Losing Throttle.

[Stomper]

Hey all.
My D40 has been having a few issues, first came with a chip malfunction where the vehicle wouldn't fire.
The chip was removed and the car would start, continually get a P0238 fault code but only with the engine light once in a blue moon and only if new chip not plugged in. replaced the boost sensor as recommended by Nissan after having to get the injectors recoded which also happened at the same time. There the car had no power at all.

I now have this problem where the throttle drops out, usually once in 4th and around 2500rpm, if you push the throttle you get nothing, take your foot off and then its all good, sounds like a electronic niggle.

when the chip malfunctioned i got this horrid injector rattle, i think that has degraded my power noticeably, i still feel the car is sluggish and not at its potential, if the chip isn't fitted the car is a slug.

any ideas on the throttle drop out would be handy, i am running a dawes valve set at 21lb.

 

[Old.Tony]

Sounds like there's a few things getting in the way of each other there, hard to tell where to start. If it's not too difficult, bring the car back to standard (no chip, no Dawes valve).

If it's sluggish there could be a few reasons for it:

* Dirty MAFS in the air intake. Unbolt it, pull it out (carefully), spray inside with electrical contact cleaner (don't touch the insides with anything solid) until the cleaner runs clear then let it dry (a minute or so) before reinstalling.

* Sludge in the intake from EGR + blowby. Block the EGR first. You may need to clean the intake - all the way from the manifold through the hoses, intercooler into the turbo. Blow-by carries oil vapour and gums things up, add the soot from the EGR and you've got a black sticky mess.

* Turbo actuator faulty - vacuum loss, sticking vanes. Fix the hoses first. Even if they LOOK ok, if they're hard or can turn on the barbs then replace them (all of them) right back to the vacuum pump on the right-hand-side of the motor (near the oil filter). Once you've done that, at idle watch the little arm beneath the actuator - it should move up and down easily, about 3-5mm, constantly. If not, the vanes may be sticking.

Performs better?

Then return ONE of the additional items and see if the performance improves, then the other.

The most common cause of intermittent faults is electrical contact issues - so unplug everything (including your accelerator) and plug it back in twice just to make sure.

Let us know how it goes!

 

[Stomper]

Thanks for the reply Tony, the EGR is blocked, the dawes valve has replaced a dead factory boost control solenoid, i have cleaned the MAF sensor.
I will replace the vac hoses to the actuator, i should add the turbo is very noisy, i recently had a 3 inch fitted to it and thought at first it was only induction noise, i think that actuator may have an issue.
i will try these and reseat the electrical connectors etc, I will let you know how i go. Thankyou

 

[happy john]

Not sure about that fault code Tony can confirm i suspect rail pressure you don't mention the make of chip or how it malfunctioned it should return good performance without the chip if it feels like a dog the problem is elsewhere.

Don't listen to the dealer perhaps you are used to the chip and when removed it feels slow a well tuned chip returns about 30 more h/p to the wheels either replace the chip or a quick run on a dyno should show around 100hp at the wheels for your rig sounds like the drop in power is limp mode back off and it resets.

 

[Stomper]

The chip was a chip it, originally with pet injection, that never played ball though, chip it have replaced it with the newer one, the car has no bottom end at all with no chip plugged in.
I drive D40's at work so i do notice the comparison, its a huge difference.
the only reason i have the chip in at the moment is so it is at least drivable. chip in or removed i still have the dropping out with the throttle.
i have just purchased some vac hose, i will get onto that now, im suspect on this actuator, i cant see any movement. The fuel rail has the factory sensor removed and replaced with the chip it part.

when the chip initially failed, you couldnt start the vehicle, bypass it, no problems.

i am in no way suspecting anything with the chip at this point in time, i can drive the car without it but is extremely sluggish.

 

[Old.Tony]

P0238 indicates the boost level is too high. At about 36psi the sensor reaches 5V and triggers a panic attack in the ECU.

It could be a loose connection, a short or a bad earth. There are three earth points the manual discusses:

1) Behind the ECU on the vehicle's right-hand-side inner guard

2) Near and below the air conditioning service valve, and

3) on the inner guard in front of the ABS unit (it'll be under the air box).

Take the connectors apart to the boost sensor, inspect, clean and reinstall. Check the loom for any crush damage. If you have a multimeter handy, check all three wires for continuity to vehicle chassis - there shouldn't be any.

Disconnect the boost sensor and test pin 3 against ground with a voltmeter - should be 5.3V present.

If you suspect loom damage, you could rewire it. Pin 52 of the ECU connects to pin 2 of the boost sensor. Pin 1 of the sensor to pin 71 of the ECU. Pin 3 should connect to pin 64.

Don't hear of too many boost sensors failing. Certainly have some odd things happening to the system when people pressure-wash the engine bay or do deep-water crossings.

 

[happy john]

Playing with injection and boost is your problem it's not a race car it is a 2.5 tonne brick rip all that crap out and drive it normally without the added things it will be normal and you won't need to ask for help here but plenty of info available if you need, a standard d40 returns more than you require for NORMAL driving

 

[Rumpig]

Have a read of the 20th Jan post on Gturbos facebook page, could be your VNT is jammed. https://www.facebook.com/pages/Gtur...0891624305172?ref=stream&hc_location=timeline

 

[Stomper]

Thanks for the advice guys, still no luck, i will keep chipping away.

 

[Old.Tony]

What does the little arm do below the actuator when the engine is only idling?