VY Feels Like It's Choking and Shaky on Start

[Alcyone]

Pretty sure this is my first post. Been here since last year and always come back to look stuff up. Great site with some awesome people helping out.

Okay, having an issue with my Mum's VY 2003 Gen1 Auto. The problem is beyond me. I only started learning about cars last year. I often get part names wrong too so heads up on that Hope I can explain the problem properly.

Car is dual LPG & Unleaded. LPG added about 10 years ago. Great mileage on both. The problem we're having happens on either LPG or Unleaded. Start the car and it feels like it shakes a bit and idle is rough. Give it 30 secs and it usually comes good. Cars not a daily driver. Gets driven maybe once or twice a week. 360,000km on the clock.

Problem 1: A couple times, after starting the car, let it sit for a minute, then start driving for maybe 30 secs, you notice that if you try to accelerate, feels like it's choking or missing or something. Put your foot down and you really notice it. Can come good after a few minutes.
Went for a 1 hour drive on a 40deg day (we live in the country), left the car for a couple hours. Started it back up and seemed okay but after about 30 secs, I realised that I couldn't accelerate properly again. It ran rough as guts for about 20 mins even when I got it up to 100kms/h. Eventually came good after the 20mins. Exact same thing happened a couple weeks before.

Problem 2: Continuing from above - drove an hour back home, turned the car off and tried to start it again. Car wouldn't turn over. It tried to turn over but the engine felt like it was about to shake itself out of the engine bay. Wouldn't start until it cooled back down 15 mins later.
Mum drove about 4 hours down south and she said the car ran fine. Next morning, she started it and it choked and splattered for about 5 mins or so. Couldn't get a smooth idle. Worst it's ever been she said. I don't think she notices the acceleration issue because she is pretty soft on the accelerator.

So it seems that after a long drive, it either won't start straight back up or even if it's left for a few hours, its a mongrel to start back up and run smooth. Always after starting, it sounds sick for a minute and then it comes good but still the occasional acceleration 'choking'.

History: Last Summer was towing a load and top radiator hose burst. Got that replaced but the car kept overheating. I replaced all the cooling and heating hoses and heater tap straight away. Car kept randomly overheating. We were told that it was the intake gaskets or maybe head gaskets.
- Head gaskets tested fine and intake gaskets were replaced by a mechanic ($700.00 later). The mechanic couldn't figure out the overheating problem so we got the car back still with the issue.
- Another mechanic replaced the spark plugs, leads, serpentine belt and a pulley ($500.00 later). All up those mechanics charged $1,200 so that's when I decided to do everything myself and start learning about cars.
- A mechanic replaced the Fuel Pump and Filter approx 2-3 years ago.
Things I've done;
- Replaced the other pulleys, cleaned the throttle body, MAF, IAC, new Air Filter.
- Replaced PCV Valve (Fuelmiser), Upper Intake/Plenum Gasket (metal OEM) & Plenum Rubber Seal/O-Ring. Also cleaned the Plenum Chamber.
- Replaced Gann hose on LPG.
- Replaced EGR Gasket coz it was rusted. Used the red gasket stuff for where the metal hose connects from EGR to Throttle Body and to the EGR plate thingy. Is that stuff permanent? I went to re-torque the EGR bolts later and they wouldn't budge.
- Bought a new Natrad radiator and swapped it. Pulled the old one out, yanked the sides off and it was full of what appeared to be metal shavings. They were really fine but on the lower right side I guess that's what was causing the radiator to be blocked.
- Replaced the thermostat, flushed the cooling system again and put in some Nulon coolant. Bled the system. All was going well then.
- Replaced oil filter and oil twice in 1,000kms coz to see if that helped in any way.
- Flushed ATF and replaced. New Gasket, Filter and Seal Thingy. Worked a treat! Dirtiest job I think I ever did draining that Transmission Pan. I know how to do it properly next time though ;-)
- Tested DFI Module as per this websites instructions. Checked resistance on Leads. Checked gap on spark plugs. The mechanic had replaced them with the cooler 7 version which was correct.
- Had a check engine light for heaps but thought it was overheating related. Finally tested the O2 sensors. 1 was faulty so I replaced both with Fuelmiser brand. No more check engine light.
- Had an issue for a couple months with the Thermostat Housing weeping a tiny bit. Swapped out the gasket 3 times but finally after I went beyond torque a fraction, it seated properly. All my old-gasket razor blading might have caused that but I block sanded the top housing until it was smooth as.

Next thing I want to do is remove the air hoses from Air Box to Throttle Body and do a home made pressure test with it all out to see if any leak. Then put some air through the Throttle Body to see if any hoses leak from the other side. Not sure if I said that right. Bloke I know told me how to rig up some PVC and a flush plate with a valve on it to put the compressed air through. Does that sound safe for a novice to do? I'm a bit worried about the MAF - maybe don't test that area or disconnect it first?
I also want to test the Crank Angle Sensor and Cam Sensors. Gonna look that up now. I read it's best to replace them with OEM. Is that correct? I prefer OEM but if I can get a good deal and know the parts are solid and/or reputable, then I'm happy to take that road.
Roughly how long does it take to go from closed loop to open loop mode? Is it when the O2 sensors have heated up? After starting to drive, would that take maybe 30 secs to a minute?

Mate just lent me a VT-VY Service/Repair Manual too. Chuffed!

Any help or thoughts would be greatly appreciated.

Cheers,
Matt

 

[SavVYute]

Start with the easy stuff first...
Did you fit the right plugs for the LPG V6? they're a different gap to standard.
Oops...see you've checked that.

 

[Alcyone]

Start with the easy stuff first...
Did you fit the right plugs for the LPG V6? they're a different gap to standard.
Oops...see you've checked that.

Using the BPR7EFS-15 Plugs. Gap is set to 1.5mm. I've heard people saying that you set the gap to 1.0mm but that doesn't make sense to me because it runs on both LPG and Unleaded. Moving from the 6 to cooler 7 Spark Plug should compensate shouldn't it? Never had a backfire issue. Was thinking of buying some new plugs and throwing them in anyway. I'll grab some new ones next time I'm in Supercheap. Just bought a Compression Tester so the plugs are coming out anyway.

 

[SavVYute]

About the only thing you haven't done is replace the coils.
They have to be in good condition, especially when you're running gas.
They'll cause misfires when the engine is under load and play up when they get hot too.

 

[strgas]

BP6EFS gapped at 1.0mm , spray some craby clean around the base of the injectors to test orings sealing correctly , check the engine breather pipe has been redirected correctly - before the mixer and after the MAF - ECT sensor may be giving incorrect readings during warm up , check egr valve is isnt leaking by spraying craby clean over it , checke pure hose under throttle body isn't split or cracked same at other end

 

[Alcyone]

BP6EFS gapped at 1.0mm , spray some craby clean around the base of the injectors to test orings sealing correctly , check the engine breather pipe has been redirected correctly - before the mixer and after the MAF - ECT sensor may be giving incorrect readings during warm up , check egr valve is isnt leaking by spraying craby clean over it , checke pure hose under throttle body isn't split or cracked same at other end

I forgot to mention that I got a Fuel Injector Service Kit and swapped out the O-Rings and Filters. Vas'd the O-Rings up. Everything seemed to seat properly but I'll spray some Carby Cleaner around the bases, one at a time, to see if I hear anything. Is the Engine Breather Pipe the one that goes from the Left Side of the Upper Intake to the Front of the Throttle Body? Not sure why, but that hose goes from the Left Side of the Upper Intake to the Air Box. I think they moved it there when they did the LPG install. You mention that it should go in between the MAF and the LPG Mixer. Is it okay where it is? I kinda broke the small capped hose which they plugged up at the Throttle Body so I shoved a large bolt into a replacement hose. I might spray that too or cap it off properly. ECT sensor looks like it's prehistoric so I guess it can't be a bad idea to get a new one. Thermo fan works okay. I just had a read of an ECT post here and the chap said his idle is tonnes better with a new sensor. Will give the EGR valve a good dose of Carby Cleaner too. Will check the Purge Hose too. I kinda checked all the hoses but only visually. Is Carby Cleaner better than pulling them off and doing a manual low PSI test on them with some soapy water? Will the Carby Cleaner be very noticeable in regards to the pickup if there is a bad seal or split?

EDIT: Come to think of it, the idle did go to the crapper after the mechanic swapped out the spark plugs. I have no idea what was in there or what gap it was because he kept them. They were pretty fowl though. So you think go back to the 6 temp and only use a 1mm gap?

 

[NewbC4KE]

Totally random and its probably wrong, but I had a similar issue in my gfs old Barina and it turned out to be a blocked CAT.

 

[Alcyone]

Totally random and its probably wrong, but I had a similar issue in my gfs old Barina and it turned out to be a blocked CAT.

Pretty sure it's still the original one. Did you swap it or were you able to unblock it?

EDIT: Was it throwing a Code? I haven't got an ALDL connector or anything to scan with as yet. No error codes showing now and when I did the Dash Combo + Ignition, only codes were all zero's which I think means no errors? I have no idea how to read the 2 lines.

 

[greenacc]

Mechanic might have cracked a spark plug when he put the new ones in so that would be a good thing to check.
Gas and petrol are 2 different animals and they ignite differently hence the different gaps.
A vacuum leak would also make the idle go to crap so you will have to eliminate each one until you find the issue.
When did you service the injectors? Did it run properly after that?

 

[Alcyone]

Mechanic might have cracked a spark plug when he put the new ones in so that would be a good thing to check.
Gas and petrol are 2 different animals and they ignite differently hence the different gaps.
A vacuum leak would also make the idle go to crap so you will have to eliminate each one until you find the issue.
When did you service the injectors? Did it run properly after that?

Pulled the spark plugs to check them out a few weeks ago. They didn't look brand new but they looked better than the ones in there. They had only been there about 3 months with maybe 500km's on them (car doesn't go too far even though we live in the country). Showed them to a mate and he said they looked okay. The idle issue on start (sounding sick) has been there for about a year now all up. Plugs and leads were both changed about 3 months ago.

I did the injectors a few weeks ago. All seemed to go well with the replacement but I was doing a few other things at the time too (Oil, Coolant and ATF service). No change with the injectors. Even dumped some stuff in the fuel to see if that helped. Honestly, I reckon that made it worse!

The 2 problems - (1) Choking on acceleration & (2) Will turn over but won't turn on after a long drive - came about after we got it back from the mechanic who did the upper intake gaskets (but who couldn't figure out a blocked radiator which was causing the car to intermittently overheat). The idle has been up the crapper for about a year I guess. About the time that the top radiator hose burst. I can't be 100% with what went on health wise before the Radiator hose blew as it's Mum's car and I only started driving it when my car needed work done.

Car gets back from holidays tomorrow so I'll check the intake hoses, ducting, EGR and Fuel Injectors (carby cleaner test as mentioned above). Will also test the IAT to see if it's within specs.