ZD30 intermittent, cutting out under load / boost

[Lieney]

Engine is ZD30, manual GU IV wagon. 3" exhaust EGR blocked and dawes valve set at 17psi.
While driving engine hits about 3500 and shuts down. Releasing the accelerator and re-applying will make power return. No warning lights, just engine power loss for the time your foot is down.
Diagniosis by Hi-Tech diesel was pinched vacuum line at a cost to me of $90.
Still have problem now and is getting worse / more often.
Checked for 'this pinched vacuum line fault' today but couldn't find anything. Connections, plugs & hoses etc all appear good.
If foot is kept flat, engine cuts out between 2000-3500rps randomly. Occasionally plumes of white /grey smoke, but generally engine dies momentarily and then goes again. Almost as if fuel had air bubbles in it.
Boost is at 16-17psi set by dawes valve.
Any ideas as I am stumped

[threedogs]

White smoke not good, have you checked your fuel filter?
I'm thinking clogged or water in fuel, someone else may comfirm this
If possible disconnect the battery for an hour or so as well. Maybe a member in adelaide could check
and clean the MAF. Trying to remember a post recently where fuel wasn't holding pressure, but thats $$$$$
Try fuel filter, fuel lines, MAF and disconnect battery, that'll eliminate most

[mudski]

Engine is ZD30, manual GU IV wagon. 3" exhaust EGR blocked and dawes valve set at 17psi.
While driving engine hits about 3500 and shuts down. Releasing the accelerator and re-applying will make power return. No warning lights, just engine power loss for the time your foot is down.
Reduce the boost to max 15 psi.


Diagniosis by Hi-Tech diesel was pinched vacuum line at a cost to me of $90.

Easiest $90 he's made.


Still have problem now and is getting worse / more often.
Checked for 'this pinched vacuum line fault' today but couldn't find anything. Connections, plugs & hoses etc all appear good.
If foot is kept flat, engine cuts out between 2000-3500rps randomly. Occasionally plumes of white /grey smoke, but generally engine dies momentarily and then goes again. Almost as if fuel had air bubbles in it.
Boost is at 16-17psi set by dawes valve.
Any ideas as I am stumped

Shouldn't have done any damage I think. It's just limp mode kicking in thats why your getting no power and the you aren after you release and then press on the acc pedal...
I had the exact same problem with mine. But i could drive with 17psi if i accelerated hard and quick with full boost almost straight away. If I slowly accelereated and kept the boost up and really dragged out the gears I would hit limp mode. Turned it down a couple of PSI, felt no difference in power and stopped the issue.

[boots]

What mudski reckons ^^^ or dodgy throttle position sensor or common rails with full EGR block give grief / limp mode issues , you may have to look at getting a diesel smart module to prevent this issue or some guys reckon by drilling a small hole in the EGR blanking plate solves the limp mode issue .

[the evil twin]

What mudski reckons ^^^ or dodgy throttle position sensor or common rails with full EGR block give grief / limp mode issues , you may have to look at getting a diesel smart module to prevent this issue or some guys reckon by drilling a small hole in the EGR blanking plate solves the limp mode issue .

Tend to agree with you and Mudski 'cept shouldn't be the EGR. I haven't heard of that triggering limp and I've had mine blocked for about 30,000 now and all it does is throw a code every now and then (which it should). Quick check and reset with the Scangauge to turn the check engine light off and just to make sure it is P0401 is all that the CRD's need as P0401 isn't a limp code trigger.

I didn't see the point of drilling the blocking plate so I just bolted in one the Ferrets mostest awesomest products in and went for it.

[threedogs]

Just Checking if awesomest is a word, and too righty it is, X 2 on The Ferret products.
Now we know its a Di Z30 not a Cr
As for Mechanic, he was there we aren't think $90 for him to stop and check was
sorta ok. why is it everyone puts their hand out, GMF

[BearGUST]

What does the ECU cut when it goes into this limp mode? I always assumed it was boost but that can't be right if it still occurs when a Dawes valve is fitted. So it must change the fuel map, can someone confirm this???
I'm just trying to get an understanding to help diagnose the fault.

[threedogs]

May be the Info you need in one of Chazs {guru} threads in the search engine.
heaps written about this Topic. I thought just cut throttle.

[mudski]

What does the ECU cut when it goes into this limp mode? I always assumed it was boost but that can't be right if it still occurs when a Dawes valve is fitted. So it must change the fuel map, can someone confirm this???
I'm just trying to get an understanding to help diagnose the fault.

Just because there is a Dawes fitted does not mean there will be no limp mode. Well it does, but you have to have it set right. I don't know the exact number but I have found 16 is the limit, absolute, on my troll. I Could run anywhere up to 22psi but I had to drive it like I stole it to prevent it from going into limp mode. Reasons for that I don't know why. I set mine back to 15psi, found no difference is performance between 15 and 17psi so its no loss. Only I don't get limp mode now.
I would bet my left and last nut that if you reduce your boost the problem will disappear.

[threedogs]

X 2 Mudski, I was getting very frustrated with it, found that sweet spot and driving very well now, frisky if you like
Don't even think I get to 15 now but close to it

[Lieney]

Cheers for the feedback all.
As mudski said, the easiest $90 they made and it pi$$ed me off.
The engine light never came on at all so I didn't think it was 'limp mode'. Engine light comes on when this occurs doesn't it??
I still have to send Hi-Tech Diesel an email so they can explain to me exactly which vacuum hose it was, cause its got me stuffed.
Theres ones they installed while doing the Dawes valve, and all others are well out of the way.
I dropped the psi from about 17 to 16ish and also zip-tied the butterfly valve open before it hits the manifold, which I have recently been told plays a part in restricting air flow and over-boost.
Please correct me if I have been told a furphy on this one.
Pushed it on the home run and it ran SWEEEEEEET!!!! Didn't climbe above 18-19psi at all
No lag, no drop in torque during up-shift (manual) maybe due to the butterfly being constantly open, and smooo-oooth driving.

Thanks to you all for your input.

[mudski]

Cheers for the feedback all.
As mudski said, the easiest $90 they made and it pi$$ed me off.
The engine light never came on at all so I didn't think it was 'limp mode'. Engine light comes on when this occurs doesn't it??

Not always. Mine never came on, only when I stupidly set the dawes for about 25psi :)


I still have to send Hi-Tech Diesel an email so they can explain to me exactly which vacuum hose it was, cause its got me stuffed.
Theres ones they installed while doing the Dawes valve, and all others are well out of the way.
I dropped the psi from about 17 to 16ish and also zip-tied the butterfly valve open before it hits the manifold, which I have recently been told plays a part in restricting air flow and over-boost.
Please correct me if I have been told a furphy on this one.
I have never heard of that but there is a first time for everthing... In a manual the butterfly doesn't really do anything, as once you accelerate it opens and when your idle it closes. I do believe a few manual owners here have removed the butterfly and it made sweet f.a difference anyhow. But the butterfly is needed for auto owners, I believe again, because something to do when the car is idle its needed to help control the revs so it wont stall. There is a thread on this somewhere I did read.


Pushed it on the home run and it ran SWEEEEEEET!!!! Didn't climbe above 18-19psi at all
No lag, no drop in torque during up-shift (manual) maybe due to the butterfly being constantly open, and smooo-oooth driving.

Thanks to you all for your input.
Thats because you have dropped the boost, not holding the butterfly open. But i could be wrong. It may be only 1psi but thats all it took for mine to stop going into limp mode.

[choppie]

I have the same problem with mine, I dont have a dawes or boost gauge but put it down to computer picking up an over boost & cutting out,
does it around 100ks-2800revs

[macca86]

bloke at work had a similar problem I suggested a fuel filter change cleared up his problem

[mudski]

I have the same problem with mine, I dont have a dawes or boost gauge but put it down to computer picking up an over boost & cutting out,
does it around 100ks-2800revs

Best you get it sorted I reckon. Boost and EGT gauges first, then the Dawes and EGR plate, then needle valve, then catch can, then 3inch zorst, then chip, then a bigger intercooler, then! You have no money left for anymore then's...

[Lieney]

[QUOTE=I set mine back to 15psi, found no difference is performance between 15 and 17psi so its no loss. Only I don't get limp mode now.
I would bet my left and last nut that if you reduce your boost the problem will disappear.[/QUOTE]
Well Mudski, I do very much appreciate the feedback I have received from you, Boots, threedogs, roofy, Big_Fletch, Dieselsmart, the evil twin and many others on this issue. :)
It has been driving me up the wall as I have not found the answer. I lowered the boost to about 13psi and it goes the same as at 17psi until after 3200 with foot flat, then it hits an intermittent 'flat spot'. Not one flat spot, but feels as though you were having a fit on the go pedal. No lights etc and boost gauge / vacuum dopping slightly (1-2psi) causing the pulse. As if the boost is cutting in and out.
Also got an issue turning right and then straightening up (doesn't happen turning left) and the engine dying followed by a big cloud of diesel smoke (had this verified by trained eyes).
If I keep my foot flat around the roundabout / corner and then straighten up it dies & then after a single splutter or so the power returns. Its almost as if when turning the vacuum dies completely and the actuator on the turbo sits in the 'low pressure' area until vacuum returns. Monitoring vac and boost there is a considerable drop after turning.Vac 30hg" to 5hg" Boost 15psi-3-5psi.
I have checked everything suggested & everthing I can think of, inlcuding Google.
I plan to get an electric vac pump from somewhere to see if I can isolate this as an issue.
So far I have checked, rectified, adjusted or swapped out the following (including test drives between fiddling): checked engine mounts, checked ECU mouting and wiring, boost pressure adjusted from 13psi-19psi, Dawes valve checked clean, turbo & flange etc mounting, egr flanges & mounting, oil level, intercooler (leaking & now repaired +2psi), inlet manifold leaks, remove and check vacuum pump, all vacuum & pressure lines replaced & purged (ensure none were being ppinched), swapped vacuum lines around to different areas, zip-tied butterflies open, check security of all electrical connections to engine I can find, test MAF & then replace (nothing wrong but ran smoother), test function of actuating lever on turbo, fuel filter drained / checked (no water), air cleaner checked, good enough.
I have either missed something or there is another issue I have yet to discover. I reckon vac pump issue.
No load - full rpm range
Load - problems above 3200rps approx
Round corner - problems anywhere from 1500rps upward but sometimes doesn't happen until higher RPM
Adam from DieselSmart said he might be able to assist. I'll keep you in the loop.
Thanx again

[threedogs]

Did you end up changing the fuel filters??? They bring on the engine light.
Can't you ask a member nearby that has the same mod to check and make sure yours is 100% correct.
You should have no hoses going to vacuum solenoid

[Lieney]

Did you end up changing the fuel filters??? They bring on the engine light.
Can't you ask a member nearby that has the same mod to check and make sure yours is 100% correct.
You should have no hoses going to vacuum solenoid
Threedogs, I drained the filter thinking water might be in there. I have not replaced it yet as I do not believe I am having a problem with fue. Cheers for the heads up and might just do that tomorrow anyway.
Original solenoid for actuator is not in circuit.
Vac pump goes to Dawes, then to turbo actuator. Other input is from inlet boost.
Read over all the diagram etc I have to make sure and found the 'air flow' solenoid not in use. Does nothing much anyway.
Fuel filter it is tomorrow

[Lieney]

Changed the fuel filter when I got home from work. No water on obvious debris that I could see.
Drove it like I stole it & no splutter at high rpm, under load while pushing it up the highway. Makes sense to me at high rpm at near full noise with a clean filter. Thanks Threedogs & macca86 for the reminder.
What i don't get is that it didn't choke & smoke around the roundabout though. I am curious why this in particular happened but only after turning right. Glad to hear some theories cause I got no explanation except ZD30.
Glad I'm a member of the forum.

[threedogs]

You'll find a lot of people here think winding the boost right up will turn their 4x4 into a rocket ship. no two are the same,the best boost is what ever suits your set up. Mine as an example
runs great at 14psi and like a dog higher, I'll get it turboed now Its running well. higher boost no neccessarily better.

[Lowy44]

Sounds to me like a fuel problem. I had a very similar situation, whitish / blue smoke, power cutting out. I'd bet my money its your fuel filter. When I did my one, I changed both fuel and air so I could not elimante exactly what the fault was, but it was definately one of those two, as I no longer have the problem.

[Veno]

Hi guys
Im having a similar problem with 09 gu6 common rail. My simptoms are. At 105 ks the engine looses power untill speed drops them picks up power again. A similar feeling to a speed limited truck. This seems to have started after I had the preasure relief valve repalced after getting clagged up after a bad dose of fuel. I have now changed the fuel filter and added a 30 micron exceedy in line filter after the standard filter.
Veno

[Rumcajs]

The reason you are getting the limp is because MAF voltages exceed either 3.77 V under 2,500 RPM when cold or 3.99 V under 3,000 RPM when hot ( engine).

This is well known problem on Di ZD30 with EGR blanked off and boost control bypassed with Dawes/needle valve.

Time to go to next stage which is more advanced but my what a difference it makes again. Search Jaycar voltage modifier and fuel cut defeat module.

Cheers

[threedogs]

I've tried to find this in the JayCar catalog,
with no joy but if someone know a pt. no. that would be great

[big_fletch]

Voltage modifier is KC-5490 and hand controller is KC-5386. Both are kits that have too be assembled

Fletcha

[threedogs]

Thanks, so at the front of the catalog

[Rumcajs]

FDC (Fuel Cut Defender) kit p/n is KC5439.
It is originally for MAP (boost) sensor signal clamping but as luck would have it, it limits signal to max 3.98 V so using it for MAF signal wire is just perfect.

You can try FDC only by splicing it in to MAF to ECU signal wire but best results are obtained having it wired in series after JDVM. That way one can manipulate AFRs and have limp limit.

Standard disclaimer: this is all advanced stuff and can result in damage if you don't understand how these things work and what they do. It is not a rocket science but cautious approach is required.

Regards