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LIMP MOP due to leaky vacuum? P1687

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Old 03-16-2020 | 03:40 PM
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Jose Zuma's Avatar
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LIMP MOP due to leaky vacuum? P1687

Hi guys,

Today my car went to Limp mode and is showing P1687.
This happened few hours after I rerouted the intake vacuum lines (Jet, OMP, etc).
When I checked the car, the OMP hose was a bit lose, put it back, reset ecu but problem came again.

Just want to be sure if running the car with a leaking OMP hose could damaged something?
If not, then, I'll try to change the position of the MOP yet this wasn't touched like 30k km ago.

Important: I'm running top mounted turbo, but the downpipe is properly wrapped, I doubt is due to heat as the
problem only happened after a short trip (did long ones and all fine)
Old 03-16-2020 | 04:46 PM
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What is the omp hose you're referring to? The vacuum line from the injector to intake?

P1687 has nothing to do with the OMP though...
Old 03-16-2020 | 06:37 PM
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Originally Posted by Loki
What is the omp hose you're referring to? The vacuum line from the injector to intake?
Yes, that one, my fault no being specific


P1687 has nothing to do with the OMP though...
So, what is it related to ?
​​​​​​
The description of the code is Metering oil pump control circuit high flow. I found in the forum few cases related with bad position of the mop. But I would like to discard easier causes first before doing that ( it's really hard to reach mot due to turbo setup ) .
Old 03-16-2020 | 06:53 PM
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Oh I see it has a different meaning for Mazda than other makes. Weird that.
It's not the typical failure case of maladjusted position. Possible wiring to the OMP has been damaged or disturbed?

Last edited by Loki; 03-16-2020 at 06:59 PM.
Old 03-17-2020 | 04:07 AM
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That could make sense as the connector is very close to the downpipe....

Today I will do a smoke test to see if any vacuum line is not properly closed, and then check the wires.

Thanks man.
Old 03-17-2020 | 04:07 AM
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I have been chasing this p1687 and also P1688 for a while now. I documented this in another thread. In short I think the main issue has been a short circuit due to either oil or coolant that can throw these codes. They are a PIA due to limp mode.

I suggest the following before spending any $$.

1. Spray lots of degreaser on plug wires in and out of plug.
2. Spray lots of electrical contact spray in/ out of plug. Allow to dry.
3. Apply electric grease to pins sparingly.
4. Join plug ends ( don't use electrical tape in attempt to keep contaminants out like I tried as I found it kept some oil dribble in there instead!
5. Possibly cable tie OMP plug off to side to aid cleanliness!
6. If still no luck then adjust OMP switch.
7. Start saving for a new OMP and it will cost you your first born child!!!!

Hope this helps you as I am code free from above.
I am not a pro mech and so much to learn with this car!
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Jose Zuma (03-17-2020)
Old 03-17-2020 | 01:20 PM
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Originally Posted by XDragon8
I have been chasing this p1687 and also P1688 for a while now. I documented this in another thread. In short I think the main issue has been a short circuit due to either oil or coolant that can throw these codes. They are a PIA due to limp mode.

I suggest the following before spending any $$.

1. Spray lots of degreaser on plug wires in and out of plug.
2. Spray lots of electrical contact spray in/ out of plug. Allow to dry.
3. Apply electric grease to pins sparingly.
4. Join plug ends ( don't use electrical tape in attempt to keep contaminants out like I tried as I found it kept some oil dribble in there instead!
5. Possibly cable tie OMP plug off to side to aid cleanliness!
6. If still no luck then adjust OMP switch.
7. Start saving for a new OMP and it will cost you your first born child!!!!

Hope this helps you as I am code free from above.
I am not a pro mech and so much to learn with this car!
Thanks for the info mate,

I think some wire might be melted... Seems like I will need to the remove the Turbo and possibly even the downpipe to reach it.

I'm considering to remove all the wiring and keep the MOP working in a fixed position as even I have isolate them better, there's the risk of failing again, I would need to investigate what's the best fixed rate.

Some people running turbo remove the MOP, I understand the point of doing it as it removes 1 more point of failure, yet running the MOP in a fixed position might be the best of both worlds.

Old 03-17-2020 | 01:29 PM
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The MOP limp mode that usually occurs for the position switch does not throw a code
if you have a code it is more likely to be the wiring or the pump in this instance where the turbo has likely heated things up

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Old 03-18-2020 | 07:19 AM
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From: 2017 Miata RF Launch Edition
DTC P1687

This looks like an electrical problem to me.
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Old 03-18-2020 | 08:08 AM
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Yes guys, I'm like 90% sure it's related with the 2 connectors that goes to the MOP.

The connector is touching the wrap of the downpipe (and this things gets really hot), sadly I didn't see this before.

Thanks for all the help and will notify you when fixed.
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