Automotive handbooks / manuals

The Mitsubishi Pajero Owners Club®
The Mitsubishi Pajero, Shogun, Montero, Challenger, Raider and EVO 4x4 Owner's Club
 
The POCUK - it's not just a Club, it's a way of life!

 FAQFAQ   SearchSearch   Watched TopicsWatched Topics   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your personal messagesLog in to check your personal messages   Log inLog in 
Click here to link to the Pajero Owners Club UK FaceBook Group!POCUK FaceBook Group  POCUK home pagePOCUK Home  POCUK ForumsPOCUK Forums  CalendarCalendar

Alternate cause for P0190 fuel rail pressure loss?


 
Post new topic   Reply to topic    The Mitsubishi Pajero Owners Club® Forum Index -> Petrol model specific Q&A
View previous topic :: View next topic  
Author Message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Mon Sep 21, 2020 7:44    Post subject: Alternate cause for P0190 fuel rail pressure loss? Reply with quote

The usual and well known cause of loss of power and P0190 and P1200 fuel rail pressure loss in the 2001 onwards era GDi is blocked microfilters in the high pressure fuel pump (HPFP).

My 2003 3.5 GDi has been randomly exhibiting similar, but not identical, symptoms over the last few months and I've still not pinned down the cause.

What differs in my case is that it is occasional, often seems related to going uphill (often as part of a slight right turn), and can cause what feels like one bank of the V6 to cut out entirely so the vehicle severely limps. I have the feeling that keeping the tank topped off and using the XFR additive has kept the symptoms at bay.

E.g Recently I did a 50 mile outward bound trip at 70 mph without issue but on the return journey had several glitches meaning I had to treat the accelerator very gently.

If it were the microfilter in the inlet to the HPFP I'd expect the symptoms to be more consistent and get progressively worse as the filter captured more debris. I've bought replacement filters and O-rings just in case.

I'm currently exploring three other hypothesis and wonder if experts here have any thoughts? I've talked to Mitsubishi service centers and they're reluctant to touch it due to the randomness and lack of a clear cause.

1. Earthing fault causing the in-tank pump to stall (planning on trying to fit a bypass direct from battery to tank header connector to test that)

2. Faulty fuel pump relay in the engine bay (going to pull it, open it, and test it)

3. Failing in-tank pump or blocked tea-bag strainer (looking for a replacement unit - can anyone recommend a supplier and part number?)

Could it be heat-related (generally doesn't seem to happen immediately from cold start, or for a while after the vehicle has been standing for a day or two). Last week it went almost the entire week doing regular 20 mile commute then got seriously bad on the final day!
Back to top
View user's profile Send personal message
Google
Sponsor







PostPosted: Mon Sep 21, 2020 7:44    Post subject: Google Ads keep the POCUK free to join!


Back to top
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Mon Sep 21, 2020 20:40    Post subject: Reply with quote

Today it suffered a particularly bad episode just after turning (right) onto a trunk road such that I had to limp it into a lay-by at 20mph. This location always causes the issue - it is a junction after 3 miles of particularly bumpy cross-country rural roads that have the Shogun bouncing about terribly. After standing for 10 minutes it drove OK again.

I managed to get our farm mechanic to take a look this evening and after an hour or so of testing various scenarios he's got a different suggestion and some questions to ask of the Mitsubishi 6G74 GDi experts.

Firstly, he suspects the common cause of this and several issues he noticed whilst testing is a fault in or around the fuel pressure sensor or its electronic circuit to the ECU.

He found that whilst holding revs at 3,000 when the air-con switches in revs drop by nearly 1,000 and do not recover until air-con switches off again. We noticed this repeatedly whilst operating both the front and rear air-con units. At normal idle revs ~600 the revs increase approximately 100 as would be expected.

He also noticed that with the vehicle standing, on one occasion when the accelerator was floored the revs couldn't get beyond 3,000. On another occasion they reached 5,000. If slowly increasing the revs they'll reach 5,000 reliably, although with all tests the high revs were accompanied by mild pops and bangs suggesting misfires or similar (my interpretation, not his).

He's suggesting checking how easy it is to get to and test the electrical connection to the fuel pressure sensor, and investigate how easy (or hard) it would be to replace it, and to find out how much one costs - he says it'd be pointless buying an expensive part in case it isn't that without clear evidence of a fault.

He also asked if the Mitsi experts know if the in-tank low pressure pump is required only whilst starting or at all times (some systems apparently rely on the high pressure pump vacuum sucking fuel through once the engine is started rather than the low pressure pump) to help rule in or out the in-tank fuel pump hypothesis.

He reports having solved a similar issue in a Mercedes van where the fault was a leaky o-ring on the fuel pressure sensor.

What do the Mitsi experts think?
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Fri Sep 25, 2020 22:07    Post subject: Reply with quote

Here's a conundrum  - this week I've done a couple of jobs on the truck and so far they seem to have solved or seriously reduced the problem!

Tuesday I double-flushed and replaced the engine oil, added Ceratec, replaced the air filter. Thursday morning I had all five 285/55/R18 Pirelli Scorpion Zero tyres replaced with 265/60/R18 Michelin CrossClimate SUV (£677 @ KwikFit).

There was a stutter Thursday morning before the tyre change but since then it has felt like a different truck entirely and not had a hint of the fuel starvation. Probably only coincidence but definitely puzzling. I've bought a replacement fuel pressure sensor (~ £30) so I'm prepared anyhow!
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Sun Sep 27, 2020 7:09    Post subject: Caused by sticky inlet valve? Reply with quote

A few days and miles on and still no failure, no problems in high revving, delivering full power on kick-down, accelerating well, fuel economy up.

I'm tending to another hypothesis entirely now.

I suspect the fault was caused by a sticky inlet valve that was remaining open at times and has been cleared by the double oil flush and change. I can imagine it would cause the same symptoms due to the fuel injectors being on a common rail so a valve sticking partially open could cause a pressure loss when other inlet valves are open and also presumably cause a very lean fuel/air mix reaching the intended cylinder causing a loss of power.

The 'up-hill' aspect of the issue could well have been due to oil level being at the low end of the range - in the last few days before the oil change there'd been an oil level warning light for about 1 minute approximately 2 minutes after a cold start.

Time will tell but I'm feeling much more confident that the issue is mostly cured (could be a mix of issues) and this was the primary cause. I shan't be changing the fuel pressure sensor or replacing the microfilters for now.
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Sun Oct 18, 2020 19:29    Post subject: Reply with quote

Scratch the previous hypothesis - it wasn't a sticky valve! Since then it has stuttered a few times and struggled badly once when towing.

I mentioned that our farm mechanic had suggested focusing on the fuel rail pressure sensor. I've had problems figuring out where, precisely, it is located and how to access it. Until today all I knew was it is on the rear of the engine next to the bulkhead and on the near-side bank of cylinders (at the end of the U-shaped fuel rail).

With daylight and a WiFi boroscope I explored that area today and finally discovered the cause, and it is something no-one could have predicted.

There's a wiring loom runs from atop the intake manifolds with two sensors attached. The one I could see, and as it turns out, the fuel pressure sensor that is hidden beneath the manifold. The boroscope revealed that one wire had a section approximately 5cm long cut out and a replacement section badly soldered in its place without any attempt to insulate it. That wasn't the cause though - another wire had the insulation cut and a 90 degree elbow bent into it and was resting on the manifold. As best as I can tell this wire has been shorting to earth due to vibration and inclination of the vehicle, presumably causing incorrect signals to be sent to the ECU which was either cutting fuel supply or flooding.

I explored that loom up to the top of the manifold and found a connector block. On the other side of that connector, back of the plug, I found another 5cm section had been cut from a wire leading to the pressure sensor and again, a badly soldered replacement in its place.

I've removed and replaced those patches and fitted heat-shrink sleeving to all the exposed parts. I can only theorise that early in its life the vehicle had some kind of immobiliser that caused fuel flow to be cut.

Initial test results are good - engine will now reliably and repeatedly reach 5.5k revs under load without hesitation or stuttering. I'm not going to say this is the fix lest I tempt fate but if a week goes by with no further problems then this would seem to be the explanation.
Back to top
View user's profile Send personal message
ShogunItHurts
Newbie
Newbie




Joined: 29 May 2019
Posts: 9
Location: Leek

PostPosted: Thu Oct 29, 2020 15:26    Post subject: Reply with quote

Please keep documenting your journey, you are giving me many more options to look at chasing very similar issues!
Good luck!
Mark
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Wed Dec 02, 2020 3:22    Post subject: Reply with quote

Well, several weeks on and it still isn't solved!

Intermittently, and with no well-defined scenario any more, the engine will 'kick' (stall) momentarily and the check engine light will show. Most often it is while accelerating medium-hard such as when pulling out from a junction and matching traffic speed. Other times it'll happen during a steady cruise on flat roads.

I've noticed three times where, after a run, short stop, restart it'll suffer more with power-loss where the accelerator has to be treated gently. This suggests a temperature issue - most likely thermal contraction and expansion - bit where and what I've no idea!

After a few trips over three or four days it'll behave and the check engine light will reset and it'll be happy for a few days; lulling me into a false sense of optimism!
Back to top
View user's profile Send personal message
ShogunItHurts
Newbie
Newbie




Joined: 29 May 2019
Posts: 9
Location: Leek

PostPosted: Wed Dec 02, 2020 15:53    Post subject: Reply with quote

Do you have a fault code reader and is it always the same error code?

Checking the obvious, but have you changed the microfilter recently?

Good luck
Mark
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Fri Feb 05, 2021 12:20    Post subject: Reply with quote

ShogunItHurts wrote:
Do you have a fault code reader and is it always the same error code?

Yes, always 0190 Fuel Pressure Rail

Mark

I haven't checked the micro-filters although originally that was my prime focus - the randomness of the symptoms argues against those being the cause - especially after the electrical wiring fix improved matters dramatically.

I've got the Mitsubishi recall/service document that details the symptoms and the replacement job and the symptoms don't precisely match - micro-filter blockage should cause a permanent problem with fuel starvation and thus power loss.

The only way I can imagine it being related is if there's a larger 'lump' of debris got past the in-tank filter and is lodged in the fuel feed pipes.

I'm planning on replacing the fuel pressure sensor next - if it is sending an erroneous signal then that's a quick fix - and if not should rule out a problem with the sensor itself.
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Fri Feb 26, 2021 20:41    Post subject: Reply with quote

Last week the symptoms got markedly worse so I took it off the road. One symptom that doesn't match a pure micro-filter issue was a stop-start chugging randomness with speed down to less than 30mph and struggling on the level.  It felt like a problem with the in-tank fuel pump. Fault codes are still only P0190 and occasionally P1200 though.

So I decided to do the entire fuel system - replace the in-tank pump and filter, replace the micro-filter on the high pressure pump inlet, and (as others have done) add an inline fuel filter as was fitted on mark 2 vehicles.

Struggled to find a supplier of the fuel-line adapter needed to join the outlet of the filter (ADC42350) to the feed pipe (M12 x 1.25 to M14 x 1.5 male to male) 1.25mm thread pitch is extremely difficult to source. Ended up buying M14 to M14 adapter, grinding the threads off one end and milling an M12 x 1.25 thread onto it. Amazingly I found an M12 x 1.25 die in my grand-father's tool set that he collected whilst working as an engineer for Raleigh Cycles in the 1950s - amazed they used metric back then!

Started the job this afternoon. The access aperture from under the rear-offside seat through the floor and lower skin to top of the tank is difficult to work in. The hardest part was finding a way to access the 6 x 8mm nuts that secure the clamp ring that seals the sender/pump holder. The bolt threads are exposed to the elements so are rusty and I was afraid of shearing them. I struggled to find a way to access the 4 that are hard to reach. I had to use an 8mm socket 1/4" drive with a socket to hex adapter and a 10mm ratchet spanner. There is no room (vertical clearance nor ratchet sweep) for anything larger because they are under the outer metal skin.

It took a while to find a technique to get to the so-called quick-release clip on one of the three fuel pipes and manipulate its release catches. The other two have spring clips that are easy to get to with long nosed pliers.

The pump is housed in a quite complex assembly which clips together from three pieces - the top head containing outlet, return, vapour and electrics, the mid-section with a couple of quick-release clip hoses on the outside and pump in an internal tube, and a lower end-cap that holds the pump in the tube. It wasn't until I'd fitted the filter sock on the new WALBRO GSS342 pump that I noticed its outlet is longer than on the original pump and has a spigot end where the original is a smooth tube with a plastic spacer and rubber seal on top that mates into the top of the mid-section of the  housing assembly.

Due to the extra length the WALBRO pump is about 10mm 'longer' than the original and prevents the lower cap from clipping onto the mid-section. I'm not sure what to do at this point because the spigot outlet has a small valve in the top so I cannot simply cut it to the correct length.

Typical that I hit this end of day Friday when the supplier ( driven2automotive ) is off for the weekend!

I plan on tackling micro-filter replacement and installing the inline filter tomorrow. Might have to refit the original pump but will try to source a replacement filter sock for it.

I briefly ran both pumps 'dry' from a battery and can confirm other people's observations that the WALBRO is extremely loud in comparison to the original.
Back to top
View user's profile Send personal message
sani king
Newbie
Newbie


Age: 25
Zodiac: Leo
Joined: 24 Mar 2021
Posts: 3
Location: Uk

PostPosted: Wed Mar 24, 2021 8:07    Post subject: Reply with quote

iam_TJ wrote:
Today it suffered a particularly bad episode just after turning (right) onto a trunk road such that I had to limp it into a lay-by at 20mph. This location always causes the issue - it is a junction after 3 miles of particularly bumpy cross-country rural roads that have the Shogun bouncing about terribly. After standing for 10 minutes it drove OK again.

I managed to get our farm mechanic to take a look this evening and after an hour or so of testing various scenarios he's got a different suggestion and some questions to ask of the Mitsubishi 6G74 GDi experts.

Firstly, he suspects the common cause of this and several issues he noticed whilst testing is a fault in or around the fuel pressure sensor or its electronic circuit to the ECU.

He found that whilst holding revs at 3,000 when the air-con switches in revs drop by nearly 1,000 and do not recover until air-con switches off again. We noticed this repeatedly whilst operating both the front and rear air-con units. At normal idle revs ~600 the revs increase approximately 100 as would be expected.

He also noticed that with the vehicle standing, on one occasion when the accelerator was floored the revs couldn't get beyond 3,000. On another occasion they reached 5,000. If slowly increasing the revs they'll reach 5,000 reliably, although with all tests the high revs were accompanied by mild pops and bangs suggesting misfires or similar (my interpretation, not his).

He's suggesting checking how easy it is to get to and test the electrical connection to the fuel pressure sensor, and investigate how easy (or hard) it would be to replace it, and to find out how much one costs - he says it'd be pointless buying an expensive part in case it isn't that without clear evidence of a fault.

He also asked if the Mitsi experts know if the in-tank low pressure pump is required only whilst starting or at all times (some systems apparently rely on the high pressure pump vacuum sucking fuel through once the engine is started rather than the low pressure pump) to help rule in or out the in-tank fuel pump hypothesis.

He reports having solved a similar issue in a Mercedes van where the fault was a leaky o-ring on the fuel pressure sensor.

What do the Mitsi experts think?

thats really bad situation for you Rolling Eyes
Back to top
View user's profile Send personal message
iam_TJ
LifeTime Member
LifeTime Member


Age: 56
Zodiac: Gemini
Joined: 10 Apr 2013
Posts: 106
Location: Nottinghamshire

PostPosted: Wed Mar 24, 2021 8:49    Post subject: Reply with quote

Micro-filter was definitely the problem despite all my over-thinking of the symptoms!  Three weeks on and there are no more problems, performance is as expected in all situations. Additional in-line fuel filter added.





I  accidentally posted the follow-up in a new topic so I'm copying that here to complete the story!

Fitted the inline fuel filter in the engine bay after getting a local agricultural workshop to mill the correct thread with their lathe since I couldn't keep the die perpendicular and messed up 2 attempts to do the M12 x 1.25 thread. Took a LOT of effort to break the seal on the fuel line joiner - brake pipe spanners couldn't do it so ended up with large mole grips on the 14mm captive nut on the tank-side of the joint. The fixed side on the flexible pipe uses a 19mm solid nut so you hold this still whilst unscrewing the 14mm. Added PTFE tape on the threads of the machined adapter and added the copper washer - no sign of leaks.

What I expected to be the most difficult job due to the location of the high pressure pump turned out to be the most straight forward. I started off by disconnecting two electrical connectors above the pump, removing the mounting bracket, and pushing the connectors out the way between engine and bulkhead. To access the two bolts that secure the fuel inlet pipe I had to disconnect the two flexible return pipes from the solid pipe on top of the engine. Each has a compression clip so moved those along the pipe with pliers and then manipulated the flexible pipe with pliers until petrol escaped and lubricated the join, then wiggled and pulled the tubes until they slipped off.  Captured a small amount of fuel spill. Tucked them up in the bulkhead.

Had to remove the horizontal oil breather pipe that runs across the back of the block above the inlet to get to the near-side bolt.

That gave access to the two bolts securing the inlet flange. The off-side is a 10mm hex nut but the near-side is a Torq T30 with round head. Both need long-reach (25cm) attachments but aren't particularly tight so easy to release. Inlet has to be pulled out quite forcefully. At this point I replaced the O-ring on it and tucked it out the way. Soaked the remaining fuel out of the recess then carefully inserted an 80mm long M5 wood screw into the top of the micro-filter and screwed it in about 3 turns. First attempt at pulling it out failed as screw pulled free. Re-inserted the screw and went in about 4-5 turns and used constant pulling force with pliers on the screw, wiggled it a bit, and eventually the filter came out in a rush, and, thankfully, was complete!

Certainly looked dirty as the photos show. Inserted the replacement 6mm x 14mm micro-filter until its ferule resisted then used a copper drift on top to tap it down flush.

Reassembled and tested. Took it for a longer run with conditions almost guaranteed to provoke the P0190 fault and it behaved perfectly. Prompt acceleration, no 'drag', kick-down and under load all seems fine. I'll give it a week before declaring it fixed though - especially as its fooled me before!

Photos of In-Tank Pump, Inline Filter and Microfilters
Back to top
View user's profile Send personal message
Display posts from previous:   
Post new topic   Reply to topic    The Mitsubishi Pajero Owners Club® Forum Index -> Petrol model specific Q&A All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum


All contents © Hobson's Choice IT Solutions Ltd 1997 on
Powered by phpBB © 2001, 2002 phpBB Group