Knee Dragger

On the way to work this morning I ran into a problem that I need to diagnose before the end of the day. I did a WOT run passing some cars and then went back to cruising. When I approached a red light after a few miles the car immediately stalled. I have to feather the throttle to make it idle more than a few seconds. What little idling it does is very rough and sporadic. When driving, the car drives OK on constant throttle, but has no kick when hitting boost whatsoever. It feels like it's running on one rotor, and sounds a bit like a diesel engine when applying much throttle. Car is not running lean, hot, or anything else out of the ordinary that I can tell. I limped it a few more miles to work and parked it. Is this more likely to be something small such as a vacuum hose somewhere, or am I looking at major engine failure? I need to either get the car in driving order by later this afternoon, or have it towed back home. Any insight anyone can provide is greatly appreciated.

Mahjik

iTrader: (1)

Tow it back and then do a quickie home compression test. IMO, its easier to start with a compression test.

BlueTII

Check the vacuum line going to the map sensor, if it is connected then tow it home.
Also check to make sure you didn't pop a spark plug wire off, after that it is compression test time like Mahjik stated.

Knee Dragger

I've been out of town and haven't done any work disgnosing it yet. I looked it over for a few minutes last night and discovered a wiring harness that runs along the firewall right behind the engine that has about 8 different wires in it, and at least 4 of these wires are broken. I don't know if it could possibly be related or not, but those wires have to do something. Anyone know what those wires might do? I can snap a picture of it later this evening if need be.

Knee Dragger

Here's an update...

I soldered some new wire in place to repair the wiring harness and nothing has changed. My boost gauge is showing consistent vacuum levels, but levels are low. I'm seeing approximately 13 vacuum versus the normal 15 or so on cold start.

I'm not very familiar with the power FC Commander options, but I was advised to check for sensor failure using the units sensor check function. As far as I can tell all sensors are working correctly, but I have no idea what voltage levels I should have for each sensor. Here is a picture of the readout I'm getting in case anyone can decipher it better than I. Barring any other suggestions from members here or from the shop I've been talking to I'll look into what's involved in doing a home compression test.



Thanks for any information provided.

effedi

I guess: Sparks? try clean / change, maybe you are running a little too rich

Knee Dragger

I changed the plugs last night and the car now runs better than before, but still not right. The plugs were in pretty poor shape after a limited number of miles, so I may need to lean things out a bit. Here's a rundown of the symptoms after the plug change:

-Car will now idle, but somewhat poorly. It would not at all before the plug change.

-Car pulls stronger than before, but still not as well as it should.

-Car sounds different when under load. The best way I can describe it is almost an exhaust leak kind of sound.

-Car takes longer to start when cold, and is VERY difficult to restart once it's hot.

Seems like some sort of a spark issue would be logical.

Mahjik

iTrader: (1)

Did you get a compression test done on it?

White94RX

You may have a vacuum/boost leak. Check all your couplers, especially the one from the Y-pipe to the pipe that goes to the intercooler. That ones prone to fail. Definately check the all, like the ones that go to the intercooler. then start checking vacuum lines too. make sure the vac line is hooked up to the map sensor.

tiger18

iTrader: (1)

Im agreeing with mahjik,,,,motor needs that compression test because its sounding alot like engine failure. (also the wires you repaired if im not mistaken there needs to be certain wires cut when running an apexi FC on american RX7)??? mahjik?

tdazmansFD

iTrader: (1)

Lets see, You did a WOT Run and immeditley after coming to a stop the problem began.
Listen to these guys^^ Test the compression!
You should have done this when you were replacing your plugs.

dabigesii

iTrader: (4)

I'd check the vacuum line that connects to the MAP sensor first before assuming the absolute worse. The MAP sensor is along the driverside firewall. If thats connected.....then you might want to assume the worse and check compression in the engine.

crxturboh22

jst a quick Question how did you check that on the PFC i got one too.. and i have no manual i checked apex but um yeah how you log into that..??

Xeros

Crank shaft position sensor, take look at that! Had a problem just liek your with my other car turned out to be the wires to crank position sensor

HKStreetRaceRx7

iTrader: (3)

I hate to say it but your symptoms sound almost exactly like mine did not too long ago whenever I cracked my rear apex seal. I agree that you need to check the compression first before you assume the worst. But the good news is if you do need a rebuild I see you're located in TN and Kevin at Rotary Ressurection does great work for an unbeatable price.