rxseven

Questions: Does the fuel pump come on when the ignition switch is turned on? Mine does not. It will come on only when I short the connector by the afm. Haynes mentions a "circuit opening relay" for the fuel pump. Where is it?
The reason I ask this is that I have a no start situation and I have checked the compression and spark. I can also hear the injectors spray gas when the afm door is propped open.

FJ

" Does the fuel pump come on when the ignition switch is turned on? "

Yes and no: It doesn't get power with the key in the "run" position, it does get power with the key in the "start" position. Once the engine starts and the key is returned to the "run" position, a switch activated by the flap in the air flow meter keeps the pump running.

"Mine does not. It will come on only when I short the connector by the afm. "
Presuming you meant the ignition switch was in "run" and not "start", that is normal. To check if the switch in the AFM is good just remove the air filter, put the ignition on (run, not start, of course) and gently open the flap in the AFM with a small screwdriver. It takes very little force to move the flap. You should hear the pump run, and I suspect you will. All the same, for future reference(and just to know) here's the info on the relay:
The circuit opening relay is located under the passengers feet, below the rug and a metal plate, right beside the ECU. It has two coils and one set of contacts: the first coil is energized when the ignition key is in "start", the second coil is energized by the switch in the AFM. When you short the fuel pump test connector, you are grounding the same wire that the switch in the AFM does.
You can safely try to start the car with the fuel pump test connector jumped if you have any doubt about it running while the key is in "start", (I know, you can't hear it while the engine is turning over): you are simply activating the relay manually.
Bottom Line: if the pump runs when you short the connector, the relay is working on that coil, and it's not a relay ground problem. It probably runs with key on start also.
If indeed it won't start with the pump running (by jumping the test connector), post with a little more detail of your problem, I.E., were the plugs wet when you pulled them to check the compression, "it's been running well and just didn't start this time", are you familiar with the flooding problem, etc.
Good luck, John.

rxseven

Well, I have been posting a lot of info on my problem (see my other post in the last 2 weeks). Basically, my engine stalled once while idling and would not start right after. Started up 6 hours later and stalled once again (soon after warm-up). I tried it next morning, it started but was idling rough. when it died, I checked the plugs and it appeared flooded. I then proceeded to unflood it many times. Yes, I have checked for spark, compression was fine also (100psi, 105psi, cold). I replaced the leading ignitor, plugs and swapped coils. This morning, I tried to start it, it started for a second (sounded like it was running on one rotor). Checked the plugs, very little gas splattered. I noticed it was not flooded even after cranking 4 times. So at first it stalls, it's flooded. Now it's fuel starved??? WTF?? It's been a bizarre week with the car, to say the least. I am not a complete novice at working on cars so I think I done a pretty systematic diagnostic so far. The only thing left, I think, is ECU and testing fuel fuel pressure. When the injectors kick in with the afm flap open, it does sound like the gas is under pressure.

FJ

I've not been on the forum much lately, so I responded to the question I read. I will go back and read your previous posts tonight or tomorrow morning. In the mean time (you may have answered this in previous posts):
-I imagine you have changed the fuel filter?
-If it started and then died, maybe the AFM switch is defective? As I mentioned previously, the ignition will run the pump untill it starts. If the AFM switch doesn't take over, it will stall and the plugs will be dry. Have you had a chance to check it as per my previous post?

-Do you usually add injector cleaner to the gas? They usually stick open, resulting in flooding, but maybe at least one is sticking closed or is just too blocked to flow reliably? You mentioned it appeared flooded the first time it stalled and then dry this morning. Flakey injectors will do that.
-When the plugs were wet or dry were they the same for both front and rear chambers?
-Did you have any smoke( in particular, white) at start-up before?
Just a few thoughts off the top. I'll read the other posts and see If something rings a bell.

I've just read one of your previous posts regarding the clicking sound under the hood. Do you hear the relays clicking now? They are the main relays,as someone already mentioned in that post, and if you have an intermittant connection around them, all kinds of strange things will happen...
-John.

rxseven

fj, your posts have been a great help, thanks. I cranked the heck out of it and removed the plugs. The trailing plugs had splatter and the leading ones were bone dry. I shorted the fuel pump connector and propped open the afm flap. Yes the pump came on and I could hear the injectors spray gas. When I tried to start it like this, still no combustion. I verified what you said about the 2 coils in the circuit opening relay, one for the "start" mode and the other for the "on" mode of the ignition switch. Seems to be 2 distinct circuits and my problem seems to be no fuel in the "start" mode and everything working fine in the "on" mode. This means that either the coil in the relay on the start side is bad...or....my ECU has crapped out. What do you think?
Since my engine first stalled due to flooding, it may be the ECU.
The only other possibility is bad relay and "flaky" injectors.

Looking forward to receiving more input on this subject. Anyone reading this ever had to replace and ECU before?

Pele

iTrader: (28)

I've got a non starting GSL-SE. Compression is good. (Was WEAK, but present, soaking in ATF. It got notocably stronger after only a few minutes.) Spark is good as well, so I'm suspecting fuel pump.

Is this jumper technique listed in the Factory service manual or the Haynes? I was just gonna tie the fuel pump straight to the battery temporarily.

Should I just jam the ATM door open with a screwdriver?

rxseven

Right by the afm there will be 2 connectors that are test connectors not connected to anything. The green one is for testing the tps and the black one (has a black rubber boot) is the short connector for the fuel pump. If you jumper the prongs of that connector, your fuel pump should come on with the ignition in the "on" position. The afm flap is also part of that same circuit but propping it open will trigger the pump and the injectors.
It is mentioned in Haynes, i don't have the factory manual.
On page 302 of haynes, it shows another circuit which originates from the ignition "start" (while cranking) and the wire "BR" is shown going to the ECU terminal and the same wire branching to the fuel pump via the circuit opening relay. The afm flap and short connector are not a part of this circuit so you can't use them to check if the fuel pump is working during cranking. In my case, I am just gonna pull the main fuel hose out and check if it is spewing fuel during cranking.

FJ

Hi. Well, first lets clarify the relay detail. (Also for Pele) You mention you jumped the connector and opened the flap. Do you mean at the same time? If so, what I meant was to open the flap with the key on(connector not jumped) and you should hear the pump come on and turn off as you release the flap. That is just to check the switch in the AFM. If you tried to start it with the connector jumped, you don't need to worry about the flap or the ignition running the pump in "start": the pump should run as long as the connector is jumped and you eliminate the relay and pump activation as your problem.
(Pele, don't "jam" the flap open, just gently push it a bit to check the switch. It wouldn't take much to bend the flap, and a new AFM is $$$. Yes the test connector is listed in the FSM: it is the black connector beside the air cleaner.)

Rxseven, I'm not sure that you are hearing the "injectors spraying gas". I'm not sure what you're hearing but the sound from the injector has to travel up the intake, through the throttle body and through the duct before you hear it at the AFM. It may be, but I wouldn't put too much faith in what you hear at the AFM.

So, disregarding what it did originally for the moment and looking at what you have now, you are not getting fuel: in a previous post you mentioned it would start if you put starting fluid in the intake and then die (so as you had already verified, you have spark), and after cranking now the plugs are dry. Seems to me, either the injectors have no voltage as a result of your electrical problem or they are gummed up and operating erraticly.
-Was it starting easily and running well before the electrical problem? (If yes, it's hard to see gummed up injectors as the problem as they usually leak and cause starting problems, not act up all of a sudden.)
-You had mentioned in a previous post that you didn't hear the main relay click when you put the ignition on. Is that the case? (If so, it shouldn't have started when you used starting fluid as the relays supply voltage to the ignitors and other important bits.)
-You would have to remove the upper intake to check for voltage at the injectors, but it is on the same circuit as the ignitors and the coils and the voltage for those three parts comes through one of the main relays, the ones that click when you turn the ignition on. So if you check for voltage at the primary of either of the coils with the ignition on and you have 12v, the injectors will have it also. The only reason they would not is if the connector near the injectors itself has bad contacts, but again you have to remove the intake to check that.

The next step would seem to be to remove the intake to check the injector voltage and if it's there then to remove and clean the injectors but I'll wait to hear abuot the above questions before guessing too much further...
-John.

rxseven

FJ,
I shorted the connector by itself and the pump came on. tried to start it like so, but no luck. I then propped the flap open and cranked it. An yes if you are in a quiet garage, you can hear the injectors activate if you put your ear by the throttle body, quite audible actually.

Yes it ran likea champ right up until the electrical problem I had. It would start up in under 2 seconds no matter what and idle at a steady 800 rpm. I did not even have the infamous GSL-SE surging.

Checked the main relay, it checked out ok.

FJ, could you look at the wiring diagram and explain to me how the fuel pump could stay on even with the conector shorted in the "start" position. I am not very good with electrical schematics but in that case you would not need 2 coils in the relay.

FJ

If you look at the diagram of the ignition switch, there should be a line joining the run and start contacts within the switch. The wire going to the main relay is shown coming from the run position only, but the line between the contacts means the contacts are common (or shorted) within the switch, so the main relays will get 12v in run or start, and so the jumped connector also will operate the pump in run or start. If the line between contacts in the switch is not there, you're right, the pump would not come on in start.
The main activation for the pump is the switch in the AFM. No need for the pump to be on if the the engine is not running. But that means you need to power it during starting, untill you have airflow , so thats why they used a relay with two coils for one set of contacts.
If my discription doesn't make sense, let me know and I'll clarify.

I had mentioned to check the voltage at the coil as it is on the same circuit as the injectors. If you were not aware, with a bad connection you can measure 12v with no load (I.E. with the key on) and it could drop as you try to start, when the current flows through the bad connection. As this circuit for the coils, injectors and ignitors comes from one of the fusible links, it could measure good then drop when you try to start. Had you cleaned the fusible links as someone mentioned in a previous post? Then again, if you can hear the injectors...Might be worth cleaning the links anyway.
If the injectors are working and the pump works and the fuel filter is new but you still have dry plugs , hmmmm. I'll look at the diagram and see if I can spot anything that might have gotten hurt when you had your short.

One other thing that is important is the water thermo sensor. If it is bad the mixture will be all wrong and I know it can cause a no-start. It is located just behind the thermostat housing. Green connector. It should measure 2.45 kohms at about 70 degrees F. Definitely worth checking!! I should have thought of that before.

_John.


John.

rxseven

FJ,
Before I read your post I went ahead and unclipped the main fuel hose and cranked the car. Fuel pump seems to be OK since about a 1/4 cup of gas poured out with a few cranks. Your explanation of the wiring diagram makes perfect sense now. Ok, so everything checks out except I don't have the actual fuel pressure reading. But assuming that is fine, all i would be left with is the thermo sensor? Can the ECU still be the culprit? Come to think of it, the first couple of times it stalled, it seemed to fast idle just fine and when the rpm dropped to 800, it died a few minutes later. Both times just after it reached normal operating temperature. Hmmm... Anyway, i'll check the resistance and let you know.
Thanks for the input.

FJ

"I shorted the connector by itself and the pump came on. tried to start it like so, but no luck. I then propped the flap open and cranked it. An yes if you are in a quiet garage, you can hear the injectors activate if you put your ear by the throttle body, quite audible actually. "
Interesting. I'll have to try that.

"Yes it ran like a champ right up until the electrical problem I had. It would start up in under 2 seconds no matter what and idle at a steady 800 rpm. I did not even have the infamous GSL-SE surging."

The surging is a minor fix, usually, as you may know. I bet you're wishing that was the reason for your post! If it takes a full 2 seconds to start, that is long to me. It might be a number of things, including gummed injectors, but it doesn't seem to be the main problem now.


"Checked the main relay, it checked out ok."
As it was fine before the short, I'll get my mind off the injectors for now. I looked at the diagram and I presume when you mentioned the engine fuse blew, you meant a 20 amp fuse in the fuse block and not one of the fusible links. That would seem to be the case looking at the air supply valve wiring. That fuse is the same one that supplies the coils of main relays. Relay"s". :p Plural. You mention "it" checked out. I'm not sure if you meant both, but in case the only one you checked was the one I mentioned earlier (12v at the primary of the coil): the other one supplies part of the AFM, goes to the ECU, the O2 sensor and the mixture adjustement resistor: BE SURE IT IS GOOD. When you had the fuse blowing, it could have spiked enough to kill this relay coil. You would still hear the click when the key is turned on, but it may be only one of the two you hear. The only easy test point, as most are sealed connectors for that circuit, is to disconnect the air mixture connector and check for 12v with the ignition on at the pin for the Red with White wire.
Again, it may measure good with no load, so it would be best to check both relay outputs while trying to start.
Somehow, I don't think the ECU is the problem: You can hear the injectors working, the ignitors work, etc. I would expect it to either work or not (we don't have the localized solder problems some of the Sec Gens get).
I had noticed you had said it started and died as it warmed, that may be what made me think of the thermo sensor. It would be a coincidence that it went bad at the same time as your short but stranger things have happened.
So, I would check the thermo sensor and both main relay outputs while trying to start next.
After that?? Don't know what to suggest. We'll see...
-John.

rxseven

Ok, I checked the thermosensor resistance. It is 3.43 Kohms. Haynes mentions it needs to be 2.45 at 68deg water temp and 0.32 at 176. Assuming a linear relationship between temp and resistance, the ecu must think it is 50deg cooler than 68, ie at 18deg, brrrrr. My garage air temp was around 65 deg and the water temp probably 50-55. Doesn't the ecu use the input from the 2nd temp sensor at the bottom of the radiator when it is below freezing? I could have sworn I read that somewhere. Let me know what you think.

I will check the main relays next.

FJ

Hi Rxseven.
"Assuming a linear relationship between temp and resistance, the ecu must think it is 50deg cooler than 68, ie at 18deg, brrrrr."

That would be enough to cause a no-start, I'd say. Unfortunately, the factory manual mentions a third temp/resistance: 16.2 kohms at minus 4 so it's not linear, it's exponential. My guesstimate for 3.43 kohms was high fortys, not far from your estimated water temp. My garage temp is about 35 F (time to start the heater, we've been spoiled by high temps so far this year.) and mine measured 3.6k, so it doesn't look like that's your problem. It was well worth checking, anyway.

"Doesn't the ecu use the input from the 2nd temp sensor at the bottom of the radiator when it is below freezing? "
That one is just a switch, not a "sensor" like the thermo sensor (it's a thermistor: resistance varies with temp.) It does send a signal to the ECU, but it is just open below 59 F and closed above that. I'm not sure what it does, but it's not as important as the thermosensor.The only idea I had was that it triggers the cold start assist system, which I disconnected many years ago as it causes problems and doesn't seem to help anything.

*There's a thought... is your cold start assist still connected? IF indeed it activates below 59 by the switch on the rad, and your water temp is about 55 recently,... At any rate, it's easy to bypass : just unplug the connector at the bottom of the bucket and try to start. I know, you would still expect to see wet plugs and it doesn't make complete sense, looking at the original starting and then stalling. But it's easy to try and would make sense, with the lower temps lately. It is a known starting deterrent, Mazda's good intentions aside.

Good luck, I'll try to come up with other possibilities, but the list is getting shorter...
-John.

rxseven

FJ,
The main relay voltages checked out fine. Having ruled out the possibility of the thermo-sensor, I went back to fuel injectors issue thinking about what you said previously and once again listened for the fuel spray by propping the afm flap. It was there. Now I connected a jumper wire accross the fuel short connector and put my ear close to the dynamic chamber. Similar sound. I take it it's just fuel moving through the lines then. I guess I will remove the dynamic chamber next and test the injectors. It's gotta be an electrical issue. It's almost impossible to believe that both injectors are suddenly stuck shut since the car was very responsive prior to developing the ASV short.

jrx13

iTrader: (3)

I think you should try the basics approach. Are you getting spark and are you getting fuel. I just spent hours figuring out why my car wouldnt start after installing an msd on the trailing ignition. Turns out the igniter sends the signal for the fuel injectors to fire. I would check to see if your getting spark from the trailing and leading ignition first. Then if you are, see if the injectors are getting pulsed.

rxseven

I have spark on leading and trailing. Checked that about 5-6 times now. Don't know if the injectors are triggering. That's next on the agenda.

FJ

Rxseven, it seems what you hear is a "rushing" sound as the fuel returns to the tank. I thought you meant you heard the rapid clicking sound they make as they open and close while someone else cranked the engine. With just the fuel pump running by the test connector they wouldn't operate. If they did, severe and immediate flooding!
Check your PM.
-John.

Denny

Hey, Fj....

Nice work, wrench-hand. Love your posts, and your obvious knowledge. Glad to have yuh with us.

A tip of the 'ol Stetson,
Denny, from the abandoned corncrib...

p.s. Santa Claus is comin'....

FJ

Why, Thank You.
-John.

killjoy7

iTrader: (6)

This might be completely unrelated to all your electrical theories but last week my 85 GSL-SE wouldnt start and would just crank and flood. I had spark and compression and (it seemed) fuel (plugs were fuel wet).
BUT it turns out I din't have correct fuel pressure (invest in a gauge--trust me. The fuel pump was delivering pressure but it was not getting to the injectors. And it was all because of an old and dead fuel pressure regulator. Of course this friggin gem is buried under the upper intake manifold so the whole top half of your intake has to come off to get to it. My regulator's diaphragm just plopped out onto the concrete when I unscrewd it. After replacing it the car runs great. (the part was $208 at the dealer tho--ouch).

A good way to check if your regulator is dead is to clamp the fuel return line with a vise grip or something. (that's the hose right next to the fuel line) That will close off the return line and, if your regulator's bad, force the proper fuel pressure to your injectors (SE's like 49-70psi).

might help.

rxseven

Thanks for your input killjoy7. I will also check the fuel pressure like you suggested while i have the dynamic chamber removed. Right now, it looks like I have a connector to one of my injectors come loose or some wiring problem because the wire from the front injector to the ECU registered 0V at the end that hooks into the ECU terminal whereas the other injector wire registered 11V with the ignition on.

I want to thank everyone for their input. I will be working on it all of next week so i'll keep y'all posted.