Engine Query?

concept-e · Post by **concept-e** » Mon Apr 26, 2004 1:57 pm

About 3 months ago, I changed my MK3 Polo Coupe headgasket after it went during a major overheat when the fan switch broke. Anyway it has been fine since, except for what looks like a very slow oil leak. Not even sure that is what it is. May just be left over deposits from the overheat etc.

In the past few weeks however I have experienced problems. When in 1st/2nd pulling away, the car sometimes pulls, then stops, almost stuttering. It does this in 3rd/4th too, when I apply pressure to the accelerator pedal. The exhaust note changes from the usual deep purr of the performance backbox to a really fast thudding, (like heavy artillerary gunfire!!!!!). Not sure what is causing this loss of power, it may only happen a few times in a journey, but is very off-putting!

Ideas/help please!!!

Steve

concept-e · Post by **concept-e** » Tue Apr 27, 2004 1:31 pm

Has anyone got any idea because it appears to be getting worse!

Steve

DanW · Post by **DanW** » Tue Apr 27, 2004 1:54 pm

have you tried cleaning everything? Maybe it's your clutch going? I get a bit of studdering now and again pulling off.

The air filters always agood place to start cos that's easy. And if the dizzy lined up properly. Also take a look at your spark plugs. If you've got a hanyes manual It'll tell you the colour they should be...

I fell this isn't the best advide as you've probably heard it all b4, but I've gotta start the ball rolling.

Tahrey1043 · Post by **Tahrey1043** » Tue Apr 27, 2004 10:58 pm

Knackered lambda making the engine overfuel/have too rich a mixture? Screwed up ignition timing? Other things like carbon buildup leading to preignition (backfiring)?

Hm.

Or maybe you should stop running it on baked beans - these things require petrol!

concept-e · Post by **concept-e** » Wed Apr 28, 2004 10:17 am

will check it out. But It has been running for nearly a year up until the head gasket change fine, with no problems from say the spark plugs. Could try the ignition timing considering the camshaft etc has all been out, and put back in after the gasket change. Thanks for your help, more needed tho!!

Steve

hayesey · Post by **hayesey** » Wed Apr 28, 2004 10:22 am

if it seriously overheated did you get the head skimmed when you changed the HG? as it could be warped.

concept-e · Post by **concept-e** » Wed Apr 28, 2004 10:49 am

yeh got it skimmed, looked lovely when I got it back! My bro thinks it might be loosing compression tho. Seriously, is it worth it? How much would another engine, maybe a bigger 1.3 cost, including everything id need to whack in? Mine has done 91,000 now, maybe I should call it a day?

Steve

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Wed Apr 28, 2004 12:49 pm

Could it not just be damp causing a misfire? My black GT is doing a similar thing at the mo. (without the gunfire) Which reminds me - I need to get some wd40/wetstart on mine!

hayesey · Post by **hayesey** » Wed Apr 28, 2004 2:58 pm

91k is nothing as long as it's been well looked after. Think about it, the car is at least 10 years old so 91k is only 9100 miles a year, that's low mileage.

these engines have been known to last well over 200k.

it could just be damp in the ignition system, although that quite often leads to the car being hard to start or not starting at all.

Does the problem happen at any time or only when the engine is either cold or warm? when did it last have a new set of plugs & leads?

concept-e · Post by **concept-e** » Wed Apr 28, 2004 5:30 pm

Yeh I see your point with the engine lifespan. Just it really overheated when the HG went, and with these aluminium blocks...I have only had the car a year. It has been really well looked after. I haven't replaced the plugs and leads so not sure how many years back they go. I just feel guilty because I got it as standard, in mint condition, and since ive started the modding process there has been problems.

With regards to the cold/wet start, I am used to that. It chuggs away for a bit before finding it's proper idle. And it idled badly thoughout the winter. This problem seems much worse. The complete loss of power is worrying. I can't pull out of a junction without praying!! It happens all the time hayesey. I guess more when hot, but I usually have to wake it up in the morning anyway.

Don't want to spend vast amounts of Â£Â£Â£ as iam (trying!) to save for a G40.

Steve

GroovyCarrot · Post by **GroovyCarrot** » Wed Apr 28, 2004 8:59 pm

I can't really offer any specific advice, but if there's any chance of some kind of residue being left over from the overheat, give your engine a proper cleanout with redex (pour it into spark plug holes, leave for half an hour, turn the engine over).. has been known to work wonders when the engine's got a bit gummed up for whatever reason. Check the condition of your spark plugs as well, they're very handy things for working out what's the matter with your engine..

Tahrey1043 · Post by **Tahrey1043** » Wed Apr 28, 2004 11:06 pm

i know its not the same as saying "it wont backfire when damp", but when i had problems caused by dampness and rubbish cables it manifested itself more as complete misfires and resultant lack of power and response (ie, you'd put your foot down to try and pull from a junction, the spark is too weak to properly ignite the richer mixture, two of the cylinders then totally fail to produce any power (or sound!) and you go nowhere, barely maintaining idle speeds. and without even the grand sound of someone unloaded a 12-bore into your block to signal to everyone that you're not moving because your car's knackered, rather than you've fouled up your clutch control!

hayesey · Post by **hayesey** » Thu Apr 29, 2004 10:58 am

you could also try cleaning the fuse box under the bonnet.

take each fuse out & clean the ends & the contacts with sandpaper. bad contacts here has been known to cause problems. if nothing else at least its one thing you can rule out.

concept-e · Post by **concept-e** » Fri Apr 30, 2004 10:41 am

Right, I am going to try the spark plugs today. Any specific make I should be buying? I heard Bosch were the only ones to get, or is that just worth it with the G40?

Steve

Just thought id add, it starts fine, just idles poorly as if it has a performance cam and has this often loss of power. It doesn't loose all power, just seems to go from firing on all cylinders to just one or something!

concept-e · Post by **concept-e** » Sat May 01, 2004 4:23 pm

Changed the spark plugs, still does it! They needed a change tho. Matched up the deposits on the end with those example pictures in the Haynes Manual, and it sounds like I need to adjust the fuel mixture or sort the timing out. Any ideas?