Could it be vapor lock ?

[yoeddynz]

50 minutes ago, Flash said:

. I wonder if that van also suffers from vaporlock since the conversion.

Yep - the fella I fitted that carb to is having very similar issues,  much like he'd been having with the original toyota carb which it replaced.  

I think the above suggestions for a electric pump plus a vent to pull the heat from the bay would be a great start. 

[GregT]

Now I've seen two applications where injection would be preferred.  Van with a tight engine compartment - and any speedway car with a lazy owner which runs on Methanol.  Carbs get dirty and won't run right on watered methanol. But injection vaporises bad methanol just fine.

Sorry/sidetrack

I run a Hiace with the 2L injected engine. No probs.

[fletch]

3 hours ago, GregT said:

and any speedway car with a lazy owner which runs on Methanol.  Carbs get dirty and won't run right on watered methanol.

Drain the carbs after the meeting and refill with petrol. Then when you get to the track next week, enjoy the instant start and crisp high idle as your 16:1 comp engine runs right on the edge of knock. Then just as your envious competitors womble over to see how you got it to start so easily, and run without Italian tune up amounts of throttle, flick the fuel pump on and the idle will drop back to the typical methanol idle, albeit not as bad due to the glowing plugs and hot chambers from the brief burst on petrol.

[GregT]

6 hours ago, fletch said:

Drain the carbs after the meeting and refill with petrol. Then when you get to the track next week, enjoy the instant start and crisp high idle as your 16:1 comp engine runs right on the edge of knock. Then just as your envious competitors womble over to see how you got it to start so easily, and run without Italian tune up amounts of throttle, flick the fuel pump on and the idle will drop back to the typical methanol idle, albeit not as bad due to the glowing plugs and hot chambers from the brief burst on petrol.

You're talking to the wrong guy. I set up most of the carburettored TQ's and minisprints at Ruapuna for some years. I'd get sent a set of carbs from the coast which would be a block of white corrosion which was typical of the lazy owners who simply would not do maintenance.

There were performance benefits using carbs over injection. But for most the ability of the injection to keep going without maintenance was the telling factor.  Lazy bastards.

[Flash]

14 hours ago, yoeddynz said:

Yep - the fella I fitted that carb to is having very similar issues,  much like he'd been having with the original toyota carb which it replaced.  

I think the above suggestions for a electric pump plus a vent to pull the heat from the bay would be a great start. 

Thanks Alex, interesting to hear that he had similar issues with the factory carby as I suspected it may have something to do with the Weber conversion. Were you able to retain the factory Toyota carby spacer when you fitted the Weber?

[Flash]

13 hours ago, GregT said:

Now I've seen two applications where injection would be preferred.  Van with a tight engine compartment - and any speedway car with a lazy owner which runs on Methanol.  Carbs get dirty and won't run right on watered methanol. But injection vaporises bad methanol just fine.

Sorry/sidetrack

I run a Hiace with the 2L injected engine. No probs.

So, with your 2L injected engine the golden ticket might be the electric fuel pump. Just a guess.

[sleeektoy]

18 hours ago, Flash said:

Thanks @sleeektoy. My current mechanical pump has a return line fitted so would you suggest that I look at substituting the electric pump for my existing mechanical one or somehow running the electric as an auxilliary? I'm thinking it would be a simpler exercise from a plumbing point of view for me just to replace the mechanical pump with an electric job. Unless you have a cunning plan that I haven't thought of.

Its typically best to mount a pump to something solid close to the tank. however I have replaced my factory pump with a facet steel electric one mounted to the engine block and have had zero issues in 13 years of operation. It only gets a little rowdy when idling at the lights for a long time. I'd steer clear of a plastic pump too - i had one split and it sprayed fuel all over the engine bay - very lucky the car didn't flambe

[Flash]

51 minutes ago, sleeektoy said:

Its typically best to mount a pump to something solid close to the tank. however I have replaced my factory pump with a facet steel electric one mounted to the engine block and have had zero issues in 13 years of operation. It only gets a little rowdy when idling at the lights for a long time. I'd steer clear of a plastic pump too - i had one split and it sprayed fuel all over the engine bay - very lucky the car didn't flambe

Thanks for that. Nothing can be rowdier than my Astra power steering pump. Sounds like a jet engine winding up.

[Flash]

@sleeektoy, I've just taken a gander at the facet pumps available.

I'm assuming it's one of these little jobs that you are referring to:

This particular one is their model 40104 which I'm guessing would do the trick.  I'm assuming that since your pump is mounted very close to your fuel tank you haven't worried about fitting a return line. Is my assumption correct?

[GregT]

In my experience most Facets don't have a pressure limit switch. Ie keep pumping at all times. With this type of pump you're best to have a return line to avoid over-pressuring the carb.

There are a number of OE bike pumps which do have a cut-out once a set pressure is reached. The FZR Yamahas and CBR600/1000 Hondas are examples. They are quite capable of the volumes needed for a car engine.

[sleeektoy]

1 hour ago, Flash said:

@sleeektoy, I've just taken a gander at the facet pumps available.

I'm assuming it's one of these little jobs that you are referring to:

 

This particular one is their model 40104 which I'm guessing would do the trick.  I'm assuming that since your pump is mounted very close to your fuel tank you haven't worried about fitting a return line. Is my assumption correct?

Yes - The 2-4psi low pressure one for carbs - that is the one i have mounted on my engine block in the factory mechanical pump position. My car has a factory return line. Runs mikuni twin side-draughts no problem

[Flash]

Thanks for your latest input @sleeektoy and @GregT. My current mechanical pump has an inlet, an outlet and then a separate return outlet built into the pump. If I was to fit a pump that does not have a built-in pressure switch, what would be the easiest way to plumb in my current return line ?

[GregT]

A Tee at the carb entry.  I've set up a lot of bike carbs on TQ's or sidecars with a tee at the carb entry - and a Hilborn bypass in the return line set to give approx 1.5lb pressure. Bike carbs can only take about 1.5lb but your Weber will take the full 4lb output of the Facet.

But you're using the return line to circulate cool fuel, not to set the pressure. So both lines remain completely open.

[yoeddynz]

@Flash I can't remember more if I managed to refit the plastic insulator / heat shield. I'll find out because it's due back for other work. 

 

[Flash]

14 hours ago, GregT said:

A Tee at the carb entry.  I've set up a lot of bike carbs on TQ's or sidecars with a tee at the carb entry - and a Hilborn bypass in the return line set to give approx 1.5lb pressure. Bike carbs can only take about 1.5lb but your Weber will take the full 4lb output of the Facet.

But you're using the return line to circulate cool fuel, not to set the pressure. So both lines remain completely open.

Thanks @GregT, a Tee at the carby makes for a really simple solution.

[Flash]

3 hours ago, yoeddynz said:

@Flash I can't remember more if I managed to refit the plastic insulator / heat shield. I'll find out because it's due back for other work. 

 

Thanks Alex, would be interesting to know.

[Flash]

Well fellas, I conducted an interesting experiment today. Needed to head into town for some supplies, but before I did, I stuck my head under the dashboard and quickly moved the radiator thermo fan relay exciter wire across from my ignition fuse box to the adjacent battery fed fuse box. Drove into town and as soon as the engine temp hit 95C the thermo switch activated and the radiator fan kicked in. My first stop was a short 5 minute one. I switched the engine off, but as planned the thermo fan kept running. Got back to the van and the fan was still running. She fired up on the first turn of the key and no stumbling which I was kind of expecting for such a short stop. My second stop was about the same length of time. My third stop was for about 20 minutes, and this is usually when I have issues. When I got back to the van the thermo fan had stopped. On entering I immediately noticed a difference in the ambient temperature inside the cabin and the engine cover only felt luke warm (normally after a longish stop the metal cover is pretty hot to the touch). Engine started promptly and there was no stumbling at all. Got home and parked up in the driveway. Again, the thermo fan kept running and I timed it to see what would happen. Fan ran for 12 minutes then stopped. At 15 minutes I climbed back in and she fired up first go. Again, no hesitation when driving. I'm thinking that long term I can live with the extra drain on the battery if it cures my issue. Time will tell I guess.

 

[igor]

How much battery juice does the fan use in twelve minutes? Suspect not a huge amount. Sounds like a win to me.

[RUNAMUCK]

Im sorry,

But i cant not post this here.

/ling

[yoeddynz]

Gold.

This whole thread. But Baarts bit especially.