kramykram

Ok so I had some freinds drop there 94 rx7 off to me. It's a single turbo pushing about 650hp. I do not know all of the details.






I know its running an aftermarket ecu. Not sure of brand. Well the shop that built the engine is in lousiana and did a horrible job with the oil lines as one blew off while my buddy was driving. blew all the oil out. Not sure how long he was driving before the car shut off either. Now he dropped it off to me, i fixed the oil line and the oil pressure gauge wire had gotten wrapped around the steering knuckle. So i add oil start it up and its running great. He drops it back off the next day and there is water on the oil cap. I figured its just condensation. I let it idle for about an hour while working on my z then take the rex for a drive. get back check the water not really gone. So i take him his keys. He tells me he wants to get rid of the synthetic and run regular oil. So I change the oil. I pulled the ignition fuse so i could get oil thru the filter as to not dry run the car. After a good amount of turning over oil pressure goes up. I plug the fuse back in and try to start the car it then backfires and now will not start. I check the trailing and leading plugs and all covered in gas. It seems like it was to crank but just turns over. I am thinking that the short amount of time it was ran without oil messed up the apex seals but sas I know nothing about rotorys I honestly cannot say. I tried doing a search on backfire and nothing I found gave me a clue to the problem. Any help would be great. Thanks guys and I am sure as I have no become the new mechanic for this rex you will be seeing more of me.

dgeesaman

iTrader: (7)

I think you just flooded it. Unlike a piston engine, letting it sit still will not clear the issue.

First remove the plugs and pull the ignition fuse again to prevent spark. Put the accelerator all the way down (disables fuel injectors) and crank a couple of times. This should blow out excess fuel through the plug holes. Now replace the plugs with new ones and attempt to restart the car, again using the throttle wide open to avoid injecting more fuel. When it catches and starts use the throttle to modulate things and make sure it doesn't die. It will smoke and burble but after a minute or two things should be ok.

Many RX-7s will flood when you only let the engine run for a minute or two so that's something to watch for. However in your case you described cranking with no ignition and that flooded it. (Probably would have been fine if you had the throttle held wide open)

On my stock FD I've never worried about the installation of a brand new filter. Just change oil and filter and start it up.

kramykram

I have changed the plugs, and held the throttle wide open. It's like doesn't even want to start. The backfire it did kind of worried me. I am really more concerned about the oil line blowing. I do not have any idea how long he drove it before he noticed it had no oil. He said it just stopped running and thats when they towed it to me.

Mahjik

iTrader: (1)

The fact that you added oil and it ran is an indication that the blown oil line didn't do much. If the engine didn't seize, then it had some lubrication. You can always do a compression check to see how healthy the engine currently is... Since you said the plugs were covered in fuel, as dgeesaman said it sounds like the car is flooded.

Try this:

1. Remove current spark plugs
2. Remove EGI fuse
3. Crank motor for 10-15 seconds
4. Clean area around spark plug holes
5. Squirt some ATF or a little motor oil into the chamber (for lubrication)
6. Re-install spark plugs (if usable or replace) and then the EGI fuse
7. Start the car

See if it fires on the first start after that. Make sure you have a battery charger on the battery during all this ..

kramykram

ok thanks will try

kramykram

pulled the plugs, pulled the fuse, turned her over and nothing came out. squirted some oil in each hole put in some new plugs tried to fire her up and just sputter nothing really happening. Tries to start but thats it just tries. Gotta go buy me a new compression tester as someone jacked mine off the damn car when i went to get plugs.

Sgtblue

iTrader: (16)

*Looks like a big turbo, but wondering where the hp figure came from.
*Do the compression check. You should have 3 relatively equal pulses on both rotors...hopefully somewhere north of about 95 psi.
*If that's the case, then repeat the de-flooding procedures that degeesaman and Mahjik described.

kramykram

ill have a compression tester tomorrow. ill research how to check it tonight. the problem is i think the ecu is pushing way to much fuel. just walking by the car you can smell the gas. its very bad.

kramykram

Ok got her to start but seems very weak. Still was not able to pick up a compression tester but i will have one tomorrow. She seems to be missing on a rotor i guess you could say. Will not hold an idle. When she died out and i tried to restart I got a back fire again. Will post compression test results as soon as I have them. I just find it hard to beleive after driving around with no oil it did not cause any damage to the engine.

Sgtblue

iTrader: (16)

Of course running it really low on oil could have caused some damage...bearing wear etc. But I don't think that's responsible for the hard starting and poor running. Something else is going on. That's why the compression test was recommended. The only other thing I could think of is checking the the boost sensor. It's on the firewall just aft of the throttle-body and labeled "Sensor Boost". Should have a vacuum line going to it from the intake manifold. It's proximity to the oil filter means it can get knocked loose occasionally and give similar symtoms. If that checks, do the compression check. If you get 3 equal pulses on both rotors, I think I'd be looking at ignition.

kramykram

Boost sensor is not even hooked up. Car is running on an aftermarket ecu. So there for checking anything without laptop or whatever they used to tune it is going to be difficult. Thats what is making this so complicated. Which sucks. There are so many things unhooked under the hood of this car it is not even funny. So yeah ill get those compression readings today.

Sgtblue

iTrader: (16)

Hook the boost sensor up and see what you get. It's suppose to be plugged in and have a vacuum line from a port on the passenger side of the intake manifold. This is the MAP sensor, and needs to be hooked up regardless of the ECU.