Don’t assume that just because it’s “new” it works……Standard PR148 fuel pressure regulator
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- Опубліковано 6 лип 2024
- Here is a super short video demonstrating why it can be really important NOT to assume something works correctly just because it is new. The Standard PR148 fuel pressure regulator should in theory be the ideal replacement for the now obsolete Bosch 0280160007. Unfortunately, the one we bought via Rockauto leaks as demonstrated in the video.
UPDATE: Rockauto did arrange a replacement but this unit exhibited exactly the same features - eg it leaked. So buyer beware. - Авто та транспорт
Just as well that you tested first (guess you had to calibrate it).
I replaced a cylinder head on a car of mine, started her up, and she was running rough. Were the valves in the head seated properly? Had I stuffed something else up (it was an OHV, so it wasn't the timing).
About a day later, I discovered that one of the brand new NGK plugs was kaput. Hilarious!
Thanks for your comment...you can spend a LONG time diagnosing these issues if you start off assuming that all the new parts work perfectly! Mike
I agree it is important to verify any replacement part before installation. Thanks
I thought you fixed the original regulator with B-12 and coke bottle. is this replacement for the regulators that can not be fixed?
Yes...many people wrote in and said they had regulator problems so I set about looking for an alternative. This would be great...if it didnt leak - I'm interested to see whether the replacement works. Mike
Unfortunetly due to the fact that this is supposed to be a factory replacement, I believe ALL of those units require the Allen bolt for them to do anything. In many replacement sites you end up with just the bare part and in many situations you have to swap over the hardware, this is usually seen in pumps, starters and alternators.
Many regulators work by using the bolt to keep pressure on the internal diaphragm, granted it would be nice if it had a minimum threshold of pressure however being that it's leaking past 17psi can it really be trusted?
The missing part of this experiment was to insert the Allen bolt and retry, observing if the leak ever went away with added pressure to the bolt.
I say this because Rockauto does pretty decent with their quality control and being this a sealed part it has to see quality control by the manufacturer and not Rockauto.
In my opinion the bolt + your own pressure adjustment using the air pump will make it work. Granted this is something that the average customer "doesnt or shouldnt" have to go through however this is not your average regulator. It's an adjustable regulator with the adjustment bolt missing so keep this into perspective.
Thanks for your detailed comment.
So this unit does have a 'grub screw' with an allen bolt head in the top which is adjustable. Because it is sunken, it may be hard to see this in the video.
I believe these units should be factory set at 30psi and the allen bolt would be there for fine adjustments BUT...in this case, I think it is just a matter of the unit being faulty.
RockAuto are great and have accepted the return without question. Just my bad luck I guess....but I sure am glad I tested it before fitting it to a car!
Mike
In the Mercedes manual, the allowable leak down is provided. In your test, you used air. But these regulators are meant to work on a liquid (gasoline/petrol). Perhaps it might be an idea to test the regulator with petrol or mineral spirits. The leakage rate should be much less for a liquid.
Thanks for your comment. I did wonder about that and double checked with my father in law who is a very experienced aerospace test engineer. In his words, pressure is pressure and it shouldn't make any difference whether it comes form a liquid or a gas....although that does sound counter intuitive. The thing resisting the pressure is just a spring attached to a diaphragm. The diaphragm doesn't know (or care) whether it is being pushed with fuel or air. The seal will give at a certain pressure and allow both air and fuel through. It is easy enough to test this by putting fuel (or Chemtool) into the coke bottle - I probably should have done that in the demonstration. Mike
@@MikesMercsandothercars The presuure at which the regulator will open will be the same regardless of the fluid, but the rate at which the pressure drops should be dependent of the fluid that is leaking. A compressible gas (air) in your case or a liquid (gasoline) in the car. If you still have a regulator of any type, you could redo your test with air and then repeat with water. This should show the difference between a compressible and incompressible fluid leak. (Bear with me - a retired chemical engineer ;) )
@@GrahamM-sm1hv Thanks for your comment...very interesting. OK in the interests of science, I will repeat the experiment.....not with water as that would potentially be catastrophic for the fuel pressure regulator/injectors but with Chemtool.
It makes sense that the volume of medium escaping would be dependant on the medium eg more compressed gas would escape in a given time period compared to (say) oil. However......if the valve is opening before the regulated pressure, that in my mind means the regulator is not doing its job.
Did the manual you were reading give any figures for the leak down rate?
Mike
@@MikesMercsandothercars Did you ever do more testing? I thought I had given you the FSM leak down numbers. If not, the pressure will drop to 1.7bar immediately the key is turned off and then to 1.5bar after 5 minutes. There are owners who would like to buy a regulator from Rock, but your video is a concern for them.