Motor problems :-(

[Veetail88]

I ran my motor yesterday for the 2nd time and have a couple of problems. Sorry about the large pictures.

Problem 1, the motor isn't idling. When I start it, and with the throttle all the way back, it's running at 1700 RPM.

I have fuel injection by Precision. I believe the linkage is correct as the throttle lever appears to be against the stop.

I assume that turning down the idle adjustment screw will only increase RPM.

In addition, with only about an inch of throttle movement, the motor winds up to 2700 RPM. I was afraid to move it further.



Problem 2. The mechanical fuel pump is not working correctly.

With the boost pump on, I show around 28 PSI and everything runs smoothly.

When I turn the boost pump off, the fuel pressure drops to around 2 or 3 psi and the motor isn't real happy about that.

I checked the model of the fuel pump and it is LW-15473, which is apparently the high pressure pump, so I didn't end up with a carb pump.

My red cube is between the electric pump and the mechanical pump, but others have said this isn't a problem.

Another has voiced a question that maybe the pump hasn't primed properly. The motor has a total of about 13 minutes run time on my 8.

I purchased it from Mattituck 3.5 years ago and haven't run it before. I assume this would have shown up on the test stand, but it's not like I can call them anymore.

Any help on these items would be appreciated.

Thanks

Oh, and yea, I'll torque that castle nut and get a cotter pin in it when I get out to the hanger next.

[alpinelakespilot2000]

Are you sure it's idling at 1700 or is that just what your engine monitor is showing? Your engine monitor will have a setting you have to input that will make it read correctly. It's very likely that it's reading 1700, but actually idling at 850. If it misreads, it is usually by a factor of 2 or 4. Get an optical tachometer to confirm your EFIS setting. Hope this helps.

[Veetail88]

Thanks Steve,

It sure sounds like it's running at 1700! Big difference from the sound a 360 makes at idle.

I have a digital tach I can borrow though and check it out.

In addition, I did have to configure my EFIS. On the first run it was above 3000 rpm the whole time! Setting it to 4 pulses seemed to work, per the AFS manual.

[BillL]

Well, engines don't run without air, so if you can see that the throttle plate is closed when the throttle is back, then either it is getting air from somewhere or it is the sensor factor. What was the manifold pressure for that engine speed?

Don't be too sure about Mattituck not taking your call. For what you paid, they can answer your questions. Most folks are nice like that.

On the fuel pressure. Does the engine stumble when the boost pump drops off? It may not not at idle conditions. It could be your mechanical pump, because many production dynos have pressurized fuel supply to the engine and that would just push right past the check valves in the engine pump, and they might not notice. Stuff happens.

Also, that throttle plate lever looks like the serrations are not seated either so check that before torquing, or risk part damage.

[mahlon_r]

If the engine is really idling at 1700, you definitely have an induction leak somewhere. Guaranteed! When we ran engines in the test cell we positive fed the engine fuel system with about 2 psi of fuel pressure. So the pump on the engine would have run the engine in the test cell with a 2 psi positive feed. The fuel problem sounds like either a bad pump or some form of blockage to the inlet of the engine driven pump that the boost pump is able to overcome.
Tech support for the engine should be available from Continental Motors.
Good Luck,
Mahlon

[BobTurner]

Originally Posted by BillL

Don't be too sure about Mattituck not taking your call. For what you paid, they can answer your questions. Most folks are nice like that.

I believe he was referring to the the fact that Mattituck is no longer in business.

[BillL]

Originally Posted by BobTurner

I believe he was referring to the the fact that Mattituck is no longer in business.

Oops, pardon my ignorance, I just associated Mattituck with Continental and did not know the "brand" was retired along with the rebuild facility. But at least it looks like there is some support, not that I knew it though.

[N941WR]

Could your Tach be counting double the RPM?

Are you sure you are able to hit 2700RPM? That is a HIGH RPM and you would have to have almost no prop load to hit it quickly, as you described.

Is your EFIS set up to count the RPM's correctly?

[miyu1975]

Well...at 1700 rpm you would have be on the brakes pretty hard to stay still...850 rpm, not so much or at all need brakes.

[868RM]

I was there watching and it was running 1800 + for sure. The wheels were chocked & tied to VW beetle. It was at run up RPM,until fuel pressure would drop then it would approach something that was close to idle RPM but was on the verge of stopping, like one or two cylinders only, still firing. As soon as fuel pressure came up, back to 1800+ & running smooth. Ron