For the mechs out there Weird one

[AndyStobbs]

Very interesting so far.
RE: the IAT, I suppose it would depend on the ECU mapping, as to what would happen with the fuelling - would it get all confused at having no IAT reading, or would it simply adopt a default value. I am suprised that that fault alone was enough to put it into LIMP mode. As I've always been lead to believe the IAT is mainly for trimming fuel rather than large adjustments.

I think at 52 plate it will just be before CAN, a blessing! Sounds like you'll have to break the multimeter out and see whats going on with the socket first. Pin 16 should be unfused really. I think until you see LTFT its too early to say whats going on. If it has been over fuelling - be it with oil or petrol then the LTFT will be into the negative.

Andy

 

[normspanners]

Cheers for that,
I was not sure about the LTFT being rich / neg, or whether it was in full limp mode, all she said was that the light had been on since the engine was fitted, she had had it checked and that it was IAT at fault.These ideas were just speculation, as possible answers to the low compression issue, which is the only sure diagnosis I have at the moment !
I can only speculate as to the state of ECU up to the point it was switched off, appart from the meantioned electrical disarray on its last journey, which I am assuming caused the fueling to damage to the bores.
I am sorry now I didnt bore scope it first ! But I was sure I was looking at a broken/jumped chain.
THANKS NORM

 

[pedrobedro]

I find with Vauxhalls whenever they are failing to start and running rough it's always the EGR valve no matter what else. I have seen crank position sensor problems as well but the damned EGR valve throws crap into the inlet and gums everything up then sticks itself open and shows a fault light. Not necessarily anything to do with your problem but I just like to moan about EGR valves.

 

[normspanners]

I like to moan about them too, shall we moan together ?
best not EH! my missus will be gettin the wrong idea

 

[normspanners]

Have done some research, re the fuel pressure reg, and found this on a forum re the z22se, it seems the pipe from the reg is in the correct poss.

re ; vx220



6,550 posts
Gender:Male
Location:Bucks
Posted 21 July 2007 - 08:06 AM

the fuel pressure regulator on the z22se engine works by vacuum, so at tickover you have reduced fuel pressure and high revs you have full fuel pressure.

if you replace the air filter with a better flowing filter you loose vacuum to the fuel pressure regulator and thus you loose fuel pressure at high revs, this may be why a remap is required with certain inlet systems - too compensate for lower fuel pressure.

there is a very easy fix for this, it involves moving the vacuum source to the inlet manifold and creates a stable fuel pressure = 4 Bar.

very easy to do, there are two blanked take off points on the side of the inlet manifold, simply remove the blanking plug and fit it to the intake pipe and then fit the vacuum pipe to the inlet manifold take off

you might require a new section of vacuum pipe on the vx220, mine was a moulded pipe but any vauxhall at the scrappy can provide a 150mm section of the correct pipe or the main dealer usually has it in stock.

this mod is the same as fitting an adjustable fpr and setting it at 4 Bar, the ecu adjusts for the extra fuelling at tickover and you won't notice any difference, those who have carried out this mod note improvements

here is the link with some pics z22se
( pics have expired Norm)

Next post on this Topic

Just curious..

Most fuel pressure regulators I know decrease the fuel pressure when vacuum is applied to the connection and raise the fuel pressure as it goes to atmospheric or over in case of a turbo or supercharger to compensate for the pressure over atmospheric that's present in the manifold. Most of the time on factory units it's a normal linear increase.

Progressive/rising rate regulators can be used as a bodge to stop a car (often tweaked turbo's) from leaning out on high load.

Often this variable fuel pressure trick is used with bigger injectors that can flow enough for high power, but would need to be used a too short duty-cycles during idle (<5% or so) to get consistent amounts injected and atomised.

By dropping the fuel pressure using the intake vacuum on the pressure regulator the ECU can use much longer duty cycle on the injectors and still get a good control over the amount that's injected (injectors are accurate as long as you stay away from very short or very long duty cycles) and fuel atomisation.

Unless the regulator used on the 2.2 works differently then hooking it up to the manifold vacuum would initially lean out the mixture until the ECU re-adjusts. The mapping of the ECU would not be based on this. It's mapped for a constant fuel pressure.

Has anyone hooked up an OBD reader after this mod to see how the short term and long term fuel trim is changing or hooked up a wideband lambda sensor in the downpipe with a gauge to get an readout of the mixture?

If the ECU needs to adjust too much then it may throw an engine management light and error code after a while.

Bye, Arno.

vocky
vx220



6,550 posts
Gender:Male
Location:Bucks
Posted 24 July 2007 - 07:25 PM

the z22se fpr does indeed work back to front

at tickover a bog standard engine has 0.2 mBar of vacuum to the fpr, at 4k rpm it raises to 6 mBar.

so the vacuum increases with engine load until the fpr has reached full pressure

moving the vacuum take off restores the missing vacuum caused by a non standard inlet system

Europa Blue

BUT got it on the lift today and found 2mm gap between the GB and bell housing, I could see daylight through from under the car through the engine /GB bellhousing interphase!! I got a19mm spanner to check and the bolts are finger tight !!!So I hav'nt touched the car now untill she comes and looks at it, as I don't want the resposiblity of any further probs with the fitment of the engine etc because this could end up costing me!!! until she tells me what she wants done.

 

[AndyStobbs]

What a nasty job, sounds dodgy.

 

[normspanners]

Yeh very odd situation with the fuel pressure reg eh, the vac pipe goes from the end of fuel reg, to the plastic duct between air filter and throttle body and doesnt appear to form a venturi in there, that is why I thought it had been incorrectly fitted.
So if it works in reverse (to std) as the air filter gets blocks it increases the fueling !!. And as the guy above says if you fit a high flow it reduces the fueling !
I havnt seen this method of fuel pressure increase tbh.
Norm

 

[AndyStobbs]

can you test it just for the hell of it, to be sure it does work the way you think it works?
If customer gives you the go ahead to carry on that is.

 

[normspanners]

Hi Andy
YES I agree but because the 'pull' of the vacuum is working on the end as 'normal' I am very sceptical.
Picture 1 is of az22se off google, note vac pipe disappears under the TB
Picture 2 is a 'generic' fuel reg NOT a vx one.
Picture 3 is as 'mine' is, sorry about quality but have out lined where the pipe comes from the air duct which is the black 'shaped' piece that comes in from the left and sits ontop of the TB the pipe then goes too the end of the reg as in the first pic but the vac pipe is shaped 'like it grew there' if you understand my meaning, I had found the two 'blanks' in the manifold below the fuel reg, as mentioned in the script, and had thought that was where the connection SHOULD be?

 

[normspanners]

Better pic of the actual car

 

[normspanners]

PS the large stainless pipe with the 90deg connected to the fuel rail is the feed, BUT the fuel return is connected on the opposite end of the rail!! so unless there is a drilling the full length of the rail how does it reduce the pressure?

 

[AndyStobbs]

Pictures aren't really clear enough to comment with much confidence. Where is the pressure test point - might give a clue.

Andy

 

[normspanners]

Where is the pressure test point - might give a clue.

There isnt one! it looks like an unbolt and TEE

 

[normspanners]

Hi Andy
Got back on this one today, it stood for a week started off the button, I have found the problem with the gap in the bell housing looks like the joint has been double dowelled and the two dowells are holding off that bolt that means engine or gearbox out coz the dowels will prob be mushroomed out. But she is going to get the guy that fitted the engine back to sort that!
I did another comp check when hot after it had run and was 16 bar!! on all, albe number 4 took a little more cranking, number 1 was up there in a couple of turns, I should have started with number 4 coz the later cyls sometimes do take a little longer having taken the 'top' off the battery.
There is still a lot of blowby but considering there was NO compression it is hard to believe it is still running !
I managed to get the reader to work on it and have reset any dtc's I think every one was listed after it's Alt / battery failure have now run it for hours and not one is present Also lamba switching ok at idle and stationary, anyway.
But I still seem to have low alt output so will check alt to starter lead tomorow for any breakdown . I have tidied and clipped all the loose wiring etc which will only help the job along.
Cheers N

 

[octo0072000]

try a earth lead/jump lead from battery to block see if that makes any difference

 

[normspanners]

try a earth lead/jump lead from battery to block see if that makes any difference

Thanks already tried