ItsFun

iTrader: (25)

My religion is rx7, the FSM is my bible.

Texas_Ace

iTrader: (18)

LOL.

Well i just got a chance to try another N326 ECU, did the same thing. So it must be somthing else.

Gonna try adding some grounds here in a min.

Also, i have no idea if this is related or not but anytime the key is on i get this really annoying BEEEEEEEEEEEEEP. Not the rev limit/coolent low buzzer but a beeeeeeeep. It never stops. Anybody have any ideas what that is? no lights on the dash and no codes.

My water temp and fuel level gauge also appear to not be working.

Texas_Ace

iTrader: (18)

Oh yeah, also. Should i Tap the ground wires at the ECU or should i cut them? I assume splice them but want to make sure that won't hurt anything.

ItsFun

iTrader: (25)

I`d tap in and solder, but thats just me. A ground will take the easier path of travel I believe... Like lightening, I knew a guy who was struck and had a nice burn on his *** from when it left his body to the grass. I guess his *** was the easiest way out.

satch

iTrader: (1)

I tapped as well. I soldered also so I removed both the small and intermediate plugs to protect the ECU during soldering. I measured a couple inches or so behind the plug and took a razor blade and cut a slit in the wire sheathing all the way around the wire and then used my thumbnail to remove about a half an inch of the covering to expose the wire for soldering.

Texas_Ace

iTrader: (18)

Well heading out to try this now.. hope it works. Anythign else i should ground if this doesn't work?

Texas_Ace

iTrader: (18)

Ok, just grounded all 3 pins on the ECU, nothing. Didn't change a thing.

Anythign else? this is really starting to bug me now.

satch

iTrader: (1)

Why did you recently get a new ECU for. Was it to rectify your current problem or are you in the midst of putting a car together?

EDIT: Reread post #38. I suggest you splurge and get the led light and check for pulse. You seem to feel it is your ECU. If you conduct this easy pulse test you will get accurate insight into whether it is an ECU issue or not and it takes all of two minutes to do.

Texas_Ace

iTrader: (18)

An ECU did not come with the car so i had to buy one. I just swapped ECU's earlier today though and the problem did not change so ECU seems to be in the clear.

I have a few LED's laying around. Just put on between the wires of the injector?

I checked them with a multimeter and nothing changed so i am 90% sure they are not trying ot come on. Plus if they were trying to come on, even if the injectors were not working perfect it would not hit a brick wall at 3800.

But i will check it and see what happens. I am out of ideas.

Is there anythign else that could cause this?

I was playing with the car a little bit ago, the motor itself is great, good compression and starts every time ect. Overall mechnically not a problem.

But i was checking the timing and noticed it was jumping all over the place for some reason, not sure if the mixture is changing as well or not.

Tried unplugging the TPS and pressure sensor but still not able to rev.

Really has me stumped.

satch

iTrader: (1)

The negative wire of the led needs to go to the injector wire (light green= pin 3E, light green/black= pin3C) and positive wire goes to pin 3I and of course you check one injector at a time. Place the wires of the led on your battery to differentiate which wire is negative and such. If you feel the ECU is not the problem and you can prove the injector wires are receiving proper voltage and pulsing ground wouldn't that red flag the injectors themselves? And you didn't change the plug wires lately and get them mixed up? I didn't think so!

EDIT: Also, what year is this S4 Is it a model which requires low impedance injectors where some of yours are while the secondaries aren't perhaps. .

Texas_Ace

iTrader: (18)

Just found a spare LED, gonna go check now.

The injectors could be the problem but i have enver seen 2 injectors just die at the same time. And if either was working even a little i doubt it would cut out so hard but i guess i will know in a second.

I did change the plug wires and i was a littel worried about them at first but it runs fine. Have the Trailing going to the top and leading to the bottom plugs, 1 to the front rotor and 2 to the rear.

Timing just jumps around by ~10 - 20 degrees totally randomly. If i set it to the correct timing it runs great but then it just moves again.

The car is an 87, the motor is i am not sure 88 or somthing. But it had all of the parts that matter swapped from the S4 motor that came in the car so everything is S4 87 now.

All injectors are low impedence, checked that before installing and the resister pack is installed.

Texas_Ace

iTrader: (18)

Ok, so just checked it and when revving it up to where it cuts out, as soon as it cut out the LED would light up solid, no pulsing, just a soild light.

No clue what that means? maybe it is the injectors but shouldn't the LED pluse?

satch

iTrader: (1)

Does the light flash at all before going to solid?

Texas_Ace

iTrader: (18)

No, just from off to on. using just a cheap little 12v LED from radio shack.

Anyway to test the injectors? Seems real strange that both of them would die completely all of the sudden, i know the car was running on these before the old motor blew up.

I guess i can just touch 12v and ground to the injector and see if it clicks?

Texas_Ace

iTrader: (18)

Well i tried hotwiring the injector and it does indeed click and does spray fuel, car was flooded after doing it. So i am even more stumped now.

satch

iTrader: (1)

I royally screwed up earlier, Tex. The pins 3E and 3C were for the primaries and not the secondaries. The correct pins are 3H for the front secondary and 3F for the rear secondary. I truly apologize. Retry the test and you might/should get different results.

EDIT: Since your injectors are all the same, primaries and secondaries, you could swap them and see if the problem persists.

Texas_Ace

iTrader: (18)

Actually you didnt, i just pulled the connector off the injector and put the LED there to make sure the wiring was ok at the same time, BUT you did just give me an idea, i will go back probe the primaries and see what the LED does with those, see if it pulses with those or just comes on.

I need to play with the multimeter some more and see what i can figure out.

so the pins earlier were indeed for the primaires?

Texas_Ace

iTrader: (18)

Well this is VERY odd.

Just checked the primaiers and they do indeed pulse like i thought they should.

Checked the sec and it is just on or off. Thing is i can't figre it out, if they are switching on, why am i hitting a wall like i am? if it was injecting too much fuel then if i was WOT it should at least allow me to rev past it a little or just bog down but it just hits a wall there.

Texas_Ace

iTrader: (18)

True i could but i don't feel like pulling the intake just for that unless i have too.

Also, it seems the signal going to the injectors is the problem, why would it just be on or off?

satch

iTrader: (1)

Read post #16 in the following link.

https://www.rx7club.com/showthread.p...s+don%27t+fire

Texas_Ace

iTrader: (18)

Interesting, i will try that.

There is a wire on my boost sensor spliced into 1 of the wires, it was just sitting on the side, i might try grounding that out and see what happens as well.

Texas_Ace

iTrader: (18)

Ok, that is REAL strange.

So i pulled vacume line and tried the LED test again, at first it did the same thing then all of the sudden it started flashing and the motor kept revving slightly. So hooked the connector back up and sure enough it was revving past 3800 for the first time.

Reconnected the vacume line and it still revved past 3800.

So the secondaires are firing now. BUT i still don't have any power over 3800, it sounds totally differnt once over 3800, now i am starting to think injectors. Timing is still all over the place but it doesn't make any sudden changes at 3800 so it has to be fuel. The question is too much or too little?

And is it the injectors or is it the ECU?

I guess i might just swap the injectors and find out, not looking forward to it but when all else fails.....

satch

iTrader: (1)

Looks like you're making headway though. Did you connect the wire (possibly additional ground) by the boost sensor? I don't really know the history of the car but did you just recently come across this car? If so maybe the secondaries haven't worked in a while and are being used for the first time in a while and are reacting as such.

Texas_Ace

iTrader: (18)

Yeah, i tried grounding that wire on the pressure sensor, it killed the car instantly, so not sure what it was there for but it doesn't help anything i know that! lol

Yeah, i got the car a few months ago but just got to work on it a few weeks ago due to weather. It has not been touched in over 5 years so i know everything is tired but the primaires are working fine?

I might try swapping the injectors and see what happens although i have this feeling nothing will change.

satch

iTrader: (1)

Do you know what the color of the wire in the boost sensor loom was tapped into? And I wouldn't connect a wire while the car was running if that is indeed what you did. Perhaps you could double check to see if it was the boost sensor ground and if so reground it again with the engine "off" and give it one more try. If I understand it right, your car is now able to get past the 3800 barrier?