Pain in the A**

[smidsy]

Hi All, Iv been having a nightmare for a while, iv been trying Australian(im from Ireland, but live in Aus) forums, but no luck. So thought I would try here.

 

Ill copy & paste my posts from the other forum. The good thing about duel fuel is it heps eliminate a good few things !

 

*sorry for the waffle !*

 

Post 1

Hey All,

My car is a 2000 Nissan Pathfinder ST with 135,000 kilometers.

I bought the car about 3 months ago.

Iv been having an ongoing problem for the last 2 months.

The car runs fine on LPG, but on petrol its cutting out.

At first I thought it was dirty fuel.

So, long story short, after doing lots of things, I eventually emptied the tank, and changed the fuel filter(actually changed it twice).

The fuel that came out seemed dirty & oily to me, so I figured I had solved the issue.

Put 20 litres in and it ran fine, cut out once early on. Then filled up & it ran for half a tank. Tonight I take it for a run and now its started cutting out again regularly. This can happen at any time, be it idle, cruising whatever. As soon as it cuts out, if im going fast enough and put my foot down, it will get going again. But if im stopped at lights or something, I have to put it in park & start it up, usually starts on first of second turn.

The fuel pump seems fine, as thats how I emptied the tank. Unless its intermittently stopping working(do fuel pumps do this?).

The weird thing is its fine on LPG. So im at a loss, and thinking I should just give it to a mechanic and get him to solve it. Cause its now pi**ing me off !!

 

Post 2

 

Gave it to the mechanic today.

There was proper fuel pressure, but low fuel flow. Doesnt quite make sense to me, as I think they are the same thing ?? But maybe im wrong ??????

He said that a new fuel pump was his diagnosis.

To be fair he did explain further as to why they would be different, but I was in the office and distracted by something really important so wasnt really listening properly.

Anyway, thankfully, I had already located & removed the fuel pump access panel when presented to them, which was under the back seat. So I knew that would save the task of the tank being removed, and hence a **** load of labour costs. He did say its was a bit of a pain in the ass, which I can well believe, as its such a tight space working through a tiny access panel.

Again being fair, he said it might be somewhere around $320 to $380, and I asked if he could try to keep it to $300, with no promises is something else popped up.

Arrived to collect it & it was exactly $300, so I really think he was being fair. He could have easily got away with $350, and I wouldnt have complained.

Labour:$180(1.8 hours testing for faults & also the actual fitting of the fuel pump)
Pump : $93
GST: $27
Total :$300

Im off on a 200kms run tomorrow for work, so I will see how she goes. I think ill run a few tanks of petrol through her and see how she goes, no LPG for a while!

Based on this => http://www.aamcovenice.com/4-common-...-pump-failure/ which I read last night

Its very similar to my problems, so perhaps this is it !

Fingers crossed !!

 

Post 3

 

*UPDATE*

All went fine for about 200kms, then the b1tch started acting up again !

So at this stage, fuel filter changed twice, fuel emptied, and fuel pump changed.

Total bill so far, $400. Excluding the axle stands, jack, injector cleaner(x2).

I checked the spark plug leads for tightness, and the MAF for dirt, this evening but all looked good, air intake bolts were a bit loose but thats all.

Was going to work through the ECU diagnostics i found on the net, but that requires taking out the front seat. As my garage is tiny and poorly lit and its getting late, ill do it on the weekend.

But while sitting there she's idling on petrol reading the service manual regarding the ECU, I was playing around with putting her in the different 4WD modes, and out again listening to the servos/motors, & she kept cutting out. Hmmmm.

So I put on all the lights, radio, aircon, wipers etc and changed 4WD modes, while running LPG and she was running fine, never cut out at all, and idle was fine !!

Did the same again on Petrol, and 3 out of 4 times she stuttered & then died !

So any ideas ??????

At least I can now sit with the mechanic and demonstrate it cutting out !

I know the battery is old and should probably be replaced anyway, but that doesn't explain why its cutting out as its the same battery on LPG or petrol. However there is an issue with the higher demand of petrol required by the increased electricity. So, does this help pin it down at all ?

[smidsy]

Only realised how log the post is with the excessive spacing. Was going to edit it to make it a bit more compressed, but dont have permission.

 

Sorry its a bit hard to read.

[devonianwalk]

I'm guessing the SES light is not on? Have you or your mechanic checked for underlying codes?

[smidsy]

Hi, Thanks for the reply.

 

No, there are no engine lights until it dies. Which are the same as ignition "on" before starting, so they dont help much.

I think I will check for codes tomorrow, it was getting late today.

 

I have a theory, although electricity is a bit of a mystery to me. Can old batteries start a car(ie. have voltage), but when there is full demand from the alternator, and it then draws from the battery, cause the fuel pump to stall, and/or the car to breakdown ? I had a similar problem with a battery with a bust cell, but that one wouldn't start the car. Im probably way off here ?? Or could it be an alternator problem, that kills the fuel pump, but on LPG this isnt noticed ? Yes, im pulling at straws.

[HitMan]

I wouldn't say it's the alternator unless your having trouble starting back up once it cuts out on you. However I would check the ground wire for the alternator, because if it moves around at all, it is possible for it to kill itself. A long shot, but worth checking. Also, I would check the MAF wiring. Try running it and then moving the wires that connect to the MAF and see if there is a loose wire anywhere. I had that problem before and could not figure out why my truck kept stalling out on me. Do you run high octane gas, when running gas?

[Precise1]

I doubt it is the battery. Yes, it could drain and stall the vehicle, but it wouldn't be able to turn it over to restart it. The problem almost sounds electrical due to the random cut out, but it doesn't do it with LP, so that doesn't make sense. It only stumbles and dies running gas, so that leads me to believe it is a fuel delivery issue. Has the pressure regulator been checked/replaced? Maybe it maintains the correct pressure but not enough flow as the mechanic said?

 

How is the LP plumbed in? It has to get into the fuel rail and injectors, so how is the gasoline supply shut off? Is there a valve somewhere in the line that could be restricting flow? One time I had an intermittent dying issue that turned out to be a fuel additive cap seal floating in the gas tank. It would get sucked against the fuel puck up in the tank, block off the flow, starve the motor and kill it. After 5 minutes it would fall back off and the car would run another random length of time. I wish I knew the dual fuel systems to better diagnose.

 

Yes, I don't know if the OBD2 reader is used world wide, but there has to be a plug to check the computer for fault codes.

 

B

[fleurys]

reading your story makes this issue interesting. Having not seen how a dual fuel system works, I cannot help you with a direct answer, but I can say this: Whatever the problem is , it seems to be related to something that , WITH TIME, starts degrading.... So I would definitely rule out any mechanical component as those usually either work or not. Your instinct to think about something electric could very well be it... If you think it could be related to your battery, try to take a reading of the voltage going to the battery when it happens.... you know if the battery or alternator is acting up on you...

I would also check if there is no ecu wires that have either no or less shielding. I have seen in the past that at one point, an ecu with some wires that are almost skinned or damaged, will start acting up on the ecu as it raises it temperature. If you have or could have access to another ecu , it would be also be a good test to make sure nothing in your ecu is causing the issue..

Sorry I could not help more, but I think you are on the right track with something electrical or a sensor that eventually acts up when it starts to heat up..

[fman]

depending on the type of the lpg system you have there may be a petrol cut off solenoid valve installed(as well as an lpg ) to cut off fuel in an accident if that is installed check for earthing and condition also make sure the primary fuel safety switch is operating.

cheers

nathan

[Alkorahil]

_{This sounds like a distributor problem to me.........}

_{But it should do it in LPG too.......}

_{thinking along that line though, perhaps a VTC problem you are having maybe as the ECU advances or retards the timing for petrol vs LPG?}

 

 

 

_{What is the engine type in the vehicle?}

[smidsy]

Thanks for the replies & suggestions !

 

Got the battery tested, and the reader said bad needs replacement. Got a reading 12.7V and 350 crank Amps(??). So went & bought a replacement $140.

Funny story, the new battery wasnt turning over correctly after the bloke in the shop replaced it(free service). Glad I got him to do it, as then when he tested it, it was only 330 crank amps. HUH ? Is my car killing batteries im thinking. Anyway, the other one on the shelf was the same. I told them I have electrical issues, and want to be absolutely certain to eliminate the battery. So they upgraded to a "Gold" battery for free, normally $170. Tested that on the car, and it was like 695 amps. Nice !

 

Its running well, but did stutter a couple of times, but not anywhere near as bad as before. I had previously put enough injector cleaner in it for 2 tanks, and only on a half a tank. So I drove in 3rd up the highway and got the tank close to empty. Filled her up on normal petrol, so lets see how it goes ! I got a long run on Thursday, so ill she how she goes then.

I also re-set the ECU, as since I was playing around with it disconnecting bits & bobs I would prefer new codes with the new battery. Ill check the ECU connections today, and clean the battery connectors & check the alternator connections.

My bet is she'll run great for half a tank, and act like a b1tch again !

 

Anyone know if battery can damage other electronic parts ? Alternator seemed fine at 14.7V(i think)

Edited February 5, 2013 by smidsy

[smidsy]

*Update*

 

Problems came back, but they are slightly different !

 

On a whim, I checked the throttle body, was a bit gunked up, ran a toothbrush with petrol over it, dont think thats an issue.

I tried the trick with using lots of electrical power used again & putting into 4WD etc, and this time there's no cut out at all on idle on petrol. Probably cause I got a decent battery.

 

I had a look for the ECU, its hidden high behind the dash, looks like a real nightmare to pull out. Im not sure how you get codes from it anyway without a digital read out.

 

Just to clarify, now the battery is changed, the car has gone from a stalling issue to a spluttering issue. Slightly different, the underlying problem is still there, but it was made worse by old battery & fuel pump? If im at idle it will splutter & die, but if driving it splutters and keeps going.

 

Hmmm, back to the mechanic next pay day I think.

 

Also, something else worth noting. I did have an auto-electrician fit an immobiliser on the cheap. Could be related, probably not.

 

Its getting a quite a bit tiresome now.

[Slartibartfast]

I would try bypassing the immobilizer, just to rule it out. Maybe there's some little crimp connector that's not quite crimped right and it's making intermittent contact. Do you know what part the immobilizer shuts down? I've got a hunch that it's cutting power to the fuel pump.

[fman]

<<Also, something else worth noting. I did have an auto-electrician fit an immobiliser on the cheap. Could be related, probably not.>>

 

was it stalling/stumbling before you put this in ?

you can get a nissan consult code reader for odb2 fairly cheaply off ebay usb or Bluetooth from memmory the port is located in the passenges foot well behind a panel dont quote mw though !!

Edited February 6, 2013 by fman

[fman]

<<Also, something else worth noting. I did have an auto-electrician fit an immobiliser on the cheap. Could be related, probably not.>>

 

was it stalling/stumbling before you put this in ?

you can get a nissan consult code reader for odb2 fairly cheaply off ebay usb or Bluetooth from memmory the port is located in the passenges foot well behind a panel dont quote mw though !!

do you know what timing its running at some lpg installers will bias towards lpg or petrol it may be they set the timing to +20 deg wich may make petrol run like crap although not sure whether heat will influence, it may be possible the ecu is making it rich or lean from the o2 sensor