2000 Bora 1.6 16v AUS engine - Bad hot idle and hot stalling

**Doctle Odd** · 01-02-2015,09:11 PM

Or....

swan-vestas-matches-900x900.jpg

**Crasher** · 01-02-2015,11:57 PM

The FPR has a small effect on fuel delivery by rail pressure but the ECU commands the injectors opening period which by a multiple of flow cc's per m/s is the flow rate and the ECU does this according to the data it is provided with so that is from the load MAP which uses manifold depression, throttle angle, RPM, engine temp etc to open the injectors for .............so long............and them close them which provides the fuel. Something is telling the ECU to dump fuel at the same time as saying "I have a post throttle body air leak" which is silly.

**Doctle Odd** · 02-02-2015,01:41 PM

Apologies for the matches Col, I was in a giddy mood yesterday probably due to having a megane in the yard

**Col** · 02-02-2015,06:42 PM

No worries, the thought had crossed my mind except it is SORN'd and not insured.

I'm going to replace the FPR as one is on its way anyway. I'm certain that this won't cure it.

After that I'm going to tear everything down, take it off, put it back, check it and check it again. As a DIY'er what may be obvious and staring me in the face cannot be seen, I'm missing it. For a Pro it would be obvious. Problem is I've not got the gear to check this stuff I'm thinking how I could use my air compressor somehow to test the inlet as that is all I've got.

My latest thoughts are;

It is an air leak.... somewhere!
An injector(s) has failed and is dribbling fuel into the inlet all the time.
Better stick to the desk job.
But I've managed to keep my cars running by myself for the last 20+ years without issue, I must have been lucky !

**Crasher** · 02-02-2015,06:52 PM

Injectors, virtually unheard of those to fail, I remember replacing one over the years. To pressure test it with compressed air there is a VW tool which keeps the pressure at a max of 0.5 bar. What you could do with is a smoke tester. I could not sleep last night and I sat there for hours muling this one over. Have you tried blocking off the EGR pipe with a shim?

**Col** · 02-02-2015,07:19 PM

Yes,
I made up a blanking plate and blocked the EGR off at the inlet end to eliminate it, no difference. Tried that twice. Also use two different EGR valves with no difference.

I reckon that I've either put something back on slightly wrong from the cylinder head refurb. Doubtful as I was very careful and made sure everything was really clean.

A few things I am going to check are;

Injectors, i'll crank it over with the rail off the car and observe the spray pattern. Dangerous as a dangerous thing I know
Injector seals, I put the rail back into the manifold smearing the o rings with oil, i'll check them again.
Servo vac pipe or the servo itself could be dodgy, i'll block the spiggot off near the TB to check this.
Evap system, I have blocked this off at the evap end but will pull off the hose near the TB and check it.
I'll check the MAP seal to the inlet manifold again, I've tried two MA sensors.
I'll run the engine with each sensor or actuatoe disconnected in turn. I think all it needs to run is the crank sensor, the TB and of course the injectors.

I'm proper fed up with this car and I've never even driven it!
I thought what could be better than a nice simple 1.6 petrol, how wrong I was !

I'm sure the answer is staring me in the face but I just cannot see the wood for the trees.

**SammoVWT** · 02-02-2015,07:53 PM

if you stick bottles on the ends of the injectors you will be able to check volumes too and be at least a little safer.

**Col** · 03-02-2015,12:40 AM

Sshhhh !

Don't talk too soon or count thoust blessings nut I think I may have sorted it.

Touch wood, fingers crossed (for superstitious viewers), kiss the blarney stone (for Irish viewers), hail Mary (for Catholic viewers) and well F*** my old boots (for blokey viewers) but I think it is sorted.

I'm not counting my chickens and inflating frogs with a bicycle pump until the weasel has popped and the fat lady has farted but I do believe all is now tickedy boo.

MAP sensor. Swapped back to the old one and that seemed to do the trick.

I spent a good few hours pi**ing about with it tonight double checking everything and well.....

Had it running for about 45 minutes without issue and then I got too cold and it was too late and it was snowing which never happens here.

Further good news update to follow tomorrow hopefully when I can do a few cold start and warmup cycles to check.

Most of all chaps, thank you. I've been so close to throwing in the towel.

**Doctle Odd** · 03-02-2015,10:59 AM

Fingers crossed for you mate and a small medal for tenacity!

**Col** · 03-02-2015,11:54 AM

It is not fully solved but 99%+ better than it was.

This morning I started the car clear of any fault codes.

It started on the button with maybe only half a second of cranking, very pleased with that. It idled smoothly, I watched it for a couple of minutes and went indoors.

Came back out 20 minutes later, it was still running which it would not have been before BUT the engine management light was on

Scanned it and got this...

16556 - Fuel Trim; Bank 1
P0172 - 35-00 - System Too Rich

When I went back out the engine was still running but it had the odd stutter but cleanly revved and didn't stall on the over run. It wouldn't do this before. It would have been in limp mode or would have stalled and been impossible to start.

That code above then, what do you think?

Could it be residual fuel burning off in the exhaust?
It could be the fuel pressure regulator which I put back on the car last night after taking it apart, a big no-no as they are not meant to.
Or, and this is where I need some pointers, anything else ?