Poor quality fuel pumps

[cedryck]

Disclaimer! First this is not a reflection on our hosts, or their choice of parts, they sell them they don't make them, just an observation of a part I purchased, I had a no name mechanical fuel pump on my shelf that I found. It was probably 6 years old. My existing AC fuel pump looked a little tired, and I had questions of the proper amount of fuel delivery, Sooo,,, I replaced the (I know it works but how well) with a NEW out of the box pump. It worked worse than the old one I took off the engine. I disconnected the fuel line and held it up and into a jar, and cycled the engine to see if there is a fuel stream, well I could have spit more liquid than the new pump moved. Needless to say I removed the shiny new, and replaced with the old, was there a bad batch of mechanical pumps that I missed? Has any else suspected poor fuel delivery from mechanical pumps? Has any replaced their mechanical with an electric with a two fuel cell military set up? And if so where did they place the pump(s)? Does it seem reasonable to assume I might be able to situate an electric after the changeover valve? Thanks in advance.

[slowmo]

I replaced with a new mechanical fuel pump this summer when I started to get vapor lock. The new one was worse so I went electric. Since then no issues.

My TR3 has a very similar mechanical fuel pump, also latched to the block and run off the cam shaft, and it hasn't skipped a beat. I have no conclusion to all that...just glad the electric fuel pump has seemed to work much better than the mechanical on the Series.

[cedryck]

What were the symptoms of your vapor lock issue? Did the truck stall? I am curious if my poor idle, (only occasionally) is due to that, thanks.

[slowmo]

Sometimes it would stumble on acceleration...badly. Fifty percent of the time it would die. The other times by pumping the accelerator pedal furiously, I could keep it running (not sure that pumping the pedal furiously had any effect but that's what I did).

Other times after the truck was warmed up and I turned off the engine to say run a short errand, it would start, run fine, for about 30 seconds and die (about the time it took the carb bowl to be cleared). I would disconnect the fuel line at the carb and pump the fuel pump lever and almost no gas would come out. I tried priming the pump by pouring gas into the disconnected fuel line until it was full (holding it up a bit). And then pumped very slowly. No effect. Then I would pump until my arm was a blur to disinterested observers, and still nothing. I repeated this a number of times and then suddenly, it would start pumping fuel and off I could go.

I tired of this, eventually, and installed the electric fuel pump. That problem was solved, which allowed me to go back to the punch list of 153 other items that were sub-optimal or indeed not functioning at all. I am on item 151 now, one year into ownership -- see new thread

[cedryck]

So you say installing the electric pump solved the problem, interesting. I am wondering if Venting the system somehow, would eliminate vapor lock. I sincerely have a hard time thinking that a british fuel system can vapor lock, but anything is possible.
My truck engine would just run poor, and die. Stall, or run poor. I am thinking I am still chasing the ghost.
I did order upon suggestion, a Facet brand electric pump, 2.5 - 4 psi.

[Contractor]

I bought 2 new fuel pumps from our host and neither one of them would produce enough fuel pressure to keep the old Rover running. I think they had to of gotten a bad batch of pumps at some point in time.

I ended up finding a NOS AC pump from someone else and the problem was solved.

Not a knock on our hosts as I buy 90% of my stuff from them, but am simply agreeing that some of the fuel pumps are not working correctly.


Put a gauge on it and check your fuel pressure……..that's the only way to tell. I installed a T and ran a line into the truck so I could drive it and watch the pressure with a gauge on it.

[bugeye88]

Cedrick,

You bet these trucks can and do vapor lock. Many reasons for this such as changing carbs or manifolds, missing pieces between carb and manifold, on and on. I found a facet electric pump (as you mention) after the mechanical pump with an on off switch under the dash, allowed me to both prime the carb after sitting for some time, and stopped stalling due to vapor lock. I usually switch off the electric pump after starting or when not needed for vapor lock. Insulating fuel filters in the engine bay and exposed metal fuel lines in the bay also help prevent vapor lock, which is only a hot weather concern. This crap methanol fuel is a big cause of all these troubles as it has a much lower boil point, and was not planned on the the ole Brit designers of the "British fuel system".
Cheers,
Rob
Bugeye88

[slowmo]

I bought 2 new fuel pumps from our host and neither one of them would produce enough fuel pressure to keep the old Rover running. I think they had to of gotten a bad batch of pumps at some point in time...

Couldn't agree more. Somehow these mechanical pumps now on the market are VERY temperature sensitive and prone to vapor locking. And yes,l the ethanol may play a role, but my problems in the summer was when the fuel supposedly had no ethanol.

[cedryck]

So this is still interesting to me as I drove this truck over the weekend, and in the same spot on my trip, engine dies. Starts immediatlely and runs fine till the next time. It seems like to avoid vapor lock the system needs a vent, but is not the tank vented enough at the cap? I think it is a combination of these awful mechanical pumps, and lock.

[slowmo]

When it is dying or has died, open the cap. If you hear a whoosh, you have a vacuum building up.