4g93t Libero gt not running right!!

[ICYKIL]

So i've rescued this libero gt from a neglectful owner. However, i've ran into a couple issues that I cannot resolve. first of all, since ive owned this car there has been an intermittant CEL. The autoelectrician ran a diagnostic test and came up with not fault codes. Despite this, I went ahead and replaced the coilpack, sparkplugs & igintion leads also checked my AFM for visible faults such as a bad plug and chucked some injector cleaner in an attempt to cross injectors off as the problem. After all this the car ran a little better but the CEL still comes on and off. I have noticed that when I tried running a boost controller on, the boost does not change even after setting it up in different ways. BUT, the main problem thats left me catching the bus now is that the car loses power under load and i mean if i apply abit more pressure to the gas pedal its as if i am braking especially uphill. I have noticed that the BOV isn't as loud as it used to be and that i cannot boost properly unless i slowly build up the rpms to at least 5k and then accelerate(if i step on the gas any sooner i get the loss of power issue). couple months before this happened i foolishly chucked on an hks replica ssq bov which made the idle bounce at start up, turbo stall etc but have since put the previous one back on. the car does have a little oil leak under the exhaust manifold (probably one of the oil lines). Any ideas on these problems??

 

[3zercrowd]

Hi there.

You havn't got a collapsed cat converter do you?

 

[4piknup]

First thing is a wet and dry compression test to determine overall engine health.
Or leak down test.

But it sounds like fuel issue to me.

 

[ICYKIL]

I've read up the symptoms a while back about bad cat converters and nah the car isn't showing those obvious signs but I should still consider it and I've had a compression test done and all cylinders are sweet. I'm wondering if the turbo prehaps the exhaust wheel is bad thats why I only get proper boost at high rpms. even so, it still feels as though i'm not get a full boost. but, before i got and buy a replacement turbo i'm just trying to figure out if it's anything else.

 

[jimmyratsbreath]

Hey, I had a similar problem on my GSR , no boost unless you pussyfoot it up to say 5000rpm in third with light throttle.If you then planted the throttle boost was there again. Turned out the timing was out so might have jumped a tooth on the timing belt.Hope that helps and good luck.

 

[clone]

^ exactly what i was going to say , take your cover off , wind your engine over till the crank lines up with your timing mark as well as the timing marks on your cam gears and tappet cover. Sounds like your intake is 1 tooth late

 

[BMGTZ]

check the waste gate flap is firmly shut by wiggling with your finger.

check for obtructions in the inlet tract...piece rag etc forgotten at some stage

dented exhaust

clogged intercooler

 

[EVO-00X]

Could be anything from electrical to mechanical lol... but if the electrical checks out OK in diagnostics then start checking the mechs.
Timing issue
Intake leak
Wastegate issue or turbo exhaust leak
Faulty Oxygen sensor (it could play up and throw dodgey signals when hot) - its electrical but you didnt mention it in your original post.

 

[ICYKIL]

Hey Guys

Thanks heaps for the info. Yup definately will look at the timing as a couple others have also mentined this. The wastegate appears to be functioning well and i've also had another wastegate on it and it's still doing the same. However, a mechanic has told me it could be a faulty AFM (MAF). Can anyone confirm this??

Cheers for the help once again guys

 

[khubner1]

Its possible. I also had an issue with my power tr unit (located near the coil packs ) but that would cause the car to completely shut down rather than be slugish

 

[jimmyratsbreath]

Hey ,
When it happened to me I was told stuffed turbo blocked cat etc I changed my afm but was exacly as before, emptied my cat and gained bottom end but now need a new cat.It might be different for you as you said your car was neglected by the previous owner and I had mine for 15 years.

 

[ICYKIL]

Oh yeah the power tr unit is working fine i remenber testing that during the coilpack replacement. Alright i've got some possible directions to take including replacing AFM, cat converter and the timing out by abit. I've just sorted out the miss's car so i'll get a move on with my car now and post up the results. In the meanwhile keep those ideas flowing

Cheers fellas for the advice

 

[ICYKIL]

Just an update,

I've checked the timing and the cams are in line with the markings so i think the timing should be sweet. However, I thought i'd take a look at the external wastegate if the diaphrams crap or for any exhaust leaks. its bolted straight on top of the manifold and when i took it off i noticed a large crack going through the wastegate's port circumference and onto the manifold. the crack is about a thumbnail (possibly longer) long and looks like it cuts all the way through the wastegate port in depth. I tried a leak test with soapy water and sprayed abit on the manifold and noticed it bubbling quite violently. Could this possibly be why my performance has reduced dramatically and at whole make my bov quieter and turbo not producing boost properly as well as having an intermittent CEL? I will none-the-less replace it and see the results.

 

[clone]

Good luck mate

 

[ICYKIL]

Oh Shoot!

Sorry for abandoning this post but have found the problem a couple months back now. So turns out the external wastegate port hada good sized leak which has now been welded up. A few other things have also been resolved that contributed to the problem. The timing was actually not in line at the bottom, only the top and the exhaust side of the turbo aparently was seized or starting to..But yeah its up and running well with an upgraded turbo. Thanks heaps guys for your input and advice

 

[clone]

lol good to see your working well then. i had a timing issue also exactly like this before but it was on the intake side.. atleast you have found this and now rectified it