Having Trouble With my VY SS

[350VY]

Hey Guys, I have a 2002 VY SS and has been running great the past 3 years iv had it, all of a sudden its started running really rough to the point it stalls trying to idle. I think its a bit of a coincidence that it happened after I filled up the other day.

Any way seen that it happened after I put pretty much put a full tank of fuel in I was thinking it was a fuel issue, but I have checked for fuel pressure and seems to be plenty there, and also changed the fuel filter even though it was only 6 months old just to make sure. there was no water or contamination in the fuel so I believe its nothing to do with the fuel I put in (Was Shell 98)

I have found sometimes when I start it, it runs fine, and then if I give it throttle to about 3000+ rpm it seems to go out of time and then when I try to bring it back to idle it wants to stall, and I have to leave it for a bit so that it starts up normal again. I have disconnected each coil pack and also injectors and not one really made a difference to how it was running, at one stage I had the front 4 disconnected at once and it was still running the same

Just for extra info it is obviously an LS1, MAFless Tuned with an Ramjet OTR (had this for at least 2 years with no problems), Pacemaker 4into1 headers, std cats, Manta 2.5 catback, other than that stock engine wise.

Plugs, Leads, fuel filter, are all pretty new, any one got any ideas? will try get a video tonight

[jc_sv8]

My bet is O2 sensors, or PCV pipes...

[350VY]

My bet is O2 sensors, or PCV pipes...

Cheers mate, I was thinking along those lines from a bit of research, I just found that most people with that problem could still drive there cars it was just a bit rough where mine is undrivable, so was just wondering if there could have been more going on.

[white lie]

What was the fuel pressure when you checked it? How much is "plenty there"?

To be able to pull out 4 cylinders and have no change is a bit odd.

Guessing its not throwing any fault codes?

[Micks]

02's are not in the equation at all whilst engine in warm up, don't rule them out altogether if running the originals?

[350VY]

What was the fuel pressure when you checked it? How much is "plenty there"?

To be able to pull out 4 cylinders and have no change is a bit odd.

Guessing its not throwing any fault codes?


im not actually sure to be honest but I pressed it while it was running and had a cloth over it and it soaked it within a split second. maybe a stupid question but can I but a regular air pressure gauge on it to check the pressure and just clean it out with air after or will it stuff it??

no fault codes at all, had a scan tool on it as well and still nothing even when it was idling really rough.

and yeah I assume they are original

[white lie]

I don't think you'd get all the fuel out if you did that.

Does it run alright when it's cold? Ie first start for the day

If they're the original O2's they'd have to be well overdue for replacement

[macca_779]

Is it reading nominal coolant temp or always staying full cold. If its the latter that's your problem and the plug has probably broken and a wire has come off. Its at the front on the side of the passenger side head. It makes the engine run very rich and run like shit as the PCM thinks its -40c

[350VY]

It runs crap from the very second it's turned on now

[350VY]

I do agree they are probably up for replacement but I don't think they are my problem, and also temps fine

[Micks]

Crook fuel perhaps or perished vac lines?

[Tuned_LS1]

I got my VY SS MAF-less tuned and Headers and cars etc back in Aug - Sep '15. I have actually noticed since the start of the year that the car has a slight hesitation when cold and has to have a couple goes at firing up in the morning. I'm leaning towards 02 sensors as I reckon the coating of the headers is fouling them up. I've been super lazy though and haven't done anything about it yet because it drives fine when at operating temp.

[wally01]

My VY SS does similar but only when it is first started in the morning nearly stalls going out of the driveway and is hesitant under light throttle at take off once warm its all good ,i have a set of 02's sitting here that i have had for 3 years maybe i should now replace them ,can't rush these things..

[Woodchukka]

Have you pulled the plugs and had a look? You'll be able to see if it is limited to specific cylinders or all of them. Once you know this you can start focusing your search. Look for vac leaks. Might be a brake booster causing a vac leak? Pull the line and plug it see if that helps. Mine had a similar issue however it was a perished HT lead causing the fault.

[Micks]

Have you pulled the plugs and had a look? You'll be able to see if it is limited to specific cylinders or all of them. Once you know this you can start focusing your search. Look for vac leaks. Might be a brake booster causing a vac leak? Pull the line and plug it see if that helps. Mine had a similar issue however it was a perished HT lead causing the fault.
Yeah Woody terrible amount of heat emits from the exhaust causing the leads to fail over that time.

[Woodchukka]

Yeah Woody terrible amount of heat emits from the exhaust causing the leads to fail over that time.
Sorta threw me at first. All was good and gave it a bit of a leg stretch and when I tried to get above 3k after that it missed badly. The 3k limit got lower and lower until I could get a chance to diagnose it and get the appropriate parts. Nearly undrivable. I've put boots on the new ones to protect them.

[PeterS]

My bet is O2 sensors, or PCV pipes...

I had the same symptoms with my VX GTS, new O2 sensors fixed it.
Cheers,

[kjcooling]

Have you checked all your plugs? I've had had the manifold vacuum sensor fall out the back of the manifold and cause problems like this, and separately, forgetting to connect the I take air temp plug. I would replace o2 sensors first though.

[350VY]

Hey Guys Thanks for all your replys, I ended up changing my plugs and leads kind of just because it was due for it but still with no fix and didn't want to just start spending money on sensors and new vac lines and then possible still not have the problem solved so eventually took it for a 40 min drive on a flatbed to an auto sparky and they found nothing so they look it down to a Mechanic and they suspected a broken inlet valve spring, turns out they were spot on and the inlet valve spring on cylinder #4 had snapped at the top, so it was still sealing at low revs and then not at higher and wouldn't seal again. Very surprised there was no tapping or anything though, just a very slight noise in the intake manifold.

very lucky the valve didn't hit the piston!!

would post a picture but I haven't posted enough :(

Regards,
350VY

[white lie]

Wow, very lucky indeed!

[Micks]

Hey Guys Thanks for all your replys, I ended up changing my plugs and leads kind of just because it was due for it but still with no fix and didn't want to just start spending money on sensors and new vac lines and then possible still not have the problem solved so eventually took it for a 40 min drive on a flatbed to an auto sparky and they found nothing so they look it down to a Mechanic and they suspected a broken inlet valve spring, turns out they were spot on and the inlet valve spring on cylinder #4 had snapped at the top, so it was still sealing at low revs and then not at higher and wouldn't seal again. Very surprised there was no tapping or anything though, just a very slight noise in the intake manifold.

very lucky the valve didn't hit the piston!!

would post a picture but I haven't posted enough :(

Regards,
350VY

Yes if they were oem springs you are lucky! One of the first things I change on these LS engines & they are cheap as, generally the chink in the chain so to speak!

[Tuned_LS1]

Yes if they were oem springs you are lucky! One of the first things I change on these LS engines & they are cheap as, generally the chink in the chain so to speak!

Are OEM LS1 springa are no good Mick? Thats a worry :(

[white lie]

I'd recommend changing them if they're anywhere near 14 years old like the OP's!

[Micks]

Are OEM LS1 springa are no good Mick? Thats a worry :(

They are ok but a little weak, take them over 5 grand & you'll hear your valves bouncing. A good set of beehives will take you right through to your limiter no probs.

[350VY]

They are ok but a little weak, take them over 5 grand & you'll hear your valves bouncing. A good set of beehives will take you right through to your limiter no probs.

I do hit over 5k more than I probably should :s im heading to Europe in a few months but I will go and replace then all when I get back, is there any you would recommend?

oh and realised I had to make a an external picture hosting account so here is the spring: http://i1255.photobucket.com/albums/hh629/350VY/DSC_0140_zpsf3rtfifl.jpg (http://s1255.photobucket.com/user/350VY/media/DSC_0140_zpsf3rtfifl.jpg.html)

[Micks]

I use PAC beehives in my LS & haven't broken any. Though will probably change them before they hit 60K for insurance ;)

[white lie]

Another on the PAC wagon. Good value springs. 1215's would be more than enough