87 GXL wont start

vex · 04-08-2011, 11:43 AM

Quote:

Originally Posted by Kevyn

ive replaced all filters, plugs, wires. I m the process of flushing the coolant, replacing all other fluid, and getting new hoses and belts. I guess in the mean time i should check compression.

Because you replace wires does not guarantee that they are without defect. You'll need to check the Resistance of each line to ensure that there is no break in the wire or tear in the insulation. Once that's done you'll need to verify the coils are functioning properly and delivering the proper voltage to the plugs as per FSM instructions.

Compression numbers are good to have, but require good battery voltage and cranking RPM. It's good to know that all 3-faces are holding compression as well as the total amount of compression they can provide. Or if you have the money you can purchase a rotary compression tester from one of the vendors on this site which will provide a much better analysis of the condition of the engine. I plan on purchasing one in the future, as I'm poor right now.

Pete_89T2 · 04-08-2011, 12:09 PM

Lacking a compression tester (rotary specific or otherwise), you can do a quick "poor man's compression test" to get a quick thumbs up/down assessment of your rotary engine's compression. Here's the gist of it:

1. Remove the EGI fuse, and disconnect the CAS (Crank Angle Sensor) - this kills spark & fuel, preventing the car from firing while testing. The EGI fuse is located in the fuse box under the hood, driver's side strut tower.

2. Make sure your battery is fully charged, and/or have another car handy to hook jumper cables to your battery. You'll be cranking your engine repeatedly and won't want to drain your battery down.

3. Remove the trailing (top) spark plug from one of the rotors, doesn't matter which one you do choose to do first.

4. Get yourself in earshot of the spark plug hole - don't need to be TOO close, leaning over the fender will work, and have an assistant floor the throttle open while cranking the engine.

5. While it's cranking, listen to the sounds made -- you should hear a consistently strong & rythmic POP--POP--POP sound coming from the open spark plug hole, meaning you've got compression on all 3 faces of that rotor. If the loudness of the POPs are weak, or more importantly, if the rythm is broken up, i.e., POP--POP--(silence)--POP, then you've got internal problems with that rotor that most likely will require a tear down/rebuild.

6. Repeat steps #3-5 for the remaining rotor, after replacing the spark plug in the one you just did.

04-08-2011, 12:09 PM	#2
Pete_89T2 Lifetime Rotorhead Join Date: Apr 2010 Location: Elkton, MD Posts: 874 Rep Power: 16	Lacking a compression tester (rotary specific or otherwise), you can do a quick "poor man's compression test" to get a quick thumbs up/down assessment of your rotary engine's compression. Here's the gist of it: 1. Remove the EGI fuse, and disconnect the CAS (Crank Angle Sensor) - this kills spark & fuel, preventing the car from firing while testing. The EGI fuse is located in the fuse box under the hood, driver's side strut tower. 2. Make sure your battery is fully charged, and/or have another car handy to hook jumper cables to your battery. You'll be cranking your engine repeatedly and won't want to drain your battery down. 3. Remove the trailing (top) spark plug from one of the rotors, doesn't matter which one you do choose to do first. 4. Get yourself in earshot of the spark plug hole - don't need to be TOO close, leaning over the fender will work, and have an assistant floor the throttle open while cranking the engine. 5. While it's cranking, listen to the sounds made -- you should hear a consistently strong & rythmic POP--POP--POP sound coming from the open spark plug hole, meaning you've got compression on all 3 faces of that rotor. If the loudness of the POPs are weak, or more importantly, if the rythm is broken up, i.e., POP--POP--(silence)--POP, then you've got internal problems with that rotor that most likely will require a tear down/rebuild. 6. Repeat steps #3-5 for the remaining rotor, after replacing the spark plug in the one you just did.