Now then, my 1992 polo 1.3 (AAV) is a bit poorly at the moment. Its running very rich and slightly lumpy. Its got the original SPI engine with 97k on it, compression tests suggest its a healthy engine @200 psi on all cylinders.

Engine wise, it has a genuine K&N, and a 4-2-1 de-cat manifold.

Known issues - Slightly blowing exhaust where the back box attaches (crap andrew pages parts!!), potentially blocked breather on the known issue pressed in dome part on the engine block.

recently renewed parts: Blue temp sensor, lambda sensor, dizzy cap, arm, and plugs.

Is it possible to connect a diagnostics program up to the 2+2 connector? I have the correct wires and VCDS lite, but cant seem to get anything from it.

Suggestions? I'm planning on fixing the exhaust blow this weekend, which should at least help things, but I'm pretty sure there is something else wrong.

Cheers, Ste

Edited 14 June, 201214 yr by RetroSteve

Does the engine actually run at normal temperature (90° C)? If not, it would be worth fitting new thermostat and possibly thermostat housing.

The above is based on the fact that, even a brand new temperature sensor can't work correctly if the engine never gets up to temperature.

If engine temperature is OK, it might be worth checking for petrol leaking in via SPI throttle body.

Regards.

This is good advice, it is getting up to temperature though. How do I test for petrol leaking in (at the risk of sounding like a tool)

You may be able to see petrol wetted areas in the throttle body, or even a pool of petrol inside the inlet manifold under the TB.

When the engine is running, there is, what looks like a constant spray of petrol in there, but when it is standing, it should be more or less dry.

SAFETY NOTE: It is not really good practice to look into carburettors or throttle bodies when the engine is running (although I wouldn't mind £1.00 for every time that I have done it!) There is always a chance of a back-fire, which could cause you to lose your eyebrows.

Regards.

Right, bit of an update to this. I did find that the small pipe to the idle bypass valve had been blocked up, i unblocked this and connected this to one of the outlets on the side of the golf elbow. Does it matter which one of those it connects to?

Also, connected my friends wideband lambda sensor up (innovate motorsports, fairly expensive and quality kit) and taken readings. Its running nearer to normal when under load/ normal driving up through the gears, but quite erratic jumping between 12 to 16 (14.7 being optimum). Sat ticking over its running quite rich at around 11.5 - 12

As mentioned. It has a new lambda sensor, but I'm wondering if it, or the original loom that feeds it is still at fault. Is there guide on what voltages i should get with a multimeter on the connections?

Same, but for the dizzy hall sender? Does that sound a likely cause of my problems? (I know they're common fault)

Does anyone have a link or PDF of a technical guide to the mono motronic?

Finally, how to i get any diagnostics on the aav? I bought the 2 x 2 adapter lead and have VCDS lite installed but i cant get anything to happen?

Cheers, Steve

I'm having some issues with hesitation on initial startup with mine & over fuelling too,

When you start it, you have to slowly build up the revs or will stall but then it's ok, and just smells of fuel and only does like 36mpg.

I'm not sure if the fuel pump is noisy as fuck or just the wrong one.

Disconnecting my blue temp sensor makes it hesitate then plugging it back it settles it down.

Ignition side of things seems ok, so I'm gonna have a look around for test figures for lambda reading and such this morn hopefully, and will post them up so you can check yours out.

I wasn't bothered by mine tbh but i think MOT is due before I'll be swapping everything over!

Nick

Also, connected my friends wideband lambda sensor up (innovate motorsports, fairly expensive and quality kit) and taken readings. Its running nearer to normal when under load/ normal driving up through the gears, but quite erratic jumping between 12 to 16 (14.7 being optimum). Sat ticking over its running quite rich at around 11.5 - 12

How did you take the measurement?

The innovates need calibrating before use in a new vehicle, also if the stock sensor wasnt fitted at the time then the engine would be running rich.

While 14.7 is the full burn ideal there is no actual power at stoich. 12.5-13.5 is in the power band area, idle your looking at between 14 and 15.

Idle & unloaded rpm should be around 14.7 or emissions would fail lol

i passed with 13.7 idle hahahaha. but the car was still burning oil off from leaky stem seals. lol. but it was a clenching moment as it sat at 1150-1175 HC's (1200 being the limit).

So is the earlier catted emissions test 1200 HC? Mines a K reg so it's 93, or would that be the 200 one?

yep mine has the same test limits as the mk2, yours is also the 1200HC one. as its the same model car and it no modifications were made between 1990 and 94. (possibly because they all came with cats anyway)

BUT i think under the new MOT rules the you still need something that looks like a catalyst on the post august 92 cars.

heres some info that may help, i have more pinout data for ecu and such also but i cant be bothered to sort all that out, this should be virtually in order and some use..

Thanks, that's very very helpful. Any chance of the same screenshots but for the self diagnosis section that it mentions near the bottom when checking Ecuador voltage

Just working on the car, I tried disconnecting the blue temp sensor and the revs went up and the car ran much smoother. If you reconnect it it dies down to low idle and gets all lumpy. What does this show? I replaced it about a month back but I'm thinking wrong or faulty part

Mk2 Polo warning lights and gauges not working - Page 2 - ICE, Electrical and Lighting - Club Polo

Anyone with these issues, see the above thread, might help.