Fuel problem in KE70 4AGE.

[Sprinter-Saurus]

Evenin'.

Rob and myself are having fuel problems with our 4AGE KE70, which can be found in this thread here: http://www.toymods.net/forums/showth...299#post630299


Once the car has been running for about 15 minutes, the motor seems to drop a cylinder, run really rough, then eventually cough and splutter and die. We've worked out it is a fuel problem. BUT, it did it again today, but hasn't for the last 4 days when I've driven it. The problem seems to be fairly sporadic, but when it happens, it only takes a few minutes and then the car dies. We've put a new lift pump in, dropped the tank to account for air blocks, made sure the surge tank is getting fuel, the car actually has fuel in it, and the non-vented fuel filler cap is now vented. The VL pump from the surge tank is also still working, but it is noisy, so I'm going to change that to cancel one more thing out.

After that, there's only one more thing to do, and that is change the pick-up inside the tank. Anyone got any other ideas or things that we could try to find or fix the problem?

Cheers.

[3BarSuperstar]

Get yourself a fuel pressure gauge and check to see if it is a fuel problem or not. If it is dropping pressure might be a relay problem?

[Sprinter-Saurus]

Already checked that aswell, when the car is running correctly, it has 50psi of fuel pressure, more than enough, but when the problem rears its ugly head it drops to around 5/10psi.

[3BarSuperstar]

Does the pump stop working when it happens? Listen to the pump or get a test light and check for power at the pump when the problem happens.

[Sprinter-Saurus]

The pump still keeps chugging along when the problem happens, sometimes it's noisier, sometimes it's not. Methinks it might be time for a new VL pump.

[3BarSuperstar]

You might be right. Does the return line from the motor return to the surge tank or the main tank?

[Sprinter-Saurus]

It used to go to the surge tank, but we thought that was the original cause of the problem, that the hot fuel was going to the surge tank then straight into the VL pump causing it to cut out. So we changed the return to go straight back to the main tank first so the re-turned fuel could mix with the rest of its brethren, but the problem is still there, although not as bad or as frequent as before.

[3BarSuperstar]

What are you using as a lift pump? The way you have it set up now your lift pump needs to be able to pump more fuel than the main pump. Or you can run the surge tank dry depending on the power output of the motor? Is the lift pump still working at the time of the problem?

[The Witzl]

i might be stating the obvious, but have you eliminated fuel filters?

[Grega]

fuel pressure reg on the rail playing up?

[Cuzzo]

fuel pressure reg on the rail playing up?

Id go with this one. BTW 50psi seems a bit high on idle/startup?

Do you have an adjustable reg or standard reg?

If you remove the vaccum hose on the fuel reg does fuel come out? (apparently this is what happens when they go) id still swap it even if it seems fine.

Also injectors not have a wiring issue or is this ruled out now?

[roadsailing]

ill second the witzl, check the filters, i have seen things similar caused by blocked filters

[Grega]

mmm. thinking about it; is your fuel filter an EFI fuel filter or carby fuel filter......slight flow difference...

[fatboy13]

I had the same thing with my Crown (MS55 with a 7MGE) ages ago, and it ended up being the filter clogging up with shit... i had to change them every second week for a while as the tank was obviously full of crap, and the filters would block completely. Meaning it would start dropping a cylinder then stalling altogether...

Just like your car...

[EVOSTi]

what happens is when the problem occurs, the lift pump stops pumping fuel. its a carter gold and can flow shit loads more than the VL pump.

i know its the lift because you pull the outlet off the lift pump and its pumping alot of air and not much fuel but its still running so not electrical.

i took the outlet out of the tank to see if the steel line is blocked but its not, and the tank is full of fuel. the fuel filter is also new. im thinking possibly its a dud lift pump but we're gonna run a bigger hard line into the tank and see if that sorts it just to makle sure its not a feed problem.