Zeroto300

So first off, 87 GXL N/A
What works:
Fuel Pump - does not prime on initial key to ON (haven't gotten a solid answer on whether or not this is supposed to happen, but my guess is it should, unless it just doesn't on this car). Pump while and after cranking, pump also runs when jumping the fuel check connector (Yellow connector on Emissions harness) Key ON, Pump also runs when AFM plate is opened again Key ON.
Spark - Have check leading coils and they spark no issue
Injectors (But only manually) - at no point have the injectors sprayed fuel into the engine while cranking (so no it's not flooded). By manually grounding each injector at the ECU pin I can hear each injector fire, also after doing so I can smell gas from the plug holes and if cranked the engine does sputter from fuel being in the housings.
Circuit Opening Relay - relay tested good, have done multiple checks for continuity and voltage and check out with FSM
AFM - tests within FSM specs
Fuel system flow - fuel is pumped through the entire fuel system, return line into a container jumped fuel check connector and fuel gets pumped into the container – ALSO NO FUEL LEAKS ANYWHERE
Main Relay
Fuses

Issues -
Injectors - again injectors only spray fuel when manually grounded from ECU pin
Rushing noise coming from engine bay that sounds like fuel is flowing freely through the system, this is in combination with the fuel pump running
Fuel pump runs constantly - have to turn key OFF in order to for pump to shut off
Will not start - obviously cause there is no fuel in the engine

Tests performed -
Fuel pressure test - used loaner tool tester and placed in line pre-filter, gauge read 0, so I took the return line off and plugged it and ran the fuel pump again, still read 0, not sure exactly what the deal with that was but when the return line was plugged the fuel pump did stop running as the pressure in the fuel system was enough to shut it off.
So many multimeter tests - Injectors tested good, fuel pump tested good, AFM tested good, Injector circuit tested good.
CAS - continuity tests between it and ECU, also continuity tests between pins on CAS, Ohms were within spec with FSM
Main Relay - power two prong and test continuity on 4 plug
Fuses - Engine bay fuses and under dash fuses good

New parts -
Fuel pump - Aeromotive Stealth 340- PN 11542
New FPR - OEM quality
Two ECUs - not new but original one and a "known working one”
PD Elimination Banjo Bolt – old one was broken and a 12-dollar banjo bolt is a better option than the 150 dollar pulsation dampener on the S4s

So fuel pump circuit is working, I can activate the fuel pump in multiple ways all that are known ways to do it, however it never shuts off, I believe that is directly related to the fuel pressure in the system. Video is a recording of this sound. A couple of questions though I guess to start this off.
Should the fuel pump prime the fuel system upon IGN ON signal? Again I haven’t been able to nail down this answer on an FC yet. My general rule is yes it should.

If I have fuel flowing through the entire system, because the fuel pump is doing what it’s supposed to be doing, why can’t I build fuel pressure? Are both my original and this new OEM FPR busted? I just don’t get it, unless that tester I used was completed busted, or it has to do with this rushing sound I’m hearing from the engine bay.

If I have spark does that mean I can rule out the CAS? Knowing that the CAS tested as it should, stated in the FSM, and I have continuity between it and the ECU, could it just not be good, or maybe misaligned (I haven’t touched it yet, just tested pins)?

So, all I can tell is that the ECU is not grounding the injectors correctly, I can manually fire each injector and listen to them all fire, I can then smell the fuel inside the housing and the engine attempts to fire when cranking. This tells me my injectors are good, but they just aren’t being told to fire. This has been tested with two ECUs, still possible neither of them works, but I’d like to think it’s something other than that. Is low fuel pressure (that’s what I can only assume for now since the tester showed nothing and this rushing noise makes me think it’s not pressurizing the system, along with the pump never shutting off) something that can make injectors not fire?

Seems to me that even if I had to manually run the pump constantly during cranking to ensure fuel was there at the injectors in the rails, and even if I had really low fuel pressure, this would NOT keep the injectors from firing. So, I feel like my main issue for the car not starting is the ECU is not sending the ground signal to the injectors to send fuel into the engine. But is that because of a bad signal to the ECU or a bad ECU? Does anyone have a sure-fire way of figuring out if a CAS has crapped out? Anyone know what that signal should look like coming into the ECU?

Eight months of restoring and this is what I’m stuck on, I just want to hear the car run for the first time, let alone be able to drive it for the first time.

Well thanks in advance for anyone brave enough to make it through this whole post.
Hopefully this triggers a thought in someone’s head and comes up with something I can try.

Brandon

Rotary Alkymist

Ok. Do you still have a fuel pressure tester? If you don't go buy one, you need it ... forever.

The pump should turn on when you crank the car. Pump will not be on in the ON position... unless it's already started of course.

Are you sure your injectors aren't firing? A way to check is, in a quiet setting, turn the engine with key in the ON position. Do you hear them clicking as you turn the engine(by hand)? Post results.

Your pump is probably stronger than stock... the fpr being stock and non-adjustable has left you with improper fuel pressure for certain. You need to buy an aftermarket fuel pressure regulator(you have no choice) if you want to run that pump properly. You'll also have to upgrade/replace your secondary fuel rail. Otherwise you'll be running rich as hell man. It should still start though.

Rotary Alkymist

Also to do a proper line pressure test input your pressure tester in between pulsation damper(bango fitting) and fuel filter. Post results.

Zeroto300

Alright so good to hear about the pump not priming with just Key ON and nothing else, seems as though my pump and circuit is working properly then, it just won't shut off once it kicks on, from cranking, jump check connector or opening AFM plate.

So i did run a pressure test, inline right before fuel filter, I did rent one though just to do a quick test to try and rule something out but it left me with more questions unfortunately. But again even with the return line plugged the tester showed 0 PSI in all of my tests.

I have not done a test where with Key ON I turn the engine over by hand. But in no situation other than manually grounded the injectors myself with Key ON is there any evidence that fuel was actually in the engine. I also have not tried using a can of starter fluid to see if it will actually run but i'm to the point where I'm almost certain it would.

I did wonder about how strong that pump was compared to stock but didn't think it would cause that much bleed off through the FPR (if that's what is actually happening). With proper fuel pressure should i need to do that with the secondary fuel rail?

I'll do another pressure test after the filter and see if anything changes, going to probably buy one cause like you said, i should have one, haha. I just want to see what it actually is cause i got nothing the first time around. I'll see if the hand cranking with Key ON produces anything new.

Thanks for the replies,

Brandon

lduley

iTrader: (1)

when you check for fuel pressure you NEED to jump the fuel pump test plug thats by the air pump, IIRC should be yellow (or green) with only 2 plugs, check the FSM on foxed.ca to see exactly what it is

Rotary Alkymist

Iduley speaks truth, I forgot to mention jumping yellow connector for test.

To help you better we need line fuel pressure. We also need to know if you hear clicking with key ON and turned my hand. We can't move forward until you post results of these two tests.

Edit: I forgot you are s4.. is the fpr not removable? you might be able to salvage your secondary fuel rail then... I had to change rail because rail and fpr are integrated on s5. One less thing to buy for you. Sorry for the mix-up.

Zeroto300

The fuel pressure test was performed by jumping the yellow connector (passenger front strut tower area), same process as i do in the video, however this test resulted in tester showing 0 PSI, will definitely need to rerun test in order to get actual pressure in the fuel system. When turned by hand with Key ON there are no audible clicks in the engine bay/fuel rail area.

Yes removable FPR on the S4s, was wondering if it had something to do with the design of the secondary fuel rail, did not realize they were integrated much like the Pulsation Damper on the primary rails on the S5s, but removable on the S4s.

Brandon

smikels

Hmm I would unplug the hose above the fuel filter and see if you get fuel... If you do just move down the line.

I thought I had a fuel problem once. I puled the line and received fuel. Then I pulled primary injectors and saw if I seen fuel. I just jumpered the connector and unjumpered once I saw there was fuel.

Never needed a FPR as I have an aftermarket ECU that I can control the fuel levels.

Rotary Alkymist

No clicks... I would run a wire for the Neg post and test for continuity of all grounds at the ECU. You're searching for resistance. Hopefully you find it because that's an easy and cheap fix! Your ground under the UIM might need to be cleaned up. Check the ground running to the firewall on the passenger side as well.

Also check for continuity of wires at CAS to make sure that you have no resistance there. I would start with testing all grounds for continuity.

Zeroto300

Update:

Ran more tests on the ECU today, used the Pin out test from the FSM and here are some inconsistencies that I found. All tests were performed with KeyON and ECU plugged in.
1) Pin 1K (Shift indicator light) has 12V on Ignition switch ON, should have below 1.5V when Ignition switch ON and 12V when at Idle
2) Pin 1W (Heat hazard switch) - under the passenger seat for exhaust heat warning - has 12V on Ignition switch ON, should have below 1.5V when Ignition switch ON and 12V when at Idle
3) Pin 3B (Starter Switch) - when cranking does not have 10V, stays around 1.5V which should be at Ignition switch ON and at Idle
4) My entire Plug #3 (smallest ECU plug, houses wires for Injectors) has continuity to ground on every pin except Pin3J (Battery). Pins 3A and 3G are ground wires so that's good but I'm wondering if they all should be grounded. I know it's a pain to ask but if anyone would be willing to possibly test this on a working car and post which pins do and do not have continuity that would be a massive help.

All ECU pins that are for CAS were within spec for Ignition switch ON, this leads me to believe the CAS is working as it should and it's somewhere in between, possibly grounded a circuit where it shouldn't have been but I just don't know for sure.

Brandon

Rotary Alkymist

You shouldn't have ground on all pins. Pins 3C and 3E should read battery voltage with key ON. Those are your primaries for rear and front respectively. If you don't have voltage there then you're getting closer to finding the issue. 3A and 3G are the only ground wires on the connector. How are you testing for ground? Sorry to ask... just for them to all be grounded means there is a melted mess of wires somewhere and it's grounded to the body or to a ground wire or your ECU is fried.

3I should also have battery voltage with key ON... this wire runs from your main relay.

Sorry if you've read this and I've changed it. I wrote some incorrect advice. These wires should be tested with connector in.

Rotary Alkymist

Just had an idea... plug everything back up. Check B/W wire at main relay for 12V with key ON. Should be 12V. Then check 3I for 12v at the ECU and post results.

Zeroto300

So, it would seem as I did not have KeyON in my previous plug #3 continuity test, reran test -
Pin 3A (Ground) has continuity with negative battery post – 17 ohms
Pin 3D (Inhibitor Switch) has continuity with negative battery post – 17 ohms (car is 5 speed M/T)
Pin 3G (Ground) has continuity with negative battery post – 178 ohms
All other pins tested no continuity with negative battery post

3I and main relay both have 12V with KeyON; all Injector pins (3C, 3E, 3F, 3G) have 12V with KeyON as well. Multimeter from negative battery post to pin on ECU plug (while plugged in). Funny enough I thought B/W was my issue and started tracing it through the entire car, it has 12V everywhere I could test it (fuse block, main relay, ECU, starter, ignition switch, starter cut relay, check connector, fuel pump relay, etc.)

Brandon

Rotary Alkymist

That's good. Up to now your ECU seems good.

3G has high resistance for a ground(too high). Anything above 25 ohms on a ground is too high(generally).
3A seems OK.
I want you to try something. Run a wire from negative post to ECU and backprobe 3G . Maybe you could alligator clip a paperclip and backprobe the pin. Try and start your car. Post results.

(A continuity test can be done without the connector plugged in... the reason it has to be connected for voltage readings is because they are all outputs.)

Zeroto300

So, running a wire from the negative post straight to the back of Pin 3G, best I could get the resistance dropped to was 75 ohms with KeyON, but still no fuel, no start.
Going to start tracing that wire through the harnesses and see if I can find an issue with it. Weird that even with a jumped line from negative post it would still read that high.

Brandon

Rotary Alkymist

Damn I thought that was gonna work.

Yeah, that sounds high. Are you reading high when checking ground between engine and battery post? Should be very little resistance... basically none. Maybe your main ground is dirty(driver's side strut tower(ish)).

3G runs to the main ECU ground which is located under the UIM. Ground 24 in FSM. Unfortunately it sounds like yours is dirty or definitely worth checking out but start with the easy stuff -main grounds. It might be affecting the ECU ground -meaning that if you don't address the mains then cleaning the ecu ground alone might not fix anything. All grounds should be cleaned and tested to be certain so you can move on with confidence.

I'd clean main ground on or below strut tower, I forget, and starter and ECU ground under UIM. All your grounds should be less than an ohm..basically zero resistance. Even 17 ohms is high enough to suspect a dirty ground or a corroded ground wire.

Zeroto300

So after taking apart and cleaning the 3 grounds in the engine bay
1) Bell housing to firewall on passenger side
2) Emissions harness to rear rotor housing
3) Starter bell housing bolt to shock tower - this is a wire I installed as part of the battery relocation that was done (using all 2AWG wire for battery), so all power/ground wires are run custom, following the setup on the FC3SPro.com page about battery relocation. Negative battery terminal to clean ground in the rear seats tray, and cable from long/top starter bolt on bell housing to shock tower bolt on driver side

When checking continuity between the wires and their respective grounding point both bell-housing to chassis grounds showed ~0 Ohms resistance. However, on the Emissions harness to rear rotor housing there was a resistance of 2.535K Ohms between them. Will start checking down the emissions harness for where the resistance to negative post starts to ramp up.

Also, and I feel bad for not putting this in my first post, but I did do a complete emissions removal on the car, following the procedures on the rotaryresurrection.com page. Not sure if that puts me into a different scenario when it comes to the issue I am currently having but figured it should be mentioned.

Brandon

Rotary Alkymist

Sounds like you're on the right track man. I wouldn't worry about emissions delete although I haven't had much experience as my emissions system is intact.

I just want to confirm a couple of things:

1. You have checked for resistance between Neg post and engine and have you have zero resistance.
2. You have checked for resistance between Neg post and body and you have zero resistance.
3. When you tested the UIM ground wire for resistance it was not connected on either side(hopefully).

If these are all true then inspect both terminals on 3g wire... is it green in behind either terminal? I say this because it's usually where the resistance occurs due to corrosion and the problem isn't usually in the harness. Try testing for resistance between a terminal and its backside.... you might find that the problem is in your hands ... literally lol. Then you could just cut the terminals and cut back a bit and get some nice shiny copper and crimp some new terminals on.

Edit: When probing backside be sure not to probe the terminal itself but to probe the wire. I'd also like to say you're a ******* animal man... bet you can't wait to hear this pos start!

Zeroto300

That is correct, 0 ohms of resistance between negative post and both engine and body.

As far as the UIM ground terminal test it was still plugged into the ECU when it had 2.535K Ohms of resistance to the rear rotor housing. However, when unhooked from rear rotor housing and from the ECU it has no continuity with the negative post, (so I unplugged both Plug #2 and Plug #3 from the ECU and went from UIM ground terminal to negative post). When just the ground terminal is hooked back up to the rear rotor housing and not to the ECU, there is continuity between it and the negative post with a resistance 0 ohms.

So, it’s green only on the UIM ground terminal, but I checked resistance from ground terminal to Pin 3G on the ECU Plug #3 and it’s 0 ohms. I also check with ground terminal attached and ECU unplugged, and it reads 0 ohms to negative post from Pin 3G.

And here’s why I get so frustrated with electrical issues, so after I cleaned the grounds and did those tests I back probed Pin 3G with line straight from negative terminal as you suggested doing earlier, tried starting the car, no go. However, it started to make some more noise like it was trying to start. So floored gas pedal and tried cranking again, well this time it started to pop and what not. Then took the back probe out and tried those same two steps again, gas pedal up and then down, same result as with the back-probe in. Now when I check resistance at Pins 3G and 3A, they both read less than 5 ohms of resistance, not a stable value though, they bounce but never go above 5 ohms. 3G more unstable than 3A.

I’d love to hear this thing run, means everything I’ve done over the past 8 months hasn’t been a waste of my time and money, but until then I have nothing to show for my hard work.

Brandon

smikels

Zero... Have you checked to see if you are getting any voltage at the fuel pump? If not maybe a fuel pump rewire would be a possible fix. I did this just to make sure I was getting enough fuel since the old wiring does not put out a full 12v. Just want to see you get some where with this.

Rotary Alkymist

Ok. So you're engine is grounded, your body is grounded. We still have to get 3G figured out.

Do these steps:

1.Disconnect 3g connector at ECU.
2.Disconnect ground wire from UIM.
3. Take one lead and clip it to the now loose ground wire at UIM and take other lead and stick it in 3g at connector. You might need to run a wire to make this possible. Note the resistance.
4. Take one lead and clip to loose ground wire at UIM and take other lead and stick it hard into the wire about three inches down from the terminal(that the other lead is clipped to) making sure to puncture through insulation. Note resistance.
5.Take one lead and clip it to a paperclip and shove the paperclip into 3G. Then take your other lead and stick it hard into the wire about three inches down making sure you go through the insulation. Note resistance.

Post all three resistance values. The last two tests are testing for resistance between the terminal and the wire. If you follow these instructions perfectly you should be able to deduce it to a bad wire or a corroded terminal... or possibly two corroded terminals. These tests will give you the answer guaranteed.

Edit: A sewing needle works well to puncture a wire, then you can just clip an alligator clip to it or just hold the lead on the needle.

Also, this could be important... now that you're playing with the effected wire you may be experiencing intermittency. When testing you should be doing a wiggle test. Bend and play with the wire when you're testing. There were many times where I would do a wiggle test and the problem shows itself instantly on the meter spiking way out of range. If you're good with your hands hold your lead and bend the wire at the terminal while keeping an eye on the meter and look for spikes.

And finally if you do see green I would buy another terminal, cut the wire back and crimp a shiny new terminal on there. Green is bad and terminals are cheap as hell.

Zeroto300

So a couple of updates with this,
Got myself a fuel pressure tester, as I stated the first test kept showing 0, no idea why, but this tester placed before primary fuel rail shows a PSI with the pump running off of check connector at ~44PSI, after the power is cut the pressure drops to ~35PSI, after about 2 minutes the pressure bled off to~29PSI.

For some reason after messing with it last night (was testing spark) my clock come on, this has never lit up before, and has since gone away. Not sure if that's related to a grounding issue or what but it was awesome to see it pop on and then sad to see it go away. Might also be internal on the warning light piece, I don't really know.

Edit: I also removed the CAS and inspected everything I could with it out, installed the CAS as stated in the FSM, yellow mark to needle and line dimple with tab on shaft, install. It was far off the spot where it was, thinking that was from factory alignment cause it looked like it had never been touched before. But everything was lined up as it should have been.

I did the test as you stated but the initial test (step 3 in your post Rotary Alkymist) showed a resistance of 0.0-0.1 ohms (disconnected from ECU and disconnect ground wire from UIM). However with the ECU still unplugged I tested the resistance from the disconnected ground from UIM and the engine, this gave me a resistance of 19.20K ohms. This to me seems really bad, seeing as how this is the ground for the ECU and when unplugged from both end it has resistance to the engine, where else does the emissions harness ground to the body/engine? Or should it? I know the FSM wiring diagram only has one ground listed but it could be grounded through another connection with another harness, I don't know if this is the case or if this grounding circuit is a 'closed loop' circuit just within the Emissions harness.

Might not have used the exact right words but I think you can understand what i'm getting at.

Brandon

Zeroto300

Okay so that disconnected ground from UIM is also being grounded through the ECU at Plug #2, this I believe done through both Pins 2C and 2R. However when doing the same test as with ground terminal and 3G with 2C and 2R, these are the results I get.

Disconnected Plug #2 from ECU Pin 2R and disconnected ground terminal from UIM - Continuity with a resistance of 0.0-0.1 Ohms, same as what shows with 3G
Disconnected Plug #2 from ECU Pin 2C and disconnected ground terminal from UIM - No Continuity

So then I reconnected the ground terminal from UIM and tested resistance between Pins 2R and 2C and the negative post, again unplugged from ECU.

Disconnected Plug #2 from ECU Pin 2R and negative post - Continuity with a resistance of 0.0-0.1 Ohms
Disconnected Plug #2 from ECU Pin 2C and negative post - Continuity with a resistance of 2.234M Ohms

Don't quite think that is what it should be.

Brandon

smikels

Zero have you looked around at any other threads for this issue? I am posting a link below. Take some time and see if this provides any insight. I looked at it and some good information in there it looks like. My clock does the same thing it fades in and out. Not sure what to tell you there. Maybe a fix for it, but doesn't bother me that much. It won't cause you any issues though. As far as your CAS goes as long as you are getting spark which you said you did then I wouldn't think there is a problem there right yet. I would focus on what the ECU is supposed to do when injectors are firing. Are you getting the voltage at the ECU and grounds required.? If so then do you get that under the hood. The thread I linked had that information in it from what I could see. If I am way off base I apologize. But I think you should focus on pins 3C, 3E, 3F, 3H.

https://www.rx7club.com/2nd-generati...r-help-484220/

WayneBrady

iTrader: (4)

did you adjust the idle using the throttle stop screw? this needs to be done after the rotary resurrection emissions delete or else your car wont start and idle.