26 replies to this topic

[yannsB4]

Hi all. Really stumped on this one..

On sunday, i filled up with caltex 98 at 9:30am. At approx 2pm, the car spluttered to a halt after turnig right on a roundabout. Sat there with the engine cranking with no result.

Had a mate come help out, we pulled the fuel filter (which was filthy) and found the fuel in the tank to be of a brown colour rather than the light purple that 98 should be.

Managed to crawl home with no filter installed albeit with the engine coughing and spluttering and with absolutely no power taking off.

I've since put a clean filter in.

Now, when i start the car up, it cranks for 3-4 sexonds before coughing into a spluttery, coughy, missy type of idle below 1000 rpm but smooth above 1500. When I attempt to rev it a little, the engine coughs then revs up again, coming to rest on 1500 rpm smoothly but slowly dropping into the previously mentioned rough idle, which then corrects itself as ot revs back up to 1500rpm.

Now for the actual question.

Does this sound like a fuel pressure issue or a bad fuel issue?

If theres any other questions i can answer to help qith this, let me know. Would really like to fix this up asap...

[Robert]

The tank will need to be drained at the least, i would be pulling the fuel pump out and checking the sock for blockages.

 

Get a fuel pressure gauge and see what the pump is outputting once reinstalled.

 

Hopefully no damage was done to the fuel system by having no fuel filter on

[migoreng]

What fuel filter did you get? Genuine, ryco or something else?

[yannsB4]

Got a ryco filter.

Yea fuel was properly brown...but i dont understand why its a polar oposite to what i was experiencing sunday.

Sunday (no filter)- idled fine, wouldnt rev.
Monday (filter)- wont idle, but revs

[allpaw4]

Get the injectors cleaned and flow tested. May have an issue there, and flow testing isnt all that expensive once the injectors are out.

The other thing to do (after the tank has been emptied and cleaned out) might be plug another hose into the fuel supply line in the engine bay and run it to a large bucket with a lid on it (lid to stop the splash back) just to clean out the lines.

Certainly an issue there. Sounds like you got a bunch of crap with your fuel in the morning.

[Mitch.]

that fuel was pretty brown, this might be a dumb question but your not still running that fuel in the tank now are you? 

[yannsB4]

Not a dumb question. Yes im still running the fuel that i hsd no problem with for four hours on sunday...

[TSG]

Fuel quality seems to be out the window atm. I've just had a terrible experience myself. We're wondering if the MAF might be dirty on mine too though.. next thing we're going to check. Sensors and vac leaks. But I'm probably up for a tune because of it. Tried injector cleaner?

[allpaw4]

This might be considered overkill, but consider removing the fuel tank itself from the car, putting 5L of fuel in it and slosh it around manually. You may need 2 people to get this done, but will should gather all the crap in the tank and put it in suspension with the fuel. Drain it out (and tilt the tank to the drain point too) and repeat until the fuel comes out as clean as it went in. Dont use a different solvent like kerosene as there will be a residual left that may tarnish the first batch of fuel you put into it.

I know its a fair bit of work to get the tank out, but given the fuel came out brown, I'd be cleaning EVERYTHING.

 

A bad batch of fuel can cause major problems, I know of an XR6T where I am got a tank of fuel contaminated with some sand. Scratch one motor.

[allpaw4]

Something that twigged my curiousity in your first post too. Premium unleaded fuels should NOT be purple in colour. They should be yellow. Both BP and Caltex 95/98 fuels are yellow as stated on their respective MSDS. If you have had a batch of purple fuel out of a premium pump, they are giving you regular 91 (or worse, ethanol blended) and charging you for 95/98. Big no-no, lawsuit material.

 

Should be mentioned that Aussie fuels will be changing colour this year (commenced late last year).

91 unleaded (no ethanol) - Purple/Bronze fuels will be phased out over this year, being replaced with a red/orange colour.

Premium unleaded (All brands, law requirements) will remain unchanged - Yellow.

BP E10 fuels are Purple. (Most aussie ethanol based fuels are now purple, although maybe not E85, I havent checked that one)

BP Diesel is clear (well, undyed)

BP Racing 100 is Green

BP Kerosene is a light blue

 

Keep an eye out on what colour you are getting. I cant be bothered pulling out all the relevant colours for every company as it involves going into the MSDS for each fuel. BP has their colours nicely listed on their website.

 

But yes, check that colour man, if they sold you the wrong fuel, and it can be proven, they can have the book thrown at them.

[yannsB4]

Wow, i had no idea rhat pulp was supposed to be yellow! Always thiught all fuel was purple. The more you know!

Ill get some fuel out of the tank and post a pic. Aswell as a video of exactly what its doing.

Ill also test fuel pressure and get back to you.

Tha ks for all your help guys.

[yannsB4]

Hey guys, bought the gauge. Can anyone tell me what the pressure should be?

[Robert]

bout 200 KPA would be healthy

[yannsB4]

Right.. thanks!

200kpa = 29psi

I always thought it was more than that.

I'll test pre- fpr and after fpr to find out whether its just the fpr playing up...

[Robert]

Anything lower than that you may have a problem, anything over by a small amount is fine.

[yannsB4]

Hi all. Checked pre- fpr pressures and found that when it primes, it gets about 18 psi. When its idling nicely (1500rpm) it holds about 18psi.

However, the psi suddenly drops to around 6 or 7 psi. It starts to idle rough as guts and wont rev etc.

Then randomly, fuel pressure will rise up to 18 psi and the car will idle at 1500rpm again. Theres a video coming where you can hear the wngine almost stalling aswell as what the pressure gauge is doing. Its about 70secs long and is being uploaded as we speak via photibucket.

I'm thinking its the fuel pump, but why would it suddenly and randomly drop pressure like that?

[Murf B4]

throw that intank filter asfar away from the car as you can- head into a wrecker and get the bracket for an under bonnet filter and replace in with a repco WRX/FOZ black filter -

 

18psi not enough bruz - fuel pumps Farked - Discount Auto Warehouse are selling deatswerks kits for 180ish 300lph pump awesome!!! -

 

38-40psi u need up the front -

[B4TT]

I'm thinking its the fuel pump, but why would it suddenly and randomly drop pressure like that?

Because it is a dying fuel pump.

Not an uncommon thing - easy job to change it over at least which is good.