VR Calais idle problems

[Poor old Dad]

Hi all,
new to forum. Well set out and very helpful people. Thanks for the opportunity to seek help.

My daughter's '94 VR Calais conked out on her way to work last Friday. There were no symptoms leading up to it, it just died. She tried starting it but although it fired, it wouldn't idle. It's exactly as if it's run out of fuel. Tilt tray home where she got RACQ to have a look. According to RACQ guy the vacuum was ok but he couldn't pull any codes as he couldn't get a connection between scanner and ecu(??).

So, dad gets to play with it

On reading this forum I've cleaned throttle body and IAC (managed to break gasket so a new one made... and then broke one of the IAC screws. Drilled and tapped a new thread, so all good again.)
It idled better after that but still dies particularly if any accelerator is used. (It will rev and hold revs, eg 2000rpm, if accelerator is "feathered" to get it past flat spot, but will eventually die if throttle is released.

Further reading and I used the paper clip trick for self-diagnosis.
At first, code "12". Then code "13"
I reset ecu and then code "12" only.

During one of it's better idling performances (30 seconds) I thought I'd put it in gear but when I put my foot on the brake (to save running into the garage door) it immediately cut out. Tried it a couple more times and same thing - immediate drop in rpm with brake application. More reading in here and then tried expelling brake booster before starting and seeing if pedal got firmer after starting. It did, so maybe no joy there?

I tried fault codes again and after a "12" I got a "13" and then 4 continuous blinks as in "4" - definitely no pause after the first blink (to denote a ten). From then it would not reproduce the "12" then "13"... it just kept blinking 4 times.

So, where it's at now is a very erratic idle. If it will idle, it sounds like a very lumpy cam. It varies anywhere between 500 and 1000 rpm. A huge flat spot if accelerator used. There's no check engine light on.

I'm lost so would appreciate any help you guys can share.... cheers.

edit: just removed throttle body again and checked IAC operation. It seems to work ok... about 2mm movement??

[FstStig]

Daughters phone number if she is over 18 and I'll give you the answer LOL :P

Seriously though

Sounds like its either your Coil Packs and DFI Module, get yourself a Multimeter and test these, make sure they come to the factory specs. You may need to get yourself a Gregories or a Haynes workshop Manual. Try giving your MAF (Mass air flow sensor) a clean its the sensor after the Air box. Test this with your multimeter as well. Check the Spark plugs gap and also the resistance on the Spark Plug leads..... If all of the above check out ok, move onto your Injectors as it sounds like your missing on a cylinder or 2.

[FstStig]

Edit: Just notice it was a VR so no MAF, you will instead have a MAP sensor (Manifold Absolute Pressure sensor). This will be located at the back on the fire wall on the Passenger side.

[FstStig]

Edit 2: code 13 = O2 Sensor or Oxygen sensor. These are a sensor that go into your exhaust, not that hard to replace and is most likely your problem

[Poor old Dad]

Thanks for taking the time to reply, Mumboman.

I was thinking about oxygen sensors but am a bit concerned about throwing money at it when the codes are inconsistent or at least it seems that way to me.

I'll get the 02 sensors tomorrow and let you know how it goes.

(if you're a Commodore mechanic I'll send my daughter's phone number along, I'm getting too old to be crawling around cars, lol)

[Brett_jjj]

If the engine is stalling or changing revs when the brake pedal is pressed,then it sounds like theres a vacuum leak somewhere,Id first try disconnecting the brake booster vacuum line from the booster,then block it off with your thumb and run the engine,keep it blocked and see how it runs then,if it runs fine,the brake booster diaphram is probably faulty.If theres no change,then reconnect the booster vacuum hose and check around the rest of the engine's vacuum lines for splits, cracks ,disconnected hoses etc.Pay particular attention to the rubber hoses and lines that go to/from the plenum on the top of the engine.Theres also a vacuum reserve line under the left front guard.It looks like a black plastic ball,this has a vacuum hose going to it,so check that as well.Id also try another IAC valve if nothing else works.Ive seen one cause problems before with idle etc,and it didnt even set off an error code...

[FstStig]

I suggest you give everything a good clean first and do the vacuum leak test as Brett_jjj has suggested, these are cheap and generally free and easy to do. If you do all of that and the problem is still there, then I would suggest moving on to the O2 Sensors as this is the code it is spitting out. Each code will repeat its self 3 times over before moving onto the next code. So did it throw out a code 40?

[Poor old Dad]

If the engine is stalling or changing revs when the brake pedal is pressed,then it sounds like theres a vacuum leak somewhere,Id first try disconnecting the brake booster vacuum line from the booster,then block it off with your thumb and run the engine,keep it blocked and see how it runs then,if it runs fine,the brake booster diaphram is probably faulty.If theres no change,then reconnect the booster vacuum hose and check around the rest of the engine's vacuum lines for splits, cracks ,disconnected hoses etc.Pay particular attention to the rubber hoses and lines that go to/from the plenum on the top of the engine.Theres also a vacuum reserve line under the left front guard.It looks like a black plastic ball,this has a vacuum hose going to it,so check that as well.Id also try another IAC valve if nothing else works.Ive seen one cause problems before with idle etc,and it didnt even set off an error code...

Thanks for that Brett. I checked vacuum lines as best I could and couldn't find anything suspect. I thought about getting anotehr IAC but again wasn't sure about it and didn't want to spend $500 on different bits and pieces when I don't know what is what and how it's 'sposed to work. I actually did crimp the booster vacuum line with a pair of pliers. It didn't make any difference to the idle (which I thought meant it is ok?) So, if the booster diaphragm is faulty does it effect idle at all times or only when brake is applied?

I suggest you give everything a good clean first and do the vacuum leak test as Brett_jjj has suggested, these are cheap and generally free and easy to do. If you do all of that and the problem is still there, then I would suggest moving on to the O2 Sensors as this is the code it is spitting out. Each code will repeat its self 3 times over before moving onto the next code. So did it throw out a code 40?

Thanks again Mumbo... yep will follow your advice. Maybe a trip to the wreckers and pick up a few second hand bits and replace one by one until problem solved.

Probably it was a code 40. Didn't think of 4 x 10 - was thinking of 4 x 1. I'll look up code 40 and see what else in in store... cheers

edit: can't find a code 40 - there's also no code 30 or 50 either - or am I the only one who doesn't know where to look for those?

[Brett_jjj]

Id just get a second hand IAC valve for a few dollars,see what happens then,also usually when the booster is faulty it will either leak all the time or make a hissing sound.I cant remember if the it makes a difference if it does it when the brake is pressed or not,its been a while since ive seen one,but you can test the booster,just try the following,with the engine off,push the brake pedal a few times to deplete any reserved vacuum.Then hold the pedal in firmly and start the engine,if the pedal sinks in as the engine starts,then the booster is ok..

[Poor old Dad]

if the pedal sinks in as the engine starts,then the booster is ok..

Yep, pedal sinks and then builds up pressure. Ok, busy day tomorrow
Cheers mate...

[BottleFedVS]

Check the fuel pump pressure as it may not be able to keep a consistant feed to the injectors & they need approx 180psi consistantly to run properly.
I hope that helps.

[88GreenVN]

I just spent the better part of 2 months chasing a stalling/bad idle V6 and after replacing all the usual suspect items I spent $66 on a new IAC stepper motor. Now runs and idles like new. I would highly recommend replacing this item first before all else if the idle is the problem and the vacuum ball is holding pressure.

[FstStig]

The first flashes of the code are in 10s so if it flashed 4 times it would be 40, then it will flash again with 1 units so if it flashed 2 times after the 4 it would be code 42, this will happen twice more before moving on.... Didn't think a Code 40 ever existed.

[Poor old Dad]

Check the fuel pump pressure as it may not be able to keep a consistant feed to the injectors & they need approx 180psi consistantly to run properly.
I hope that helps.

Thanks mate. It runs reasonably well at 2000rpm with no load so I think that the fuel pressure is ok?

I just spent the better part of 2 months chasing a stalling/bad idle V6 and after replacing all the usual suspect items I spent $66 on a new IAC stepper motor. Now runs and idles like new. I would highly recommend replacing this item first before all else if the idle is the problem and the vacuum ball is holding pressure.

Cheers, got a second hand one today. Definitely idles better but still not good.

The first flashes of the code are in 10s so if it flashed 4 times it would be 40, then it will flash again with 1 units so if it flashed 2 times after the 4 it would be code 42, this will happen twice more before moving on.... Didn't think a Code 40 ever existed.

What it's doing is 4 rapid flashes. No gap between any of them. You'd think that would be 4 or 40 but neither exist. At least the 13 is gone now. Just 3 x 12 and then 3 x 4

Thanks for replies guys. As I said I replaced the IAC with a second handy which improved idle a bit. It will actually idle but it's as rough as guts and fluctuates with a 1500rpm spike every now and then. Anyhow I managed to take it for a drive up our driveway a couple of times. It misses and farts and carries on. Same sort of thing as if the engine was washed and got water in distributor.

I'm far from an expert but I'm thinking in no particular order, coil/ecu/dirty fuel.

Any thoughts on those or whatever else it may be?

[88GreenVN]

The computer learns the idle setting again after you take it for a bit of a drive. After I installed the new IAC it would rev no probs but instantly stall when you let off the peddle. By the time I had driven down to the mechanic (yes I had given up on getting it running right) it was idling no worries and the only issue was it was dual fueling when I tried it on gas. So petrol it is for now

If it's running stupid and poping and so on you would think it would be along the lines of leads/plugs/DFI/coils. The cas and balancer can make it run poorly also - is the balancer in good nic? If it's moving around a little (on the way to it's death) it can chop the CAS up which in turn kills it and the engine from running.

[FstStig]

Agreed with 88GreenVN, next would be the coil packs and DFI module, having one of these coil packs can make the car run like a retard. It's unlikely to be the balancer and CAS as its rare thing for these to fail, but that's not to say that they don't fail because just like everything else in the car, they can fail. Take the DFI module and Coil Packs off (the DFI Module is located under the Coil Packs) and take it to a mechanic or auto electrician and get them to put a multimeter on them to see if they test out ok.

[FstStig]

I'll show you my photos if you show me yours

Here are some pics of the DFI Module and Coil Packs


The DFI plug will be held in with a 10mm Bolt


Then the bracket will be held in by 2 17mm bolts (I think they are 17mm been a while since I have changed them)


Hope this helps a bit

[Poor old Dad]

Thanks again guys.

I bought a Gregory's this afternoon. It's got the testing procedure for coils etc in it so when I finish work tonight I'll see if I can figure it out.
Really appreciate the effort you fella's are putting in. Cheers...

[VrWagz1]

The only problem, with testing coils with multimeters is their voltage is way tooooo low to detect any breakdown of the coil unless its good an proper fugged. Not saying its useless but an insulaton tester is much more appropriate but its not an everyday item for most people.
But follow the procedure, but if you find nothing all im saying is still dont totally discount that a coil could still be busted.

[FstStig]

Cheers for that VrWagz1, didn't know that Guess you learn something new everyday.

[Poor old Dad]

Thanks Wagz, that being the case I'll just go down to the wrecker and start with the coil pack. My daughter has borrowed a car for a couple of days so the pressure is off a little.

[Poor old Dad]

Still no go

Today I changed over the coil pack and ecu and also replaced the fuel filter. I also double checked the vacuum lines.

I'm at a loss. It's now actually worse than it was yesterday. Idling very rough (or cutting out), huge flat spot when attempting to accelerate. FWIW you can smell it running rich as, and the inside of the exhaust pipe is black soot.

Looks like a mobile mechanic to add a few dollars onto that which I've spent.

Any final ideas/strategies before I shut the shed up?

Cheers...

[FstStig]

Fly me up and I'll work it out lol :P So hard to tell over the internet..... Only thing left I would say is your injectors need either replacing or a real good flush out. Put the old Coil packs back on and see if that helps with the idling, you may of been given a crap set of coil packs being second hand.

[Brett_jjj]

If it seems to be running heaps rich then Id check that the fuel pressure regulator isnt leaking fuel into the inlet manifold,they can do this when the diaphram inside the regulator splits,and fuel leaks past it straight into the engine making it run crook..also low fuel pressure caused from the dodgey fuel pressure regulator wont allow the injectors to run properly as they need the fuel to be at a certain pressure to work properly,so Id be giving it the once over too,make sure its working fine.

[Poor old Dad]

Thanks guys. I'll spend an hour on it in the morning. It seems simple enough to check the FPR for faulty operation.

If you hear of a car ablaze in Brisbane and a madman on a high rise with a sniper rifle, you'll know who it is...