Kangarooing and hunting when warm

[Steve205 18 1 Cars]

Good afternoon all.

 

1989 

205 1.6gti. 

Oe in every way possible. 

No pas/ no aircon

 

 

Help needed. I booked my NCT (mot) for Tuesday. 

 

Car has suddenly started acting up. Hunting about 250rpm while warm and kangarooing like crazy at times at low speeds especially in 2nd/3rd gears. It is intermittent.  

 

She has always hunted when cold started since I bought her 6 years ago.  Once throttle feathered for a minute or two she always used to idle smoothly.

 

While cruising at higher speeds she feels wavey but no dials are showing this hesitation.  

 

When being driven on all hesitation seems to disappear. 

 

Nothing has been altered in her set up in last year.This has developed in last few days. 

 

I was on a road trip last weekend (400+miles) and all was good until she started this on way home. 

 

Any ideas as to the most likely cause?

 

All air intake pipes on top of engine are in good order and tightened in place. 

 

Thank you 

Stephen 

[Leslie green 165]

When started from cold the "sad" valve should operate to bring the idle up to 1500 rpm for a minute or 2 until things warm up ,it sounds like it has never worked and could not be stuck open allowing extra air in all the time if you now have a high idle .You could cap of the end of the sad pipe near the battery but you also need to cap the bellows it fits into to eliminate the sad altogether for testing , its only used during warmup anyway. Metering the sad valve pins with a multimeter will give you a resistance reading if its out of spec its for the bin. The spec in in the haynes manual which if you haven't got one buy one of ebay as it will be a great help.

 

Its just as likely a hose has split not an air intake one  unless its the boot  after the airflow meter or an oil breather hose down the front of the engine making the car run very lean . Once it goes for Nct you should see what the co reading is , it should be around 1.5% if its very low that would point to an air  leak causing a lean mixture.

A failing airflow meter could make kangerooing a lot worse too if the track is worn but id look at cheaper possible causes first. Its not likely to be that easy to find the problem but the co reading will be a start. Mines hunts a bit too when warm and I suspect the dissy is worn but otherwise it runs ok with some shunt at low speed at times when you come on and off the gas at low speed  and as they say they all do that !

Edited September 19 by Leslie green

[Steve205 18 1 Cars]

Thanks Leslie.

 

 

After cold start and initial feathering of throttle rpm does go to approx 1400 and then eases back over a few minutes to approx 1000rpm.

SAD was checked when 1st bought and seemed to be functioning ok.

 

I feel it could be an air leak in a breather hose that I can't see. 

 

Good point on the co reading.  It will be a good starting point.

 

The fact the faults are intermittent are what's confusing me. 

 

Thanks

Stephen 

 

[Leslie green 165]

Id have a look at the rotor arm and cap for cracks and inside the dissy for oil too as an o ring can leak , intermittent faults can be a real pain especially old cars with no fault codes to read and just because the sad was working 6 years ago it may not be now and may only close sometimes but if it goes to 1000 rpm that's not bad at all.

Edited September 19 by Leslie green

[ALEX 103 1 Cars]

The hunting symptom sounds fuelling rather than ignition.

If you eliminate air leaks, poor fuel pressure. and the ECU Coolant temp sensor, id next look at the AFM.

Faults I've seen are bearings for the flap go stiff and the tracks on the ceramic plate wear out.

There's instructions on how to bring some life back into an old AFM (I think on the main 205gti drivers site).

But id look into buying a new or reconditioned one, it's always worth having a spare on hand.

  

The kangarooing could be fuelling aswell, but could also be a poor ignition connection.

a common fault is the distributor fly lead to the ignition module. 

Also check the obvious stuff HT leads , plugs, dizzy cap, rotor (as mentioned above). If they're due a service it'll be worth changing them anyway.

 

Edited yesterday at 11:55 AM by ALEX

[Steve205 18 1 Cars]

Monday evening the car was making all kinds of trouble. Backfiring and running very lumpy. Seemed to be running on 3 cylinders. 

Checked obvious things.

Was making good spark at ht leads. Distributor looked relatively clean and no cracks or oil.

Removed plugs. Chambers 3 and 4 looked oily and these 2 plugs were sooty.

Test was at 10.30 the following morning. 

Rushed to motor factors at 8.30 that morning and got 4 bosch plugs.

Swapped them in.

Car ran perfectly. 

 

Sailed through test mechanically. 

Was failed on rust in footwells.

 

Due to get this resolved as soon as possible. 

Then give her a full service to see why cylinders 3 and 4 are oily and fix this then. 

 

The never ending roulette wheel of 205 ownership.....

It's all part of the fun....at times!

 

Thanks for the advice. Really appreciate it.

 

Stephen 

[ALEX 103 1 Cars]

16 hours ago, Steve205 said:

Monday evening the car was making all kinds of trouble. Backfiring and running very lumpy. Seemed to be running on 3 cylinders. 

Checked obvious things.

Was making good spark at ht leads. Distributor looked relatively clean and no cracks or oil.

Removed plugs. Chambers 3 and 4 looked oily and these 2 plugs were sooty.

Test was at 10.30 the following morning. 

Rushed to motor factors at 8.30 that morning and got 4 bosch plugs.

Swapped them in.

Car ran perfectly. 

 

Sailed through test mechanically. 

Was failed on rust in footwells.

 

Due to get this resolved as soon as possible. 

Then give her a full service to see why cylinders 3 and 4 are oily and fix this then. 

 

The never ending roulette wheel of 205 ownership.....

It's all part of the fun....at times!

 

Thanks for the advice. Really appreciate it.

 

Stephen 

Oil or unburnt petrol. could be from the misfire issue. It'll likely clear up in time. Is it smoking much?  

 

I'd change the HT leads as well. I had the same misfires issue recently. I had good spark on all plugs when out of the engine, so I spent ages chasing other potential causes.

Turned out to be a high resistance on one HT lead. The plugs would spark fine under normal atmosphere, but in compression it must need more current than the lead was providing.. 

Swapping them for a new HT lead set fixed my problem.

BTW you can test HT leads quite easily with a multimeter (not just continuity but with the resistance measurement), if you want to check before buying a new set.

 

Edited 13 hours ago by ALEX

[Leslie green 165]

Sorry to hear you have some rust , I'm thinking I would do a compression test next as the head gasket could have gone between 3 and 4 , make sure to take all plugs out for this otherwise it could mask the fault. I hope it isn't but you really need to know ,aa compression tester is cheap to buy .

[Steve205 18 1 Cars]

 

 Rust in 4 floor panel areas according to tester. Booked in to panel beater Monday week. Fingers crossed it won't be terminal. Will know more when he starts stripping the underside.

 

Plugs 3 and 4 were oil stained at top end and Sooty at firing end.

4 was cleaned down before photo taken. But 3 is definitely the worst. 

In need of full service once panels are replaced. 

[Steve205 18 1 Cars]

Can't upload photo due to low memory.  Not sure why this is happening.  Sorry.

[Steve205 18 1 Cars]

[ALEX 103 1 Cars]

6 hours ago, Leslie green said:

Sorry to hear you have some rust , I'm thinking I would do a compression test next as the head gasket could have gone between 3 and 4 , make sure to take all plugs out for this otherwise it could mask the fault. I hope it isn't but you really need to know ,aa compression tester is cheap to buy .

Usually the header tank bubbles if head gasket gone. staining on white part of plugs is probably from a leaking cam cover gasket part number 0249.48. plugs look fine to me.

Premier Rocker Cover Box Gasket Fits 205 405 Boxer 309 1.6 1.8 D TD 1.9 2.0 | eBay UK

Edited 7 hours ago by ALEX

[Leslie green 165]

True Alex but id want to make sure all is good just for peace of mind and a blow between the 2 cylinders may not show up as pressurising the system in the beginning . It sounds like 3 and 4 are not firing right so you have something to go on ,check for a spark there , the cam cover is certainly leaking oil into the plug holes as Alex says , mine is leaking at the back and it seems if it sits over the winter it leaks the next year which is a bit annoying .

Edited 5 hours ago by Leslie green

[DamirGTI 364]

4 hours ago, Steve205 said:

That crusty deposit on the plugs is burnt oil (burnt oil additives phosphorus , calcium etc) ..

Could be stem seals , rings or simply oil breather piping stuffing the inlet with the oily emulsion which tends to accumulate in the entire breather system like mad if it's humid and you do not drive it as often .

 

Stem seals also rot if you only drive it periodically ..

 

Take a look in the breather system if there's emulsion inside the hoses and filler neck mesh , if there is try cleaning that first .. and see what happenes afterwards .

 

Also check heat range od those plugs , colder grade plugs can make this too as they cannot "self clean" they'll be fouled and engine will misfire/run on 3 cylinders .. say like two grades colder than OE spec can be problematic especially for short drives around every now and then and loads of idling .

Edited 4 hours ago by DamirGTI

[Steve205 18 1 Cars]

Will check these things. For reference purposes car is rarely parked up. I have her 6 years and and have averaged approx 4500-5000 miles per year. 

 

Used a few times every week as a daily at minimum.  Also used for a few long runs a couple times a year.

 

Thanks again.