So, trying to get a 88 TII I just bought running. Whoever had this car before me wired the fuel pump to run constantly when the key was in the on position, not the start position.. So I suspected I had flooded the engine on accident. I did a compression test and got 60 and 65 with even bumps.. So I was like "Well, ****." .. But I did the deflooding procedure with ATF and my compression is at 90 and 95 now. My questions are:
A) Is my compression 60 or 90? and
B) how can I be sure fuel is being injected into the rotor? The pump is running, i can hear it.. but I can't verify I have fuel actually being injected. Starting fluid was making it stumble at least.
C) Do I have to have the intercooler piping hooked up to the throttle body in order to start the car?

 

Intercooler piping needs to be intact or pvc in its place or there is too much of a vacuum leak I believe.

W/the coils disconnected (to prevent spark) you can remove a spark plug and w/key to start you should see fuel spray come out the plug hole.

Flooding reduces the compression so the more accurate number is the deflooded one and a hot engine has higher compression than a cold one.

 

1. as you've discovered; the compression varies a lot with the engine being flooded or not. so we are more concerned with even bounces. and besides, without knowing the cranking RPM the actual numbers are literally meaningless.

2. usually you can tell if the injectors work because the engine is flooded. if the engine isn't flooded, then its possible that injectors aren't being turned on. more below.

3. yes. the airflow meter is before the turbo, and so everything after the AFM needs to be hooked up an vacuum leak free.

below; barring any big vacuum leaks, the ECU really only wants power and an RPM signal to run the injectors. if you have an extra crank angle sensor, plug it in, and spin it by hand, if you hear injectors clicking, you're good. if no, then you need to see if the ECU has power, if yes, then see if the injectors have power, etc etc

 

So I sprayed some starter fluid in the throttle body and then hooked everything back up. It ran for 3 seconds at idle and sounded good, I tapped the throttle and heard a clacking noise and then it puttered out. No idea what that clacking noise could be.. but it didn't seem friendly. It's likely the timing is off considering the screw for the crank angle sensor is missing :/

 

time it the dumb way. rotate the engine so its on the leading mark.

take the cover off the CAS. there is a plastic plug in the cover, remove this. put the cover back on. turn the CAS until one of the big teeth is in the center of the hole in the cover.

tighten the CAS down. put the plastic plug back in the cover.

your timing will now be within a degree or two, which is close enough

 

could just be the ether and a lean condition if that is all that the engine was using to run on. you can try to keep the engine alive by having a helper spray it into the AFM while it is removed from the airbox. i'd still start with checking the timing though.

 

Set the timing... get this.. . if I let it sit overnight..it starts without ether.. runs up to 3000rpm then dies. Then won't do it again until I let it sit for 6-8 hrs. Was thinking fuel pressure? Replacing the fuel filter today. Air flow would be repeatable I would think.

 

Could possibly be a vacuum leak. And you might try jumpering the fuel check connector.

 

Jumpered FP. No difference. Starts and runs up to 3-4k. Sounds fine btw.. then Dies. Then won't start again. Throttle has no effect. Would vac leak cause it to only start once every 6-8hrs? Too much fuel maybe?

 

How long does it run (few seconds)? Not sure of the answer to your last statement.

 

Or not enough. Have you tried checking the fuel pump pressure? Auto Zone will do a loan a tool on one. At least they do around here.

 

I have a FP pressure tester. Will do that next.

 

It runs long enough to blip up to 3-4k and then back down then dead. Does not pass go or collect 200$.

 

If you can get a tee in the line, leave it hooked up when try to start it again and check the reading when it dies.

 

Where's the best place for the tee? After filter and before FPR I assume..

 

Yes.

 

sounds like you are trying to run it without an AFM.

make sure it is installed, tight and nothing else ahead of it in the intake is open and allowing large amounts of air into the engine.

 

So, an update, I have checked the fuel pump pressure and everything looks good. I had the AFM on. I tested it with a multimeter. Everything checks out except the last test.. Testing the plate pressed all the way down reads 20ohms when the range is 50-500. I'm not sure how big of a deal that is practically? Also when I move the plate it's constantly bouncing out of range of the multimeter. But when I stop the plate the multimeter reads it fine. So this might be my problem? But not exactly a big fat obvious yes. Before I drop a few hundred dollars on a new AFM it seems prudent to ensure there's no big vac leaks. So that's my next task.

 

Nvm. The 20 ohms is correct for Turbo car.. was looking at wrong page in FSM. Guess I'm back to massive air leak somewheres.

 

an easy way of verifying it is just a vacuum leak is by having an assistant manipulate the AFM vane while you try to start the car, or vice versa.

 

The ecu in the rx7 is so crude...in the same time period when GM started introducing AFM's if the AFM was lost, the ecu would just revert back to speed density maps and throw a check engine light.

 

Update.. tore down the UIM looking for vac leaks. Found multiple sources..and for some reason P.O. had the secondary rail's vac nipple plugged into the primary rail's air bleed.. ???.. Fixed that. Plugged any other major potential vac leaks... Put everything back together.. Now only runs on starting fluid. Will run as long as I spray. Manipulating the AFM doesn't fix the problem.

Since it only runs on starting fluid, I think it's safe to say I've narrowed it back down to a fuel delivery problem.

Main relay clicks..

I wandered under the dash to check injector voltage.. turned key to ON.. checked voltage at the ECU connector by using my multimeter:

3A (ground) to 3C (rear primary) - 12v
3A to 3E (front primary) - 0v
3A to 3F (rear secondary) - 0v
3A to 3H (front secondary) - 0v

It seems unlikely to me that all of those injectors would be bad? Though, I suppose they could be...

Going to tear it back down and check the connections on the injectors and the injectors themselves.. Unless you guys think I'm way off

 

So car is running now. Thank you all for your assistance. The P.O. hooked the fuel lines up in reverse. I just noticed it when I was checking the injectors. Not sure why the injectors weren't showing voltage at the ECU..

Funny story though. I turned the ignition off and the car kept running. Even after I unplugged the negative battery terminal.. Then my smoke alarms went off in my garage.. and the rest of my house.. and then my baby woke up. So. Long story short wife said I can't work on the car anymore tonight.

 

lol, merry xmas! the house is on fire!

 

The ECU pulses ground to the injectors, so thats why it looks funny, and it only does that during start and when the engine is running.

Glad you found your problem though! Happy belated Christmas!