So I'm putting my NA FC back together, early 87 NA. Had spark yesterday and the car started, but now I've got nothing. There is voltage at the coil, the cas is hooked up, the ecu is hooked up, and it's getting fuel, but no spark for some reason. Anyone have any insight on this issue?

The only thing i can think of is maybe there's no power at the coil while cranking? Or the CAS died on me? Just looking for some ideas, I don't have a 2nd person to help me out.

 

Check the 30 amp Comp fuse. After that make sure the B/W that powers the ECU at pin 3I has voltage w/key to on. You can check the B/W wire at other places such as in the engine bay by checking for voltage w/key to on at the B/W wire at any of the emission solenoids or the 6 pin green plug which is for diagnostic purposes and thus not connected to anything located near the leading coil.

 

Well the major fuses must be good if you have power to the coils...the two EGI fuses and the Engine fuse in the interior......so it must be something else.

When you crank the engine over does your tach needle make small movements up/down?

IF not........try this and it only takes a moment or so. Disconnect the AFM electrical plug and the boost/pressure sensor plug and TPS plugs and try again. Watch the tach needle for small movements as you crank the engine. IF the tach needle makes small movements that means there is indeed spark at atleast the trail coil assy's. That's what the small movements indicate.

The only reason for removing those plugs is to see if one of those items is killing the 5vdc ref output from the ECU's internals. No 5vdc ref signal and there will be no spark ability from the ECU.

If you have a digital meter you could see if that lack of 5vdc is the problem. Remove the boost/pressure sensors elect plug. See if the BROWN/WHITE wire in the elect plug has approx 5vdc or not. It should have that. If it reads something like 2-3vdc........not a good indication.

 

I guess I'm missing something but if the B/Y wire at the coils has power then that indicates the INJ fuse is good and the Main relay is allowing the voltage to pass from B/G to B/Y, but it doesn't validate that W/L is passing voltage onto B/W via the Main relay, so the Comp fuse in this instance can be blown unless I'm misunderstanding what he means by stating the "coil has power."

 

I'll check everything early tomorrow what you've got so far. I'll have to try and find a multimeter as for now all i have access to is a test light.

I'm pretty sure the main relay is fine, if you mean the large 2 connector one by the master cylinders, as i pulled it out of my T2 and it was working just fine when I pulled it, though I guess I could check it anyway. I was jumping the wires in the large 4 pin connector as the original relay was bad (i left it upside down and it got water in it)

I guess i should assume it's good though, i was running a standalone on the T2, so I guess it's possible it went bad too, but it was working prior to the haltech install.

Either way i'll check what you've told me to check so far, thanks.

 

Well ok................ the EGI INJ fuse is proven good so to prove the EGI COMP fuse is good.......either pull the plug off any of the solenoids on the vacuum rack and make sure the black/white wire in the plug has power or seeing as how you had a haltech you probably don't have the solenoids on the rack so go to the green six socket check connected near the Lead coil assy and see if the black/white wire there has batt voltage or not. If it does then the Main Relay is doing it's job and passing power to the computer and the injectors/coils.

BUT if the tach needle makes movements when cranking the engine over there will be no need to check that 'cause the ECU is doing it's job and has power.

 

Check your IAT sensor, it is a little plug on the drivers side of the dynamic chamber, I broke one of those wires on my 87NA and had weird issues with intermittent spark.

When this happened I checked every voltage on every pin in the ecu, grounds coils etc and it was all normal, the tach jumped and everything.
I almost ripped my hair out I was so frustrated

 

I'll check the IAT, also at the moment no the tach needle is not jumping.

 

Then your ECU is likely not powered up so check the fuse I suggested and how to check for voltage on the B/W wire as Hailers suggested.

 

The odd thing is that I can definately smell the unburnt fuel, that's what's driving me nuts.

 

No power at that white/black wire.

 

Then go make SURE the EGI COMP fuse is good and the White/Blue wire connected to the bottom of the engine bay fuse box is on good. The White/Blue should be located just below the EGI COMP fuse.

IF they are good........go to the Main Relay and pull the four wire connector attached to it apart. Then put your meter on the White/Blue wire there and make sure it's got batt pwr. No key required.

IF power is there on the White/Blue...........then maybe the Main Relays contacts are not passing the power thru it.

There's a easy way to prove that. At the four wire plug, jumper the W/L to the B/W and the Black/Green to the Black/Yellow.

Then prior to starting the engine........see if there is power now on that black/white wire at the green six socket check connector near the lead coil assy. It should be there now for sure. IF it's not there.........then the engine will not start if you try and something else needs to be done to fix this lack of power on the black/white wire. But I can tell you now, there is no other connector b/t that wire in the check connector and the four wire plug that attaches to the Main Relay. Failure is not an option 'cause I've no other fix for this.

 

i'll check that later, probably not today, i just dropped like 20 degrees outside last night, lol, thanks for the help man.

 

relay was bad, car starts now, but dies after running for about 3-5 seconds, the afm is jumpered so i don't think that's the issue, any other ideas.

 

Did you replace the Main relay? If you did, do you have it wired up normally w/o the jumpers? If it is wired normally and no jumpers is the Black wire in the two wire plug at the relay grounded properly? If not, then the relay will/might place voltage on the B/Y and B/W wire in an intermittent manner. When the car dies "leave the key to on as in don't touch it" then check for voltage on both the B/Y wire and the B/W wire but check it "not at the relay," but at the leading coil (the B/Y wire) and either at the diagnotic check connector (one suggested by HAILERS) or emission solenoids (for the B/W wire).

 

No i just have it jumped for now.

 

Having it jumpered will eventually drain the battery so take this into account. When the car dies still check for voltage on the two wires suggested to see if that's the problem or if it something else. You said the AFM was jumpered. Does this mean you have the fuel check connector jumpered? If there is a large vacuum leak it would cause the engine to die out immediately as well. If you have the fuel check connector jumpered there might be a problem with one of the two wire in that connector. Find the Circuit Opening relay located below the dash and just to the right of the steering wheel and the relay is Black in a Yellow plug. Jumper the Brown wire to the solid Black wire (that is solid Black and not Black/White). This is another way to jumper the fuel check connector but at a different site and uses a different ground source.

 

i guess i'm going to recheck for vac leaks again, i changed every intake gasket on the motor already though. and the vac lines.