Ok, here is where I am. My S5 vert went into limpmode. I had 20,26,27 cel codes.

I found this terrific thread in a search. https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/page3/

I bought a claimed good MOP. I tested said MOP per the chart, tested good. The harness (short harness) tested good for continuity. Installed MOP, now I have #26.

I'm pretty unhappy with the situation at this point. Part swapping with 18 year old parts is ridiculous and frustrating.


Where do I go from here? Is my ecu fried? Can I test it or do I have to just do a visual on the circuit board?

 

I say fried. sorry dude.

 

when a buddy of mines s5 went into limp mode it took out the ecu tps and omp ...what we had to do was replace all 3 at the same time and voila no limp mode .if you look in your ecu two resistors will be burned ...trust me you have to do all three ..its a common problem with s5 series ...if your on ebay and you see any for sale buy them for spares...

 

Well, that's obviously what I suspect as well, but does anyone have a suggestion as to how to verify this without just buying some more old parts, plugging them in and hoping the New Old parts are good or not?

It's not like these parts are laying in big piles at the auto recyclers.

 

So, I started the car and moved it inside the garage (82* and 40 mph winds today). Now I have 20, 26 and 27. The ECU is storing the codes and I can read them, so does this mean that the ECU is NOT burned out? I am preparing to pull out the ECU to look for burned circuit board devices.

 

9 times out of 10 your ecu is fried but i could be wrong ...you will see two resistors fried if i remember correctly...but usually it takes out all three items ...ecu tps omp ....good hunting if you find them parts

 

i am sorry guys but you really dont know to much of what your talking about.

as for you, jackhild59, me and another member of the forum have discussed this in great length and if you would like some help that will turn out some answers then please pm me.

i will post in the other thread our findings but it is very lengthy and will take some time.

 

Before I got the carpet up, I could smell the acrid stench of the electrical burning.

When I get the ECU open, the same two devices are burned on my ECU as in the MOP Failure Analysis thread.

Tomorrow I am taking of the MOP and retesting it to determine if the ECU fried the MOP.

Update to follow.

 

blackball7 we appreciate the thread you have up and all the theory about the omp, but i have like 7-8 buddys of mine who ran into the same problem i told them change the tps omp ecu and reset ecu, and it worked every time it got them out of limp mode its very simple but expensive unless you find it on ebay cheap ....they have to be changed together then reboot ...zooooooom...im an s4 man myself

 

no offense, but i have never heard of the tps being taken out as well. that may have been a pre-existing problem because that is in no way tied to the omp injection system except for the fact that they both use the same ecu to run, but so does the rest of the engines components.

 

Followup:

I got a known good ecu from a good friend. The MOP tested good per the FSM+1990TurboII-75K test protocol.

Tested the TPS because Blackball7 and Dennis blackistone warned that it could be a problem as well. Both TPS tested fine,

Car works fine, I have an engine air thermosensor, code 11 cel showing up. Shouldn't be a problem but I just want to thank all involved helping.

I am still considering conversion to S4 because for the first time in 4 years, the car feels frail to me. I don't want to have this happen again.

Thanks to all for all the help.

Jack

 

I agree the TPS may not need to get replaced but I would still check it to make sure.

The full range TPS is used only for the OMP so that is the one you would need to check if you wanted.

 

I MIGHT have passed out bad information. Well, I did to some extent. See the series five FSM, Fuel and Emissions section and a page called Relationship Chart. It shows what the narrow and full range TPS signals effect.

Although the series FIVE FSM and the relationship chart does not mention the TPS effecting the OMP, If you go look at a 1993 Relationship Chart, IT does show the narrow range TPS effecting the OMP. I wrote Full Range, NOT narrow range......because for some reason I thought the full range effected the OMP. Where did I learn that? Got me. I've a message sent to one of the RTEK chip sleuths asking about the series five TPS vs the OMP. He might answer, he might not.

I think my thinking was something like this: On a series four OMP, there is a rod attached to the OMP and the throttle linkage. More throttle equals more delivery by the OMP to the injectors. I ***..U..ME..D that the series five was influenced in the same way by the Full range TPS. Might be wrong about that.