Jump to content
The mkiv Supra Owners Club

Twin Bosch 044 pumps over heating fuel!


JamieP

Recommended Posts

Well thats what i think is happening unless somebody can suggest otherwise?, if i drive for about two hours the pumps whine a bit and the afr's start to shoot all over the place, let it cool down or put some fresh fuel in it and its fine.

 

Going to talk with Ryan to see if i can set it up just so the one pump is running at anything under 4000rpm then after that the second pump cuts in, Lee suggested adding a fuel cooler an all.

 

Just a word of warning for anyone considering going twin bosch pumps.

 

Jamie.

Link to comment
Share on other sites

  • Replies 124
  • Created
  • Last Reply

Top Posters In This Topic

It's quite hard to actually heat the fuel from hot pumps ; they are moving lots of 'cool' fuel per hour , fuel pressure heats the fuel but this is usually diesel type pressure .

Pump current draw is high with large pumps and low voltages , this can heat the pumps and cause issues , there are some step up voltage units I believe that reduce current thru pump windings ie double the voltage , half the current for the same power .

Long or heavy duty cables also drop voltage on load , this increases current draw by pumps , thin high quality cables help here .

Link to comment
Share on other sites

I think the key here is exactly what you said Jamie. Have one pump running all the time and the other controlled by the ecu, only running when needed. Also a fuel cooler on the return line for added cooling, the cooler the fuel the better tbh.

Link to comment
Share on other sites

Put a small fan on the fuel cooler Lee? otherwise it wont do much when in traffic, maybe set the fan up so it comes on when the rad fans come on? rad fans only ever come on when im in traffic and thats when i will want the fuel cooler fan on.

Link to comment
Share on other sites

My pump whines a bit if I'm below half a tank and then am driving around for a long time - I guess it could be a similar thing albeit your dual pump setup is obviously worse.

 

Have you considered wiring in a temp sensor first to check the fuel is actually getting hot before you go to the bother of cooling it?

Link to comment
Share on other sites

My pump whines a bit if I'm below half a tank and then am driving around for a long time - I guess it could be a similar thing albeit your dual pump setup is obviously worse.

 

Have you considered wiring in a temp sensor first to check the fuel is actually getting hot before you go to the bother of cooling it?

 

I know its getting hot Dan as i can only just hold my hand on the big fuel filter under the car.

Link to comment
Share on other sites

I was just going to say to stick your mits on the fuel filter. Would be good to get a temp sensor on there just to get an accurate reading, so that you can then tell the cooler is doing a decent enough job. Some kind of screw in, in-line type setup would be ideal so that you can remove it if you don't want to keep it.

Link to comment
Share on other sites

I was just going to say to stick your mits on the fuel filter. Would be good to get a temp sensor on there just to get an accurate reading, so that you can then tell the cooler is doing a decent enough job. Some kind of screw in, in-line type setup would be ideal so that you can remove it if you don't want to keep it.

 

Iirc the fpr has a spare take off, could maybe put one there, I think its just down to running two big pumps all the time though tbh, im confident with controlling them better all will be good, fuel cooler wont hurt though.

Link to comment
Share on other sites

I cant find any fuel temperature gauges, water temp gauges only seem to go down to 40c.

 

Can your dash 2 or S6 not take the temperature if you could find a sensor?

 

Would you be looking at a temporary gauge? Just wondering if you would be happy with a cheaply branded gauge to get a feel for things or whether you would want premium to fit in better with the rest of the car, for a more permanant setup.

Link to comment
Share on other sites

Can your dash 2 or S6 not take the temperature if you could find a sensor?

 

Would you be looking at a temporary gauge? Just wondering if you would be happy with a cheaply branded gauge to get a feel for things or whether you would want premium to fit in better with the rest of the car, for a more permanant setup.

 

Good thinking on the Dash2, that might be an option.

Link to comment
Share on other sites

I would be carful there mate sounds like you might be driving a time bomb ! If the fuel is getting that in the system can't be good , what's the flash point for petrol ?

 

Thats why this thread is here Matt, needs sorting, but i still very much doubt its getting hot enough for that though.

 

Its not as if it does it all the time, you got to be on a good couple of hour run and get caught in traffic for it to heat up, i did a 5 hour drive in it the other week with no traffic an all was good.

Link to comment
Share on other sites

Im hoping changing my twin walbros for new ones has sorted my fuelling issue out albeit I had a fooked pump but my fuel was overheating and when it reached the engine it was to thin and it throw my AFR's all over the place as you know

Link to comment
Share on other sites

The flash point of petrol is very low - something like minus 40degrees C. That's why you can just set fire to it at room temp whereas something like diesel is closer to 70degrees C so (normally) you cannot light diesel with a match.

 

I think what you are thinking of is the "Auto ignition temperature" and that's temp when the fuel can ignite without a spark. It's more like 250 degrees C and you'll be miles off that so neither is of concern here.

Edited by dandan (see edit history)
Link to comment
Share on other sites

for fuel to ignite with no ignition source is 240oC I think you will be okay.

 

p.s. Thats what Wikipedia says. But as is said. the cooler the better. get it into -oC would be quite cool.

 

Just saw your post when mine came up....I didn't intentionally reiterate what you said :D

Link to comment
Share on other sites

Its not as if it does it all the time, you got to be on a good couple of hour run and get caught in traffic for it to heat up, i did a 5 hour drive in it the other week with no traffic an all was good.

 

Where is the Wide Band sensor mounted, does this AFR reading lead to a car that drives peculiarly?

Link to comment
Share on other sites

Where is the Wide Band sensor mounted, does this AFR reading lead to a car that drives peculiarly?

 

10"ish from turbo, not sure what you mean by the last bit but the afr's start playing up when the fuel gets how, put fresh fuel in it and all seems good again.

Link to comment
Share on other sites

Does the car start to exhibit misfires or lack power? Do the AFR's go back to normal when cruising?

 

Yes, not sure if afr's would go back to normal after cruising, its only done it twice and both times ive let the car cool down itself.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.