Hi everyone,

I'm helping out some guys building a race FD running a powerFC + datalogit on a streetport 13b. The engine was just rebuilt, and will not start. It gets spark(checked with timing gun, and visually spark plugs). It gets fuel, can smell it in the exhaust.

The car does not even try to start, no popping sounds, not firing at all. It just cranks until it floods itself out(cranking speed increases).

I am unfamiliar with FD crank sensors, is there some way to confirm with a timing gun that the spark is happening at the right moment? The crank trigger wheel was painted over, but there is a notch visible in it, anybody know what this notch corresponds to in degrees BTDC?

Finally, since this is a race car there are many systems that are gone, such as OMP, all emissions, the EL (electric load) unit is gone too. Would any of these prevent it from starting?

Thanks,

Nik

 

All the PFC should need to run is just key engine sensors - MAP, intake air temp, water temp, TPS, etc. Have you checked the Sensor Check screen to make sure all sensors are reporting in?

The FD basically has locked timing pickups. Unless you physically damage the front pulley, timing is not a problem. If you're getting spark, that stands to reason that it's picking up a timing signal.

New motors can be an out-and-out bitch to start sometimes. Might also have to swap a new set of plugs in. I would get it running on stock plugs - race plugs can easily foul out on a new motor, and you're not going to be loading the motor during break-in enough that it could be a problem.

Dale

 

We tried for about 6 hours today to get it started, basically it floods everytime. Tried everything from BUR7EQ to BUR9EQP, brand new plugs, etc. The fuel temp sensor is not plugged in, and a bunch of tranny gear sensors (neutral switch, 5th gear,etc) are not plugged either.

Could somehow the spark be too weak to get it to fire? Out the exhaust pipe comes a mist of fuel/oil mixture as we crank...

more info: car has stock primaries, 1600 secondaries. Has HKS twinpower ignition. Most of the stock wiring is gone. All that remains is the powerFC, the emissions harness, and bits and pieces of other harnesses to make it all work electrically. Does powerFC depend on any other computers in the car?

I just don't understand why it would be firing injectors and spark plugs, but still unable to start. Compression is real strong on the motor, don't have a number but the pulses are quite loud.

 

Make sure the connectors for the two crank sensors are not swap as both fuel and ignition timing would be off.

Make sure the two primary injector connectors are not swaped as fuel delivery timing would be off.

Make sure the MAP sensor is correctly hook up with it vacum/boost sesning hose.

Check static fuel pressure at 0 psi and max voltage (speed resistor bypassed).

There is always the posibility of leaking injectors.l

Be sure to totally deflood the engine, squirt in some auto trans oil and spin the engine to coat all surfaces, reinsert the plugs and retry.

 

Thanks Chuck. Btw, I read quite a lot of your posts regarding the secondary transition settings. That will definitely help when we get this thing to the dyno.

We confirmed wire colors with the wiring diagram so we are correct there. (I suppose we could swap them and see what happens...)

Also, I reduced the timing retard vs water temp in Settings 4 and increased overall timing in the IGL map cranking areas to try to get the engine to turn over quicker.

Confirmed via wire colors.

We are using the GM 3 bar map. Set to 44000/357. The PFC does read '0' when the car is off. Connected to one of the rear nipples on the UIM.

FP is at 38 psi.

We'll just have to keep trying that, I suppose. We are using the base cranking values (32.0 @ 30C and 59.0 @ 10C), we have spark, and we what seems like more than enough gas. There is no reason the damm thing shouldn't start!!!!!

 

Interesting, all my rebuilds started without a problem.

Do confirm that you did a monitor mode check of all the sensors and that all are reading correctly.

Sounds like you verified that the primary injectors are wired correctly (it's easy to swap leads between primary and secondary injectors btw), that the crank angle sensors are right, ignition has a strong spark, right fuel pressure, ... perhaps you can do a reinit or compare your map to a base map using the datalogit compare feature.

Did you verify compression?

 

sounds like you may have the fuel rails after the FPR so eventhough you see fuel pressure going into the FPR, there're no fuel pressure at the rail.

Double check your installation on your fuel system....


also, check to see if you see rpm while cranking. if you have both sensor wires backwards, it won't crank.

 

Turns out the motor has low front rotor compression(3-0-0, mazda tester), and out of spec rear rotor compression(6-8.9-6).

I guess the lesson for me is, no matter how loud the pulses you still need a guage to test it proper.

Thank you to everyone for replying.

 

If the motor was just rebuilt, and was done properly, you may just need to build compression up enough for it to start and begin sealing. Plenty of oil in the combustion chamber can help out a lot.

Dale

 

Maybe they did not lubricate the housing surfaces while rebuilding, or left something out?

 

apax seals inside out? so maybe the spring is riding on the housing instead of the seal

 

If the auto tranny oil in the rotors doesn't work, then it is teardown time!

 

Pulled the engine today, it will be taken apart when there is more time. The apex seals are all there and pushing on them by hand through exhaust port reveals there is some spring action to them.

 

It was definately a blown engine. Put a new one in last night and it fired right up.

 

What was bad with it?

 

We haven't torn apart the olde one yet.

But the new one, with JHB housings and 3mm Ceramic seals is doing quite well!!! Now we can also get some good data on the JHB coatings to end some of the squabbling.

Too bad the fuel pump died on the dyno. Going back next week, hopefully.