ZD30 High/fast idle.

[adz14]

Hey guys, have been poking around for a while to get a feel for the place. Plenty of info around here, but after plenty of searching, haven't been able to find any help for an issue with my 06 STR with ZD30.

I have recently had an issue with the NPS, and it is unplugged until I replace it, but I believe this issue is separate to that.

Anyway, the ute is idling fairly fast @ around 1600rpm or thereabouts. This has been happening the last few days. Once the car has sat for a while or overnight, the next time you start it things seem back to normal. Once car is up to temp, the idle shoots up again.

Also, I was nursing the car home last night from work, high idle and all, and from about 80km/h in 5th gear I lost all power. Engine just gradually slowed down as I went through the gears to eventually stall. No throttle input made a difference to the revs.

Hoping the idle/power loss issues are related, and was thinking it's maybe a TPS issue? If so, or for any other possibilities, what are some ways of diagnosing the problem? I am a fair way from capable mechanic where I work, and I can usually give things a crack myself if needed. Don't really want to risk driving 300km to town if the car will just die on me halfway.

Much appreciated,

Adam.

 

[Old.Tony]

Welcome aboard, Adam!

Has any work been done (including servicing) on the car recently? Does the "Check Engine Light" (CEL) come on at all?

A high idle could be caused by the fuel rail pressure sensor being blocked or faulty, if the injectors are in good order. It's possible that there are some deposits on the injectors causing them to remain open longer than they should, but it could also be an adjustment on the accelerator pedal - there are lots of things that it could be.

The idle going high when the engine is warm would make me think the pedal is probably fine, it's more likely injectors or pressure - and I'd lean more towards the injectors.

A good dose of injector cleaner might assist - and won't hurt unless the only thing holding the injectors together is the crud on them!

That's where I'd start. Toss the whole bottle of cleaner in the tank, doesn't need to be a full tank either.

Hope that helps.

 

[adz14]

Cheers Tony, will give that a crack. Have not noticed the CEL at all.

There has recently been a service done in town. Well I say recently, but it was in February. Since coming back to work, it has done very little driving. Up until last weekend it hadn't driven in about 2 months.

Hopefully the injector cleaner can get it sorted. I however, just filled up with fresh fuel, and the nav runs a long range tank!

 

[Dave]

ZD30 isn't CRD in the D22's, so count the fuel rail out.

My guess would be the accelerator pedal.

Whats the primer like ?

 

[tweak'e]

check the TPS plug is in right. sounds like the idle switch on the TPS isn't working.
also if you can ge the engine running and up to temp, let it idle for 10 min. that resets the TPS data in the ecu.

edit: disconnect the battery over night, that should clear the ecu. not all sensors trip CEL codes.

 

[adz14]

ZD30 isn't CRD in the D22's, so count the fuel rail out.

My guess would be the accelerator pedal.

Whats the primer like ?

Primer seems fine to me. Doesn't take many pumps to go firm, if that's what you mean?

Also, with the pedal, anything I can check/do to confirm if it's something to do with the TPS/fly by wire system?

EDIT: sorry to sound like a noob, but this TPS Plug, where would I find it?

 

[tweak'e]

TPS plug....wired to the TPS actually i just re read your post. don't worry about it. more than likley the unit itself.

one thought, check your heat switch isn't on and that your NPS is working. ie turn heat switch on, rpm goes up, put in gear rpm should come back down.
possibly the NPS isn't working which can cause a few glitches with TPS.

 

[adz14]

TPS plug....wired to the TPS actually i just re read your post. don't worry about it. more than likley the unit itself.

one thought, check your heat switch isn't on and that your NPS is working. ie turn heat switch on, rpm goes up, put in gear rpm should come back down.
possibly the NPS isn't working which can cause a few glitches with TPS.

As I mentioned in the first post, NPS is disconnected. Can this cause all these issues? I have a new NPS to be fitted Tuesday... I would do it myself, but alas, I don't have a 19mm spanner!

I originally thought that the high idle was related to the NPS switch being fubar'd (which it is, too)... but even after disconnecting the NPS, the high idle issue remains.

Could the fact the NPS is unplugged screw with the TPS/idle?

The ute is currently idling, and after 10 mins or so the idle dropped back to normal. I assume the issue will return next time I start the car and bring it up to temp.... Will keep you posted.

 

[Dave]

NPS switch shouldn't effect it.

Nope. The 10 min idle is the idle reset.

Heard that one on the pommy Navara forum.

But that usually effects the YD25 non CRD.

 

[tweak'e]

a little suprised the idle reset worked without NPS.
i thought it had to be in neutral for the reset to work. thats why faulty NPS could cause a TPS issue as it doesn't reset as its never in neutral.
however you may have proven me wrong.

fingers crossed it fixes the issue.

if it continues just check theres not a lot of oil in the intake pipes.

 

[adz14]

Okay.

So went for a bit of a drive around after the idle dropped back to normal. Idle remains normal and ok, but the nav definitely feels down on power. Probably 15-20%. If I was driving a petrol car, it would feel similar to timing being pulled out of the engine, if you get what I mean?

This vehicle is a work car, hence I have never modified anything on it. Having the NPS unplugged won't affect power delivery?

There is a little oil in and around the turbo outlet and silicon hoses. Maybe it's time to chat to the boss and fit a catch can.

 

[adz14]

Oh, and thanks for all the tips so far guys, I am pretty new to fiddling with TD's.

 

[tweak'e]

check fuel and air filters. i wonder if the ecu was struggling adjusting tps due to another fault. blocked up air/fuel filter, air in the fuel lines or poor fuel.

btw is the egr blocked off at all ?
with NPS not working the egr system is operating all the time.

 

[Old.Tony]

If EGR is operating all the time it'll feel sluggish at full throttle, when the EGR valve is supposed to be closed.

 

[adz14]

Ah beautiful, that explains it.... I thought I remembered reading that in another thread, but wasn't certain.

So hopefully when I get the NPS fitted Tuesday, that will take care of that issue.

I will be speaking to the boss regarding Catch Can and EGR mod this coming week. We have blanked off the EGR on all of our work Troop Carriers, so can't see there being an issue for him with the Nav.

tweak'e: Fuel filter + air filter are less than 1000km old.

 

[tweak'e]

egr valve could be stuck open but what i was meaning was egr system is still running. at idle that means butterfly is partly closed. could have problems with poor burning if idled for long periods of time. possible sooting up of combustion chambers. but thats only in theory.

bit of crap could block filter 10 minutes after fitting a new one. also an air leak could be made worse as the filter starts to clog up.

 

[adz14]

So, I had to dash into Darwin today, so I grabbed a shiny new 19mm spanner whilst I was in there. Got back to work and fitted the new NPS. Surging is now gone and the heat switch test worked fine.

Car is still a bit sluggish though. So have isolated it for the night, and will see where we are at in the morning.

 

[adz14]

Bugger, car is still sluggish. So, maybe, unplugging the NPS and having it running the EGR constantly for a few days (maybe 100km total), has done some damage/sooted up intake/combustion chambers.

Any ideas guys?

 

[Old.Tony]

I'd block the EGR to start with. Run some injector cleaner through the tank, add a little Chemtech Diesel Power if the urge takes you.

 

[adz14]

I'd block the EGR to start with. Run some injector cleaner through the tank, add a little Chemtech Diesel Power if the urge takes you.

Roger, have thrown the injector cleaner in already, and the EGR will be done on my next trip to work in a couple of weeks.

Cheers Tony.