Huge fuel consumption problem

Kremmen · Post by **Kremmen** » Sun May 20, 2012 3:26 pm

My JA is now consuming well over twice as much fuel as it used to. It amazes me is that it's still running fine. In my experience, vast changes in fuel economy are usually accompanied by other changes in the way an engine performs but there are no obvious changes in power or anything. It just uses astronomical amounts of fuel.

The engine has been burning oil for some time (err, years) and this causes my mechanic's equipment to give totally bogus interpretations for the exhaust gasses. So, he said it could cost a fortune to try to diagnose the issue when none of their diagnostic equipment is useful.

I'd be really grateful if anyone has seen something like this before and has any idea what to check.

ProZac · Post by **ProZac** » Sun May 20, 2012 3:31 pm

The typical reasons would be a chronically dirty air filter, or leaking injectors/injector seals.

Kremmen · Post by **Kremmen** » Sun May 20, 2012 3:50 pm

I'm sure they checked the air filter and I'd guess that would get progressively worse, rather than happen really rapidly.

Is there any easy way to test leaking injectors/injector seals?

ProZac · Post by **ProZac** » Sun May 20, 2012 4:47 pm

Take off the cross-over pipe (the pipe to your intake manifold, that goes over the rocker cover), and crank the car, watch the spray pattern of the injectors. Should be a fine mist, with no big drops. Once you stop cranking, there should be no dripping from the tip of the inejctors. Also, look for fuel flowing down the walls of the injection mixer, as that'll indicate a seal higher up.

Kremmen · Post by **Kremmen** » Wed May 30, 2012 10:21 pm

Thanks. Mechanic says the throttle body/injectors/etc have had it and it would cost thousands to fix.

enthuzed · Post by **enthuzed** » Wed May 30, 2012 11:52 pm

Sounds like another case of modification to aftermarket computer and MPI then. Or dump the car.

P.S. Hundreds is closer to the mark, your mechanic doesn't want to fix it, they are a pain in the arse but many on here have fixed theirs themselves...

Kremmen · Post by **Kremmen** » Thu May 31, 2012 12:51 am

enthuzed wrote:P.S. Hundreds is closer to the mark, your mechanic doesn't want to fix it, they are a pain in the arse but many on here have fixed theirs themselves...

They not only don't want to fix it, they won't do it. They'd send it away to be fixed and charge whatever that comes to. Their only other economic recommendation is for me to find a good one from a wrecker, but that seems unlikely.

OLD FART · Post by **OLD FART** » Thu May 31, 2012 6:06 am

I have a pair of JA injectors for sale that have been tested and are not leaking if you want/need them.

ProZac · Post by **ProZac** » Thu May 31, 2012 3:39 pm

Kremmen:

http://prozac.orconhosting.net.nz/eciguide/rebuild.html

They're really not that complicated. Its around $10 in parts, and maybe a day of your time, taking it super slow. Ive done a few now, and every single car has gone 100% better afterwards.

Shit, send it over to me, I'll rebuild it for you. Just have to hope your injectors are okay, could get them ultrasonically cleaned while the unit is apart.

Kremmen · Post by **Kremmen** » Thu May 31, 2012 5:30 pm

Thanks a lot for the offers!

ProZac, I'd happily take you up on it if you were in Melbourne, but I'm not sure it's worth it as you're in NZ. ... Or at all, given the amount of smoke it blows. There are clearly other costly issues lurking in its future.

Post by **Alspos** » Thu May 31, 2012 7:16 pm

Where in Melb are you?
I think I have an injector top somewhere, take it, swap it over and see if it changes anything. If it's still running ok it may be a temperature sensor messing it up, thinking the ngine is always cold when it's warm.

Kremmen · Post by **Kremmen** » Thu May 31, 2012 9:39 pm

Alspos wrote:Where in Melb are you?
I think I have an injector top somewhere, take it, swap it over and see if it changes anything. If it's still running ok it may be a temperature sensor messing it up, thinking the ngine is always cold when it's warm.

It idles normally, at higher revs when cold, so that aspect appears to be working. (The 35l/100km fuel consumption is a bit of an issue though.)

I'm in Box Hill.

mizuno man · Post by **mizuno man** » Fri Jun 01, 2012 1:26 pm

Have you checked for fuel leaks from the fuel pump to the engine bay. Can you smell any fuel?

thrash · Post by **thrash** » Fri Jun 01, 2012 1:31 pm

Kremmen wrote:
I'm in Box Hill.

someone syphoning out your fuel perhaps rofl

do you smell fuel at any time within the car? if the running of the car hasn't changed, I would be checking the fuel tank and lines under the body to be sure there are no leaks or holes..

seb · Post by **seb** » Fri Jun 01, 2012 6:39 pm

My Dad said he was driving his old nb years and years ago, started using huge amounts of fuel on one of his journeys, checked around and found a vacuum pipe had come away, think he said from somewhere near the bulkhead?? Worth a check, Seb

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Huge fuel consumption problem

Huge fuel consumption problem

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