Bmiller

First time poster, I hope I am posting in the right forum. I have a 91 MSPNP2, with a pieced together turbo set up. Back in June I completed the build and drove the car around for a couple hundred miles. Something did not seem right, felt like lack of power. Brought the car to a reputable Miata tuner. Found out the motor was junk, really low compression. The tuner then sold me a JDM 1.6 motor to swap. Swapped motors, install went well, tried to start and all it did was crank. Brought it back to tuner and we are all stumped.
The trouble shooting I have done includes-
-Tested spark using MS test mode. With a timing light and a spark plug tester.
-Tested spark while cranking. I visually saw spark with plug out and hooked up to wire.
-Tested fuel pump with MS, I can hear it turn on.
-Tested fuel pressure with fuel pressure gauge, while using MS and while cranking. 35-40psi.
-Tested injector harness with noid light.
-Tested injectors with MS and while cranking, can hear them click.
-Tried the thing where you use a wire the connect the FP and Grnd on the diagnostic port
Some of the bits I have replaced include, DW200 fuel pump, new coil pack, 60psi FPR, tried swapping CAS (from og motor and jdm motor), I put the CAS in the middle of the adjustment range, motor is mechanically timed. I am running FlowForce 640cc injectors, NGK iridium plugs, the blue NGK plug wires.
A couple strange things are that when I removed the vacuum line from FPR there was fuel in it (why I replaced FPR) and oil sitting under valve cover is diluted with gas, the dipstick also smells like gas. (gas leaked past rings from cranking so much?) I thought I was on to something with the FPR because I tried cranking it over with old FPR vacuum line removed and it fired up for about 10 seconds. Thats when I put the new FPR on. Now i am back to no start. I am going to attach the tune file and few pictures. Any input is greatly appreciated. Thanks in advance!


Little log from cranking after 5-6 seconds.

Compression test done before I purchased motor.





Fuel pressure after installing 60psi FPR.

patsmx5

iTrader: (16)

Not familiar with the 1.6L's, but I'll try. I'm assuming you got compression on all cylinders based on gauge pic.


Install battery charger make sure you have strong voltage, pull plugs, unplug fuel injector connectors. Throttle to 100%, spin over for 20 seconds, let it sit for 1-2 minutes. Do this 2-3 times to make sure all fuel has been removed from the cylinders.

Pop in fresh new plugs gapped to .040" or so.

Install everything but keep injectors unplugged so it can't get fuel. It should crank over with compression now, but no fuel so no start.

Spray some starting fluid in the TB for 2-3 seconds, then try again. It should pop off and run for 2-4 seconds. If it doesn't you have a spark problem.

If spark problem, it's wasted spark so coils could be backwards. If you don't know what I mean, a google search will show you but it's a common mistake.

If it did fire up then connect injectors and try to start it. If nothing happens at all, check plugs and see if the new plugs smell like gas or they smell dry.

Report back what you find.

Bmiller

Okay so interesting turn of events. Did what you mentioned above. Fired up after the starting fluid. Hooked injectors back up and the darn thing runs now! Needs to be tuned because it only starts with slight throttle and will dip way low in rpms and just about die if you let off throttle. But it runs! So it must have just had bad plugs and flooded?

patsmx5

iTrader: (16)

Good deal. Yeah, that happens sometimes and then it won't start no matter what.

richbobby

It’s a good idea to change your oil asap if you really flooded it that bad.

Lokiel

@Bmiller FYI: It's"good form" here to award a "pos-cat" on the post that helped you out.