Series 2 Legnum Woes

leekscurlock

Crunching Gears
Location
WA
First Name
Lee
Drive
VR4 Legnum
Hey everyone.

So I've had my leggy for a few years now and have loved every moment of it!
It's run perfectly without a fault for most of that time. That was until about a year ago.

It all started with the odd cut out while driving long distance, it would run fine and then just loose throttle response and drop revs right down to all but 0 but not stall, after a couple of seconds the throttle response would come back with quite a jolt and then be fine for half an hour or so and then do it again.

The car then spent a while in the drive way and was only driven occasionally and still had the same problem but slightly more frequently. In the last couple of months things have steadily got worse to the point of not being able to drive the car at all. The symptoms are the same as before but much worse and with a few strange twists.

So the car now runs fine for 5 or 10 minutes and then starts to cut out in the same manner as before but instead of doing it every half hour or so it does it constantly once the car heats up (on hot days it cuts out straight away). The cutting out/loss of throttle response now also occurs when I indicate and reverse! The final thing is the car now hunts for idle when stationary. It idles fine when cold but once it's been driven for a while it hunts and occasionally stalls.

Once the loss of throttle response started to get really bad I started systematically replacing or repair parts trying to isolate what could cause such a problem all to no avail. Now I'm starting to run out of ideas and it's starting to wear thin.

At this point I have replace the plugs, fuel pump, fuel filter, MAF, serviced the coils and cleaned and re oiled the K&N air filter all of which have had very little impact on the performance of the car.

While replacing the MAF I happened to disconnect the original MAF while it was hunting for idle and it settled at just under 1000 RPM and ran fine without the MAF if a little rougher and a lot richer than with the MAF connected but did not cut out at all. With the new MAF the idle dropped right down and now runs really smoothly, I was sure that was the end of it and the problem had been found. I was wrong! After a quick drive the car started to cut out and hunt as before, so back to square one.

My final thought and only thing I have yet to change is the Crank Angle Sensor. Any thoughts on whether this sounds like a faulty CAS or anything else that could cause such a problem would be much appreciated.

Thanks a lot everyone.

Lee
 

VOLK

Stabbin' technique!
Location
QLD - BNE
First Name
Joey T
Drive
13 RA Lancer Hackzilla
When warm do your experience ignition break down?

Run codes yet? Link in my sig.
 

naughtika

OzVR4 Stalker
Location
Brisbane, QLD
First Name
Christian
Drive
'96 Galant VR4, '17 MB A180, '25 Macan GTS
your plugs are screwed..

how long ago since the last spark plug changed?

is your car boosting past the oe setup? if so, old coils + old plugs will definitely give you the symptoms that you're experiencing..
 

VOLK

Stabbin' technique!
Location
QLD - BNE
First Name
Joey T
Drive
13 RA Lancer Hackzilla
Loss of power when indicating and reversing too huh...electrical short or issue with the charging system is a possibility. Chuck a multimeter on your battery with engine running and off and post voltages.
 

Rabit

Leaving Skid Marks
Location
Qld
First Name
Robert
Drive
2000 Legnum Mint with 44589ks when I got it. Now with black leather seats. After 3 years of fun some terminal engine bay wiring issues raised their ugly heads and it died. I Now drive a 2002 Legnum and have retired the 2000 to spare parts duty.
Check the neg. side of the battery at the battery and the other end of the cable.
 

leekscurlock

Crunching Gears
Location
WA
First Name
Lee
Drive
VR4 Legnum
I have run the codes and only got an ABS sensor and a TPS, which i have read somewhere is quite normal. Ill have a poke around with the multi meter and see what voltages come up and post them. Pardon my ignorance but how can i tell if i'm getting ignition break down?

The plugs are brand new, maybe 200km old! I can't remember what make they are, maybe bosch, I had to trust the guys at my local super cheap for suitable alternatives as they didn't have the NGKs that are known suit our cars. As for boost it runs about 12 psi but does spike a bit as its only a shitty MBC that the previous owner installed.
 

VOLK

Stabbin' technique!
Location
QLD - BNE
First Name
Joey T
Drive
13 RA Lancer Hackzilla
By ignition break down I mean miss-fire. Pull a spark plug out, take a decent pic of the business end and post it up. While you're at it, check make and model of the plugs and post that too. I'm gonna assume they'll be black from overfuelling. Done a boost leak test?
 

leekscurlock

Crunching Gears
Location
WA
First Name
Lee
Drive
VR4 Legnum
So I've finally got it together and pulled a plug and it looks fine and no signs of over fueling :( and I'm not getting any ignition break down at all, the car actually runs nice and smoothly when it's in boost and not trying to stall. I gave the MAF another clean with CRC contact cleaner, rest the ECU and let it run for 20 minutes. All was well for that 20 minutes and then the car just started to surge and hunt for idle and stalling again!

IMG_6854.JPG


The plugs are BOSCH FR7DPX which are platinum with a 1.1mm gap. Which i know aren't perfect so I'll be picking up some NGKs soon.

I had a mate of mine who's a mechanic for Bentley have a look yesterday and he said there wasn't a boost or an air leak and couldn't come up with much else.

Now I've put a Walbro 255 in I can hear the pump surging and dropping just out of sinc with the idle of the car which i couldn't before, could this have something to do with the problem? Like the fuel pressure irregularities maybe?

Oh and I've still got to check the voltages as a mate has "borrowed" my multimeter.
 

Jonson

1 AYC Bar
Location
SA
First Name
Jon
Drive
MY15 X MR
Lol, they are Mc.Fucked. 1.1 is too tall and I've had no success whatsoever with Bosch plugs...in any car. That will cause a miss, not a cut.
Sounds like faulty crank/cam angle sensor.
 

leekscurlock

Crunching Gears
Location
WA
First Name
Lee
Drive
VR4 Legnum
Yeah I'll get some NGK BKR6EIXs next week and see if it has any affect. I think you're right in that its the crank angle sensor. Is it possible to determine if it's the crank or the cam sensor that's on the blitz? Here is a quick video I took today of the car dropping revs while lightly holding the throttle down and then letting it idle.

 

VOLK

Stabbin' technique!
Location
QLD - BNE
First Name
Joey T
Drive
13 RA Lancer Hackzilla
Possibly borked or misaligned tps and subsequently idle switch. Cheap datalogging cable and evoscan/mitsulogger is the easy way to check idle tps % and to check your isc step for abnormalities. I'll find my guide to manual setup.

Edit: found it. Read from here onwards. http://ozvr4.com/forums/showthread.php?p=260568
 
G

Guest

Unregistered
The Denso Iridium Tough plugs are a popular alternative around here.
 
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