Texas_Ace

iTrader: (18)

Ok, so i have owned more then my share of 2nd gens before this so i am well aware of how rotarys work and such, this is just my first 3rd gen.

So this car more or less fell into my lap at a price i could not refuse. I picked it up and now i have the task of de-ricing it and restoring it.

So here is how i got it, overall very clean, it does have some front end damage but luckly it is mostly cosmetic, a bumper and hood should fix it up. Otherwise the rest of the body is very nice and clean.




I will snap some more pictures of it later, interior needs some TLC but it is also clean for the most part, i think he just randomly decided to leave screws and tabs out for some reason in there, got a big box full of them as well.

The car is riced out but it also has some tastefull mods from the owner before the guy i got it from. Motor is said to be a streetport rebuild, it has a FMIC, radiator, greddy exahust, PFC and various other good mods on it. Still running stock twins.

So, when i got the car it was not running, he said he didn't know what was wrong and it just would not start one day. I messed with it and knew it was flooded right away. So i got it home, de-flooded it and got it started right up.

But then it flooded again, start playing with stuff and it turns out that he had messed with the PFC after it was tuned and TOTALLY screwed it up. Reset it and what do you know, it started and no more smoke or bad idle.

So now for the issues.

so now the car starts and runs but there is a catch, i will be driving/revving it and it will sound great, just like it should. Then all of the sudden it is like a switch is trwon and it runs like junk and is running pig rich.

I am almost positive it is somthing to do with the MAP sensor as when it runs bad (at least after i noticed this and started looking at it), the PFC reads about 0psi on the boost give or take a little even when it is idling and pulling vacume acording to the manual boost gauge. Then the switch will flip back and it runs great again. I have not found a trend on what causes this at all.


And ideas? i have checked the MAP sensor, it appears to be fine, it is plugged in and the vacume line gose to the lower port by the TB.

I am sure i will have some other stuff come up i will need help with as well but first off i want to get the car running right.

Texas_Ace

iTrader: (18)

Oh, and yes that batman wing is coming off ASAP, stocker is going back on.

Texas_Ace

iTrader: (18)

No one has ever heard of the map sensor randomly reading right and then reading boost at idle but yet still working as when i rev it the reading still changes as it should, just the wrong numbers?

zack4173

iTrader: (3)

I dont see how it could read boost at idle even if it were damaged. Did you check the rats nest and make sure everything is correct. chances are the last guy may have messed it up.

Texas_Ace

iTrader: (18)

Rats nest? remember this is my first 3rd gen, so still learning, heck this is the first time i have even seen a 3rd gen up close lol.

Yeah, i don't have a clue what is going on, my manual boost gauge reads fine so i know that it is not a mechincal problem.

It must be eletrical, the problem is i have no idea where to start looking.

rx7rcer09

rats nest is a cluster F*** of lines under the UMI that mazda put there just to be a PITA. lol and if anyone of those is crossed or not plugged right you will have boost issues.

Texas_Ace

iTrader: (18)

Hmm, that is possible actually, i noticed at least 1 plug not connected near there.

That does remind me of somthign else, after i shut the car after it getting warm, i hear a buzzing from what i guess is the rats nest, it is somthing eletrical as when i disconnect the battery it stops. It sounds like a relay clicking on and off real fast.

Could that be connected? i only hear it after the car is warmed up and i shut it off.

Anyone have a vacume diagram and wiring diagram for that area? i will pull it apart and check it out if so.

LagunaFC

haha, that is perhaps the best and most accurate definition of the "rats nest" I've ever heard.

Texas_Ace

iTrader: (18)

Ok, so i just pulled the UIM to see what i am dealing with, and first thing i noticed is that everything was lose, the ground wire on the back of the UIM was hardly even on, that might have been part of the problem.

But then i found this:






Needless to say i am totally lost, i have no idea what i am looking at but i know it is not OEM. I see a few of the noids are missing altogether so i am pretty much screwed for going back to stock unless somone has some laying around. Lots of things unplugged and not hooked up. That is hopw i found it, all i did was remove stuff that was connecting the UIM to the motor.

Any ideas or suggestions? I looked in the FAQ and found a vacume diagram but it is not real easy to follow in my case with stuf going everywhere, gonna take a while to get that back together.

Are the missing noids a must have? i am looking to go back to as close to stock as i can get, i find that to work best 90% of the time.

Texas_Ace

iTrader: (18)

Anyone got any pictures from under the UIM like mine of a car that is good to go?

Oh, and i also am starting to get a parts list of stuff i need to restore this car if anyone has any of this stuff let me know.

Seat belts (no idea why the PO removed these, said somthing about saving weight)
Hood (red would be nice but let me know what you got)
Some of the missing noids for the rats nest, i will get the exact ones later
mics interior pieces
Possibly some black seats for the right price

I am in DFW if anyone local has somthing.

Texas_Ace

iTrader: (18)

Ok, just spent all day working on those vacume and wiring under there, finally got it as close to OEM as i could, actually only had to move a few vacume lines around and found 1 or 2 missing lines that were supposed to go to vacume other then the missing noids.

Put it all back together and tried starting it, it is still doing the same thing. The map sensor reading is all screwed up, i am starting to think that the PFC might be to blame, that buzzing from under the UIM came back so i tried unplugging the PFC, and sure enough it stopped. So i then tossed in the stock ECU, and it stayed stopped. BUT the stock ECU that came with the car has BAD written on it so not sure how acturate that is.

Anyone in DFW have a spare stock ECU i could try?

Somthing is up for sure, i noticed that if i watch the PFC commander, with the key off (BTW, should the commander stay on with the key off?), it reads a vacume of about -50, if i turn the key on it instantly changes to about .1-3 bar of boost. Obiously like this is won't start.

I did find that if i lean the map out by a whole lot, i can get it to start, so mechincally it is fine, it is just giving it way to much fuel due to thinking it is at a much higher vacume level.

The wiring on this car is pretty bad, i am slowly cleaning it up but all the easy stuff is more or less done, now i am left with wires leading to who knows where and for who knows what.

So any ideas on why the map sensor is all screwy? The map sensor worked fine for a litlte while the other day and the car ran great, no issues at all.

Rx7_Nut13B

iTrader: (1)

Rx7_Nut13B

iTrader: (1)

Are you looking at the commander to get this 0psi reading, because it doesn't read in psi

You need to go into the settings on the commander and do a sensor check when the car is not running well, this will help to see if there is a sensor that isnt reading right sometimes (Water Temp, MAP Sensor) These will cause the map to inject more or less fuel.

Texas_Ace

iTrader: (18)

Thanks, found that in the FAQ and used it to get it as close as possible.

Yes, iam using the commander. I know it doesn't read in PSI but i don't know what the metric vacume is called, i know it reads boost in bar.

Either way, with the key off the commander shows me about -~50 vacume of whatever it is, if i turn the key on without starting the car, it instantly jumps to .1-.3 bar of boost on the map sensor. If i then start the car it stays around .2-.3bar of boost at idle unless i rev it, then it will go up and down like normal only in the wrong vacume/boost level.

I looked at the sensor readout ont he PFC but could not figure out which was the map sensor, i am 90% sure that is the issue, as when it showed the correct vacume on the map sensor the other day the car ran great.

Now where the issue with the sensor lies, i have no idea. might even be the PFC to blame, i reset it a few times, no help. That buzzing under the UIM stops if i unplug the PFC i know that.

Rx7_Nut13B

iTrader: (1)

The buzzing is just a silinode, proably the boost one if the map sensor is saying that there is a intake pressure, the power fc is trying to control the wastegate or one of the pre controlers. But that can be a normal sound.

Texas_Ace

iTrader: (18)

Ah, ok that makes sense, so the map sersor reading being off is messing it all up.

Now why is it messed up?

Anyone know which wires go to it on the harness so i can back probe them?

Rx7_Nut13B

iTrader: (1)

Well there are three wires going to the map sensor, one will be a positive 5 volts, a ground, and a sensor wire to the PFC, the 5 volt positive and ground are common with the TPS sensor so if that isn't having a problem I would start by just running a temp wire from the map output 0-5v to the PFC just to make sure that wire is fine. You can find the pin out on thepfc by looking atthe fd wiring diagram in the FAQ. I would try and make sure the map sensor is good before going they all the wire running. Get a volt meter and check the output ofthe map while u either pull a vacuum or positive pressure. See if it changes with the pressure change. U will have to get the 5v and ground from the stock plug with the ign turned on

Texas_Ace

iTrader: (18)

Yeah, i was figuring i would more or less do that, just no place to backprobe the MAP sensor at the MAP sensor unless i punch through the wire shelding, which i don't like doing under the hood.

The strangest part is that the MAP sensor seems to work all the time, just reads wrong. when it reads boost at idle, it will still change the readings if i rev it like it would normally only at the wrong load cells.

Wish i knew what the voltages on the PFC sensor check were to, anyone have an english manual for the PFC? i could only find japan manuals.

Texas_Ace

iTrader: (18)

I just looked again for a wiring diagram in the FAQ but came up short, only thing i could find was the thread about the wiring harness and showing what the connectors do. Could not find a diagram though.

Rx7_Nut13B

iTrader: (1)

Send a pm to chuckwestbrook he is the PFC GOD!

He has a complete easy to read notes for the PFC

Texas_Ace

iTrader: (18)

I will do that, i might have found the problem by pure luck though.

I was working on it and set my socket down, i heard a click, so i started playing around and realized i could make that click happen on demand. So started tracing things and found that the EGI relay was semi broken (the outside plastic was broke off).

Started fiddling with it and noticed that i could make the PFC read high or correct map sensor readings by playing with it. So it might just be a bad relay. Problem is now i can't get the car started at all. Think i might have the plug wires mixed up, anyone know which wire goes where? can't see the coils to read the lables.

Would be nice if this is the issue, gonna pick up another relay today hopfully.

Texas_Ace

iTrader: (18)

Hmm, well now it is not getting enough fuel. I think playing with that relay seems ot have fixed the map sensor but now it does not seem to be getting any fuel. I can start it on starter fluid but it won't start without it.

gonna look up to see if there is a way to test the fuel pump. Any ideas if that checks out?

Texas_Ace

iTrader: (18)

Ok, so after some more testing and work i have found out this.

I was out of gas, thats why it would not start, also found out why the gas gauge was not working, the float came off in the tank. Also found what looks to be an 044 fuel pump in tank.

So got the car running again, the relay was part of my problem for sure but not all of it. After overriding the relay the car worked a lot better, no more random eletrical issues as a whole.

BUT the map sensopr once again messed up after the car had warmed up some. Started checking voltage on the wires and they don't make sense at all.

when the map was working right i got ground, 5v on 1 wire and the signal wire showed me about 2.5 volts.

After it messed up i see 2.3-2.6 volts on the 5v wire and 3.5volts on the signal wire? how is that possible? grounds appears to still be ground.

What feeds the 5v signal for the map? the PFC?

Rx7_Nut13B

iTrader: (1)

Yes the PFC feeds 5 Volts to the TPS, MAP

On the Coil Packs, the easiest way to tell where everthing goes it like this.

Look at the coil packs from the driver side fender

The front single coil is T1
The Center Twin (Duel) Coil is the L1/2
The Rear single coil is T2

Hope that helps

Texas_Ace

iTrader: (18)

Thats what i thought, which doesn't help me much. If it is the PFC that is dropping the 5v ref down to ~2.5 why does it only do it somtimes and mostly when warm?

And how in the world does the the signal wire have more voltage then the ref wire?