Chamele03

1990 GTU
car starts runs and Idles awsome, once it has been idling a few minutes it begins to smoke (light color smells burnt positive its oil) after the car has warmed up and is running awhile the Check engine light illuminates. the only code that is shown when I check is a 20 (2 long flashs i think) the MOP Position sensor. I have procedures to check but no Ohm meter so I will not be able to check it yet, so I am aking you all these questions.
Has anyone encountered a problem with the MOP position sensor that caused the car to smoke? (I assume it is just allowing to much oil in.?) Is this fixable or should I just go ahead and swap the MOP out?

thanks for any help,
I read the MOP/ECU thread and have searched with not much coming up on the position sensor (but I am lame at searching in gereal)

RotaryRocket88

iTrader: (7)

Time for a new one. MOP codes will put the car into limp mode.

No_love_for_pistons

iTrader: (4)

And ohm meter is pretty inexpensive... wouldn't hurt to pick one up at your local auto parts store. Or if you have a some funds... get a multimeter.. will have resistance on it as well.

another7driver

I think he meant voltage... ohms are a measure of resistance.

Chamele03

I remove the battery every time I leave the car (use it in another vehical) and it takes a while for this code to pop up (I understand it takes a few miscommunications for the CEL to go on). but just turning the car off and checking the codes makes the CEL go out for awhile as well. I drove the car for the first time this evening and beside the smoke it ran as I expected it should (no limp mode, accelerated all the way up to 6.5k smoothly).
since I have a spare of everything I swapped out the harnes for the MOP and still get the code 20.
I suppose my next step is to swap MOPs but I would still like to know if anyone has had anything like this happen before: code 20, no limp mode, constant oil smoke?

jjcobm

iTrader: (18)

http://www.rotorwiki.com/index.php/TPS_Adjustment

Check connectors E to D using a ohmeter set to the 1K setting it should read:

* Idle: 0.6k to 0.9k
* WOT: 3.4k to 5.1k

You will get the idle and WOT values by moving the plastic plunger in and out. It is the one closest to the throttle body. This will check to make sure the ECU is getting the correct amout of signal to relay to the OMP as throttle changes.

Hope this helps.

no piston drifter

+2 i see you caught that as well

jjcobm

iTrader: (18)

No I believe he ment ohmeter. You can check the resistance on the TPS using the link and information I posted above using an ohmeter or multimeter with ohm setting. Whatever works.

jackhild59

iTrader: (7)

No, He meant ohms.

Honest to God, guys if you don't know what you are talking about, don't answer with your best guess. Those guesses are going to be in this thread FOREVER.

Ok to the OP- You have problems. You need to thoroughly test your MOP. You don't need opinions, those don't count. You need an ohm meter. You can buy one cheap, under $10.

No, your MOP is not injecting too much oil It is broken. Basically the 20 code means the ECU can't find it's MOP *** with both hands.

The ECU has set it for minimum oil and the engine for minimum rpm. The oil smoking is not related to this MOP issue.

You are in limp mode, your MOP is very likely bad. If you are unlucky or if you keep clearing the code and running the car, your ECU will get fried. Ask me how I know.

Here is the thread you need to diagnose the problem. It is great info and should be stickied.

https://www.rx7club.com/showthread.p...t=omp+test+mop

One more thing: Do all the tests from the thread. Print the chart. When you get a replacement MOP, test it before installing it. Also, only buy a used MOP with the understanding that if it fails the above tests before install, you get your money back.

Good Luck!

Chamele03

switching MOPs has cleared the problem (checked per ALLDATA before installation), no excesive smoke or CEL.
everything I read both on alldata, mitchell and I believe the FSM state the MOP sensor can cause excessive oil consumption.
thanks for the ideas and confirmations.