graniteguru

iTrader: (1)

I am having a difficult time with the S5 MOP position sensor. I have read most of the posts on the site and really have had no definitive answer to this question. In the FSM of an 89 TII, it says that the resistance reading across VO-E2 added to the resisitance of VO to Vc should read less than 2Kohm. I have a reading of .707 and 1.503. Added together this puts me out of spec. According to most on the website, thiers do not test out below 2Kohms. Is the manual wrong, or do I have 3 bad OMP testing out the same. All other tests on the OMP are ok. NO the answer is not pre-mix! I do not want to do this, I just want to fix it right. Does anyone have a definitive answer?

graniteguru

iTrader: (1)

Someone has to know the answer to this. Come on.......

RETed

Why don't you just plug them in to see if it triggers and error code by the ECU?


-Ted

graniteguru

iTrader: (1)

I guess I am a little gun shy on this. Apparently, on the S5, the ecu going bad will cause the OMP to go bad and vice versa. In my case, it fried the ecu at the place on the circuit board that would indicate a failure of the omp. I found a new (used) ecu and I don't want to hook it up to the new(used) omp that I bought if it is going to fry the ecu again. The S5 TII ecus are getting hard to find and very expensive.

jackhild59

iTrader: (7)

There is a helluva good thread on this if you search. It has a much more extensive testing protocol than the FSM. My MOP fried my ecu and I had to get a new ecu. The MOP tested good in every test in the FSM, yet with the expanded testing, I found the fault. I got a new/used MOP, tested it per the expanded protocol. It tested good and everything has worked fine since.

Edit: \Found it-searched for 'MOP test'.

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

graniteguru

iTrader: (1)

Can someone please measure the resistance at the 3 wire Oil Metering Pump Position Sensors? If you unplug the plug on the harness (the 3 wire plug just to the left of alternater looking at the engine) and look directly at the plug on the oil metering pump side, place the nipple that secures it to the bracket down. Now from left to right (1, 2, 3) , please measure the ohm readings between 1 and 3 and 2 and 3. Please add these together and tell me what you get. It does not matter if this is an NA or a Turbo, they use the same pump, It just needs to be an S5 (89-91) electric oil metering pump.

The factory service manual says this should total less than 2 Kohms. I have 3 OMPs that are all testing higher than this reading. I am trying to get a consensus on whether the FSM is wrong, or if this really means the omp is bad.

Most of the people I have read about so far have tested out to the over 2 Kohm side.

I have read the posts on how to test the omp itself, but nothing is definitive on the position sensor for the omp. I have a new ecu to go in and I don't want to fry it with a bad omp. THanks a bunch. Please help. It will only take a few minutes to test this and post it.

HAILERS

What does Vc to E2 read????????

Same as Vo to E2 plus Vo to Vc?

Seems their reading the pot.

First the coil of the pot alone.

Then measuring the wiper to one end of the coil and then from the wiper to the OTHER end of the coil and adding the two together.

Then seeing if that addition is equal to the resistance of the coil itself. Something like that.

Vo would be the wiper. Vc would be one end of the coil the wiper rides on and Vc would be the other end of that coil.

graniteguru

iTrader: (1)

VC to E2 reads 1.698 K ohms, VO to E2 measures .68 Kohms and VO to VC measures 1.699 K Ohms. Added together, these exceed the spec of 2.0 Kohm by
.379 Kohms. The funny thing is, that all three of the OMP's that I have, exceed the spec by around the same amount. I was just asking Sean at 915 racing about the one that he is selling and it tests out the same (exceeding the spec by
approx .35 Kohms).

Let's say for instance that the FSM was wrong and the spec is too tight. Somehow, it still fried my ecu at the point where it should have fried it with a bad OMP. I wish someone could test a new one so that we could clear this up once and for all.

Sean was telling me that on the 6 prong connector to the omp that he has found sometimes that the wires are not in the same position on the plug. I wonder if mine is right as I had a JDM motor (OMP) plugging into an american harness. Most of the posts that I have read on this where people are having problems are with the JDM swap, not a US Spec engine in a US Spec car.

graniteguru

iTrader: (1)

UPDATE: I stated in the last post that the 3 omp position sensors tested out the same. I was a little off in this statement. The one that is on the car that is bad (or at least caused the ecu to fry) tests out at 2.576 KOhms. The two that are off of know working cars tested at 2.350 and 2.395. Again, the factory spec reads less than 2kohms is acceptable. Several other posts had stated that thiers tested in the 2.3 range as well. Although I do not have access to a new one to test it, it is looking to me like the FSM's range is too narrow and that in fact 2.3-2.4 is more of a normal range for this test on the position sensor. I put the one that tested out the best on last night and I will fire it up and let you know if it works or not. In the meantime, I am going to run a little pre-mix for safety sake.