URGENT HELP! Loss of Boost should I be driving the car?????

Hi chaps,

I'm hoping someone can help me out or at least give me some advice.

On the way to dropping my wife and her friends in town I noticed that my boost gauge was not registering anything at all. The car felt a little bit sluggish and there was a hissing/wirring sound coming from the engine under acceleration. I limped back home...

What could the problem be, is a connection loose on my boost gauge or is it something more sinister?

I also will need to head back into town to pick the girls up, is the car ok to drive or should I get it looked at asap??

I don't really know what to look for so any advice much appreciated!!

Cheers,
Rusty

Are all other gauges, indicators ok? It could have just rubbed through your line to your boost gauge somewhere, check all your lines and intake pipes make sure all are tight and well sealed. Check all your hose clamps are pulling up well also.

Yeah not entirely sure what I'm looking for in this department, I didn't install the gauges and my mech trouble shooting knowledge is pretty limited.

I'm hopefully gonna be able to get it into my mechanic tomorrow morning.

Judging from the hissing sound it sounds like you have mentioned above. Other gauges are all good, egt's are a little higher but that's to be expected with no boost is that right? Engine was revving slightly higher for not much throttle.

Would a problem with the line to the gauge make the engine perform differently at all, because there's def no boost when accelarating from a stand still.

Thanks for the feedback :)

Is it just no boost on the gauge or can you not feel the boost in the acceleration? If you have a broken boost hose it will leak boost with a hiss and be a little sluggish as it is leaking boost kinda like a tyre going down.

Keep an eye on everything else but I would have thought you probably could do th drive in.

What engine is it? Your boost line will be coming out the side of the intake close to the intake pipe have a look you should b able to clearly figure out hich hose it is, it will be a 2 to 4mm hose only,

Good luck mate

I just meant like there are no other lights coming up on your dash or anythin as well. If nothing else seems to be wrong then it should be fine to take to your mechanic just give it a good eye over before driving to make sure nothing looks out of place.

Thanks heaps guys :)

Drove back in and home again, taking it easy and everything else seems to be fine (besides slightly higher egts). I didn't go above 2000 rpm and cruised at about 50km/h with not much throttle. No lights on in dash or anything.

Mudrunner, no Im definitely not feeling the boost when accelerating or it's not 100%, and the sound is similar to a tyre deflating, so hopefully it's just as u mention.

It's a ZD30, I'll check it out tomorrow morning and let you know how I get on.

Thanks for the prompt replies they've been a great help :)

Cheers

Unfortunately don't have access to any tools so couldn't even get the engine cover off, but I followed back what looked like the boost line, and the end of the skinny white plastic tube wasn't attached to anything at the other end, so I re-attached this to the obvious spot. Pic is re-attached tube.

Went for a spin around the block and I'm getting boost back but pressure is still low, it didn't seem to want to go above 10psi where usually I'll get the usual ZD30 spikes above 16psi. The hissing sound is much less too, and it's def a bit more drivable. So there may be a leak further in or air still escaping?

I can't really see any other connections which look loose. My mechanic won't be open till Monday so I think I can wait till then and monitor things.

Is there any other things you think I may be able to check?

Cheers,
Rusty

other boost leaking areas are the egr valve area or leaking turbo gaskets or when I has this problem it was a blown turbo but you'll hear a metal rattle and boost hiss with that one.
Zd 30 boost leaks are normally leaking intercooler or intercooler hoses not on properly or the gaskets on turbo or egr valve

A similar thing has happened to me a few times , small split in the actuator pipe , intercooler hose leaking/blow off , have a real good look at these areas , even if it means taking them off to see underneath .

Hey guys,

Car is at the mechanics today, he found a few hoses slightly loose and tightened them up, came back for a drive and while it's registering boost, it still seems low compared to where it was. But when not looking at the gauge the car seems to feel fine through acceleration.

I left it with him and he will delve deeper, but I wonder if these boost pressures I'm getting now are 'normal' and my readings before were abnormal?? Would it be a good idea now to fit Dawes and block egr or try and rectify 'problem' before doing these mods?? It's doing my head in a bit haha

My problems are:

1. Looking at the in depth 'EGT survey' on the Patrol4x4 forum , my 'new' readings would fall into the category of a 3.0L without NADS, maybe a little low boost, but there are a wide variety of different boost levels and EGTs

2. Looking at the boost graph on Chaz's website for an unmodified engine my 'old' boost levels were more like this, with the initial spike then drop etc.

Now under not much acceleration (ie taking off from the lights conservatively), it will boost to under 5psi and I'd have to really floor it to get the big spike and higher readings.

Should I be worried at all or just accept that I may now have lower boost? Will this result in anything like high EGTs?

I think if my mechanic can't find anything else wrong I'll try and get in touch with Chaz or anyone else in Adelaide with NADS to check if it feels 'normal'.

Any comments greatly appreciated

Cheers,
Rusty

I would isolate your problem then fix it before doing the nads as these affect your boost and delivery and need to be adjusted back to what they should be if you did them now it would be doing it blind. How's the intercooler and egr valve leaking there? also have you checked play in the turbo? If there's play it's an expensive job to replace I done mine 10 000km ago. are you using oil or have heaps of blue/ black smoke from the exhaust more than usual and if it smells oily that's another sign of a blown turbo

Quote:

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Originally Posted by macca86

I would isolate your problem then fix it before doing the nads as these affect your boost and delivery and need to be adjusted back to what they should be if you did them now it would be doing it blind. How's the intercooler and egr valve leaking there? also have you checked play in the turbo? If there's play it's an expensive job to replace I done mine 10 000km ago. are you using oil or have heaps of blue/ black smoke from the exhaust more than usual and if it smells oily that's another sign of a blown turbo

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Thanks Macca,

There are no leaks at all around intercooler and egr, and the turbo is fine too. Not using oil, no smoke at all.

He tested straight into the turbo and the boost showed the typical boost curve with higher levels (as before problem), so it looks like it may be the ecu is cutting the level for some reason. It's not throwing any fault codes though so it doesn't think there's a problem. We thought that by doing Dawes, needle and egr block this would be bypassing the ecu anyway and would probably fix things.

it would help you'll just need to test and tune using chaz info and see how it goes

Been speaking with Chaz, who thinks it's most likely a faulty MAF caused when the mechanic cleaned it which could've made it worse. Although a faulty MAF causes overboost usually under heavy throttle, it can cause low boost under light throttle, which is more like what I'm experiencing, as I'm driving like a grandma because of the problems I've been having and rapidly rising EGTs when you try to push it.

I'm going to test it with a new MAF before buying one, just to make sure this is the problem.

Chaz also mentioned he wouldn't be surprised if the egr valve was stuck open or having problems, so blocking the EGR will fix this.

I'll let you know how I go with the new MAF, hopefully this sorts things out!!

Cheers

Met up with Chaz yesterday, and I'd like to thank him for his time and knowledge, we spent a while talking about his set up and why he's done mods he has etc, it was great seeing such an awesome rig, it's definitely a goal to have a rig half as capable as his!!

We tried a few things, new MAF didn't change anything but I'll keep the new one in there and the old one as spare, as, although the old one seems to work, the sensor looks pretty dodge so it's good to know you've got a newy in there to start with after doing the other NADS.

We isolated the problem to probably being the ecu solenoid giving an incorrect reading, maybe caused by the MAF but not immediately fixed with a new one. I'm gonna disconnect the battery for a bit to see if that helps clear any faults. We checked vacuum and that all seems fine and the turbo is definitely working as it should too.

Dawes and Needle and EGR block should fix all this up (fingers crossed)

Will update soon, waiting on delivery of Dawes.

Good to hear you are sorting your issues out Rusty . Where you gunna mount your needle valve ? or are you that keen its already done mate .

haha, nah mate it'll be done when dawes and egr block is done, not sure exactly where it'll be best to mount, I'm after the more 'set and forget' so under the bonnet somewhere rather than in the dash.

Dawes FINALLY arrived the other day and everything will be installed tomorrow, getting the manifold cleaned at the same time. Boost has still been odd and low but I'm used to it now and know how to drive it to get the best levels while keeping EGTs low.

Had a moment last week driving up the freeway where I pretty much had no power and the EGTs would skyrocket to 550+ when I tried to accelerate. I actually had to back off the throttle a little and get the revs back to around 2000rpm where the boost would sit at about 10psi lowering the EGTs. But under such a load (steep hill) I could only crawl up at about 40-50km/h in the left lane, about the same speed as semis!! Had to stop once or twice, bit embarrassing really, but once I was over the first couple of big hills and on the down hill near Crafers exit, I could get up to speed and get some momentum and keep it around 100km/h.

Can't wait for this to be fixed.... :)

Everything installed on Friday and wow what a difference! Honestly feels like a different car!! Boost problems all solved, constant power throughout the revs, much more get up and go, no lag etc. And EGTs are down to about 230 deg 60km/h around town, rather than 350-400. This would also have something to do with the manifold being cleaned, which did contain a heap of gunk built up.

I've been fiddling a little with the Needle valve but it's pretty much set up to Chaz's guides so it's probably about right. It spools up quite quickly to 15 psi but won't go above that, unless under heavy load I guess where I might get a few more PSI. Cruising it will sit around 5-7 PSI under a bit of load around 10-12.

Thanks heaps to everyone for their help and suggestions, I'm stoked I've got this sorted out.

Cheers,

Rusty

A whirring and hissing sound is not something you want to hear from a turbo engine. Hissing I could get over until I got home but markedly lower boost levels combined with a distinct variable whirring sound would have me pulling the turbo intake elbow and exhaust outlet for a look and feel ASAP. Compressor and or turbine impeller / mainshaft bearing failures can turn ugly $$$$ pretty quick. Typical turbo shaft tolerances are measured with micrometers / dial indicators, any impeller damage or contact with the housing snails is a stop operating immediately condition, if you don't want your engine to ingest a good dose of metal. Any dramatic unexplained loss of performance needs to be investigated. ZD30's pre 07 need some post nissan TLC toensure reliability.

Quote:

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Originally Posted by ZD30 victim

A whirring and hissing sound is not something you want to hear from a turbo engine. Hissing I could get over until I got home but markedly lower boost levels combined with a distinct variable whirring sound would have me pulling the turbo intake elbow and exhaust outlet for a look and feel ASAP. Compressor and or turbine impeller / mainshaft bearing failures can turn ugly $$$$ pretty quick. Typical turbo shaft tolerances are measured with micrometers / dial indicators, any impeller damage or contact with the housing snails is a stop operating immediately condition, if you don't want your engine to ingest a good dose of metal. Any dramatic unexplained loss of performance needs to be investigated. ZD30's pre 07 need some post nissan TLC toensure reliability.

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Cheers mate, yeah the initial hissing/wirring was the boost line which had blown off. I'd just had the turbo checked and have had it checked again and all seems well. This episode has definitely got me switched on to what's what with how my engine runs or should be running. All a learning experience I guess :)

Thanks for your input

'ZD30 Victim' doesn't sound like a user name that's had a good ZD3O experience, did yours blow on you?