Major Running Problems Of Thy Xu9j4 Mi16 Variety

[KRISKARRERA 2 1 Cars]

A few nights ago I made a short journey into town. The engine started and drove fine for 5 minutes and then midway through warming up it started missing badly for a few minutes and then it completely died! So, I restarted her. And it was ok....

The next day I was a bit I miffed. But I found the TPS connector to be loose and thought it might be that.

Alas I did the same journey tonight and the problem happened in exactly the same time and way as a few nights ago!

 

A bit of background...

 

Engine has always had a starting problem.

Starts fine when stone cold. Starts fine if it was switched off and restarted within about five minutes. But after that approx. 5 minutes and say 12 hours it will turn over for 5-10 seconds before reluctantly starting.

 

Also...

If I'm drifting along in traffic at say 2000rpm in 2nd gear with foot off gas pedal and then I go to accelerate the car will jerk a few times before smoothing out. And when taking foot off accelerator it jerks again as if the fuel cut off wasn't immediate...

 

I'm thinking all these are related. And it seems like whatever is playing up is not liking certain temperatures.

 

Anyone else experienced this or have any ideas what could be causing this?

 

I am upsettings.

 

Thanks

[ORB 227 1 Cars]

engine coolant sensor (blue one in the thermostat housing) could be faulty ? ? ?

Edited September 28, 2007 by ORB

[DamirGTI 327]

Hi !

 

I was having same problems , just as you described and it was -> The ignition module , at the back surface of the ignit. module is some sort of thermal transfer paste and this paste was dried out which cause ignit. module overheating and because of that overheating when the engine was up to operating temp. first it started to misfire badly and shortly after that it shuts off completely (when the engine was started from stone cold was fine , but once it reached operating temp -troubles started..) , so i have to wait 5min. for the module to cool down and then i was able to start the engine again ... but shortly after it all repeats again -> stop - wait/cooling time - go - stop - wait/cooling time - go ......

 

Either you have bad module (try with some spare one ..) , or first check/clean ignit. module connector and re-apply the thermal transfer paste at the back of the module and then try/go for a spin .... if that doesn't helps try with another module (but don't forget to apply the thermal paste at the back !)..

 

Apart from the module it could be coil also , anyhow as the problems starts only when the engine reach operating temp. it's 90% something of these two as because that it's typically diagnose of a bad module or bad coil (but my vote is for the first one - check the ignition module !)

 

Hope this helps

Damir

Edited September 29, 2007 by DamirGTI

[KRISKARRERA 2 1 Cars]

But the only thing that doesn't add up is that once the engine is boilling hot it doesn't cut out or miss badly, it's as if it's only when it's luke warm.

The fact that it goes like hell must eliminate alot of things.

[KRISKARRERA 2 1 Cars]

When the engines stone cold, first thing my CTS is 1700ohms. Anyone fancy testing there's so I can compare?

 

I tried heating up the ignition amp with a hair drier earlier but the car still started fairly quickly (as it does first thing when left overnight) so that eliminates that. In theory. Or does it?

[KRISKARRERA 2 1 Cars]

I just pulled all the HT leads off and stuck some spare spark plugs into them and tried to start the engine. Did I get sparks? Yes - BUT each plug sparked in firing order as if the engine was turning over about 20rpm! What does that indicate? (when the starters turning engine over it's doing over 100rpm isn't it?)

[Miles 331 1 Cars]

Hair Tongs?? they get allot hotter than a hair dryer

[KRISKARRERA 2 1 Cars]

Hair Tongs?? they get allot hotter than a hair dryer

Oi you that's no help!

 

I've done some research.

The starter motor turns the engine at 165rpm. So assuming one spark per revolution of crank I shoulda been seeing a spark every 0.36 of a second. Well I was seeing about a quarter of that many sparks!

Edited September 29, 2007 by KRISKARRERA

[Guest Bart VDA]

Oi you that's no help!

 

I've done some research.

The starter motor turns the engine at 165rpm. So assuming one spark per revolution of crank I shoulda been seeing a spark every 0.36 of a second. Well I was seeing about a quarter of that many sparks!

 

Since it is a 4 stroke engine, a spark will fire every 2 revs.

[jim21070 2]

Kris,

 

If it is not ignition-related and I reckon it isn't from the checks you've done, have a long hard look at your AFM. They can cause all sorts of vague fuelling problems and the culprit in your case could be the air temperature sensor thermistor just inside the AFM, given that the problem appears temperature-related.

 

It would also be worth having a look at fuel pressure. If it's a bit low due to a tired pump or partially bocked fuel filter it could give rise to your symptoms.

 

For cold starts, the ECU makes the mixture incredibly rich. For warm starts the mixture is not made nearly so rich as you might think.

 

Don't discount a minor air leak either.

Edited September 29, 2007 by jim21070

[KRISKARRERA 2 1 Cars]

Since it is a 4 stroke engine, a spark will fire every 2 revs.

I'm confused about that. If it's 4 stroke then at any one time one piston is sucking, one is squeezing, one is banging lol, and one is blowing. Every time the crank turns it's being forced down by a piston that's just had an explosion above it so there's got to be a spark every turn surely??? (EDIT: Unless you mean one spark per 2 turns on each cylinder?)

 

I've got a spare AFM I can use - though of course it's always possible that that AFM is tired too.

 

Probably not a tired fuel pump else how would the thing go so well when pedal hits the floor?

[jim21070 2]

Unless you mean one spark per 2 turns on each cylinder?)

 

Yes, that is correct Kris. One spark every other turn.

 

Fuel pressure - just exploring every possible possibility...

[DamirGTI 327]

I just pulled all the HT leads off and stuck some spare spark plugs into them and tried to start the engine. Did I get sparks? Yes - BUT each plug sparked in firing order as if the engine was turning over about 20rpm! What does that indicate? (when the starters turning engine over it's doing over 100rpm isn't it?)

 

Have you checked for possible current leaking ?! I've had a lot problems – and very weird electrical problems/gremlins all caused by that bloody black thing called ignition module ... and one of the problems was massive current leaking (again just on hot engine which caused strong misfiring etc. ..) passing from main coil HT lead down to chassis earth (this was visible at night like nice big blue thunder strike and clicking sound ..) - I've try hundreds of spare/new leads dizzy caps rotors .... and finally I've fix this with re-applying thermal transfer paste at the back of the module .

I know , it sounds strange but it was module causing this current leak ...

 

If i where you id try first with good known set of coil and module , and then if that doesn't helps move to fueling wiring etc.

 

Regards

Damir

[KRISKARRERA 2 1 Cars]

Still arsing about gathering parts to try but I would just like to add:

 

Kangeroo'd again today once it got up to temperature. Very violently like I'm jumping on and off throttle.

But as soon as I put foot to floor it stopped.

 

This is very intermittant in nature - must have been a week ago it last happened.

 

 

Runs ok on wide open throttle - what does that tell anyone?? (That I should drive like a maniac everywhere?)

[DamirGTI 327]

Strange enough i was having same problem few days ago after replacing dizzy (I've fit some strange spare citroen bx 1.6 dizzy ) changing ignition timing etc. ...

The engine was very jerky on small throttle opening - jumping , kangerooing , hesitating very nervous running until i put my foot down and increase rpm.

 

However I've fix this problem (a good bit of the problem , it's still a little jerky but it's better..) with adjusting the fuel mixture - the engine was running lean with this spare dizzy and on this different timing settings ... ( but i have FSE pressure valve because of ported head so I'm adjusting fuel mixture with this valve i didn't touch AFM spring tension or mixture screw in order to richen the mixture ..)

 

hope this helps

Damir

[KRISKARRERA 2 1 Cars]

Today the "K" light came on just before it stalled so I got her home and did a fault code check - code #33 - Air flow meter!

[lee-bg 0]

Try the new AFM then to at least remove that as option. Also check cabling in AFM, sometimes its not very nice.

If possible open cover and see how the needle moves on the track on running car.

I've had terrible troble before from failing AFM. just like you say you put foot on throttle then off.

Hope it helps.

The other time i was having simillar trouble was when my ignition leads were fuk*** up.

 

Its one of those problems that has to be sorted by elimination annoying.

this engine can be great fun, but also great pain.

Edited October 24, 2007 by lee-bg

[DamirGTI 327]

Hi !

 

So it's that bloody AFM thing did you try to retrack the AFM ?

 

Damir

[C_W 3 1 Cars]

Today the "K" light came on just before it stalled so I got her home and did a fault code check - code #33 - Air flow meter!

 

Mine only has come on when I forgot to connect the AFM (it somehow started!). Try cleaning the connector/make sure the connector is secure.

[KRISKARRERA 2 1 Cars]

Hi !

did you try to retrack the AFM ? Damir

No but I've put a spare one on. And cleaned it's terminals.

Behaved itself today but I'll have to wait a few weeks to make sure.