VE Omega Series 2 - Misfire - Odd Issues

[bigdaddycool]

So we just bought a VE Omega Series 2 unreg to try and fix up for our daughter. Very much a mistake.

Drove fine, bought it......... got it home hestitated going up out drive way, drive fine otherwise. Owner said when it got hot it'd loose power and go into Limp Mode. Tech 2 showed multiple misfires. Coolant while running check showed head gasket was likely not the issue.

Replaced the water pump, injectors, spark plugs and coil packs (for sake of it being like new type thing). Went around in circles for a bit due to buying some cheap chinese injectors not realising (that story). Got some geniunes through in, fired up no misfire...... seemed fine. Backed it down the driveway put it under load with foot on brake no misfire...... few mins later started running rough and misfires on 2, 4 and 6.

Prior to the work it was generally just all over in terms of the misfire. We also replaced the crank sensor and updated all the various computers etc. It's got some 95 fuel in it.....

The fuel trims are reading like -39 for the LTFT and STFT is like normal........ but at one stage one side of the engine went the opposite. When we had the injector issues we had cylinders being flooded by stuck open injectors...... I'm wondering if the o2's or cats are stuffed........ also someone else on the forums here said they had a similar thing and it turned out to be a broken valve spring or something.......... but yeh I'm at a loss and about to loose me sh*t.

It's the 3.0 LFW V6. *shrugs* I don't know.... I've tested all the wiring back and forth to the injectors from the ECU and thats all fine...

 

[krusing]

"We also replaced the crank sensor and updated all the various computers etc."

Why ?

Wasn't the original ECU ok ?

if 2, 4, 6 misfire, there has to be a common denominator for Bank 2,
Earth/ground ?
Look at the connectors under the bonnet, corroded or damaged, or lose at the ECU.

Don't worry about the fuel trims until you get it running correctly,
Then address those by re-setting them later.

 

[bigdaddycool]

Well I've checked all the injector wiring all the way back and all thats fine. I haven't checked all the coil pack wiring, some of it and it seemed fine atleast to the ECU and that the ECU is supplying power but thats all.

The injectors earth at the ECU, the coil packs also I beleive... maybe not I have checked all the earths...... So I dunno.

It didn't have overly rich trims before the injector swap nightmare. It was maybe -5 to -10 at most......... now it's -30 to -40.

I got no history on the car so I'm trying to figure this out. It had a weird hesitation/stumble coming up my driveway when we got it which is why I just ran through the motions, plugs, coil packs then injectors........ As at that time it just had a misfire and trims were normal etc it wasn't running rough etc.

Fuel pressure seems fine so...... I'm really at a loss short of maybe an intake leak but that would result in a lean condition. I don't think the O2's even if they were completely stuffed would cause this rich condition, misfires on the one bank and the stumble ......

Weirdly if you hold ya foot on the brake and rev it up it's fine, but if you drive it on a slope...... it doesn't run good.

I figure once I get the misfire and fueling sorted properly whatever it is........ the weird hill stumble will sort itself.

 

[lout]

you may have fouled the plugs with the crap injectors
what injectors are in it now
do you have your own scan tool and if so which one
double check your work that everything is plugged in correctly
the plugs and coil packs, where did you buy them

 

[bigdaddycool]

So it seemed fine this morning, some white smoke came back....... no misfire....... however once the car heated up at a certain point it just crapped itself........ Either it's got a clogged cat causing mahem...... as just before it crapped itself, an o2 got stuck on bank2 and then it just got richer and richer......... these cars by default enrich fuel the hotter the cat gets.......... I didn't look at the cat temps so thats next on my list...... to start from cold and watch what temp the cats get upto....... I got a feelin it's either the passenger side cat being stuffed or....... there's some really minor head gasket issue thats only showing up once it's upto temp for a bit.

 

[Fu Manchu]

coolant in the exhaust gases would ruin a cat, so if a cat collapsed, there would be a logical reason why.
Have a compression test done on the car to confirm if the head gasket is compromised.

 

[lout]

cracked heads/head could account for your symptoms

 

[Fu Manchu]

this isn’t going to be a hose or a sensor playing up. Parts swapping is not going to resolve it. Something big is going on.

Heads off. No matter what. Then chains and oil pump should be done at the same time.

 

[uglyoldfatbastard]

When we changed out the last LF1 for a LFW and they are the same engine in reality just the ECM on the LFW handles E85 fuel it was doing a lot of similar things as what this one is doing. Part of stripping the front of the car to take the engine out requires to remove the radiator overflow which we found had quite a lot of oil at the bottom and both cats were knackered.
Good place to have a look in the coolant overflow and if there is a lot of oil then you know you have a major issue.

 

[bigdaddycool]

When we changed out the last LF1 for a LFW and they are the same engine in reality just the ECM on the LFW handles E85 fuel it was doing a lot of similar things as what this one is doing. Part of stripping the front of the car to take the engine out requires to remove the radiator overflow which we found had quite a lot of oil at the bottom and both cats were knackered.
Good place to have a look in the coolant overflow and if there is a lot of oil then you know you have a major issue.

Yeh my plan is to run it and monitor the cat temp.......... I got a feeling it's just one side. Weirdly its fine cold, it handles reving to 4000rpm whatever fine....... but once it warms........ much richer and what not.

I can't get the O2's out........ even with a proper o2 tool so I figure I'll just unbolt both sides down to the secondary join underneath and take em out and chuck a camera scope thing down the pipe and take a look at them. Get the damn o2's out and soak em in some brake cleaner or somethin....

To those talking head gasket........ yes I will after doing the exhaust checks perform a compression test and probably a leak down test to check the valves.

But that said I have performed a Cylinder Power Balance test via the Tech 2 to check cylinders and they generally seem fine within 10 rpm of each other.

This was a project car for my daughter.... Had a bunch of little things which I've fixed. Now just the engine. I'm debating whether to sell it or just spend the time and rebuild it. I have had the rocket covers off and seen nothing out of the ordinary.

Things mostly left on my list are a compression/head gasket issue, clogged cat/s, buggered o2's, ecu, high pressure or low pressure fuel pump maybe two.

I have another commodore the same which I am going to check some readings from. The fuel rail pressure for example is meant to be 4.0 at the rail at idle/light load....... it drops to 3.5 which might be normal as the fuels a tad rich.. The rich being a symtom ......

If it is a compression issue or a head gasket issue I recon it won't even show up when cold.... the coolant doesn't boil or weird things like that.

I really don't like repairing things for the sake of it, and this motors not really something you could upgrade like an LS. If it was a LS I'd take it out and redo it all with upgrades.

I'm gunna bet on a CAT being my issue..... which is still a pain to fix/test and diagnose. I'll post whatever I find as I have seen around the place there are alot of threads with questions on this 2,4,6 bank thing etc and never a solution. I did find my coil packs pins were rusted oddly, and I find with fixing x electrical issues on the car just using some circuit cleaner, a file to file connectors down and then just twisting the pin lightly it creates better contact. eg. SRS issues....... their special plugs are crap, doing that plus an extra zip tie ...... proper fix.

There's also an earth down under the ABS near the alternator too worth a clean. I paid for all the manual stuff so I got most of the wiring diagrams and all the rest..... I did all the ohm and connectivity tests across, I guess also monitoring the ECU's control wires to the coil packs and the earths on the injectors is also another thing. The Tech 2 does show injector driver voltage as well which I'll compare to our other VE here...... it runs 65v which is 10-11v per injector....... which is probably normal.

Sorry for the rant.... Just annoying.