[ConorD]

hey guys,
just got the car running after months of being off the road, it's running really rough and we thought it was dirty fuel or a dodgy filter so we replaced both and its still doing the same thing.
As the topic title suggests the car is only running on 4 cylinders instead of 6. we have switched coils between one that was working and one of the cylinders that weren't. Did the same with the spark plugs and the fuel injectors and the injector cords. just a bit lost as to what it could be or if any of you had a similar issue.
the cylinders that aren't working are if you're standing at the front of the car it's the left-hand side bank the middle and rear cylinders.

Also if we take the car for a drive for longer than 10 minutes the catalytic converter goes red hot and if your standing at the front of the car with the bonnet up you can see the smoke coming from it.

if anyone has any ideas let me know

Cheers,
Conor

[30ONA]

How do you know which cylinders are missing?

well till you add info to answer above not sure on injectors. But sounds like you have at least a blocked cat.

[ConorD]

30ONA wrote:

How do you know which cylinders are missing?

well till you add info to answer above not sure on injectors. But sounds like you have at least a blocked cat.

We know the cylinders aren't firing because when you unplug the coil there is no change in revs, if you were to unplug a cylinder that was firing the engine would start to miss and run worse. When you unplug those 2 cylinders that aren't firing there is no change to the way that the engine runs.

[Gwagensteve]

My guess is the car is running red hot because the fuel from the two non-firing clylinders is burning in the exhaust manifold.

Sure that bank is timed correctly?

[ConorD]

Gwagensteve wrote:

My guess is the car is running red hot because the fuel from the two non-firing clylinders is burning in the exhaust manifold.

Sure that bank is timed correctly?

It starts pretty well and the front cylinder on the left side (standing at the front) is firing really well and all cylinders on the right hand side are all firing as well.

If the timing is a little bit out surely it would affect all 3 on the bank and not just the 2? I could be wrong though

[30ONA]

Is there fuel in the missing cylinders?

[ConorD]

30ONA wrote:

Is there fuel in the missing cylinders?

Yeah mate the spark plugs are wet and you can smell the fuel

It seems to run rough (the cab and engine shake) until you hit about 2500-3000 rpm and it all smooths out, I thought that if the cat is blocked that the pressure might build up and stop the valves from opening/closing but then I wasn't sure why that would only affect those 2 cylinders and not them all

I might call up RACQ tomorrow and say it's having trouble starting and hopefully the person that comes out might have a OBDII scanner and so I can see what codes it's throwing

Let me know if you guys have any ideas

[Gwagensteve]

Quote:

pressure might build up and stop the valves from opening/closing but then I wasn't sure why that would only affect those 2 cylinders and not them all

Huh?

[ConorD]

Just trying to throw ideas out there

asking if the cat is blocked would the exhaust pressure that isn't escaping cause the valves on those 2 cylinders to stop opening and cause the cylinders to stop firing? Or is that not possible?

[30ONA]

I have a 2004 gv. and racq couldn't read the codes. But try if your a member because it's free.

I feel like it's an injector fuel issue. Have you tried a full tank of 95 or better and a bottle of injector cleaner?

[fordem]

Have you done a compression test? Are the numbers within spec and comparable across all six cylinders?

You say you're getting fuel to all six cylinders, and you've swapped the plugs & coils - is the ECU firing the plugs?

Can you get access to a lab scope or some other method of checking the ignition coil drive signals - you can try an inductive timing light - try it on one of the working cylinders first - look at the coil connectors, you'll see three wires going to each coil, one is +12V, one is ground, one (the center wire) is the drive - my timing light will flash if clipped over the drive wire.

[Gwagensteve]

ConorD wrote:

Just trying to throw ideas out there

asking if the cat is blocked would the exhaust pressure that isn't escaping cause the valves on those 2 cylinders to stop opening and cause the cylinders to stop firing? Or is that not possible?

That is not possible.

[ConorD]

It only has 91 octane fuel in it but I put a whole bottle of injector cleaner into the tank as well

I've done a compression test and both cylinders that aren't working are sitting at 220psi and most from memory all were between 200-220

Yeah the ECU is firing all spark plugs because when you take the spark plug out with the coil and everything still attached, I held it to the manifold and turned the car on, and you could see the spark

Yeah i should be able to get my hands on a timing light to test it but if there is spark there shouldn't be anything wrong right?

If the 2 non working cylinders are getting spark and fuel is it possible that they are getting too much fuel from the injectors and while at lower rpm it's just soaking the spark plug and it's getting too wet, then by the time you hit about 2500rpm it smoothes out because now the spark-fuel balance is correct? Which would also mean that fuel is being dumped down the cylinders and then getting stuck in the cat and burning up (hence the red glowing cat) is I'm right it would be a seal issue between the injector and the manifold or maybe from the injector to the fuel rail?

The injectors aren't the issue I don't think, because even if you switch the 2 non working injectors with 2 that work the cylinders don't fire up

[Gwagensteve]

OK. This thread rang a bell so I just did a search.

After you were cranking the motor without the timing chains connected, did you remove and rebuild the heads? If not, how did you confirm you don't have bent valves, bent valve gear etc etc etc.

If you did have the heads rebuilt, did you actually confirm that both cams on that bank were properly timed? Just because you're getting compression doesn't mean the spark is happening at the right time or that a cam isn't 180 degrees out.

Are you getting a CEL? if not, there's no codes to view with a reader.

Currently, you're telling us you have fuel, spark and everything else is good/normal. It's clearly not. Your troubleshooting is also implying you have fuel and spark. to that bank.

You're messing with a pretty complex motor (mechanically) and your previous mistake of cranking the engine with no timing gear connected implies you're not deeply experienced mechanically. That's fine and good on you for having a go, but it seems like there is something quite serious amiss with your engine. Did you seek the advice of a mechanic and/or triple check everything against the FSM before hitting the key?

[Aussiesumo]

Hi Guys lets restart the story.
4 months ago while camping my son drove through some water (quite deep) & had to get towed back to the camp site. We had a quick look over, removed the plugs & let the motor air out. We then turned it over by the key, without plugs in just encase there was water in the cylinders, but no visible signs of water. Cleaned the plugs, but still wasn't firing up. So had it trucked back to Brizzy & there it sat for a few weeks, until we got back.
Upon arriving home spoke to the neighbour, who is mechanic by trade, and we decided to pull off the front timing cover to have a bit of look. Timing chain was fine, but off the guides was broken, which we new because it had that nasty noise they all make. So at that point in time we decided to replace the chains, guides & tension's. Now at no point in time was the car turned over via key with chains off & cams in place. The motor was manually turn over (via the crank bolt & breaker bar) but the cams were removed & no timing chain, we check the heads to make sure all valves we up & seated. This was done via a camera being placed down the inlet & exhaust holes on the head, plus we also made sure the valves we free & moving by pushing down on them. The reason for doing this I wanted to make sure the bottom was moving nice & free before re-assembling.
I believe the timing is right as all the timing gear marks where aligned with there appropriate marks on the head & block, plus the marks on the chains all matched the marks on the timing gears. Turned it over manually 2 turns & the timing marks where all still aligned to the timing marks on the head & block. So we re-assembled the rest, new spark plugs, air, oil & fuel filter, engine oil. Before fitting the radiator we did another quick manual spin just to have a feel.
The car didn't fire straight away, well it didn't fire up at all. Battery was a bit low, which is what you'd expect since it had been sitting for 3 - 4 months. So pulled it out & charged it up. Tried it again but still nothing, so we did a compression test on all the cylinders, which came up to from memory around 200psi. Check to see if the plugs where sparking all good, so went inside sat on the dummy to have a think. Upon returning the neghbour asked if I'd checked all the fuses & I said yes except for the ones cover with the rubber boots. He pulled the rubber boot off one, I can't remember which one, & said it's got water in it. Sprayed it with a bit of Inox & blew it out with the compressor, and it fired up. Not wanting to idle, but a quick adjustment and it was idling by itself, rough but idling.
Which brings us to our current drama. Car idles rough especially in drive, once you get to about 2500rpm it gets a little better, there is no power at the lower rpms just a lot of stuttering. If you hold the gear (it's an auto) say 2nd let it rev to around 3500, you'd never think there was a problem. So this is what we done to weed out the problem:
1. with the engine running disconnected the coils form each cylinder(one at a time), when four of the six are disconnected the car runs rougher. Hence how we have narrowed it down to the 2 rear right cylinders.
2. swap over coils, still the same result.
3. swap over spark plugs, still the same result. But what I did notice was that the spark plug on the missing cylinders was clean as, like it was brand new (which it is) and wet, plus smelling like petrol. Whereas the firing cylinder had the usual blackness of a firing plug.
4. removed the plugs & earthed out to manifold, they all spark.
5. swapped the fuel injectors over, same thing.
So don't be to hard or dismissive on Conor he's just telling you what 3 other people (2 being mechanics by trade) are pulling there hair out about. The only thing we haven't done is spray some carb cleaner or start u b##tard around the manifold & certain hoses testing for a leak. It's a really weird one I've never come across before.
Hang on there is even more weirdness. It was suggest to me to swap the electrical side of things (coil & injector) to the opposing cylinders, which for me was like.....what the !!! Now I'm old school, but surely they would have to fire in a certain sequence, but I was what the hay got nothing to lose. Guess what no difference car running exactly the same with exactly the same conditions, which doesn't make any sense to me. There is no CEL light on, so I don't know if a test would pick up any O2 sensors, but we are at a complete lose & don't know where to go from here. Electrical......mechanical.....who knows.
For those who have problems or can't believe any of the above we can gladly post a video showing all of the above.

Cheers & thanks for any help.

[Gwagensteve]

So, I'll ask again, have the heads been off since the engine was cranked with either water in the bores or the timing gear removed? Because it it sounds like they haven't been. The valves/timing gear is bent. The engine is toast. It was toast the moment it went through deep water and stopped. Everything else is denial.

[Aussiesumo]

No the heads have never been removed.
But if the valves are bent or not seating properly, why would the compression be the same as the other cylinders. Once again I could be wrong buf you have a bent valve it remains partial open and therefore no compression. Also in a leakdown test would you not hear or see (if head gasket is gone) the air through the exhaust or carb and bubbles in the radiator (if head gasket is gone) ??

[watermouse]

So from what I can tell two cylinders on one bank are not firing. Agreed that a compression test would probably show up a bent valve.
Have you tried swapping the coilpack leads for those two cylinders?

In summary
Fuel, Check
Compression, Check
Spark, Check
Timing, ?

[atari4x4]

when you say you swapped coil packs... was it just the coil assembly & not the probe that goes down through the rocker cover or were you swapping the coil pack & probes as a whole unit.

the probes have a metal rod & 2 springs that send spark from the coil pack to the spark plug & can corrode & get crusty.

agree compression test should show up bent valves.

[Aussiesumo]

Yeah we swapped the coil pack & probe as a whole unit, but only on the one bank. Even removed the spark plug & checked for spark by earthing out.
The timing hasn't been checked in regards to a timing light, but we're trying to get a hold of one from a friend.
I think it's time to hand it over to someone who has the tools to check the ECU & electrical side of things.

I like your catch phase, because I'm starting to hate this car because I don't understand.

[30ONA]

One bank not timed correctly with the chain install.

[ConorD]

So the bank being timed incorrectly would only affect 2 cylinders not 3?

[Gwagensteve]

You won't know whether that one cylinder that is running is firing on the correct cycle. You can time a 4 cylinder 180 degrees out and it will pop and bang and imply combustion on a cylinder or two- and you have a whole bank that's keeping the other bank turning over.

[Gwagensteve]

I still believe the engine is damaged. At the very least each cylinder should be borescoped to look for evidence of the valves damaging the pistons, because we know that's happened.

[Gwagensteve]

I know this seems really repetitive, and I have read your post Aussiesumo, but if everything you've posted is correct there is no fault with the engine.

It has spark
It has fuel
It's properly timed
It has compression.

So where do you think the problem lies?

[ConorD]

Aussiesumo wrote:

Yeah we swapped the coil pack & probe as a whole unit, but only on the one bank. Even removed the spark plug & checked for spark by earthing out.
The timing hasn't been checked in regards to a timing light, but we're trying to get a hold of one from a friend.
I think it's time to hand it over to someone who has the tools to check the ECU & electrical side of things.

I like your catch phase, because I'm starting to hate this car because I don't understand.

Just to bring the new post to the bottom of the page

[losfer]

Check injectors are properly seated into the seals in the head. Sounds to me like a air leak over those 2 cylinders.

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[losfer]

Air leaks over those 2 cylinders which is "unmetered" air by the airflow meter with cause the o2 sensor to tell the ecu that there is not enough fuel . The injector pulse opens for longer causing the rest of the cylinders to run rich.

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[losfer]

Over 3000 rpm where it seems to run fine the differential between metered air and unmetered air is a lot less .

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[ZUZUKI]

I've done chains on my car, and don't wish to repeat it anytime soon - what a PITA job.
Anyway, my memory of it is that once you line all the chain links up and line up cam gear teeth to dowel pins to confirm all is where it should be, then turn the engine over by hand to ensure it doesn't have interference, those timing marks don't line back up again & apparently don't do so again for many hundreds of revolutions.
Concerns me a little that your engine apparently did all line back up after 2 revolutions - makes me wonder if you were looking at all the right marks?
You did say you haven't done a spray around the injectors / manifold with start ya bastard type stuff. If the engine tries to run differently when this is done, then what losfer is suggesting (air leak) could be the cause.
Good luck with it!.
Rgs, Michael