I'm reading the FSM. I understand the stepper motor part. That made sense...

The position sensor part confuses me a little.

It says

Measure resistance between terminals Vc and E2. 1-2kOhm is acceptable, I get 1.501.

Then it says
"Add the resistance of terminals (Vo - E2) and (Vo - Vc)." Acceptable resistance is 1-2kOhm.

On two known working OMP's, I'm getting .555 for the first one, and 1.859 for the second.

The second *WORKING* OMP give similar readings (+ or - very little).

So, if I ADD the two values.. I get 2.414. Way above the 1-2kOhm they list as acceptable.


Am I reading it correctly? Could somebody test theirs and tell me what they get?

Thanks,
Micah

 

Well. I posted this too early in the morning.. How about now?

 

Bud I would just go with pre-mix. Just to know for sure your getting oil injected properly.. When I removed my metering pump lines and oil injectors, to me it seemed like a weak system.

 

if you added the values and it doesn't fall within that range then it's faulty. Double and triple check to make sure you have the right values.

 

Bud, NO.

Pre-mix isn't for everybody. I also didn't ask "What are my options?" I know my options... I'm asking how I test the S5 OMP.

So, Giro.... any ideas? No? Okay, nice talking to you.

Anybody else?

 

****. I tested this before the poor-mans method of running the car on premix while unscrewing the hoses and testing the flow. It checked out fine. Both of them are known working..... I just can't imagine they would both have almost exactly the same failing value. I was hoping for a typo in the FSM. If I follow the FD's FSM, it passes... but, thats not really good enough for me.

 

Did you do the harness continuity test?? Maybe your wires/harness have a problem.

 

No, I did it with OMP in hand.. Disconnected from vehicle. I'm cleaning/restoring every part of my car. EVERY part. .

So, I tested the stepper motor on the stepper motor plug. The position sensor you have to test on the end of the wire pigtail that comes off of it. So I tested that.

 

well if the OMP is fine and the OMP sensor is fine then it's the harness that is bad.

I don't have the FSM in front of me but if the sensor is not within range does it tell you to replace the OMP?

Go back a couple of pages and look for the harness continuity test. It will tell you which wires to check.

 

Yeah. I did the continuity test since I have the entire engine harness out of the car right now.. Figured it would be best to identify bad wires now instead of later.

I re-tested the position sensor after re-installing the sensor into the OMP... the values were different (higher on one terminal, and lower on the other), but they still failed. I'm questioning the validity of the test I guess....... That and I don't want to spend 1500 on a new pump. I'll have to post a WTB in the for sale section.

Thanks for your help Phoenix7. Still wanting a second opinion, no offense.

 

hmm, s4 omp?

also when you did the flow test did it pump enough?
if your not in limp mode and it flows enough , i would say go with it, but my engine is in limp mode, but it still flows up to par, go figure, but my idle is stuck at 2.6k rpm, go figure.

 

Either OMP sux ***. Get premix and save your rotor housings!! Ive seen proof even on a working OMP system.. THe stock omp pushes 3-4x less oil than the combustion chamber should see for emissions reasons.

 

Premix isnt' for me. I've said this once in this thread... lets try and make it the last time. Here's my reason. Lets pretend that my wife drove my car for some reason. Is she going to remember to premix? Doubtful... Even if I had a big sticker on the steering wheel that said "Remember to premix" she would still forget... So, running premix means that NOBODY can drive my car...I'd rather keep the OMP, feed it 2-stroke oil (my plan) and pre-mix MMO or something as a supplementary premix. That way if I forget to do it, or my wife fills the tank, I don't have to worry about it.

I hope that clears things up.

 

How's that OMP dilemma going. I'm in the process of replacing it. But did not have the tool to test the damn thing. So far the engine searches point fingers at the OMP.

 

Have you checked fsm for testing procedures? Rx7 foxed on google

Run the omp if you want to. Add a little premix when you can just to make sure entire rotor housing is getting more than adequate lubrication

 

I have found testing procedures one for dry test. And another test under load. Which I think is more accurate reason is because it limp modes every time I drive it after 5-10min. Im in the middle of replacing it but my most concern is the ECU burning my new OMP again because I didn't replace a new ECU to begin with. And I hear it does that from my search sources.

 

Mine OMP died 2 hours after I bought the car, but lucky for me, it didn't toast the ECU.

If the OMP toasted the ECU, it won't toast the new OMP. When the stepper motor driver circuit goes boom because the OMP toasted it, you'll just get a OMP position sensor code with the new OMP. This is because the ECU wants to move the stepper motor, but it can't because the drive circuit is damaged, so the ecu looks at the position sensor and says "hey, it's supposed to be here and not there" and thus throws the code.

 

I hear different story's of newly OMPs being toasted for not replacing ECU at the same time replacing the OMP in the first place. One guy did it 3 times! Join us on FC society on FB for the topic.

 

my friend diagnosed a T2 way back in the 90's, and it burned a couple metering pumps and ecus before he figured out that there was a bad harness ground, which causes the metering pump to BE the ground, which fries it, and then the ECU

 

The FSM testing protocol is incomplete. My S5 MOP took out my ECU. I had used S5 MOP that tested good per the FSM but burned out a second ECU. I never had a ECU take out an MOP.

This thread
https://www.rx7club.com/2nd-generati...2/#post7628548
has some additional tests that pinpointed the problems and allowed me to select an MOP that was electrically sound.

and by the way, if you are still going into limp mode, that ecu is likely fried.

https://www.rx7club.com/2nd-generati...2/#post7628548

 

Thanks for the link. Just got done installing my low mileage OMP.