Wow, that's some funky readings...Other than the wire/probe slowly falling out of the ECU pin position, I'd have to say you have extremely bad grounds, or the ECU is fried...You ARE on the secondaries, right, not the primaries' pins?

Edit- try it with the car running, not just with the key on...they should stay at a constant 14v or so, and not do anything until at least 3500-3800 rpms, like Hailers said...

 

the car i had this happen to had a high voltage at the battery while running (over 14volts)

 

14.4 volts is perfect, temperature conditions affect this figure though...

 

The first thing that comes to mind is * is he on the right wire???*. So, what wire are you on?? And what method are you using? Describe how you did this, please.

There are several ways to do it. One way is to access the ECU and backprobe one of the secondary injector wires. They are on the smallest of the three plugs. The pins are pins 3F for the rear secondary and 3H for the front secondary. The wire colors on a series four are LIGHT GREEN/RED and LIGHT GREEN/WHITE.

You don't disconnect any wires, just back probe the wire. Those wire colors are the same thru the 1991 series, but the series five pinouts are different. A series four should be the same as described above.

 

pretty sure over 14 is high for idle - even FD alts don't put that out. It's fine when the car revs though.

with the exact same car- ran wire directly from alt to battery. 12-13volt and solved the rpm block.

similar thing happened to me on another car

https://www.rx7club.com/showthread.p...hreadid=308611

still not sure why putting a seperate wire fixed that car but it did.........

 

Its been a couple of weeks since I/we (mrbob) checked this I will go back over it again when I get a chance. I have an ECU pin print out that I regularly reference. I was on the secondary injectors. The grounds are good in several places measured at the wire harness grounds and at the ECU. All readings went down to less than say... 0.4 some were 0.2. the deal with the readings is that when the key is on and the car is running we saw a constant voltage on one wire and a pulsing ground on the other wire. I don't know much about electronics so I was completely confused, but mrbob does and he was puzzled as well.

 

the wierd readings were at the injector clips, I forgot to mention....not at the grounds.

 

Okay...So, Friday I should take some probing pins and connect them to the EGI Unit wires for the Secondary Injectors and run the car while reading 14v and once they kick in it will drop? Or it will gradually lower and then jumpt back up? What is the normal flow? How would I know if they are not working?

 

All right, pull the carpet & everything out of your way, get to the ECU- reading out whatever we wish from the ECU accomplishes the entire electrical troubleshooting regimen in one stroke- you check sensors, power, and grounds (basically the entire circuit in question) in one fell swoop...On an S4, look at the far left plug on the ECU- it'll be the smallest one...Get apiece of safety wire, paper clip, whatever, and gently shove it in the bottom row of pins, 2nd one from the left (3rd one from the left will be the other one), and connect the positive meter probe to the wire (alligator clips come in handy here)...Connect the black (neg) meter lead to ground, any of the small studs around the ECU will work...Start the car...You should get about 14 volts, and it should be steady...Take the car for a spin (it's much easier to get results with a load on the engine, but if you just have to do it in the driveway, so be it)...Kick her in, and watch the meter (don't hit anything!)...At 3500, give or take, the meter should start falling in voltage (I got mine to fall to 6 to 7 volts without even romping full out)...As soon as you let of the throttle, the voltage should go back to the 14 (or so) level...Then try the other injector through the ECU also...


Sesshoumaru- 13 volts is kinda low for a charging voltage- the general consensus is 1.5v over the battery static voltage for a good charging system (or, at least 13.5v)...Your alternator should have the same voltage at idle, as at any other rpm...If it doesn't, the pulleys are not OEM, or the idle is too low, or the alt voltage regulator is on the fritz...

 

all right...Wayne's the man... I have got to try that... I gotta wait for the MM to come back to the house though. Its not really mine, though I should just go get a good one and attatch it to my hip

 

I have the same problem in my damn car. I swapped out a bad motor and put a good one in that i knew worked. Since then, i had a broken injector so it flooded, and now that i fixed that, there is a definite rev limitor at 3800 rpm. My car has been sitting for four months, and i don't think that has anything to do with it. i'd physcally take out the secondary fuel rail, and turn the car on, see if they're working. Worked for me, i'm not getting anything from them and i don't know why. car runs like hell too, i can barely get up a small incline in first.

 

well my fuel filter is new but it has been on two different cars, both had the original fuel filter on them and VERY old gas in them. I am gonna change it and check the ECU connections again. If that stuff doesn't work, I am going Holley. I hate that EFI intake anyway, remindes me too much of some damn 5.0 Ford! Carby prolly sounds better at WOT. If paying a couple hundred more in gas is the worst thing that happens this year then I'm in great shape.