j_man1100

iTrader: (5)

So I have an issue with my 1990 RX7. Its runs great until it gets warm, but then goes into limp mode. Its not TPS, plugs or wires. I've been told its not o2 sensor. I'm wondering if the thermostat is shut and once it gets hot it goes into limp mode to save it from the heat. The guage reads about half. I'll change the termostat and maybe o2 tomorrow to get those out of the way. Also wondered about grounds, but it seems wierd that it doesn't do it all the time, just after running (idling) about 15 minutes. Any help would be great. I have some help coming, but if anybody else has some ideas, I'm more than willing to try it.

Thanks

coldfire

iTrader: (1)

if it's going into an actual ECU limp mode, you should be seeing the check engine light come on. limp or safe mode can only be caused by a few things, such as an AFM error.
do you know how to check the ECU for error codes on an S5?

the O2 sensor doesn't do much and is only used for low-load closed-loop operation (i.e. cruising in 5th).

Feds

Vac leak. One of the solenoids is opening when warm.

j_man1100

iTrader: (5)

The check engine light does come on. Not sure how to check codes but I'm reading up and will try it this after noon using :
https://www.rx7club.com/showthread.p...t=engine+codes

Not sure if thats the right way but it seems to be a good write up. Any help would be great since I can't get it through an e-test in limp mode.

Thanks

coldfire

iTrader: (1)

that thread is for getting error codes on S4 cars. on the S5 ECU cars you can actually get the error codes directly from the check engine light.
the procedure is in the S5 FSM in the Fuel and Emissions Control section. i sent you a PM.

edit: read this for the S5 procedure
http://howto.globalvicinity.com/gv_w...i=50&co=1&vi=1

ScrappyDoo

iTrader: (7)

Read about thermosensors. They can cause limp mode type conditions when the ECU doesn't know the temperature of the engine.

j_man1100

iTrader: (5)

Ok, so coldfire came over today to give me a hand in figuring this out and we got the engine to go into limp mode again. The problem is that once we got it grounded to read codes, nothing showed up. As if there are no codes being stored. I'm really confused now... Tomorrow I hope to have a multi-meter going so that I can check tps again properly.

rd_turbo

iTrader: (4)

Try to deliberately make the check engine light come on by disconnecting something. Then you'll know that the ECU is able to find fault and that the proper checks are done. When you turn the key, make sure your check engine light comes on for the initial check. One thing to check is the oil metering pump and ECU. On occasion, if the oil metering pump fails, it takes the ECU with it. The only solution is to replace both. Replacing an ECU alone may result in the replacement ECU going bad. It may be that there may be some permanent ECU damage. I've had situations where codes 26 or 27 showed up and stayed there permanently even upon replacing the pump. I've also had situations where the car went into limp mode with no trouble codes.

coldfire

iTrader: (1)

Jordan, leave that check connector grounded and if you encounter "limp-mode" and the check engine light comes on you should see the code that the ECU is complaining about.
like i said the only 2 reasons i can think of that no codes are being stored after a CEL error is that your ECU power is getting reset when you turn the car off/on (clearing the codes), or there is an intermittent fault with the ECU itself.
let me know how it goes.

j_man1100

iTrader: (5)

So drove it off to get a safety with the pin grounded. Low and behold, it started to flash and give me my code. 2 long, 7 short. Code 27. OMP. I took a video of it just incase I was looking at it wrong. There was about a 3 second pause between the long and short lights but since there's no code 7, I figured they ran together and made code 27. Thanks for everyones help and once I get another OMP I might need some experience when putting it in. Sure I can figure it out, but someone whos done it before is always nice.

coldfire

iTrader: (1)

well at least you got a code from it, that's good!
yeah there's a 1.6 second pause between the long flashes and the short ones. code 27 is MOP, but it pertains to the whole MOP system. since the problem was intermittent you might also what to check the wiring, and it could even be the ECU itself that is at fault. it's a little tedious but the procedure is in the FSM for checking. PM me if you need the link to get the FSM (it's in the 2nd gen forum FAQ though i think).


by the way, if you aren't sure your MOP is working you should put some premix oil in the gas tank just to be safe.

j_man1100

iTrader: (5)

I am runing premix to be safe. I'll have to get you to come out and give me a hand to check the wiring and all. I'll grab another MOP since I've tracked one down. If thats not it, I have a spare, if it is, problem solved.