left wing of the car, closer to the rear bumper, I can hear the fuel pump working, but when there are some cuts in idle, the pump changes note, the pump's rotor increases its revs and I can hear sounds as if the pump cuts during operation or as if air bubbles are coming through it.

What you reckon about this new finding?

Thanks in advance
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

gritsop · Posted: Fri Jul 03, 2009 12:59 pm Post subject:

Hi,

Fuel delivery can be a clue about your engine stalling problems.

Have you ever had the fuel tank cleaned ? In case rust deposits accumulate on the bottom, then the pump would have a hard time sucking petrol from the tank. There is a small plastic bag on the end of the fuel sender unit which in case it breaks, then all deposits will end to the pump internals. I have seen such case in a Fiat Fiorino where the bag had many big openings and gradually all deposits ended inside the fuel pump. The car would stall, fire up with difficulty etc. We had the pump cleaned by putting it on 12V and a can of petrol so that it would self clean with petrol. The petrol turned from yellow to nearly black; bought a new plastic bag and the car now runs perfectly.

In case you decide to replace the fuel pump, then it is wise to see what is going on inside the tank. Should there be deposits or a failing plastic bag, the new pump will be ruined quite shortly.

Hope this helps.
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