Engine Driven Fuel Pump

[Mike A]

So I have started a new post on this topic. The title of the last one sound a bit too lighthearted for the pain that this has become.

Here is a recap: Bought the plane early March. It hasn't flown in 2 years. Squawks were expected. New turbo and overhauled mechanical pump went in prior to purchase. Got checked out by a MSC and immediate items were addressed. Had a 2.5 hr transition flight in South FL then brought it back to ORL with no squawks. Go to start it on a 50 degree morning and it won't run off the mechanical pump. Works fine off Low Boost. Come back that afternoon when it has warmed up and starts without hesitation. Same scenario next day. Send it over to the Cirrus Service Center on the field for their knowledge of TCM's. initial diagnosis is the mechanical fuel pump. Remove it and send it back to the supply shop that provided overhauled unit. They bench test it and give it a clean bill of health and send it back set at the proper idle pressures. Reattach it and the engine still will not start or run off mechanical pump. Will run off boost. The mechanical pump has 4 flights and 4 hrs total.

What we have done so far:

Cleared all fuel and air lines in engine, cleaned injectors

Eliminated everything FWB as a restriction to fuel flow

Eliminated everything downstream of mechanical pump as fuel restriction

Eliminated fuel spider valve as issue

Removed the pump and bench tested ourselves. Pump appears to operate normally

Checked the gears, square drive, and fit of engine/pump connection components. No abnormalities.

Removed fuel lines from firewall and ran the following tests:

Provided gravity fed fuel directly to fuel pump. Would not work

Provided external suction of gas all the way to throttle body point. Would not start.

We are literally out of ideas. Does anyone have any suggestions or other tricks that may be helpful? It still runs perfect off the low boost pump, but the moment it is shut off it appears that fuel is removed from the engine. The shop is reaching out to other shops, the pump supplier, and TCM Monday morning for ideas as well.

Eliminated air and spark with the operation off the boost pump. Full range of operation available on it.

[N601RX]

I'm not familiar with Continentials. Just a thought, but is the pump putting out so much fuel it is flooding the engine due to some other problem. Perhaps the low boost pump can't put out enough to do this?

[Mike A]

No, we left the fuel return off too and got no return off the mechanical pump. The boost pump provided return.

[N601RX]

Is there anyway to visually verify that the pump turns when bolted to the engine and the prop is pulled through?

[Mike A]

Is there anyway to visually verify that the pump turns when bolted to the engine and the prop is pulled through?

We disconnected the discharge line, pulled the top plugs, and grounded the mags then ran the starter to see what it pumped. Everyone agreed that what came out was not of the amount or pressure it should have been.

[duke]

I believe the pump is not delivering enough fuel at low rpm to keep engine running. pump has an adjustment for this. tsio-360 pump is different from other cont pumps and requires special adjustments--aneroid etc. http://www.avweb.com/news/maint/181624-1.html        another link http://www.kellyaerospace.com/articles/ContinuousFlow.pdf

[Mike A]

I believe the pump is not delivering enough fuel at low rpm to keep engine running. pump has an adjustment for this. tsio-360 pump is different from other cont pumps and requires special adjustments--aneroid etc. http://www.avweb.com/news/maint/181624-1.html another link http://www.kellyaerospace.com/articles/ContinuousFlow.pdf

I have read that avweb article at least a dozen times and have a paper version printed out and highlighted on my desk. Even at higher RPMs (>1000 RPM) it dies when you flip off the boost pump. You may be on to something though about the aneroid though and I will have to reexamine it on Monday.

Thank you.

[duke]

As I understand it, the problem started after the turbo replacement. As the aneroid is controlled by turbo boost, allowing the pump to go to higher press as boost increases, It should have very little or no affect below about 1500 rpm. Make sure the low rpm pressure is adjusted correctly. When this is adjusted, it will also affect high pressure slightly and you will have to repeat adjustments back aand forth untill both are correct. That said, tsio-360s are cold blooded and a finikity to start and keep running cold. Can you keep engine running with prime button untill eng warms a bit? It may take 5 min or more depending on temp. This is normal for these engines.

[Alan Fox]

Food for thought , The pumps usually have a series of check valves , so that when the mech pump fails , the electric pump can "bypass" the mech pump.....I would check there .... Regards Alan...

[Mike A]

Problem solved.

 

The shop "borrowed" another fuel pump and put it on the Mooney, which allowed the plane to start up and operate with no issues at all.  Needless to say I am not happy that even after returning the fuel pump once and getting a "clean bill of health" from the overhaul shop, it was still found to be the problem, but after an additional 15 hrs or so of shop time....

[KSMooniac]

Was it a Kelly overhauled fuel pump by chance?

[Mike A]

D&G Supply in Niles, MI.

 

Needless to say, I would not recommend.

[N601RX]

Several people on here have used them before and posted positive results.

[KSMooniac]

Yeah, that is surprising.  They do have a good reputation.  Sorry you had this experience!

[Mike A]

I'm not upset that they sent a bad pump.  I understand that happens.  I am upset that we sent it back to them and they swore up and down that it was not the problem and returned the same one.  Now it turns out it was the problem, but only after 2 more days of paying to troubleshoot an issue that was already troubleshot. 

[KSMooniac]

You can always talk to them again and tell them what was found, and politely suggest they kick something into the kitty for the extra effort.  If they say "tough luck" then you can file a Service Difficult Report with the FAA about their product.

[Alan Fox]

You can always talk to them again and tell them what was found, and politely suggest they kick something into the kitty for the extra effort.  If they say "tough luck" then you can file a Service Difficult Report with the FAA about their product.

What if they say , we would like to help , but if we were to reimburse you in this way , there would be no way we could stay in buisness.....we are tryly sorry for your inconvience........ 

[Alan Fox]

Also who purchased the pump , if the installer purchased the pump and was given the opportunity to make a profit on it I say he should take responsibility for the bumbling.... But if the owner supplied the pump , I believe it is the owners responsibility ......I am in a repair buisness  and I do not install owner supplied parts for two reasons.....1) If I dont make a profit on parts , I cant stay in buisness... 2) if there is a problem I have to eat it , therefore I do not install owner supplied parts........ The upside is that when I do have a rare failure of a new or rebuilt part , I buy enough volume of parts from my suppliers that they cater to me when there is a problem.... 

[KSMooniac]

Alan, I agree with your philosophy/operating rules generally speaking (and you're way more experienced with it than I am!) but in this specific case the faulty part was suspect and returned to the vendor, who then blessed it a SECOND time, which in turn caused an additional 2 days of paid troubleshooting time at shop rates before the pump was found to be the culprit after all.  I say putting a claim on the vendor for those 2 days of time is reasonable in this case, and certainly for a new pump.  (I wouldn't blame the owner for wanting a different source for the second pump, though!)  This was clearly a case of infant mortality, and the overhauler/vendor should stand behind it, and if they're really good they should eat some of the troubleshooting effort as well.  If it were me and *I* had to eat 15 hours of shop labor, I would be filing a SDR as something in the vendor's quality system failed and needs to be investigated.

 

I had an interesting experience a couple years ago when I removed my dual mag for a 500 hr check.  Turns out it was not a D-3000 that had been sold to the previous owner right before I purchased the plane, but instead it was a D-2000!  I contacted the shop that sold it as such as asked what they wanted to do about it, and they asked if their stickers were still on it, and if I had pics.  After seeing the pics, they requested I send it to them and I was provided a proper replacement unit for free since it was a quality escapement on their end.  That was the right course of action, and they made it right without me asking for anything in particular.  

[Alan Fox]

Agreed , but it shouldnt take 2 days to troubleshoot a fuel pump , you check the pressure , and volume , if they dont spec out you pull the pump.....

[Mike A]

Agreed , but it shouldnt take 2 days to troubleshoot a fuel pump , you check the pressure , and volume , if they dont spec out you pull the pump.....

I (obviously) disagree. We knew it was a fuel problem with the engine running off the electric pump, so then we had to eliminate every other part of the fuel system, from the fuel tanks forward. If you were told your #1 culprit was fine, you too would also check everything else. Other things we then came up with as possibilities and had to check were something stuck in a line that the mechanical pump wouldn't provide enough suction to clear but the electric pump would, the spider valve malfunctioning, the throttle assembly somehow acting up, bypass valves on the electric pump not working, etc. and we pulled the pump and bench checked it again, during which it pumped fuel. The higher than atmospheric air pressures from the upper deck was the problem.

[Alan Fox]

I (obviously) disagree. We knew it was a fuel problem with the engine running off the electric pump, so then we had to eliminate every other part of the fuel system, from the fuel tanks forward. If you were told your #1 culprit was fine, you too would also check everything else. Other things we then came up with as possibilities and had to check were something stuck in a line that the mechanical pump wouldn't provide enough suction to clear but the electric pump would, the spider valve malfunctioning, the throttle assembly somehow acting up, bypass valves on the electric pump not working, etc. and we pulled the pump and bench checked it again, during which it pumped fuel. The higher than atmospheric air pressures from the upper deck was the problem.

With the engine running off of the electric pump , and the fuel flow reading at or near correct , you could have eliminated everything downstream of the mechanical pump , and everything upstream of the electric pump....One thing I have learned on working on machinery , you ALWAYS work the basics first , no matter what the circumstances.....I have been down the road you travelled enough times before to know you start from square 1 ...... Ive been there and it sucks....

[Mike A]

Has anyone had problems installing overhauled fuel pumps in their planes?  Even with a replacement pump from D&G Supply, the engine is still not working.  I stopped by the TCM booth at SnF and talked to them about the issue and they immediately went to the fuel pump as the culprit.  They said that they do not release the specs on their fuel pumps so if I want one that will work it will have to come from them.  Looking at prices for the pump (649368-66A1) they are $3,900 new.  That is pretty unbelievable.  Also, there are a plethora of places that offer overhauled units, so to think that all those do not work does not seem logical.

[KSMooniac]

You might call GAMI and ask their opinion.  Sorry you're having so much trouble right out of the gate!

[Mike A]

I went over to the shop this morning and watched them run the engine perfectly fine off a pump from a SR 20 (naturally aspirated).  I have placed an order from TCM for a rebuilt pump and will deal with D&G Supply once the plane is up and running on its own.  Also, in my discussions with TCM, it turns out that D&G sent two pumps that were from 2 iterations ago (the -6 versions), although the technical service rep didn't see a reason why they would not work.