Rotary Alkymist

Damn. This is pissing me off lol. Let's recap.

1.Main ground to body is good.
2. Main ground to engine is good.
2. UIM ground is "apparently" good.

Don't worry about testing pins right now. Your grounds need all of your attention. Nothing else needs to be worked on right now. Your fuel pressure is a tad high though but that's not applicable right now.

Question
Did you wiggle or get someone to wiggle and bend the terminal at the UIM while testing?
Do you have the ground at the ECU grounded to a 10mm bolt? Could be why you see resistance.

Something to try:

Hook everything up.
Take CAS out.
Turn key on.
Turn the gear on the CAS.

Do you hear those injectors doing their thing?

Edit: There is a ground cluster underneath the trailing coil. It's a white plug. Not sure if it'll help and I'm really not sure if it has anything to do with the clock but that ground connector is connected to a lot of stuff in the dash.

Rotary Alkymist

smikels mentioned the voltage at the fuel pump. Have you checked it?

Zeroto300

So I ended up taking the Emissions harness back out of the car and tore into it again (had to dig into every wiring harness when I took the car down to bare chassis to rebuild, mice ate threw a bunch of wires in the engine bay/front). Found some irregular resistances between certain connectors, did find the high resistance though, it's between Pin 2D and the O2 sensor plug, but this is a shielded wire so this doesn't worry me. Not back in the car yet so I haven't rechecked 2C and negative post where it previously showed 2.234M Ohms.

Smikels - I checked that thread out but nothing stood out to me that I haven't checked already or looked into. On the S4 86-87.5 (manufacture date 09/86) I have the resistor pack and it tests correctly and low-impedance test correctly as well. As well as the manual ground works where as he didn't have a connection because of the combination of harness and engine/car of different series.

WayneBrady - This I have not done but I wouldn't think the throttle stop screw would keep the injectors from firing, I have no fuel what so ever getting into the engine, from what I know the S4 doesn't have the throttle fuel cut on start like the S5 does.

Rotary Alkymist - When I took the CAS out I did not spin it to check injectors, read about that after I put it back in. Also Pump has power, The one thing I haven't tried is push starting it, but don't honestly think it'd be a good test cause don't think that would kick the injectors on.

A thought - so anytime I have the CPU flasher board hooked up, and supply power to the car (have circuit breakers installed with battery relocation) the hazards are on constantly (thread on here for that as well). Hazard switch works properly (tested multiple times), but for some reason the hazards are on constantly if that CPU flasher board is powered, this is even with a brand new CPU flasher board from MazdaTrix. All electronics in the car work except two things - CPU flasher board and fuel injectors, any chance these could be connected to each other? Note my car does not have the anti-theft system, don't even have the connector for it. It is a GXL so it has power everything but no anti theft and no door speakers. Did come with the double din cassette player though. Just a long shot but thought i'd offer up the information in case something could be happening with the whole thing.

Brandon

WayneBrady

iTrader: (4)

if your throttle sensor is closed then it wont inject fuel. if youve done the RR emissions delete, including throttle body mod, then the tps will be closed. no thermowax to hold it open.

thats why you have to adjust the throttle stop position.

Zeroto300

Ah gotcha WayneBrady, thanks for suggesting that, so I adjusted the primary throttle body valve to be just slightly open (it was set to where it was completely closed), all I saw from RR Emisison removal was bump up idle with locknut and screw on the TOP of the throttle body so this is what I thought you were talking about. Didn't realize there was another adjustment screw for both primary and secondary throttle valves. Going to be putting the harness and UIM back on the car this evening. Will see if anything changes, i'll update later on.

Brandon

WayneBrady

iTrader: (4)

right on, good lucj man. also its possible your flooded now if you pushed the pedal while cranking. you may have to deflood too.

ill post a pic of the adjustment point im talking about when i get home, so theres no confusion.

Zeroto300

GOOD NEWS!!!

Alright so with everything back in the car with the changes that were made both to the harness and the throttle body the injectors are now firing when I turn the CAS by hand, however it's still not starting, getting seldom backfires and very loud (gunshot like) pops, but no evidence it's trying to start. Also not sure how a rotary should sound when trying to start, I'm getting a very smooth sound from the starter, then out of nowhere a pop/backfire, tach needle bounces during cranking. But there's nothing that sounds to me like it's attempting to compress/ignite the fuel/air mixture within the housing. Or is this my lack of familiarity with rotaries?

Brandon

Zeroto300

So kept testing cause it seemed odd to me that they worked so well, so for some reason the injectors will only fire if the CAS is out of the engine. So if I take the CAS out and turn the gear by hand they fire, if I put it back into the hole and turn the engine over by hand via the pulley they don't fire. This would explain why it still sounds like the engine isn't trying to fire, but what in the world is causing this to happen, I even tried grounding the CAS to the engine and turning but that didn't change anything, as long as the CAS is out of the car the injector fire.

Brandon

Rotary Alkymist

That's great man. Baby steps haha. Are you sure, like absolutely sure that they're not firing when turned by hand? The fact that you're backfiring tells me that they are working otherwise you wouldn't/couldn't backfire.

If the injectors indeed only fire with CAS out then I would take a close look at those wires(CAS) as well as it would be the only thing that would cause that.

Also, I feel like you're not timed. If you could do this:

1. Turn crank until yellow is lined up. Make sure you're pin is square(they tend to get hit and bent) with the front cover.
2. Remove blind cap from CAS.
3. Take a photo of the position of the points inside the CAS.

I always install my CAS with blind cap off... that way you will see if it turns away from the desired position.

Zeroto300

Yeah no kidding, the smallest of victories.

There's a noticeable tick when the CAS is turned by hand but I can't hear anything when installed and turning the crank by hand. It sounds so crazy but that's honestly what's happening. No matter how many times I install and take back out I can always hear the injectors firing when turning CAS by hand and never with it installed. I started messing with the wires while it was in my hand but never had an issue firing the injectors. I simply just don't get it, and the FSM is so light on the subject of the CAS, the pins test correctly between 110-220 ohms. I know a common place for failure is where it comes through the rubber grommet on the CAS but all wires are good from CAS to the connector.

I'm even twisting the CAS around while spinning the gear to see if maybe it's something internal but injectors will always fire as long as it's out of the engine.

That's exactly how I've been reinstalling the CAS before attempting to start, that's why I stated it was so far off of the original pin cause with the blind cap off I turned the CAS to line the gear back up with the mark I made.

Brandon

Zeroto300

Video of said issue, hard/impossible to see but yes the CAS spins as I rotate the engine by hand.

Brandon

smikels

Zero,

Here is a post from another thread by "bumpstart". Also there are lots of threads out there on google when I typed in "rx7 injectors will not fire" These might help out. I read some of a few of them and all had good information. This was just the first one I looked at. This one talks about if it fires with CAS out and CAS in and possible solutions.

to the OP.. try the spin CAS trick.. it will register as crnk unless the motor goes past 400 rpms
but,, it should make the injectors click..
if they do,, but dont with the CAS in its hole,, then one of the cas wires has an earth fault
if they dont ( with cas out or in ) then maybe broken continuity of the cas wires
,, or burned drivers ( rule that out as yours passes test mode )

https://www.rx7club.com/microtech-11...nking-1009787/

Zeroto300

So at first I thought maybe it was because the CAS wasn't grounded in my hand and that's why the injectors fired, but i held the CAS to the engine and body many times and even in the video it's just off the gear and still grounded to the engine when I spin it by hand.

Testing the continuity this is what I got -

CAS installed in engine but unplugged -
Power cut to car - all four pins no continuity with ground
Power to car - all four pins no continuity with ground
KeyON - all four pins no continuity with ground

CAS Connector, unplugged from CAS -
Unplugged from ECU also - all four pins no continuity with ground
Plugged into ECU but no power to car - Pins R,G - continuity with ground and 3.5k Ohms of resistance, Pins W,W/B - continuity with ground and .444k Ohms of resistance
Plugged into ECU power to car - Pins R,G - continuity with ground and 3.5k Ohms of resistance, Pins W,W/B - continuity with ground and .444k Ohms of resistance
Plugged into ECU and KeyOn - all four pins read continuity and 16.36M Ohms resistance with ground

Brandon

Rotary Alkymist

Damn you're car is cursed haha. Those damn mice have no respect.

Have you checked the continuity of harness wires, that lead to N,P,Q,T? I mean from end to end with connectors unplugged. That would be the engine loom. You might find an issue there. Should be zero resistance.
Have you checked for voltage with key ON at those pins with everything plugged in? Should all read below 1V.

EDIT: Checking for continuity with ground on those wires with CAS and ECU unplugged... might get lucky there.

Rotary Alkymist

Also the injectors won't click until you do a full revolution.
Have you tried turning it by hand and watch the timing mark go by twice? Might have luck there too. Cuz' in the video I'm not sure you're turning it enough.

Zeroto300

Continuity between Connector at the CAS and the Connector at the ECU are good and read 0.0-0.2 Ohms of resistance on each of the four wires (unplugged at both ends). With everything hooked up and KeyOn I get 0.7V at each Pin on ECU Plug #1.
Also tested with the Engine/Front Harness unplugged and tested each of those end to end, but still good readings on all four wires.

I tried again and spun the engine by hand for a good 30-40 seconds but never heard the injectors.

The only thing that is different from when the CAS is installed and when it's not is continuity with ground on the gear part itself, but I can duplicate that just by holding the CAS to a grounding point but still fires the injectors no problem. Is there a gasket/grommet that goes between the CAS and the engine (not the o-ring but where the CAS lip sits on the lip of the hole)? I cleaned the mating surfaces just in case.

If the wires run straight through from the CAS to the ECU, and they have no continuity with a ground outside of through the ECU itself, and not being grounded through the CAS even when installed, then it seems more likely that it'd be a mechanical failure of the gear mechanism somehow. All the wiring tests show that they are working properly and the CAS will fire the injectors but something about being dropped in and having the gears mesh together stops that from happening. But the CAS would absolutely be grounded when installed, but if the CAS was bad then it shouldn't fire the injectors when out of the engine, and the ECU doesn't seem to be at fault cause again it's firing the injectors. I simply just can't wrap my head around this issue: wiring checks out, CAS checks out, ECU checks out.

Brandon

Rotary Alkymist

Ok. Sorry if you answered this but there is a ground on the ECU side of the EM harness. It is supposed to ground the ECU itself and is located on one of the 10mm bolts of the ecu or bracket, forget which. Is that connected? I mean, is there a ground wire connected to the ECU case?

I'm running out of ideas. Maybe there is a problem with the shielding for the CAS wires. Hard to say.

Are you getting 4-5 volts on pin 2A? No voltage here is bad.

Just had a vision. You said 2C is showing major resistance. This is telling me that your ECU isn't grounded. I'm beginning to think that your ECU is messed up somehow. Hard to say with no car in front of me. If you don't see a ground wire running from your ECU case then you need to add one. Run it off of 3G.

EDIT: Sorry I noticed you tested 2C disconnected and that would be a normal reading. Is it showing 0V/continuity with ground?

Rotary Alkymist

It would be nice to know if your ECU is splitting out error codes.

Zeroto300

I have no wires on the EM harness that is a single terminal anywhere close to the ECU, it goes: ECU Plug #2, ECU Plug #3, Boost Sensor connector, front harness connector #1 and front harness connector #2 (both are a dark yellowish/orange color), after that there's nothing until after the firewall grommet for the wiper motor. So I've seen a bunch of posts about adding an addition ground wire right at the ECU(some say to negative post, some say ECU bracket) but from what I've seen this is to correct/fix the 3800 RPM hesitation, I'll do this tomorrow off of 3G and see if that happens to change something. And it definitely wasn't there when I took the car apart, I mean I've had that harness apart multiple times and have never seen a ground terminal anywhere near the ECU plugs.

2A was right at 5.0V.

So 2C, at least on my car, is a Br/B wire, not B as shown in the FSM, my 2D is B though, and it's tied into the ground system for the shielded wire for the O2 sensor. And when I completely tore into the EM harness 2C was the wire I concentrated on cause of the high resistance to ground, I redid all of the splits and tested each segment of wire before and after reassembling the wire with new solder joints and then again when fully put back together. This one wire splits into 8 or 9, it was a lot, different connectors, 2 at the AFM, so I made sure I fully tested it before wrapping the entire thing back up. But with KeyON 2C still has 133Ohms of resistance to negative post, and 0V.

I'll start with the extra ground to the bracket tomorrow off of 3G. I'll get the update on here ASAP, if that doesn't do anything would it be wise to also splice in 2C to this new ground or is that not something that should be done?

Brandon

Rotary Alkymist

Ok. So, I think I'm getting mixed up with gens. Its seems s4 doesn't have that ground by the ECU. Also I've read of wire color having indiscepancies especially is early 2nd gen.

I forgot to mention to test 2C with it plugged in and key ON. I'm unsure if the ECU grounds everything after key is ON or if it's always grounded but FSM says to have key ON.

2C should have continuity with ground, with 2C plugged in. Check a ground at any sensor, boost sensor is easy to get to. I imagine that you might be having ground issues with all of your sensors because ALL sensor grounds travel to 2C. Again have the connector plugged in for all tests on 2C. Then again, I'm not sure if you tested 2C in this manner yet, it could be working properly.

Edit: I'm not sure if running a wire to 2C will help because the ECU should be grounding that wire. I'm beginning to suspect that 2C needs to be soldered. Won't know until you test with key ON. If you don't have ground with key ON plugged in then you have a broken solder my friend. The pin itself is the ground.

2C and any ground from any sensor should have continuity with ground with 2C plugged in. The one thing you need to have hooked up is the UIM ground otherwise everything will read open... I think.

Anxious to hear what you find.... I feel like we're getting close dude.

Rotary Alkymist

Even if the CAS issue is unrelated it's important to "know" that 2C is working properly. Bad grounds cause really weird **** to happen... something like a CAS not working when stabbed... it's freaking me out lol.

TonyD89

iTrader: (10)

Wrong thread.

Zeroto300

So 2C has continuity and 0 ohms of resistance between all connectors, when totally unplugged.

With KeyOn -
ECU plugged in - 2C and all connectors with the same Br/B wire shown continuity with ground and have a resistance of ~130 Ohms
ECU unplugged - 2C and all connectors with the same BR/B wire shown no continuity with ground
It's only being grounded internally by the ECU

I added the extra ground to 3G and some numbers changed around, with KeyON -
ECU plugged in - same result as before but a lower resistance of ~78 ohms
ECU unplugged - same result as before

Now what's interesting is that 2C when unplugged from the ECU used to have continuity with the ground and now it doesn't however this hasn't changed how the injectors are behaving. While testing the CAS I've been trying to duplicate what happens when it's fully installed in the engine and all I can think of is pressure being put on the gear, so if I put pressure on the gear (like a side force to the gear) then I get less activity from the injectors when I spin the CAS gear by hand, I feel like maybe the CAS gear shaft is not balanced or secured properly inside the housing and when pressure is applied to it it just stops working, when it goes all the way down and meshes with the main gear it's gotta see some sort of pressure to get them to interlock with one another.. Other than that the only difference is the CAS is grounded, and I can simply hold it against the engine/body and ground it out but it still works properly. I tried grabbing both ends of the CAS gear shaft and seeing if it maybe was loose or not together but it didn't feel broken internally.


I want to believe it's my wiring but I've done every test in the FSM and all have proven to be within spec, at least now at this point in time. To answer your question about error codes I haven't built that light tester deal yet so I don't know if it's actually throwing codes, but as far as lights on the dash/warning cluster goes I got nothing besides the brake light to say my Parking Brake is engaged. I also don't get any lights to cycle on the dash at any point either, and if my CPU boards are plugged in i get hazards on all the time and my "key left in ignition with door open" beep will go off anytime the key is in the ignition even when turned to ACC or ON.

Brandon

Rotary Alkymist

Yeah, I still believe it's the wiring somehow. I mean, the CAS is so robust, they seem indestructible. It would be nice to get another just to see if the problem goes away. Do you have a fellow rotor head in the area that could help you out as far as ECU or CAS?

That little diode circuit is so simple to make man and super cheap. It's one of the best tools to have, I always have it in the glove compartment and even plan on installing it in the dash with a toggle on the ground.

Zeroto300

Made the ECU error code tester, check both ECUs but nothing happened after the initial 3 seconds when you first turn the KeyON. That's the setup for the test right; install into 6 pin green connector, joined anode to ABR and separate cathode to DCC1 and DCC2 and just turn KeyON?

I unfortunately don't know anyone here in the East Valley/Phoenix area with an FC. Tempted to get a new CAS from Atkins.

Brandon