1998 Leganza 2.0 cutting out

[MatesLeganza]

A friend has been driving one of these for years now..it has had several fairly major repairs over the years, mostly items in engine-bay...a complete engine failure occured about 5 years ago caused by the tiny oil pickup strainer that plagues these GMH Australian Camira/Calibra/Leganza style blocks. One with low kms from a Nubira was acquired and fitted.

the car, an auto transmission car, has developed a serious habit of stuttering and stalling when it has been brought to a halt and then the throttle opened to move off again..its persisted for a couple of years now, defied all attempts to diagnose it so far, as the car can be immediately re-started, but it is dangerous in some circumstances, usually as you are rolling to rest at a stop, first warning you have is the steering going heavy as the stalled motor stops driving the vane pump.
All things such as plugs and leads check out, there are no external signs of an obvious high tension ign breakdown . Engine-bay Fuel filter was replaced, no effect.

One auto electrician suggested it may be an issue with the throttle control "communicating" with the ECU ..it sounds plausible, but then he seemed not to be able to follow through on that avenue, I think a lot of mechanics are rightly afraid of such intermittent faults.

a certain number of the components from the old blown engine are still available to use as substitutes, such as the coil pack.

app any help.

[benzino]

ah yes... the oil pickup...
I had that happen to me a month after I did my engine swap! just lucky it didn't damage anything...

the hesitation also seems quite common
when my engine was in the leganza it took about 2000 revs under it's belt and then it picked up and flew
when I put it into the lanos that disappeared (no idea why) but there was some hesitation still if you blipped the throttle off idle (doesn't happen if it's smooth)

try making the throttle cable a bit tighter on the throttle body (get your mate to push the pedal to the floor with the car off, and if it still has a little bit left till full throttle then you can tighten it up)

also, the throttle position sensor is a very common GM part so it's cheap to pick up either new or from a wreckers
I just changed mine to a second hand one I had spare and it has made the hesitation a little better but not fully cured it (still completely drivable, I just like my cars to be functioning perfectly )
http://www.ebay.com.au/itm/HOLDEN-VN-VP ... 2308b9fef7
http://www.ebay.com.au/itm/HOLDEN-VS-VT ... 2308ba021e
http://www.ebay.com.au/itm/THROTTLE-POS ... 3f0e41bfe0
or if you want to go adjustable:
http://www.ebay.com.au/itm/Adjustable-T ... 35a6789a47

i think when the car is in open loop the only 2 sensors really telling the ECU what's going on are the TPS and the MAP sensor

another problem could be fuel pressure; it should be between 40 and 50 psi at idle (factory spec is 42 I believe)
and also fuel pressure regulator vacuum (check your vac hoses!)

so if I were you I'd go:
throttle cable tension
fuel pressure
TPS (you can use this technique before you replace if you like: http://www.daewootech.com/forum/viewtop ... 15#p110906
MAP

and if it's not any of that, it could be a problem with the auto box (let's hope not aye!)
or if the HT wires are old they may not look broken down or damaged (mine are nearly 200k km old so that could be my problem...)

let us know how you get along

[MatesLeganza]

thanks...Ill look into that. some of it I know what it is, some I dont.


what the hell were they thinking with those ludicrous oil pickup strainers...it gave warnings for a while with periods where the oil light would come on for a few minutes, then go back out again. Noone knew how to interpret this, of course if Id cracked the sump removed that feed pipe and inspected it Id have guessed the rest, but it would go back to normal and everything seemed alright most of the time, until one day the rod went through the block.

to add insult to injury, the rod went astray in the shallow end of the sump and so struck and fractured the alloy sump as well..

the Nubira engine of course had its own sump, but shallow pulley end deep flywheel end, the opposite way around to the Leganza...so another Leganza sump still had to be procured or else have the cracked one alloy-welded up.

[MatesLeganza]

intake-side Freeze plug was the latest failure on it...b4 that recently, drivers-side front wheel bearing..

I did the Freeze plugs, someone else got the job on the wheel bearing...probably id have rather done the wheel bearing job..

[MatesLeganza]

incidentally, the EGR valve vac hose...what is it rightfully connected to ?

the TPS switch, what is the location of that thing, pretty sure Ive seen it, but, yeah..so one of those is listed for Leganza i notice, are you saying that any of them can be used, including the adjustable one?

sounds promising...i sure would be the blue-eyed boy with him if I could suddenly solve this.

[MatesLeganza]

what is the issue with how difficult the oil caps are to get off and on on these cars, btw..Ive tried both caps, but when engine is hot in particular, are shocking tight to get off

is it really true that if u use non-genuine oil pan gaskets on them, they never seal properly?
luckily the original ones are re-usable for a fair few years..

[benzino]

the egr vac hose should be connected to the throttle body
you'll find the throttle position sensor (tps) there as well

as far as i know with my sump gasket, the mechanic just reused the old one with a bunch of sikaflex. a year on with zero leaking it must be ok...

About the adjustable tps, i wouldn't bother. if the stock one doesn't fix it then it's not causing the problem (plus postage is about $30 too much)

[Daniel]

Doesn't the egr vac hose have to go first to a electro pneumatic valve? Maybe different on yours but on my 1.6DOHC this valve is well hidden behind the block.

[benzino]

yeah i think you're right
i'm thinking of my manual engine that doesn't have the electro pneumatic valve - the vac hose just goes to the tb...

[MatesLeganza]

electro magnetic valve? this is on cool side of Block, somewhere under inlet manifold?

[MatesLeganza]

actually come to think of it this is an auto car , but the replacement engine I fitted on which almost everything matched up easily that i can recall (about 5 yrs on now) was from a --manual-- Nubira..

[Daniel]

electro magnetic valve? this is on cool side of Block, somewhere under inlet manifold?

This valve is well under intake manifold. At least on the 1.6DOHC. Best is to look from under car.

Edit: here's for the 2.0 DOHC

[benzino]

if it's a manual engine, it won't have that no.23 solenoid

is there wiring for it hanging loose in the engine bay from the old engine? if yes, you should be able to install a new solenoid and that could be where your problem lies...

if there's no wiring, try to determine whether it has been cut or simply was never there (assuming you kept the original wiring harness and just changed over the engine)

[MatesLeganza]

yes, Ill just have to have a fresh look under there, and post a pic of the old broken engine, which whats left of it is still here..

maybe this relates to the whole cut-out issue?

[benzino]

could be
the computer could be assuming that it is getting the exhaust gas when it isn't making it run like a pig

however, usually the problem is too much exhaust gas making it run lean, in your case though I'm not sure if it's getting too much or too little as I'm unsure of how the non-OBD2 EGR valves work
the manual has the valve but no solenoid and the auto has both and I'm unsure whether the manual gets a preset amount of Ex. Gas or if it gets none

maybe daniel knows
(maybe daniel will one day share his source!)