GQ Petrol greminlin has returned

[Travo]

The gremlin has returned on my Patrol 4.2 efi 96 model, I was having issues with he fuel light coming on and the car not really wanting to run. I have since changed the fuel filter c
and cleaned the MAF sensor and she was running great. I went to start it this morning and after my wife driving for about 10K's yesterday it is running rough again. It now will start and idle ok, when you go to bring up the revs it has a massive flat spot like it is not getting enough fuel, coughs and carries on and sort of sounds like it is back firing out the throttle body if you give it a stab on the throttle.

Any ideas would be much appreciated.

Cheers

Travo

[dom14]

Sounds like fuel pump issue.
If you can get hold of a fuel pressure gauge(or vacuum gauge, usually a single unit does both) with a piece of fuel hose & T-piece and test the fuel pressure while trying to rev, can give you an idea if it's a fuel pressure issue.
Check all visible electrical connections to the fuel pump and clean them accordingly.

[dom14]

Also, try disconnecting the battery and leaving it all night. Then try again after connecting the battery. This can clear any fault codes in the ECU and give you some idea whether your issue is fault code related.
Let us know how it goes.

[threedogs]

Have a go and refresh your earth straps,
cant beat a good earth connection lol

[Travo]

Gremlin update, must have move to someone else s car, sorry for that. I came home tonight armed with some more info and the awesome manual that i down load from this site (thanks to all involved). What do you know it started straight away no issues, I ran the codes and came up with 55, no issues there. Took her for a drive fro about 15 k to fill up with LPG and it ran perfectly on both petrol and lpg. I took it out to 4200rpm in third pulled all the way no issue.

Not at all sure what it is but I will keep trying and wait for the engine light to come back on and run the codes again. There may just be something in your comment Threedogs as yesterday and most times I have had issues it has been wet and today it is hot and dry?

Thanks again for your help

Travo

[dom14]

Gremlin update, must have move to someone else s car, sorry for that. I came home tonight armed with some more info and the awesome manual that i down load from this site (thanks to all involved). What do you know it started straight away no issues, I ran the codes and came up with 55, no issues there. Took her for a drive fro about 15 k to fill up with LPG and it ran perfectly on both petrol and lpg. I took it out to 4200rpm in third pulled all the way no issue.

Not at all sure what it is but I will keep trying and wait for the engine light to come back on and run the codes again. There may just be something in your comment Threedogs as yesterday and most times I have had issues it has been wet and today it is hot and dry?

Thanks again for your help

Travo

Yeah, it's highly likely a problem with fuel pump/pressure, which means electrical.
Ensuring the earth connections are in tip top condition keeps you out of trouble.
Check all the wires/connections related to fuel pumping electrics.

[billyj]

sounds like a dead/ dying fuel pump to me

[threedogs]

How about replacing/refreshing your fuel lines, as well as all the vacuum hoses.
Do them one at a time some you dont run into trouble.

[Travo]

Good tip Threedogs I put the original filter back in and had a look at some of the hoses and was thinking same, what are the standard sizes and I will just get a couple of meters of each to start with.

I have an LRA belly tank, would they have used the standard patrol pump in this set up?

Thanks

Travo

[threedogs]

not sure on hose size but would think all aftermarket tank makers
would use the OE sender unit

[dom14]

Good tip Threedogs I put the original filter back in and had a look at some of the hoses and was thinking same, what are the standard sizes and I will just get a couple of meters of each to start with.

I have an LRA belly tank, would they have used the standard patrol pump in this set up?

Thanks

Travo

LRA tanks use an intank electrical pump, specific for that, usually. Sender unit might be the same since it has to match with the existing dashboard gauge electrics. But, I reckon the LRA intank pump might be different from the original one.
They do develop problems over time, but I'm guessing, most of those fuel pumping problems are related to connections getting weaker over time, rather than pump itself. I have a similar issue atm, which I'm about to diagnose once for all by dropping the LRA tank in mine(RB30, carby). The best way to diagnose whether your issue is fuel pressure related is by checking the fuel pressure with a gauge. Fuel pressure tester is a cheap unit you can by off fleabay. It usually doubles as vacuum tester as well.

http://www.ebay.com.au/itm/10-PSI-Car-Truck-Fuel-Pump-Vacuum-Carburetor-Valve-Pressure-Tester-Gauge-W-Case-/131631981446?hash=item1ea5e0a386:g:NUwAAOSwo6lWJJk y

Fuel pressure can be different between carby & EFI models, as well as turbo and non-turbo engines.

Follow these video guides on how to do the test.

https://www.youtube.com/watch?v=AeVTZz0od7Y

https://www.youtube.com/watch?v=_oXLUqE4Sf0

Refer the Haynes manual(which can be downloaded from here) section 4(Chapter 4) Part B, page 2 and 3(4B-2 and 4B-3) or PDF page 12 & 13 of of the section 4(chaper 4) of the Haynes manual.

Pay a bit of attention to the fuel pressure regulator. That might be the cause of the issue.

[billyj]

95% sure that the feed and return lines are 8mm on a tb42e and 1/4 for the breather to the charcoal canister

[Travo]

Just had a chat to LRA and the pumps for the tank are the standard Patrol unit.
Might grab spare anyway as the car has done 300,000k's.

Cheers

Travo

[Ryank]

sounds like fuel

[rods gq]

My daughter's tb42e had random problems like this, did turn out to be the fuel pump. It appears that it doesn't take much drop in pressure for them to do strange things

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