Thread: Replacing Td5 fuel pump with Bosch 044 inline pump

or maybe the bosh 44 configuration has been bench tested and found not to deliver whats required under all circumstances with what is easily achievable in an on vehicle configuration. It's also not a simple drop in solution that can be done easily, effectively and reliably as an on the side of the road repair. Its also not possible to mount it up inside the tank along with the LP pump to handle the prime and filtraion in the OEM carrier due to the space restrictions of the carrier.



The 044 does not like being made to draw fuel through a filter if the filter causes too much of a pressure drop getting it to try and draw fuel through the LP pump, then the filter then the existing HP pump and then raise the pressure to whats required for the engine to operate normally, just isnt going to happen, not reliably at any rate.

Its actually possible to get the td5 to run on a 15psi faucet style pump, but not well because in reality to get it to turning over under its own power you just need to get enough pressure to fill the injectors as has been stated the injectors do all the HP work. The problem becomes your feed pressure much like the LP pump primes the HP electrical pump and feeds it the feed pressure to the injectors becomes important to ensure that the injectors are filled correctly. If you raise the rail pressure that feeds the injectors you're also raising the pressure that the spill valve acts against and that can effect the injection timing, remember that the FPR is matched against a certain capacity pump. Ive already mentioned the potential outcomes of not getting the right flow rate and low delivery pressure.



FYI.

With most dead OEM pumps I've replaced then tested and dismantled Ive generally found the LP pump to be delivering below spec which means the HP stage of the pump isnt being cooled enough and isnt being fed with enough lead pressure to prevent it from cavitating and overheating.

Tie that in with any areation of the fuel from the return line or in the swirl chamber causes further starvation of the HP pump and the HP pump develops a total failure.

at the end of the run the fraction you're going to save when you get all the bits required to setup and install the alternate pumping solution so that it works correctly and ensures the full life of your alternate parts (and thats ignoring the cost of actually doing it assuming you dont account the 10 odd hours of work required to fit it all up to a defender) I dont consider to be worth the additional failure points that will be introduced nor the potential risk to the rest of the system. In the day, each injector was worth more than the pump.

As opposed to making colourful, defamatory and insulting statements, how about a little research or reading combined with a little thinking. I could probably read this thread, find the statement if you were desperate you could... and then follow that up with links to suppliers of pumps that can (on paper) deliver enough to get it to working, notice its all in the same post and then without too much effort make the leap that maybe the person who provided said information might have actually done some testing. Hell it wouldnt take much more to make the step to considering that perhaps it was at some point even done on a vehicle as a trial fitup.

Originally Posted by joel0407

So you've tried one on the TD5?


Apart from it failing, how did everything else work?

Originally Posted by joel0407

I wonder if pump failures have been tied to dirty or infrequently changed fuel filters? Maybe it's cause to make sure we change them every service.

surprisingly the knock off was doing better than the genuine, the genuine one ran very hot and noisey and keeping the fuel lines sealed up was problematic, it was ok while the engine was cool but the FPR cross line weeped and it made the fuel cooler leak twice. As for how the engine and injectors handled it overal, Dont know none of the configurations I got through survived long enough to provide any meaningful long term info. But Id speculate that the risk of engine damage with the genuine pump running the higher pressures would have been fairly high, assuming the rest of the external engine plumbing could be setup to deal with the pressure (which wouldnt be hard) the oring seals that seal the fuel gallery in the head to the injector would be a lot harder to guarantee and when they let go one of 2 things happen

1. the diesel leaks out past the top seal and contaminates the oil and if left unchecked for long enough will lead to an engine runaway
2. the bottom seal lets go and the diesel makes its way down to the nozzle seal compomising it at which point you get unwanted diesel getting down into the cylinder but worse combustion gasses going back the other way which breaks down the fuel (heat) contaminates it and areates it which then takes out the pump.

I went through 3 044's the cheapy, one genuine and a borrowed genuine that only did one run before I pulled it out becasue it was nosiey from the start and hot by the end of the test drive.

I also tried a halbro and some other exotic pump one of the local ricer drift boys swore by. they did worse than the 044.

the main reason I gave away chasing down the solution was simply cost V reliabiltiy, While I wasnt paying for fitting parts, just the pumps I was happy to mess around and try to work it out and then go and cost the parts, including the 2 pumps by the time I counted everything and exluded labour I was repeatedly running $800 worth of line, fittings, mountings, electrical, filter.

The only permeation I didnt get round to trying (partly because by this point I'd given up doing it on vehicle and was just bench testing the HP pumps to see what would perform near enough to the requried specs) but thought it had a good chance of being sucessful for a long term fixt was this

1. fit a LP pump external to the tank, use that to feed the fuel filter and fill the swirl pot/prime the HP pump.
2. fit the HP pump inside the exsiting swirl pot so the diesel would cool it.

The biggest issue against that was that none of the pumps that made spec were setup for immersion and if the pump failed then the benifit of having an after market external HP pump that was easy to change was lost. The next issue was trying to make the pump fit in the housing.