Symptoms of a Faulty Injector Pump?

[Pragueprado Junior Member Find all posts View Profile Close Pragueprado]

Just got back from Toyota dealership here in Prague. Details of the vehicle are in my signature.

Having changed the battery and glow plugs, and still experiencing sluggishness/hesitation until warmed up (and getting the check-engine light), I finally took it to the dealership to have them read the codes.

They told me that the injectors need to be replaced (they've got about 110000 km on them, so entirely possible I guess) and the pump needs to be replaced. And the turbo might need to be rebuilt, although by the time I got there, they said that the turbo wasn't so bad. Neglected to give me the error codes or the readings on the injectors.

So, could someone please tell me the symptoms of a pump that's on its way out? The valves in the pump were replaced about 35,000km ago when the dealer thought that that might be what was causing a problem at the time - I discovered that it was in fact a faulty MAF sensor. But back to the pump - is it possible that a pump that is dying could cause hesitation until it has warmed up? Or does it just quit all at once?

Many thanks for any input.
Clive

[Pragueprado Junior Member Find all posts View Profile Close Pragueprado]

Well, no responses on that question, so let me try this: would anyone happen to know if dodgy injectors might start off causing hesitation when cold, but then show no signs of problems after they've warmed up?

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

The injectors could be under fueling when cold but this is usually accompanied by a
server rattling noise.

Honestly with a report from the dealer like that I would be getting the car back and
taking somewhere else for a second opinion.

Cheers
Leigh

[Baileys Diesel Group Member Find all posts View Profile Close Baileys Diesel Group]

Hey Clive,
Without knowing what the ECU is telling, its a bit hard to lock down just one potential reason for the issues.

Leigh is dead right, these injectors loose bottom end fuel as they wear out. But this is also accompanied by the 'dreaded cold knock'. my thoughts are that its a low fuelling issue, but that can be many things. Pump can not have to efficiency at low rpm to pump the required pressure (ECU would tell you this), Injectors are another obvious, but also on the radar would be things that make the ECU put less fuel in when the boost is first coming on.
So, Boost pressure sensor or Turbo stepper motor (not moving fast enough and therefore not generating the boost fast enough), things like Air flow / mass sensors and so on.

I would think that if you're not getting black smoke and 'cold knock' that your injection system itself is 'ok' at least, maybe best to start with the electronic / sensor side.

Like I said, without the ECU data and the car here, its a little hard, but these are worth a shot and an ok place to start.

Hope this helps!

[Pragueprado Junior Member Find all posts View Profile Close Pragueprado]

Thanks guys, appreciate the feedback.

You're right - everything I have read says that if the injectors are going, there should be clouds of white or even darker smoke on start up, and I'm just not seeing any of that at all. With regards to a death rattle, yes, it's louder when cold, but to me it just sounds like normal diesling, not anything harsh. Perhaps I can take a video/audio one morning and let you hear it.

I'll start checking the sensors; I replaced the MAF sensor about 40k km ago after the original failed - it was an after market version off of ebay; maybe it's got problems already. The annoying thing is how the hesitation (almost a limp mode, really) disappears after it warms up - and then the car has to be dead cold before it comes back; I would have thought that a bad sensor would be a bad sensor - why would it get better just because the car is warmed up?

Doesn't surprise me that the Toyota place here couldn't help - they're the same place that couldn't diagnose a faulty MAF and had the former owner throw expensive parts at it.

[Pragueprado Junior Member Find all posts View Profile Close Pragueprado]

Finally took a piece of wire, and following this excellent description here on Pradopoint, checked the codes myself - turned out to be one code - 78.

According to that same thread, 78 is:
P0627 (78) - Fuel pump control circuit (open/short/failure)
P1229 (78) - Fuel pump fail.
P0093 (78) - Fuel system leak (Large leak)

Armed with this, I did another search, and found another forum member with exactly the same symptoms, here.

As of his last post, he had corrected it by replacing the fuel filter. It's just killing me that the issue seems to come and go, and when it happens, it resolves itself as soon as the motor has warmed up - wish it would either work or not work so I can get to the bottom of this.

Well, will change the fuel filter and see what happens.

[Pragueprado Junior Member Find all posts View Profile Close Pragueprado]

Replaced the fuel filter - that's it, nothing else. Proceeded to drive about 3000 km from Prague to Switzerland (up and down various mountains), France, Germany, and just got back, and never had a single problem. I'm chalking it up to a bad tank of diesel.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Wow, you really need to find a new dealer to service your Prado. Turbo, Pump and injectors, could have been a hefty little bill on that lot and all for nothing!

Pays to always check the basics first. Every trouble shooting flow chart starts with them, be it; air filter, fuel filter, battery voltage, electrical connections etc etc.

Mick