pamdam

Hi I am new to the forum, i bought an rx8 just before christmas as a non runner to repair.

The car had just a rebuilt engine and was running ok but then one day packed up about a week after the engine was put in.

I got the car started on the day i collected it and thought great easy fix, however the car is in limp mode only revs to 4000 rpm and doesnt have enough power to drive up and small ramp.

The engine is showing cel code P1688 which is for the metering oil pump if i let it run it then shows pending codes of cylinder 1 misfire and heat control circuit low input sensor 2. and then after another few minutes these codes become active codes.

My question is should i replace metering oil pump or is it likely when they put in the new engine it was installed incorrectly as i hear they can be adjusted?

if this is the case how do i adjust it and and what exactly does the the adjustment do because i hate to do something even if it fixes the problem without learning why I am doing it.


many thanks

dannobre

iTrader: (3)

It is possible they hit the positioning switch on the MOP when the engine was removed or installed, so you might get away with adjusting the switch and see what happens

Sounds like you either have a wiring problem...or the front O2 sensor heater isn't working..check the plug to see if it has good contacts. It should run with the O2 problem though..the limp mode is from the MOP

Missfires.....try resetting the ESS and see if it goes away ( 20 stomp thing )

The positioning switch tells the stepper motor in the pump where it is...and for some reason Mazda doesn't give us the spec's to reset it...so that's why trial and error is the only waay to do it

pamdam

I have reset the ECU with a obd2 reader and the codes just come straight back on.
I will get the mop out over the weekend but how do i adjust this switch on the mop and where is the switch?

dannobre

iTrader: (3)

Don't pull the pump. ..just losen the 2 screws that hold the switch on and turn it slightly one way. reset the ecu (battery disconnect and see if it stays out of limp mode after it starts)
What code are you getting? You might want to check the wiring harness to the pump for faults as well

dannobre

iTrader: (3)

You many have to try the position switch numerous times back or forth to get it in the correct place

pamdam

Thanks for your reply sorry to sound dumb but where are the screws that hold the switch located? I have seen two bolts which hold the pump to the block from underneath and one bolt on top?

dannobre

iTrader: (3)

2 small Phillips screws on the black bit on the pump with the smaller plug in it . If you look.... it rotates on the center of the switch and the screws have slots that slow about 20 deg of rotation

pamdam

Got to the pump and and one of the phillips screws is snapped off so im replacing the pump today with a second hand unit. I have removed the top and bottom bolts from the back of the pump easy through the wheel arch but how do you remove the top front bolt? I cant get to it from anywhere?

pamdam

All done, i removed the battery tray in the end and got the bolt from the top with a spanner. Car now runs well no more limp mode or misfire, there is still a code for the o2 sensor 0037.
Also the car wouldn't shift into reverse before however i have now repaired this to. Been a busy day.
Now very happy with my bargain £775 54 plate car. It has cost just £60 to get back on the road

pamdam

thanks for all your help!!

EastTnRotary

I posted in troubleshooting but no reply. My car to in this same limp mode. The only code im getting is heated circuit upstream o2 sensor. From what i read that shouldn put in limp mode at all. Would a code show if it was my omp or the sensor?

dannobre

iTrader: (3)

Very often no code for this problem

EastTnRotary

So try the sensor adjust first?

dannobre

iTrader: (3)

Wouldn't hurt

EastTnRotary

Ok would u start with full counter clockwise then a five to ten degree turn clockwise tighten and try

dannobre

iTrader: (3)

I would start by moving it a very slight amount one direction...reset the ECU ( battery disconnect) and try it....if not try again a bit more.

If that doesn't work try moving it back to where you started...reset and try going the other direction small amounts with resets in between

pamdam

If it helps the old mop and the new one for my car both had white painted lines to show where the switch should line up.

I still have a mis fire on my car after replacing the pump but i have ordered new coil packs and new Leads so hopefully this will clear that up.

Irvinluke

Help
i changed my plugs and an oil change yesterday now when i crank it up i have full acceleration only for 10 seconds then only about 4000 rpm
it did clear up twice and i was able to go up the road but then limp mode again please help this is my dd

dannobre

iTrader: (3)

Did you try any of the suggestions in the thread?

Pimpn8

I am having the same issue with my car going into limp mode with a CEL but no codes. It first happened last week and after adjusting the sensor on MOP, the car ran good for another week. But tonight it did the same thing, and after adjusting the sensor it is running good again. I am thinking that it is possibly a bad sensor since readjusting the sensor has fixed the issue. I wanted to see what you guys thought and also wanted to know if I can buy just the sensor somewhere. Thanks for the help.

TeamRX8

iTrader: (25)

the sensor is not sold separately, they would rather make you pay $1500 for a new calibrated pump assembly

this is the kind of thing that makes manufacturers look like idiots

nycgps

iTrader: (1)

I have a used OmP if you're interested, pm me.

Pimpn8

I was afraid a new pump would be the only way to get a new sensor. The car only lasted a day before it went into limp mode again. I adjusted the sensor again and I'm up and running again but not sure for how long.

Pimpn8

Ended up buying a used pump from NYCGPS. I used just the sensor and haven't had any issues for a couple weeks now. I did notice that the spring tension was stronger in the sensor I got from NYCGPS compared to my old one. Thanks to NYCGPS. I would recommend dealing with him anytime.

nycgps

iTrader: (1)

You are welcome, anytime