Mystery Miss

[POVO VS UTE]

G'day Commodoreans,

Just new to this Forum, as I have just acquired a VS V6 Auto Ute '95. My knowledge of cars stops at the WB Holden, so EFI/ECU issues are a mystery to me. I hope you can help. Here's the story:

Just picked up a cheap VS Ute as a run around work car, knowing it had a miss. Previous owner thought it may be the knock sensor (don't they just retard the timing?). Here's what I have know so far:

290,000 k on the clock
Replaced Coil Packs (unverified - only told by previous owner)
Replaced Ignition LEADS (As above)
Does have an OTR intake (no other engine mods that I am aware of)
Does have a VZ Auto fitted by previous owner

Took it to my mechanic for RWC & general check up, and so far has done the following:

Replaced the intake manifold gasket - No Difference
Mechanic told me that he had pinpointed the miss to cylinder number 3 (but that maybe only because of the item below, I'm not sure)
Compression check showed 100 psi, all others were up around 150 psi
Tried a different Spark Plug - No Difference
Tried another injector - No Difference
Cleaned the BEJEEZUZ out of the injector, intake runners - No Difference
Scan revealed no engine errors
Scan did come up with Air Bag (it has an aftermarket steering wheel that I am returning to standard) & O2 Sensor (Would that cause a miss and how do I check it?)

The miss is always there, only slight on light throttle, and mainly audible through the exhaust, but under load, will back fire through the intake. It does not blow any smoke at all. I'd be very interested in suggestions, and perhaps common problems with this model/engine as I am not familiar with them at all.

By the way, Mace Engineering where are you located? If I am unable to source the problem, I may have to bring it down. My mechanic, whilst a nice guy who would never rip me off, is really just using the Process of Elimination to try and solve the issue, which is starting to add up.

A big thanks in advance,

Dom

 

[richardpalinkas]

Try replacing the dfu, it's under the coil packs and can become faulty

 

[adz_vy]

How much have you spent changing the lim gaskets and cleaning injectors etc. at 290,000 kms may be better off replacing engine with a s/h vy motor as you can pick them up for $300-$500 depending on ks. Or if funds permit, put an l67 in it. Just a thought.

 

[POVO VS UTE]

I don't know yet as the mechanic hasn't given me the bill, but put it this way, I'm already quivering in fear! Previous owner changed out the coils and leads apparently, so I haven't coughed up for that.

Just so I can educate myself with all related EFI hardware, dfu stands for what and what does it do?

Also, is there anyway I can test these components prior to replacing them? I don't want to be throwing good money after bad, certainly if I don't need to.

That Auto box I discovered must be from a VY at the latest I am told because the VZ'z are apparently a different bolt pattern, or so a Wrecker tells me.

Cheers.

 

[POVO VS UTE]

Found the miss, no need to guess any longer. Mechanic did a Leak Down Test, and number 3 cylinder exhaust valve is leaking. Great News! So my next question is, anyone know where I can get my hands on a cheap set of Ecotec heads? All I want is a car that runs right.

 

[adz_vy]

eBay, wreckers, jc/jc market section.

Just make sure you weigh up the costs. We've recently fitted a vy motor with 142,000ks into a vs all for under $500 and sold the old engine to a wrecker for 60 bucks.

The old engine did a bearing at 300,000ks.

 

[darcycammo]

When you say cheap how much do you want to spend? and where about's in Melbourne are you ?

 

[POVO VS UTE]

I'm in Preston. All I want is a run around car that runs ok! I've had a look at 2nd hand motors and they are way cheaper than reco heads. So far I'm looking at $850 for reco heads, bolts and a gasket kit. I've seen plenty of VS V6's with less than half the k's of my current engine (180,000) for $500. I take it VS/VT/VX/VY motors are all from the same family? So I can use any of those?

Thanks for the help so far.

 

[adz_vy]

I'm in Preston. All I want is a run around car that runs ok! I've had a look at 2nd hand motors and they are way cheaper than reco heads. So far I'm looking at $850 for reco heads, bolts and a gasket kit. I've seen plenty of VS V6's with less than half the k's of my current engine (180,000) for $500. I take it VS/VT/VX/VY motors are all from the same family? So I can use any of those?

Thanks for the help so far.

Yes you can but there are slight differences across the range like throttle bodies and/or plenums which are all completely interchangeable. But any motor vs-vy will go in without much fuss.

 

[vxcp]

i have the same issue with my vx dude