EGR valve VX

[kais3r]

I've had all the below disconnected and still get little kicks in the idle so I'm guessing something else.

IACV
TPS
O2's
MAFS
EGRV
All Vac points blocked in plenum

Only really need to know if the CAS can play up with the timing just enough to cause rough idle without causing serious issues like stalls or backfires etc.

Whichever way you look at it, something is causing the kicks, if everything was synchronised you might still get vibration from the engine but not intermittent stumbles.

 

[dirty hands]

interesting discussion going on here

 

[kais3r]

I don't know what those O2 values represent and what the range can be, so I don't know by how much those figures are different but going by highest and lowest 434/500 they are directly after one another in the list and also happened at the same time as the idle variation was at the lowest value of 7.

What does 500 actually represent?

Don't know what the idle variation values mean in relation to possible range and what the values represent either but there are signs in the data that something's throwing a bunch of values out every couple seconds.

What I see is revs at a low point (823) also indicated by the idle variation (7) just prior, and directly after this in the next line or two the O2 values rocket up, maybe from a poor burn/stumble, the injector volts shoot up and the battery drops voltage from the extra injector demand, all in order to fix the sudden dip in revs.
Again probably not the source of the problem, rather the ECU reacting to the real problem and getting the revs back up from the stumble.

 

[kais3r]

Happy to test another ECU if you think it may be the cause, I'll have to buy one to test but can prob get cheap at wreckers, but don't like to buy stuff without some sense or proof of failure, any way I can determine if it may be faulty? or can it be fixed with a fresh firmware upload?
There are ones on eBay that have a performance upgrade of 11kw rw on 98 premium which I run, but I can probably flash the firmware myself if I can find the file needed, then I'll see if it helps at all.

Just thinking about it, there's maybe a chance running 98 vs 91 could also be causing the stumbles??

 

[meady_183]

Whichever way you look at it, something is causing the kicks, if everything was synchronised you might still get vibration from the engine but not intermittent stumbles.

Stop wasting time guessing. If you don't have access to a tech 2 go to Holden, or find a good mechanic who will use the tech 2 or equivalent scan tool tomanipulate each sensor and check for ANY faults.

I'm not saying this as a forum "know it all". I finished my apprenticeship at Holden, and have seen and felt what you are talking about. We used to have customers like yourself all the time. It's not a bad thing, it's actually refreshing that you care about your car this much.

What we would do is check plugs, and vac hoses before calling them into the workshop, run an iac function test, and egr function test, reset base idle and check AFR's (maf/o2/iat).

This way the customer has been reassured that everything with the car is operating as it should. A bottle of ac delco injector cleaner and the advice to run a tank of 98 to clean the injectors a little was all we could do. Try two consecutive tanks of 98 and a bottle of injector cleaner (even though in-tank solvents do next to nothing) and see if you get any improvement

This thread has been bouncing back and fourth all based on GUESSING. I asked you for a video so I could see the vibration you were referring to, to which you declined. I've seen heaps of these motors and they all have those kicks that can be felt with the car in neutral.

And from what I've seen the CAS either fails or it operates perfectly. It won't and CANNOT partially cut ignition when in feels like it.

So I'm advising you to have a PROFESSIONAL with a scan tool run you through all the sensors you like so you can rest assured that the car is as it should be.

 

[oska]

LOL

it's perfectly normal for an engine to idle from LEAN to RICH and vary the idle speed

here's the formula



maybe you can find another problem that doesn't exist

 

[kais3r]

LOL

it's perfectly normal for an engine to idle from LEAN to RICH and vary the idle speed

here's the formula

View attachment 173829

maybe you can find another problem that doesn't exist

Maybe you should read the thread fully, I didn't have an issue with idle fluctuations, it was about intermittent engine stumbles/kicks whatever you want to call them!


Meady,

Probably no point having all those sensors checked or is there? Because I've already had them all disconnected while idling and there's been no difference in the stumbles, same with all vac points blocked off.

If you still think so, I'll do that next.

 

[dirty hands]

good luck then

 

[kais3r]

think we should leave this to kais3r ,delcowizzid and meady_183

my final thoughts
maybe this is why the confusion

to talk about and help you with your data and questions

we are saying use tech 2 equipment and software to solve this and you are using tunerpro with Vx definitions

and its like comparing a boiled egg to an orange in some aspects of the commadore idle fault

tech 2 verses your

TunerPro - Professional Automobile Tuning Software
The car is ALDL but has a OBD2 port
I don't know if it's tech2 or tech1, just works when loaded with a VX definition file.

There's no confusion, but I can see some people are becoming counter productive, when they should just move on if they don't want to help.
If I was going to go to holden or a mechanic with a tech 2, I wouldn't have come here to begin with, the tuner software was helpful with other things, not just to see what the sensors and engine are doing, I wasn't after much more, it did what I wanted.


I asked straight forward questions, if you know stuff you're welcome to answer, if you don't know or you're getting annoyed with the length of the conversation, stop coming in here, nobody's forcing anyone to reply.

I'm satisfied that all options I can take to rectify the issue myself have been exhausted so I'll take it to the next level and get it checked.

 

[Brett_jjj]

If its just a slight stumble now and then at idle, it might just be dirty or old injectors. Don't trust these " so-called" remanufactured or cleaned ones from ebay etc, as they will never flow as efficiently as brand new ones. The best they can do when they remanufacture/clean them is to get them to flow within 1 or 2 % of eachother. Found all this out after going and talking to a few different EFI places that clean them. Anyway, I replaced mine a couple of years back when one failed, and I noticed the engine ran way better and didn't have any of the slight "stumbles at idle" that these engines are known for getting once they get a few k's up. I also found after I had one coil pack fail and replaced all 3 ignition coils, that it made a huge difference to how smooth it idled and how well it ran in general. Ive also found over the years that the cheaper aftermarket coils dont work as good as genuine ones, even when theyre brand new. My old coils still tested ok with a multimeter, they had obviously lost some of their performance over time, and one was starting to cause a slight misfire under load, the three new ones made a huge difference to how it started (starts instantly) and it also made a big difference to fuel economy (I only use 98 octane fuels).