Non-turbo vs turbo diesel fuel plumbing, primers, etc for Toyota's (1 Viewer)

[sunrk]

I've been looking into this a bit because I got an incorrect (ports too big) fuel primer head a while back and didn't realise until then there were two sizes of fuel line fitted to 80's for the Australian market.

So I went looking in toyodiy at the p/n's and discovered that for mine (1992) the non-turbo diesels get 23301-17010 or 23301-17150, while the turbo diesels get 23301-17030 or 23301-17170, depending on build revision (pre-8/92 or post-7/92). The ones for pre-8/92 has a differently formed outlet port. Why Toyota went away from that is something I don't know. At present I'm using a -17150 but haven't been able to fully rule it out as a leak source (despite doing the clear hose trick).

The std fuel lines are 8 mm ID for a 1hz at least that's what my 80 has got. The turbo versions appear to have received later 10 mm ID lines and 10mm ported diesel fuel primers. I don't think there's much of the OEM fuel line parts still available as new genuine product.

I've got no idea if all the other things under the back where the two solenoid valves, etc. locate have bigger 'cousins' on turbo diesel 80's.

People have reportedly fitted 'pusher pumps' to their diesel 80's in some places to increase the pressure delivered to the fuel filter (and therefore the injector pump) but I don't know what if any difference that makes and whether the injector pump is actually designed to work in positive-pressure supply system.

 

[roscoFJ73]

I got an incorrect (ports too big) fuel primer head a while back and didn't realise until then there were two sizes of fuel line fitted to 80's for the Australian market.

Dont the fuel ports or valves come out? I was told they are replaceable. I not I would just sell the 10mm fuel primer and filter head and buy the proper size.

People have reportedly fitted 'pusher pumps' to their diesel 80's

I have never seen a valid argument for it. The feed pump inside the injection pumps as much as 4 times the amount of fuel needed. The excess is pushed through a bypass valve in the injection pump once its full and sent back to the fuel tank, so any extra fuel from a pusher pump just keeps the bypass valve open longer. Its like a carburetor, once the fuel bowl is full , it doesnt need any more fuel.
Some American trucks had weak feed pumps on their stanadyne injection pumps and needed an extra electric pump.

 

[sunrk]

I've never tried removing the fuel ports off a filter head to find out whether than are 'field replacable'. Someone might know though.

As for the pusher pump, I think it's really only something relevant to 80's (and similar 4wd's) with petrol motors as like you say the diesel injector pumps do just fine with their 'vacuum' like method to draw fuel from a tank through the filter/primer assembly.

 

[wedgetail]

Don’t know much about 80s, but 1hd-ftes (and I thought turbo 80s too) have 12mm feed lines and 10mm returns. I’m fitting 12s to my fte conversion.

People report fuel starvation in high power applications with less than 12mm lines and ftes. Pushes pump may fix this but introduces another potential failure. Fuel flow is also about pump cooling not just fuel for burning

 

[roscoFJ73]

The injection feed pumps can draw up to 900cc a minute according to the manual, which is the same as 900ml which is 54 litres an hour and thats on the 8mm 1HZ lines.
On my FJ73 it had 6mm fuel lines for the 3F. The 3F used more fuel than any Toyota diesel but managed to get all it needed through 6mm fuel lines.
When I swapped the 1HZ into the FJ73 , i left the 6mm fuel lines in place on the advice of a fuel injection shop and they were 100% right, it never suffered from fuel starvation.
I honestly dont know why Toyota decided to use such big diameter fuel lines.

 

[Greg_B]

It would be interesting to know why the Toyota engineers upped the line sizes. The line increase corresponded with the date change for the pistons/injectors and injection pump changes for the 1HD-T equipped 80's as well I believe (08/92)

There is some good discussion on pusher pumps which I'll link to here for your reading if your inclined. I'm on the other side of the fence where I have never read good reason not to put one in, however rather then clutter your thread with that discussion here are the links:

Walbro Fuel Pump

HDJ81 - no fuel when cold

Another Walbro Thread - Successful Cure of a Stumbling 1HDFT

hth's

gb

 

[bjowett]

Lines are likely larger due to the viscosity of Diesel #2.

 

[sunrk]

None of the evidence re pusher pumps with diesels seems to be conclusive as to whether the extra pump is really necessary as Toyota factory turbo diesels have never had them, though I don't know if any of the modern common-rail computer-controlled diesels have a twin-pump arrangement.