Panda (Classic) Speed up problems

[Flooky750]

Hello all!
I have a Panda classic from 1988 with the engine 750L fire (engine code: 156.A4). I have problems with cold starting and accelerating. When I coldstart the engine it stops nearly in the same moment of the start. The engine starts for the 4th-5th try, but it stops immidietly when I try to accelerate. I can accelerate after a few minutes heating up, but it stops at a harder acceleration. Fuel slowly flows back to the fuel tank when the engine stopped. And having some problems with the "EcoBox" too (green EcoBox) :S Do anybody have pictures about vacuum pipe lines and electric lines and connections please? :S
Thank You for your help!

 

[AndyPanda4x4]

blu73 Dragon Man should be able to help with this

 

[Dragon Man]

hmm interesting.. sounds like you could have a bad vac advance.. or maybe the fuel pump is not pumping the fuel good enough.. or it could be a blocked accelerator jet in the carb. maybe both!

to check the vac advance, unplug the pipe on the disc shaped dome thing on the distributor.. then suck on the metal bit of pipe sticking out of it. if you get to a point where you cant suck any air out of it, it should be fine... but if you can just keep sucking air out of it, it has failed and needs replacing.

to check the fuel pump, pull off the pipe that leads to the carb and put it into a plastic see through bottle.. then crank the engine over (if it starts that ok.. it will cut out soon as the fuel runs out in the carb's float bowl). see if there is fuel filling the bottle up. if there is the pump should be OK. if not, replace the pump.

the blocked jet in the carb requires a bit of dismantling.. as you look down into the carbs opening, you will see a small bit sticking into it down one of the sides (not the brass pipe near the top).
look down the carb with a torch with the engine off and fuel in the carb bowl, turn the throttle quickly to open, you should see a small jet of fuel squirt down. if not, i guess the jet is blocked.

here is a video i did when working on Talons carb.. the jet was all the way blocked but managed to clean it and its been good ever since! i was even able to reuse the original gaskets.

 

[blu73]

yeah i would guess from description it could be vacuum advance - easy enough to test as described above and easy peasy to swap. Check the actual vacuum lines are not split or cracked at same time though

Other than that you just need to just go through stuff methodically and replace/repair/clean anything that needs it. I was convinced i had an ignition issue with mine and it basically has completely new everything on the ignition side and it turned out to be a weak fuel pump in end.

But basically start with the stuff thats free, like cleaning out the distributor cap and rotor arm, checking condition of leads and spark plugs. When happy thats all ok them move onto the slightly bigger stuff and/or stuff that actually costs money. I'm one of them people that tends to just start replacing things as most stuff is cheap for a panda but most things can be dismantled, cleaned and repaired - more Dragonman's approach to stuff - neither is right or wrong in my view though.

Fuel flowing back to tank is normal when its sat, but should only take a couple of cranks to fill the bowl again with a healthy fuel pump which my old pump could not do, i'd not suspect the fuel pump unless you have to crank it endlessly to get it to start when its been sat long enough for the bowl to empty out.

Not really sure what you mean by the green ecobox? all i can think of is the airbox is green on a 750 but that clearly has no wires

 

[Flooky750]

yeah i would guess from description it could be vacuum advance - easy enough to test as described above and easy peasy to swap. Check the actual vacuum lines are not split or cracked at same time though

Other than that you just need to just go through stuff methodically and replace/repair/clean anything that needs it. I was convinced i had an ignition issue with mine and it basically has completely new everything on the ignition side and it turned out to be a weak fuel pump in end.

But basically start with the stuff thats free, like cleaning out the distributor cap and rotor arm, checking condition of leads and spark plugs. When happy thats all ok them move onto the slightly bigger stuff and/or stuff that actually costs money. I'm one of them people that tends to just start replacing things as most stuff is cheap for a panda but most things can be dismantled, cleaned and repaired - more Dragonman's approach to stuff - neither is right or wrong in my view though.

Fuel flowing back to tank is normal when its sat, but should only take a couple of cranks to fill the bowl again with a healthy fuel pump which my old pump could not do, i'd not suspect the fuel pump unless you have to crank it endlessly to get it to start when its been sat long enough for the bowl to empty out.

Not really sure what you mean by the green ecobox? all i can think of is the airbox is green on a 750 but that clearly has no wires

Thank you for the answers Both of you! I replaced all the seals, all the mebrans and cleaned up all the carburator, but nothing I replaced the ignition cap, the ignition coils, the plugs, the rotor and the transformator too, but the problem is the same. My intake air temperature sensor needs to be changed, but can't find anywhere :S And I have some Vacuum connections and some electric connetction I don't know :S Could you please help with them? :S

 

[blu73]

Right I not seen that before.. my 750 doesn't have that green box or that sensor in the airbox. So not sure what that stuff is doing myself. Sure someone round here will know though, I'm only on my first panda, most my fiat's have been later cars until the panda.

 

[panda1408]

We never had the EcoBox in the UK as far as I know so I think most of us will be a little lost with that. If it's causing the problems and parts are not obtainable I would say to remove it completely if possible.

Block up any vacuum pipes left by it and disconnect any electrical connectors, then with any luck the carb will work as if the EcoBox has never been there.

 

[panda1408]

Looking at your photos, one of the unknown vacuum connections will be for the vacuum advance module on the distributor and another that links to the breather pipe on the air box.

 

[kolza]

ecobox is shown on right half of the drawing


Table below gives you all info of how individual functions and parts works


@Bartpanda will know how to bypass it.


http://www.superpanda.de/index.php?...nhalt.php?inhalt=posts&threadID=4427&id=78649
http://fiatpanda-klub.pl/forum/viewtopic.php?t=991


Make sure there is no vacuum hoses connected to the yellow one way valve.
If you don't have the one way valve that will probably the reason for your problems.
There is plenty one way valves/ check valves on ebay or any scrapyard with VW, Mercedes etc., don't have to look the same.
Make sure there is no vacuum leaks inside the ecobox.


I'm actually interested to know does it works at all. It suppose to reduce the fuel consumption on cold starts, cut fuel in while braking with engine etc.

 

[Bartpanda]

I can not help Iam afraid. Though I had ecobox with 1.0 engine I didn't make it work right and finally I had removed it{ ecobox carb and ecobox box } and replaced with 1.0 carb from the car without ecobox. Only removing the ecobox and pluggng all the vacuum lines is not going to cure the problem, the ecobox carb itself is designed/jeted as a part of the system, and without the rest of the ecobox the car will probably work reasonably only with hot engine{ mne did}. Cold will run rough{ to lean, not enough fuel through advance pump etc}.
MHO the only good thing about ecobox was the cut off fuel switch when decelerating, saved fuel like injected pandas, the rest of the ecobox was crappy crap crap.

 

[Dragon Man]

i was about to say.. it looks just like a system designed to cut the fuel off when the vacuum goes under a given negative pressure.

my guess is that your 750 has a CAT converter in the exhaust pipe?
this is a lot like the system that is on the Marbella's 903cc engine.. only not ECU controlled.

you have to be careful with the carb swap mod on a car with a cat converter as over ran fuel will poison the cat and cause emission problems in the future.

my guess as to what has happened with yours is the little "switch" that detects when you are coasting, has failed in some way. the only way i can see how it would work is some kind of switch that detects when the throttle is closed, then something to detect when the vacuum pulls a given amount.

without actually getting my hands on it, i cant really think of a way to fix it. other than just swap the carb over as said.. then worry about the emissions when the time comes.

you may also be able to wire it up to a manual switch you could.. say put on the gear stick.. when you coast you can just press the switch in, then that will cut fuel to the engine.

interesting system.. hmm