Can anyone help with limp mode?

[jschw99]

Hey fellas, recently installed a dawes & needle aswell as blocked the egr plate.
I have max boost set to 15 psi, and constantly get limp mode.
I have tried opening the needle valve right up, closing it and just about everything in between and still get limp mode under any acceleration between 0-80km/h. I'm hitting max boost (15psi) at 2000-2100rpm

[jschw99]

It's a 2005 gu. ZD30

[Bidja]

15 psi max boost should be fine (should not be too high), it sounds like it is not getting the fuel as required. Check your MAF sensor, give it a good clean with a liberal spray of CRC Mass Air Flow sensor cleaner (don't touch it with your fingers and let it dry by evaporation only). Never done it, but do a search on how to check the pin voltage on the MAF sensor. Maybe get a loan of one to try out as a comparison. Have you a scan tool to identify any fault code coming up)?

Has it only started since installing dawes / needle valve?

There is a way to bypass manual boost control to assist in fault finding but requires care not to over boost. I recently did this as part of a trouble shooting exercise (CRD), different reason but had success. First check your MAF sensor out and maybe a fuel filter.

[jschw99]

Yeah mate, it has no fault codes up, fuel filter replaced 200kms ago, same as maf sensor. And yeah, only been happening since install of dawes & needle/egr plate.

[Bidja]

No experience with your DI eng first hand. Are you certain that you have installed manual boost control correctly and have no vac or boost leaks.

Try setting a max boost of 10psi at 2000 rpm under a slight load with needle closed. Then at idle, open needle valve slowly until you see the actuator arm just start to drop away from its stop screw and then close it a 1/4 of a turn. Give it a run at that and progress with further adjustment of both from here.

Have a read of Chaz's Patrol ZD30 TDi Manual; Boost Controller document.

Mudski on hear might be able to help out.

Recently, I bypassed my manual boost control sys to help identify what was causing a spool problem but I am being cautious here as mine is a CRD and can handle max spool. DIs may have a problem with max spool operation..

[4bye4]

G'day mate, I have the same engine and although I'm no expert I have had similar things a while ago. You can sometimes get a bounce over 15 psi under acceleration which can cause limp mode. There is also times where mine goes into limp under long acceleration, say up a ramp to a freeway or similar, usually when the vehicle is cold. My cure was as follows. I lowered the max psi with the dawes to 14 psi, then gradually increased it to 15psi, about a quarter of a turn at a time. I also used the needle valve to "smooth" the spool up to reduce the over "bounce" as much as possible. I have also removed the spring from the Dawes and stretch and compressed it (by hand - don't go nuts with tools or anything) and made sure its clean and not sticking. These things combined seem to have eliminated the problem, but I have no idea if any single thing made the difference. One more thing, at one stage I had a very small vacuum leak in one of the inter-cooler hoses. I mean microscopic. This caused some variations in tuning and intermittent limp. A new cuff and very tight clamps made a remarkable charge, given the leak was nearly undetectable. I think some of the Dawes valves can be very touchy. Anyway hop this helps. Cheers Tony.

[mudski]

Righto, many things will be causing this. First thing. Is the intercooler the original or aftermarket. Is the boost holding under acceleration before limp mode.? Limp mode is usually caused from over boost. So drop the max boost level to 14 psi and see what happens. Keep dropping it until limp goes and tell us what level it goes. 15psi in my opinion is a tad on the too low side for boost. These motors will happily scoot along with 25psi boost. Mine did for maybe two years before the pump shit itself.

Best mod to do to these motors is to get rid of limp mode totally. You can trick the maf voltage signals using a few resistors from Jaycar, plenty of info on the web showing you how. Or you can buy a MAF housing from HPD which are made to alter the air flow and trick the maf signals that way.
I would do this if I was to ever have a 3ltr again. Limp mode is on top of the list to be the most annoying thing on these motors.

So what to do now? Remove and clean the maf. Also disconnect the battery for atleast half an hour whilst doing so. This will reset the ECU. Assuming you have plumbed it up all right. When you open and close the needle valve. does the rod on the turbo actuator arm move up and down as you close, then open the valve?

Also who did you buy your kit from? Nearly every shop on eBay now sell the chinese copies and they are known to not work. I used to cop a lot of emails and messages from buyers blaming me assuming I was selling these kits to the other resellers. If you bought from eBay, tell me the reseller and I can tell you if its legit or not.

Getting rid of the dreaded limp mode can send one loopy. It was for me until I just got rid of it totally.

[jschw99]

Hey mate, its a oem intercooler, boost is holding at 14psi until limp mode, ive been as low as 9psi and still getting limp mode.

Yeah mate, as I open & close the actuator rod moves up and down.

Not sure on the origins of it mate, it was from a friend of mine.

[mudski]

Hey mate, its a oem intercooler, boost is holding at 14psi until limp mode, ive been as low as 9psi and still getting limp mode.

Yeah mate, as I open & close the actuator rod moves up and down.

Not sure on the origins of it mate, it was from a friend of mine.

Has the intercooler got any oil spots on it? You may need to take it off and have a look on the underside. If it does, even small amounts. The intercooler is leaking boost pressure. This is bad, and even worse when you fit a manual boost controller. As the motor is now unable to compensate for the leaking boost pressure, whereas prior to the Dawes, the ECU could simply work the turbo harder and harder to create more boost. Not an ideal thing to put the turbo through though.

[jschw99]

Not that i could see mate, pulled it off & checked underneath it also.

Just thinking, i've got both the dawes valve boost pickup & guage coming off the same boost t, is that alright or should they be completely seperate?

[mudski]

Not that i could see mate, pulled it off & checked underneath it also.

Just thinking, i've got both the dawes valve boost pickup & guage coming off the same boost t, is that alright or should they be completely seperate?

Nah that wont affect anything.
Somethings definately amiss here. You shouldn't see limp mode until around 15 psi. Next step here would be to look at the MAF sensor. Remove it, clean it with some MAF sensor spray. Do you know anyone with the same vehicle?
Where are you located btw?

[jschw99]

Hey mate, still havent sorted her out, have just replaced the maf and still doing it.
Unfortunately dont know anyone around here with a patrol, and im located in rockhampton

[mudski]

Hey mate, still havent sorted her out, have just replaced the maf and still doing it.
Unfortunately dont know anyone around here with a patrol, and im located in rockhampton

Unplug the MAF and go for a drive. Have a google on the volt mod trick for the MAF sensor. I never did it but many have with great success. If you know how to solder apparently its a half hour job and no more limp mode issue... Other than that, but the HPD maf housing. I did this and I went from 15psi limp to getting the needle off a 30psi gauge and still no limp mode.

[jschw99]

Hey mate, got a new intercooler as my old one was leaking and was still hitting limp mode, decided to try disconnecting the t piece and running the boost guage/dawes valve off their own boost pickup, and no more limp mode :)

[mudski]

Hey mate, got a new intercooler as my old one was leaking and was still hitting limp mode, decided to try disconnecting the t piece and running the boost guage/dawes valve off their own boost pickup, and no more limp mode :)

Hey nice find mate! Who would have thought! I have never seen that before. So either the T was restricting the boost to the Dawes, or there was a boost leak in the T join or hose to the gauge. None the less you found it! Out of interest, what size T were you using?

[Bidja]

Hey mate, got a new intercooler as my old one was leaking and was still hitting limp mode, decided to try disconnecting the t piece and running the boost guage/dawes valve off their own boost pickup, and no more limp mode :)

By chance did you change any of your vac line/connections?

Ideally, if possible, it is good to have a dedicated boost reference (but not essential) for dawes/tillix, and be located at a point where there is the least turbulence (cold side). Understand it is more important to use a designated port (boost reference) with a positive pressure (boost) actuator to run turbo as wastegate, but you are not.