MKII polo running nightmare

kieran · Post by **kieran** » Wed Jun 01, 2005 9:48 am

Hey guys im new to the forum and ive been reading lots about the nightmares associated with cold running and pierburg carbs but still cant seem to get mine sorted.

Basically the car starts fine but suffers from massive power loss in the first few minutes of driving, even worse in the damp and particularily bad when pulling away from junctions. I can now succesfully play with the accelerator and clutch so it doesnt stall but it just crawls away. Its giving me premature heart problems

I recently took the car to my trusted mechanic who has replaced the carb with a nearly new unit and the gasket aswell. this cured similar problems i had in all weathers but the cold start problem remains

leads, plugs, cap and rotor recently replaced.

Ive also read the hall sensor goes in the distributor

Could this be carb icing, (I live in the north east of blighty but there is no motorway cut out)
choke problems or something completely different.
Ive searched the forum and found a similar problem and no real solution so sorry for bringing this up as it seems a well trodden subject

cheers for any help

Kieran

mk2keel · Post by **mk2keel** » Wed Jun 01, 2005 11:04 am

Hi and welcome.

Carb icing normally occurs after travelling for prolonged periods o high throttle.
Do you have a heat duct that leads from the exhaust manifold to the airbox or carb intake?

kieran · Post by **kieran** » Wed Jun 01, 2005 11:14 am

I do have a pretty new heat duct that goes from the exhaust manifold into the air cleaner unit

Although the HT leads are less than a year old. I noticed that i got an electrical shock from one of them the other day. It was raining though.

The car starts first time though and runs well for the first few mins. Only then does the power loss occur

GroovyCarrot · Post by **GroovyCarrot** » Wed Jun 01, 2005 12:20 pm

If you're getting shocks from your HT leads and they're that new, I'd imagine they were pretty cheap ones to start with. Take a look under the bonnet in the dark and you'll probably see little blue sparks arcing out of some of the leads into the cylinder head. Not good for power, I've got the same thing, electric shocks and sparks, I'm going to get a set of proper VAG leads when I can afford to, should solve that particular problem.

Next thing is to check that the vacuum operated warm air flap is working properly. Where the hot air duct connects to the air box there is a flap which opens when the engine is cold to allow warm air in, and closes again when it warms up. If the flap isn't opening then this will give you some grief in terms of carb icing on cold days. Just check that it's in the right position when you first start the car from cold and that it stays there until the engine is reasonably warm.

When your mechanic fitted a new carb, did he also set the choke, idle mixture and fast idle up? And are all the jets the right size? I used to get a lot of hesitancy pulling away from junctions when by carb was running too rich, it would just flood the engine when I tried to pull away, particularly when the engine was cold, on choke and running a bit lumpy anyway.

Last thing to check I guess is the coil, as you've replaced all of the other ignition components already. Check it with a multimeter, the correct resistances are in the haynes manual somewhere.

kieran · Post by **kieran** » Wed Jun 01, 2005 2:25 pm

Maybe its me just being an idiot.

But ive read that you have to put the accelerator to the floor before starting the engine to set the choke.is this correct. Does this have to be done with the power on (ignition turned).

If this is the case would be cheap and embarassing solution

GroovyCarrot · Post by **GroovyCarrot** » Wed Jun 01, 2005 3:59 pm

Yeah, to start a car with an automatic choke you press the throttle to the floor once and then release, then start the car normally. This simply releases the fast idle lever and allows it to sit on a higher part of the fast idle cam so the engine runs quicker when you first start it. However, once you've got it started and you pull away, the choke will set itself with the normal motion of the throttle anyway so it would only really affect the initial starting.
You don't need the ignition on for this bit, it's a mechanical process rather than anything electrical.

mk2keel · Post by **mk2keel** » Wed Jun 01, 2005 6:31 pm

hmmm, i have never done that foot to the floor thing and she has always started first time

kieran · Post by **kieran** » Wed Jun 01, 2005 8:01 pm

spoke to my mechanic you dont have to put the accelerator down. The bimettalic strip should heat up as the engine does and open the flap. With the old VWs campers/ beetles ect you have to put the pedal down

Anyway things are getting worse. Power loss all over the place now.

Seems everytime i get something done its fine for a few days then back to square one. Maybe condensation is getting in somewhere as it definatly got worse with the rain we have been having.

Best send it back to the mechanic

GroovyCarrot · Post by **GroovyCarrot** » Thu Jun 02, 2005 12:05 am

The bimetallic strip will open the choke without having to twitch the throttle, but flooring the throttle before you start it is to close the choke in the first place. There may be a system in place to get it closed as you turn the engine over, I don't know.. I still found that my old pierburg started much better from cold after a bit of throttle.

Tahrey1043 · Post by **Tahrey1043** » Thu Jun 02, 2005 2:57 am

cant believe im saying this to another person

Scrape together thirty quid and get the leads changed. You shouldn't be getting shocks off them. That's the whole point of that triple thick insulation.... well.... on decent cables it's triple thick anyway. If you've got those Halfords HotWires or some other crap it's pretty thin and can be easily told from a quality item.

Hie thee to your local GSF, or their website (delivery charges aren't back breaking). Beru OEM things. Sorted.

Or halfords thick black jobbies, ten quid less, but be warned you may have to do some trial and error to find a part code that gives you the right combination of leads to actually fit (and it probably wont be "polo 1981-1990") - and though they'll do the business straight away, they might not last a full year.

After that, if its still playing up, and you're sure your dizzy / cap / rotor / coil are all ok..... stuff a pair of thick bed socks in the cold intake and see what it's like. Manually changes the cold feed / hot feed balance (cold still gets thru, but less). Then if STILL no joy, disconnect the hot feed. Perhaps it's getting too hot after a few minutes, something wierd like that.

mk2keel · Post by **mk2keel** » Thu Jun 02, 2005 12:48 pm

/\ what he said
If that lot doesnt work i'd say its time to rip the engine apart and investigate the internals.

kieran · Post by **kieran** » Thu Jun 02, 2005 1:29 pm

Ill look into getting new leads. The ones i have presently are Power train. Think they are middle of the road.

Checked the choke yesterday. Seems to be opening up as the engine warms.
If you depress the pedal when idling the engine revs slightly then hits a massive flat spot where it nearly stalls. If it makes it past this point it will will rev up again as you continue to depress the pedal.

im putting it in tommorow for another look. Would not feel overly confident taking the engine apart myself.
The rain seemed to have a big effect on the running.
Condensation getting through the air filter?
Water getting in the fuel line?
Who knows

Ill keep you guys posted anyway

Tahrey1043 · Post by **Tahrey1043** » Thu Jun 02, 2005 9:30 pm

Yup - sounds like when i had massive engine trouble also caused by the cables. Is it like there's bugger all torque when you put your foot down, til it s-l-o-w-l-y reaches about 2500-3000rpm, then it lunges forwards? (say about 20-25mph in 3rd if its a 4sp / "8P" 5sp)

PS just noticed your username (yeah im slow)... thats my brothers name. What happened to the old astra then you untalkative git, did the fuel line give way again and torch it?

Breadman · Post by **Breadman** » Wed Jun 22, 2005 11:07 pm

Kieran, from what I have read of your Polo's problems I can see no reason to start ripping the engine apart. As long as the engine has good equal compression on all four cylinders, good oil pressure, makes no nasty knocking or rattling noises and doesn't chuck out clouds of blue smoke or use/loose coolant then why should the engine itself be at fault?
Poor running from cold, flat spots and stalling are only associated with one thing, yeah the dreaded Pierburg!
Iv'e had my MK2 Polo 1043 for three years and had cold running problems from day one. The Pierburg was removed, stripped down and cleaned out, rebuilt with new gaskets, then refitted with a new mounting gasket. Vacuum hoses and hot air duct pipe have also been replaced. Choke opperation was checked and adjusted. It's even been to Southern Carburettors for a complete setup and check over.
Yet still the same problems exist. It'll start first time even in the coldest of weather but as soon as the choke drops away it stalls. Once the engine is warmed up it runs like a dream, and I have to say that the problems only occurr in the cold weather (late October to late March as a rule!)
There really is only two surefire methods of solving these problems.

1, Fit a Weber replacement carb.

2, Fit the SPi fuel injection from a MK 3 Polo.

The only thing I have against the Weber carb is that it isn't designed soley for the 1043 Polo. It's more a case of one size of carb fits many different applications so there are lots of nasty brackets and spacers/adapters to make it fit, and to top it all it ain't cheap!

Good luck with it anyway
Cheers Richard.