KhanArtisT

iTrader: (2)

You can use that method as well but I believe the voltage with the injectors firing should be 8v or so (?). I personally prefer grounding it because its a simpler test.

By ground repeatedly I mean ground the injector simulating a duty cycle. If you ground it for more than 3 seconds (?) it can overheat the coil inside the injector.

Amur_

3W - inj (front primary) - 11.4v key ON, ~8.8v during cranking

3Y - inj (rear primary) - 10.3v key ON, ~8.7v during cranking

My back-probing and probe grounding were less than perfect, so that may explain the difference between the two ON voltages.

So the ecu is sending during cranking. Does this eliminate the injectors entirely as a cause or is there something about them that's left to check? Something to think about while I'm trundling around doing the next test.

If injectors are out, that brings us back to fuel pressure, doesn't it?


Didn't see this until now. My cranking didn't last more than about 4 secs. I just wanted to crank long enough to see a reading and see that it was stable. Hopefully it didn't hurt anything.

I'm going to head back out now and do a quick crank with my fuel cut-off switch bypassed. It's performed just fine up until now (I used it to kill the pump during my key-On checks of the primary connector's voltages) but I'm going to do this anyway to completely rule it out. I do show 12v when I meter in series with the switch.

[edit] No change with the fuel-cut switch bypassed.

The battery's going back on the charger after this.

ifryrice

Sweet ****-all + almost none at all = boom? It's hard to say if it was just enough to ignite the already extremely lean mixture. Just saying

If the injector itself is submerged, but the wiring isn't wet, then there's probably nothing to worry about and they'd be working fine. But since you said you pulled them out or whatever already, I'd imagine that puddles long gone.

Do you have a vacuum gauge to see what you're pulling during cranking? Have you tried the simple test of jamming a screwdriver into the AFM and cranking? I had both primary injector rubber seals leaking air on my '89 and it wouldn't so much as fart during cranking, no fuel/anything at all that I could find, would start and run on starting fluid then stall. Had someone crank the car and moved the AFM door by hand, got it to start sputtering then eventually hit the sweet spot and it started right up and I could get it to idle perfectly by holding the door open. I don't know if it works on S4's, the last time I tried on my '87 I didn't have any luck getting it to start (it did at least fart a few times, which it didn't before).

lastphaseofthis

iTrader: (8)

did you jump the intial set connector and check voltage at pump. or at least the wires by the strut tower on the driver side rear wheel.

Amur_

Coolant might have entered the loom elsewhere...


Nope.


Nope. Interesting story. I'll try it.



I haven't. I'll do this along with the AFM test.

KhanArtisT

iTrader: (2)

You should be checking for fuel pump operation, voltage and pressure. The AFM should not be suspected, if it is then disconnect it and try to start the car. With the AFM disconnected the car WILL start everytime but shut off immediately.

My bet is on fuel pump voltage. Its very common on these cars and you may have to re-wire it. Check voltage to the pump, jump it or do whatever but thats where your problem is.

Amur_

Agreed.


This has been a few times without success.

ifryrice

You don't jam it open because it's faulty, you jam it open to simulate more air flow to increase fuel. It's a rather reliable way of identifying troublesome vacuum leaks or other ECU lean related issues.

KhanArtisT

iTrader: (2)

That makes sense, though I don't understand where that would take you in the troubleshooting procedure if it did start the car.

Rule vacuum leaks out of the possible culprits completely. A vacuum leak will not keep the car from starting, it will start and shut off immediately or won't want to idle even in the most extreme cases.

I've left a few vacuum ports open, and even left part of the LIM unbolted. Each time the car started but didn't want to idle. Give it a quick look, if nothing obvious/big is unplugged then thats not where the problem is.

ifryrice

I've had quite a few cars that wouldn't start due to vacuum leaks. Compression plays a large part into how much leaks affect starting though.

It's possible the FP relay/etc got wet/flooded, it's near enough to the scene of the original problem. You're running out of things to check.

jjcobm

iTrader: (18)

This is interesting.... this is definetly the radiator explosion from hell.... Only thing left to check is fuel pump, how odd out of all things....

Section F1-57 in the S5 FSM shows some information pertaining to the fuel pump resistor relay & circuit opening relay. I can't tell you were those are located though as I've never looked for them. Might be a good idea to check those out....

Edit: I got beat to the post, ifryrice posted the same thing about the fuel pump relay. If it's one of those relays located right in front of the radiator, that is the suspect! Hopefully it's around that area, maybe someone other users can clarify where those two relays are located...

Amur_

This got me to look in the FSM, since I don't recall a relay being involved at all. While scrolling back and forth I was reminded of something that happened when I took the manifolds off but at the time it didn't occur to me to post it.

When I was ready to remove the soft fuel lines from the secondary rail, I pulled the return line first. I *think* I heard a little gurgling after this, I'm not sure (it's been a few days and I wasn't paying attention to that.) Then I moved over to the delivery hose, wrapping a rag around it to contain any spray.

Nothing. The rag didn't soak, no sensation through the rag of an expulsion and no sound of it. Gas did run out of the secondary rail until it was empty, that took a while.

Damn, I wish I'd remembered this sooner. I award 100 forum bucks to ifryrice!

So... the pump is sending but pressure is less than spiffy. I think the next steps are that relay and then the PRC solenoid, page F1-58. After that, the pump itself. Luckily I have spares of everything.


I'll look in a sec, but I'd expect it's mounted along that rail that sits between the headlights. If it is, then the relay itself would have been protected from the blast by the plastic barrier. The relay's wiring may be another story, though...

jjcobm

iTrader: (18)

You better award me too, I got you F1-57

Amur_

I'm all out of forum bucks for tonight, but I did catch you this delicious bass.

ifryrice

Haha, the fuel pump relay, is located behind the passanger headlight, bolted on the inside infront of the filter location. Right next to the radiator....

Amur_

I was referring to the circuit opening relay on the lower half of the scanned FSM page. The pump relay was sheltered by the custom airbox.

jjcobm

iTrader: (18)

I'm in suspense, waiting to see what happens. Hope you get it started now..... That pressure regulator control solenoid (on F1-58 like you said) seems possible too, regardless it seems you are on the right track now...

Amur_

Me, too. I wanna get my *** out to see Avatar. lol

ifryrice

The COR is located under the dash, so I don't follow? I think that you've got some wet connections somewhere that's causing large voltage drop.

That B/Y wire you tested, should have battery voltage and runs from the coils, all the way back to the injectors. That could be a troublesome sign if the injectors are only seeing +6v on the battery side (they should show +12V on both wires when not cranking/running). If the B/W wire is also being dragged down, it runs to all your solenoids/fuel pump/etc through the circuit-opening and fuel pump relay.

Edit: Oh, doing the COR tests will show you the results of the B/W to see if the voltage is dropped before it even heads to the FP, if that's what you meant.

Amur_

I see it now. B3-01. That's the one the fuel-kill switch is tied into. B3-02 is the resistor pack, although the wiring diagrams don't call it that. Maybe they ran out of ink?


A few people are probably thinking that now, and some have been thinking it for a while.


That's been done. Other than the leading coil dying, I've confirmed that the voltage throughout the MAIN RELAY->CAS->ECU->COIL/INJECTOR circuit is normal and behaving normally.


They were showing a little over 10 volts, not 6v, and that was a sign that the battery needed to be topped up again.


Nope. 12v is going to the fuel-cut switch, which says to me the B/W coming from the ignition is fine. I'm going to test it because it's part of the only system left that is culpable, and I want to eliminate it quickly and get it out of the way.

The [F] harness between B3-01 and B3-02 sticks to the driver's side until it hooks in and past the rad. If the rad blew out on both the rear AND the front sides, the loom may have been hit.

ifryrice

Running out of things left to check! Do you hear the 'running water' sound with the FP jumpered? That's usually a good indicator that the pumps not completely toast (it needs to make decent pressure to escape the FPR). I guess all you've got left is checking the voltage at the fuel pump, if that checks out fine I guess you could measure the injectors spray turning the CAS by hand, but that's a lot of work. It's hard to try to think of what could've happened. Unless water somehow got in the fuel pump relay/resistor housing and is screwing stuff up it's hard to think of what would cause it to act up.

If the FP voltage checks out fine (while not running and running). The injectors could be firing too little fuel or theECU is fubared.

RotaryEvolution

iTrader: (30)

the resistor is behind the RF headlight on the firewall in the engine bay. the relay is right above the gas pedal inside the cab.

MazdaMike02

iTrader: (4)

Use noid lights to check injector pulses way easier. They're like 10 bucks at Princess Auto.

BTW ATF destroys carbon (It has a high detergent value), it also makes rubber seals swell and possibly rupture eventually. Which means you'll probably start burning oil if you put ATF In.

Any petroleum based product (even aerosols with petroleum based propellants) will destroy rubber.. Unless the rubber is specifically to be submersed or in contact with any petroleum.

IE Cup seals in your master cylinder or clutch master, they are designed to be submersed in brake fluid.

But your trailing arm bushings or control arm bushings...if you spray WD40 on them its a definite safety hazard. They may stop squeaking, but they can rip or separate at any time.

BTW this is in regards to the use of ATF in our engines...I'm not just talking out my *** here lol.

lastphaseofthis

iTrader: (8)

so what was the voltage at the fuel pump harness into the tank after this test:

Amur_

I got away early and am heading to the car shortly.

When looking at the scanned jpg from the FSM, one of the Conditions for the COR test is "Measuring plate: open." Can someone clarify just what this is referring to?





Imho, once you're dealing with hardened carbon of the kind we're talking about within these engines, detergent is ineffectual. If it wasn't, rebuilders would be scrubbing used rotors and housings with Palmolive instead of using parts washers and solvents. I have also read posts on this board from different members attesting to having attempted to clean disassembled parts (like rotors) of carbon using ATF, or of having left parts sitting in ATF without any success at all. Perhaps they should have tried Palmolive...


Given enough time, sure. Aaron Cake, a vocal opponent of ATF, has said that it was several months before o-rings left to sit in ATF had been damaged (although he failed to specify if, or how frequently, he'd checked on them in the interim.) Given that someone using ATF *properly* will only be adding a few ccs of it to each chamber, and that the majority of it will be expelled shortly thereafter with the remainder being either burned off or diluted beyond concern, I fail to see the problem.