Juscruzn

iTrader: (3)

I did search but didn't find any info....

I'm going the swap ECU route to get rid of the NATS....

Does the conector come apart? Do I have to pull out each wire and swap? If so, is there a tool to make it easier? Any pointers/tips?

EDIT: I didn't mention that I am going from a '99 ECU to something earlier.... So I do need repin some of the pins.

Nopike

iTrader: (2)

I have not done it but it looks like the connectors at the back of the ECU should just clip out. No you do not need to change each wire. It should be fairly simple and does not require any special tools.

Juscruzn

iTrader: (3)

Thanks for the reply. But, I wasn't clear in my post, please see my edit.

Nopike

iTrader: (2)

I'm not sure about compatibilty of ECU's with/without NATS. I figured you already checked if it can be done. Check the pin outs for the ECU in 98 and 99 FSM's in the EC section. Pmohr has links to the FSM's. I would not expect any difference but can not say for sure.

If I find some time later I'll check for you.

Nopike

iTrader: (2)

I compared the ECU pin outs & wiring for a 99 with NATS and a 98 w/o NATS and there apear to be quite a few differences. At this point I would not say it can't be done for sure, but it looks like it would be difficult or impossible. This is due to some signals present on one of the ECU's and not the other.

Maybe someone has already done this sucessfully but I have my doubts.

whlimi

iTrader: (11)

The pinout in the 99 FSM may not be completely accurate. I've been thinking about doing this for a while now to my 99 just to get rid of some of the codes after doing the 3.5 swap. I have purchased a 95 ECM but I havent really gotten down to tracing some of the pins which differ on the 99s.

Nopike

iTrader: (2)

Thanks, I just noticed that pmohr wrote:
"Don't bother looking at the FSM pinout for the '99, it's partially incorrect."


So, hell I don't know.

whlimi

iTrader: (11)

The way I would do it is make sure the two CKPS sensors and the CMPS sensor is wired correctly. This way you'll at least have a good chance the car starts up. From there, you'll most likely throw codes for whatever else needs to be repinned.

Juscruzn

iTrader: (3)

Great thread so far! But off track a little....

What's involved in the actual repinning? How do the pins come out of the connector?

CautiousDriver

iTrader: (2)

i'm in the same boat, hate my 99 cali slow poke. can't get rid of that damn cel no matter what i do and this is the other route. someone told me you have to change the whole harness, hope if OP figures this out i would try this too unless some one on the org did this successfully...

whlimi

iTrader: (11)

I think the OP wants to know how to physically remove the pins from the plastic molding. I havent taken a look at the harness connector but there might be clips on both ends that unlock the connector and then you might just need a really small screw driver to push out the pins.

throttlehappy46

To repin a loom plug, you will need a 'pick set', not sure what you would call them over there but I bought mine from Kinchrome. Set of three, one has a hook, one is straight and the last one is straight with a bend right on the end. The last one is the one I use. Push the wire into the plastic plug hard(reverse of trying to yank it out), release a plastic tab that holds the pin in place and then pull on the wire to release the wire with pin attached

Takes about 10 seconds per wire once you get the hang of it

Juscruzn

iTrader: (3)

Thanks Happy! That's exactly what I was looking for!!!

whlimi

iTrader: (11)

Please keep us updated on your progress.

pmohr

iTrader: (26)

Note that you will have to raise up the white plastic lock on top of the ECU harness connector in order to remove the pins. After that you can pretty much yank them out without any damage to either the pin, wire, or connector.

Juscruzn

iTrader: (3)

Pmohr,

You mentioned in another thread that I should go with a '95, '96 ECU. Please tell me more why you recommend those years. I assume it has to do with emission equipment.

pmohr

iTrader: (26)

Indeed. More so a '95, due to the extremely lax emissions requirements. For example, I had zero EVAP or EGR equipment on my car (as well as a gutted converter) with zero emissions codes.

That and there are random complexities with other year ECUs. For example, '97s have the FPCM setup which will throw a code without one, 97-98 have different rear O2 sensor wiring than '95-'96, etc.

whlimi

iTrader: (11)

Any updates on your progress yet? Have you started working on this yet?
It would be nice if you could make a list of all the connections that are different or incorrectly marked on the 99 FSM.

whlimi

iTrader: (11)

Maybe I can get the ball rolling on this. When I get some free time I will give it a shot. The repin locations are based off of the 95 FSM.

The 99 FSM has errors so we'll have to double check all connections with a DMM.

-Switch fuel pump relay from 117 to 11
-Change PNP Switch from 27 to 22
-CKPS REF should be 44 and 48
-CMPS should be 46 and 47
- Switch rear O2 sensor from 107 to 105
-NATS is on pin 17 which does not correspond to anything in the 95 FSM (Leave it or unpin it, doesnt matter)

Again, the 99 FSM has errors so its best to use DMM to check for continuity between the desired pins and corresponding sensors.

urmab

iTrader: (7)

I recommend the 95 ecu because it eliminates alot of the emission codes. I had evap leak code on my 98 now I have none the only thing I did was switch the rear O2 sensor pin from 107 to 106 pin and now codes yet. Now as far as getting rid of NATS dont rally know

whlimi

iTrader: (11)

You probably meant 107 to 105. 106 is injector #5. But thanks for pointing that out. I will add it to the list.

Juscruzn

iTrader: (3)

whlimi,

You beat me to it! Thanks! My time frame was before the next state inspection is due

A couple of ?'s...

What's a DMM?

Also, when not hooking up emission stuff (like EGR, EVAP) do I need to put a resistor inline or is the 95 ECM ok with the equipment not being plugged in. I thought for sure that a "open" circuit would throw a code. Question make sense?

Juscruzn

iTrader: (3)

I will do a detailed write up on the project.

whlimi

iTrader: (11)

DMM=Digital Multimeter. You will need it to check continuity between the ECM harness connectors and the sensors so that you're positive you're repinning the correct pin. (you can thank the 99 FSM for this step lol)

As for the emissions stuff, the 95 ECM only looks for the EGR and Canister control solenoid valve. The EGR is vacuum controlled unlike the electronically controlled EGR system on the 99s. The only issue I see with this setup is that our engine harness does not come equipped with the connector for the EGR and Canister valve. You'll need to acquire the valve as well as the connector for it and connect it up to pin # 103. Then you can supply vacuum to it and block off the other ends and see if you can trick the ECM. I'm sure someone has bypassed their vacuum controlled EGR system and hopefully they step in and correct me.

EDIT: Came across this while searching.
http://forums.maxima.org/4th-generat...relay-fix.html

Juscruzn

iTrader: (3)

Duh! I don't think I've come across that acronym.

Another question. Are all the pins that have the same pin number on the diagrams ('99 and '95) in the FSM correct? For example, intake air temp is pin 58 on both ECU. Are we 100% that's correct? That the rest of the numbers that match are correct?

whlimi

iTrader: (11)

I would assume they're correct because most of them have not changed their pin location in the FSM from year to year. I would not worry about those ones because once you get the car started, you will throw codes for whatever isnt correct and you can go back and fix them.

whlimi

iTrader: (11)

http://forums.maxima.org/4th-generat...ml#post7208760

Juscruzn

iTrader: (3)

AWESOME!! THANKS!!!

nismomaxgtr18

iTrader: (5)

These two pieces of info just gave me the solution to my p0136 code. Thanks!