Help!!! No Spark or Fuel... Checked Fuses!!!
 

I'm not getting any power to my fuel pump or getting any spark. I checked the EGI INJ, EGI COMP, & the ENGINE Fuse in the cabin, all of them are fine. Anyone know what I should troubleshoot next?

The car is a '87 Turbo II w/ a S5 J-spec keg. I was running a E6x and have reversed everything back to a N332 Harness, ECU, MAF, & Pressure Sensor. I'm using the S5 Upper & Lower Intake Manifolds with a S4 Throttle Body. The car does have S4 N/A injectors & Fuel Pump. I'm also running premix and haven't swapped front covers / OMPs yet. Just trying to get the car started before I start putting any more money in it.

The car was getting spark and fuel when the Haltech was in. I reconnected all the wires at the coils, under the dash, and soldered a new CAS plug on. I have no idea why nothing will work now that I returned back to stock.

Are you getting any voltage at the B/Y at the coils? Should be 12 volts. Is your main relay clicking when the key is set to on? There is a plug with two wires connected to the main relay and one of the wires is B/W. It should have 12 volts as well with the key also to on. Does your tach blip at all when you try to start the car?

Thanks for the reply!

I haven't had the chance to check the voltage at the coils yet. The tach does not blip when the car is cranked. I tried to listen for the main relay but I don't think I can hear it. Where is the main relay located?

exact same thing is happening to me , i am replacing my ecu which i think is the cause of this. and yea same as mine there is no reading on the tach and nothing clicks i tried everything to get spark or fuel

Its a neighbor to the trailing coil. Its bracket is bolted to the driver side fender and is encased in metal and has two plugs going into it.

per Hailers (useful info)

Anyway, seeing as how you don't get the MAIN RELAY to pull in, then go pull the elect plug off the Main Relay that has just two wires (relay has two electrical connectors). Then with the key On and everything else connected together, probe the black/white wire in that two wire plug on the Main Relay. It should have batt power with key ON.

IF it does, then put the meter on ohms and check the OTHER wire in the two wire plug. IT should be going to gnd. IF it is a good ground, then suspect the Main Relay being bad. Never seen a bad one myself though.

Or to power things up, bypass the MAIN RELAY. Just pull the OTHER plug off the Main Relay and get two jumper wires and jumper those four wires in that plug together. Like the B/G to the B/Y and the B/W to the W/L. If you do that you bypass the Main Relay and the ECU will now be powered.......the coils will be powered........the fuel injectors will be powered. A normal car would now start if the key was put to Start.

is it the one closest to the fire wall ? if so i havnt checked that one , and if its not getting 12 v do i replace lol and would mazda still carry them ?

I have 4 more FC's sitting next to my Turbo II. I'll swap the main relay out first thing when I get off work tomorrow. Thanks for the help, Satch.

so i can just use two wires and connect them to the specific colors and it will start with no power to those connections ?

Yes, but this is based on the main relay being the culprit.

If it's not getting voltage then the wiring to the relay would be the problem as opposed to the relay itself although the relay could be a problem as well in addition to the wiring but not likely. Also, if the relay is not getting voltage then the engine fuse in the car (under dash) could be a possible cause for the lack of voltage.

Well, I swapped the main relay out and still no power or spark. When I turn the key to the "on" position, I hear nothing. When I turn the key "off", I hear a click that seems to come from that area though. I double checked, and the tach is still not bumping. What is the next thing I should check?

i checked the fuses with this thingy ( SHIT i forget the name but it lights up when there is current or something :lol: ) it lit up on the fuse under the hood and dash ( egi fuses )

Remove the plug to the main relay which has two wires and check B/W wire with key to on and see if you have voltage for you should. If you have voltage then take your multimeter and switch the setting to ohms so you could check the other wire in the two wire plug. This second wire is a ground wire. Check with ohm meter to see if you have proper ground. If you don't have proper ground recheck how the relay is mounted to the fender. If you don't have voltage to the B/W wire then obviously your problem is occuring before the main relay and therefore the relay is not likely your problem. If both of the wires check out okay then remove the other plug which has four wires and use two jumper wires and hook them up as stated in the previous post and bypass the relay and see what occurs. If the two wires check out properly and you bypass the relay with jumper wires and this allows the car to start then the relay is fubar for some reason. To get a closer look at why the relay might not be clicking properly you can remove the two wire plug and then turn key to on and then reconnect the two wire plug and see if you can hear it click for you should as it should be very noticeable.

Yeah im having this problem too and i swapped out to another ecu and only thing im hearing is the fuel pumping.. my main relay is not recieving power for some reason I even switched the main relay too... i've grounded out everything.. i do however think my alternator is on its last leg no sure if that has to do with no spark though..

gonna try that in the morning thank you satch..

If the B/W wire to your main relay does not have voltage then replacing the relay will have absolutely no effect. Imagine if you will, having a lamp which has defective wiring. If you replace the bulb all day long then the lamp is not going to work. You have to figure out "why" the relay is not receiving voltage from the B/W wire which is fed power from the engine fuse located in the interior fuse box under the driver's side dash. Chances are if the B/W wire has no voltage then either there is no continuity in the B/W wire between the relay and the interior fuse box or if there is continuity then there is something awry with the wiring in the fuse box itself or between the ignition switch and the fuse box.

thank you again satch im gonna do all of that in the morning and report to you with the results and maybe drifthappy will have some results as well..

Bad ignition switch? (Been there, done that...)

do i jumper the wires on the engine harness side or the main relay side on the 4 pin connector ? just wanna double check that.. I am getting power to my main relay and ground but this jumper plan has got to work !

When the 4 wire plug is removed you jumper the plug itself and "not" the relay.

Also, if the B/W wire is giving the relay voltage and the ground is good what happens if you disconnect the two wire plug from the relay, turn key to on, then reconnect the two wire plug to the relay? Since you are standing right over the relay you should hear it "click" when the 2 wire plug is reconnected.

yeah im not hearing any clicking coming from the main relay I hear something inside the dashboard clicking only so i'll try jumping on the engine harness 4 pin connector

Are you stating your ground (B) is receiving voltage?

i meant to say i was recieving proper ground to that two pin connector but needless to say thats no longer hooked up and ive jumpered the 4 pin connector and i'm finally getting the blipping on tactometer recieving spark injectors are kicking on.. my bac is acting funky clicking pretty consistantly..and it seems like my batterys losing its power so im charging it up right now.. i'm betting that my engine is flooded at least its been flooding on rotor housing closer to the head lights..ughh i've been banging at this day and niteee for i dunno how long but at least theres progress but its just not firing up..

Well, I double checked all the fuses and studied the FSM. The Main Relay is making a light click noise when I turn the key "on" and a louder click when I turn the key "off", now. I got out the multi-meter and checked the voltage & ground on the main relay, EGI COMP, & EGI INJ Fuses, & the fuse box that holds them. Everything is getting 12V, grounded well, & fuses are good. I checked the voltage to both coils and I'm getting nothing, same goes with the Fuel Pump. From what I can tell from the FSM, It looks like the problem is going to have to be the Fuel Pump Relay. It appears to be somewhere around the airbox from the diagram. Anyone else had problems with this relay before or think it is not the problem?

BTW: I appreciate all the help, guys.

So in an attempt to start the car your tach does not blip at all?

No bliping at all.

The wire you checked at the trailing coil for voltage. Was this wire B/Y in color?

As stated earlier there is a plug which has 4 wires which is connected to the main relay. Of these 4 wires one is B/G. This B/G wire comes from the main fuse box (40 amp fuse) in the engine compartment that is bolted to the driver's side fender. There is another wire that comes from this same fuse box (30 amp fuse) which is W/L. Both B/G and W/L have voltage in them. If the main relay is working properly the B/G wire will pass voltage onto the B/Y wire which then goes to your trailing coil and the W/L wire will pass voltage onto the B/W wire which leads to the air bypass.

If I read correctly, you stated the 2 wire plug which also plugs into the main relay checked out okay. Thus the B/W wire had voltage with key to on and the B wire was properly grounded. If this were true the coil within the main relay would energize and create a magnetic field which would close both relays within the main relay.

Now with the key to on and the 4 wire plug removed from the main relay you need to check for voltage on the B/G wire. If it doesn't have voltage then it cannot possibly pass the voltage onto the B/Y wire and give the trailing coil any voltage. Also check the W/L wire when this 4 wire plug is removed and check for voltage. If both have voltage then take this 4 wire plug with the key to off and place a jumper wire between the B/G and B/Y wires as well as a jumper wire between the W/L and B/W wire and turn the key to start and see what happens.

Check out post #15 in this link for it should be helpful.
https://www.rx7club.com/forum/showth...resistor+relay

On a turbo car the B/W wire which receives voltage from the W/L as stated earlier with respect to the main relay also passes this voltage to the fuel pump relay and resistor in addition to the air bypass.

I'm going to do what you said in post #28 when I get off work this evening. I'm going to try to get this thing figured out tonight. Thanks again for the help, Satch.

I removed the 4 wire plug on the main relay and tested the voltage on the B/G & W/L. Both are getting 12V. I jumped the wires in the plug (B/G to B/Y & W/L to B/W) like you suggested and the car is still getting no power to the coils. What should I look into next?

When you jumpered the two sets of wires did you try to start the car? If not try to start the car with the wires jumpered and focus on the tach to see if it bounces at all. If you get nothing then with the 4 wire plug removed from the main relay attempt a continuity test on the B/Y wire by setting your multimeter to ohms and place one lead,doesn't matter which lead, on the B/Y wire and the other lead of the ohm meter to the B/Y wire at the trailing tach and see if you get continuity. Remember to touch both meter leads together before doing the test. You "don't" need the key in the ignition for this test.

Also, try jumping just the W/L to B/W wires and then remove one of the plugs off of the rats net where the various colored plugs/solenoids are and check the B/W wire in the rats nest plug for voltage. It should be 12 volts or thereabouts.

Yeah, I tried starting the car when I jumped the wires. The tach was not bouncing while attempting to start it this way, either. I'll try to test the continuity this evening. All of the wires for the rats nest have been removed from the harness, I simplified it years ago.

The B/W wire connects to the air bypass solenoid valve so you could check for voltage at that point. Are you familiar with the led light(s) used to set the TPS and pull codes? If you have one of these the lights it should have a red wire and a yellow wire. You could use this to test if your jumper wires are jumpering properly. If the 4 wire plug from the main relay is disconnected and the jumper wires are installed then try placing the red wire of the led light into the back of the plug where the B/Y wire is and take the yellow wire of the light and place it on a good ground. The light should light up "if" the B/G wire and B/Y wire are jumpered properly. You could also do the same thing to the W/L and B/W wires (place red led wire into the plug where the B/W wire is). This will help narrow down at least one issue. Also, when the rats nest was removed did you remove all the wires themselves? If the wires are still there then picking one of the B/W wires would work towards checking for voltage if the jumper wire is in place and jumpered correctly (W/L to B/W).

I'm not familiar with those led lights. I'll look into it. When I removed the rats nest I believe I removed all of the wires completely. If I left anything, it is cutback and wrapped up in the harness somewhere under the dash. Could anything on the engine harness cause this problem?

The led light really isn't important especially if you don't have one. To make sure the jumper wire is correctly doing its job all you need to do is place the red terminal of the volt meter into the back of the plug where the B/Y resides and the other terminal of the meter to a ground and it should have voltage. If not the jumper is not properly inserted. Same thing applies to the B/W wire.

The wiring between your main relay and coils, both trailing and leading, are part of the front (F) harness and not engine harness (E). The engine harness connects to the front harness "after" the coils but before the fuel injectors (primary and secondaries).

Another question. When you turn the key to "start" does the starter turn over or is it completely silent?

I'm pretty sure the jumper is inserted correctly but I will double check by checking the voltage on the back of the plug like you suggested.

I was just wandering if anything on the engine harness could be culprit because you wanted me to check the power in the rat's nest.

The starter is working correctly when I turn the key. So, I just hear the ol' sewing machine sound when I try to start. The car acts exactly like when you pull the EGI fuses and crank.

The harness which "was" connected to the rats nest solenoids is the emissions harness and not the engine harness. Let me double check but the air bypass solenoid should be connected to the front harness and neither the engine or emissions harness. I might be wrong on that but I'll try to doublecheck. And did you remove the air bypass solenoid valve as well as the wiring to it?

Yes, the air bypass valve & wiring has been removed.

I figured as much, but the B/Y wire coming out of the 4 wire plug is of more importance except for the B/W coming from the same 4 wire plug eventually leads to pin 3I of your ECU and that pin needs to have voltage (12v). The B/W wire of the front harness leads to the emissions harness plug which has 14 terminals but only 13 wires in it, one of these wires is B/W. You could check the emissions side of the emissions plug for voltage at the B/W wire. You could also check for battery voltage (12 volts) at pin 3I which is in the smallest plug connected to the ECU. This pin has the B/W wire going into it and it is the only B/W wire to be found in the smallest plug ( B/W wire should be upper left in the plug if you were looking at the plug from behind where the wires run into it). If you check this wire try doing so with it connected to the ECU.

Edit: The B/W wire leading to the air bypass is part of the emissions harness thus the B/W wire is part of that particular harness.

I checked the continuity between the B/Y wire on the main relay plug & the B/Y wire on the (F-43) plug, it was reading all over the place from 2-38 (M?) Ohms. I don't have any experience checking continuity so I don't know if I did it right. I checked the ENGINE fuse in the interior and it was blown for some reason. It was fine the other day. I replaced it and the car still couldn't start. I checked the voltage at the Fuel Pump Relay and it was 12V. I also checked the voltage on the 3I pin @ the ECU. It read 1.1V plugged in & 5.7V unplugged. I then checked the voltage at the fuel pump and it read 5.7V.

I'm not familiar with what plug "f-43" w/o looking at the wiring diagram but you stated previously that the B/Y wire at the coils showed no voltage. Well lets try to find out why, first off. You also stated that the B/G wire had voltage in the 4 wire plug that was removed from the main relay. Did you check with your voltmeter if you got voltage from the B/Y wire at the "4 wire plug" after you jumpered the B/G wire to the B/Y wire? Stick your red lead into the back of the plug if you can on the B/Y wire and ground the black lead and check for voltage.

Still have that GREEN TPS check connector in the engine bay. The one you use to set the TPS????? If so, then put the key to ON and with your meter, see if the black/white wire in that three socket green TPS check connector plug has voltage or not. Should have it.

And or........reconnect the Main Relay elect connectors. Then put the key to ON. Now with the key to ON, go to the engine bay and disconnect the two wire plug of the Main Relay. When the two wire plug is disconnected with the key to ON, the relay should make a click sound as it relaxes. Then put the two wire elect plug back on the Main Relay. You should hear the Main Relay pull in when you do that if the key is ON.

IF the relay does not click when doing the above, leave the key to ON and then with your meter, see if the two wire elect plug going to the Main Relay has power on it. One of the two wires should be Black/White and that is the wire that should have batt pwer on it with key ON.

IF there is no click when the two wire elect plug is pulled off/reinstalled with the key ON, and there is no power on the aforementioned black/white wire, then the ENGINE fuse is not feeding the Main Relay and fix that problem.

Just throwing in some other ideas, nothing more. I'd advise NOT ohming out any circuits and just concentrate on using the meter to find out if there is/is not voltage on the places mentioed in Sach's posts.

The FOUR wire plug on the Main Relay should have batt power on the W/L and B/G wires all the time, key in or key out. Make sure that is a truism.

Another possible reason for a MAIN RELAY to not pull in, is the gnd wire on the two wire elect plug is not going to gnd. That gnd is located below the Trail coil assy and is on a black elect plug attached to the rear of the left front strut housing. NO reason to believe this gnd point has gone bad. Does not happen that way.

It's a shame. This could be figured out in about ten minutes and fixed. Lurnin be time consumin.

when installing most standalones you rewire the coils and fuel pump. i didn't read through all of the crap but i assume you are missing that one important fact that the black/white wire that feeds power to everything probably has been cut and rewired from the main relay to a new relay that fed everything power that was switched by the haltech, which was removed or is now unplugged.

To Hailers:
This problem is much like a thread you were involved in with a member named "woot" which included pics of the "condenser" you provided.
https://www.rx7club.com/showthread.p...+voltage+coils

Don't know if you remember that one. It's strange how this thread poster has voltage in the B/G and W/L wires coming from the main fuse box but when B/G is jumpered to the B/Y wire there is no voltage at either of the coils.

A question I have for "you" is if the poster checked for continuity of the B/Y between the main relay four wire plug and coils will the fact that the B/Y wire is connected to other things such as the injectors prevent the continuity test from giving proper results and would the plug from the coils have to be removed to conduct the test effectively?

B/Y goes to a lot of items. But.....I reckon if you ohm's out point to point that would work.....maybe. I think there is a flaw in working like that. To do that I'd first make sure ALL the other items are disconnected from whatever they connect to.

Say your woking on a airplane and there is a problem with a circuit. Well let's say that wire is pinched in a clamp somewhere and touching gnd. Now you try to *ring out* the circuit from one point on the engine nacelle area to the front power panel. Well it *rings out* (ohms out) but the circuit is grounded therefore does not work right (oh dumb me, breaker would pop if so).
Well that wasn't a good example. Lets say only one strand of the conductor is making contact...........ohm's out but won't carry a load if that's the case (slightly better example). Or the same if there is a connector in between both end points and the pin is just barely making contact with its socket. Might ohm out but won't carry a load when being used (slightly better ex).

It'd be better to just KEY ON and see if there is voltage at the end point.

Just saw another thread your working on where the fellow had JC-01 out of the circuit.....therefore no Main Relay being pulled in.

Well I hate to say this, but this car is kicking my ass. I'm having a simular problem. Here is what i have checked.

Fuses
grounds
Main relay is kicking on
Fuel pump
Fuel pressure

All these are good, but im not getting an injector pulse, or spark, so that points to computer to me. With my HKS f-con pluged in the light comes on the box. Now ive disconected it and just pluged the stock ecu back in. I even switched out my cas with an extra i have, and nothing.
this is where i would have asked icemark in the past, Smart Man, and a good friend.

Have you checked for voltage at the coils, both leading and trailing? The B/Y that comes from the main relay supplies the coils and injectors with voltage. When you try to start the car does the tach bounce at all? If it does then it is a sign that your trailing coil is receiving juice.

Sorry I forgot to put that on there. Yes. Key on main relay kicks on, and i have 12 volts at both leading and trailing coils, so im just not getting the signal for fuel pulse, and spark. Anyone know where i can get a wiring schematic for an ECU. I know im getting voltage to the ECU, because of the f-con light coming on. Really appreciate the help satch