hornbm

Hey guys,

In case you havent folled my last thread I was having problems getting the coils to spark to turn over my new S5 engine that I just put in my 85 FB.

Anyway the problem turns out to be that the voltage in the whole EGI circuit is 12 volts, but during cranking it drops to less than 1 volt. The ecu drops below 1 volt, the coils, everything.

I also confirmed that the ignition system was working by using one of HAILERS ideas I found in another thread. I pulled out the CAS and unplugged one of the spark plug wires, and put a screwdriver in it. I turned the key to on and then turned the gear of the crank angle sensor and presto I got spark.

One important note is some information that might make a difference about what the problem is. Unlike the FC, the FB does not have it's starter behind a relay. The positive cable of the battery goes to one of the terminals, and a trigger wire that goes directly from the ignition switch to the starter seleniod. If I remember correctly the FC had these components controlled through a relay.

If anybody has any ideas on how to bring that voltage up please chime in! thanks!

javrosario

iTrader: (5)

Why don't you use your own relays to power up the ECU, Coils? That's an easy fix, if you know how to do it.

Scott 89t2

what kind of wire do you have going from the battery to starter?

is your battery in the back now?

jrx13

iTrader: (3)

How do you have the EGI circuit hooked up to your 1st gen? You may have it hooked up to an ignition circuit with no power during cranking. You need to find one that is "hot" while cranking too.

-Jack

NZConvertible

I think jrx13 has it. There are two ignition circuits coming from the ignition key, IG1 and IG2. IG1 has everything needed to run the engine, while IG2 has less important stuff like the windscreen wipers. When the key is in the IGN position both circuits have power, but when the key is in the START position IG2 is cut off to lessen the electrical load. If you've hooked the EGI system up to the IG2 circuit, it'll lose power during cranking as you describe.

hornbm

well that makes sence but I dont think that would relate to how I have mine setup.

Allow me to explain.... The power to the EGI circuit comes from the EGI fuse and then goes to the main relay. My main relay is activated my the On lead of my ignition switch. So all the power comes from the main relay to the EGI circuit.

Now that would make sence if I somehow wired the trigger to the main relay to the IG2 switch, but as I understand it, relays are simpily on or off, so if the voltage is droping to activate the main relay, than shouldnt it be getting nothing from the relay all together?

HAILERS

Ah fudge again. I put a N332 ECU in my 82 along with a cas. I lost interest in the project when I came across a 87TurboII. Sold the 82. But the deal is, I fed the Lead and Trail coils out of a 87, using the existing wires for the 82. Well, the 12v feed wire anyway. The trigger was just some wire run from the ECU to the coils.

I don't know if that helps or not. The car ran but I know the ECU maps wouldn't have been right for a 82. But it started and ran if that helps, without doing anything tricky. Then again, a 85 ain't a 82.

HAILERS

Hmmm. My 87 has the battery positive terminal connected to the starter and the battery negative lead going to the starter attach bolt. There is a 18 gauge wire to the solenoid that gets its power from the ignition switch, thru a clutch switch, then thru a jumpered connector near my trail coils, then to the starter. No relay unless the car has Theft Protection, then the jumper mentioned above is replaced by a relay that is theft protection driven.

1SxyRXy

a guy down the street from me did a 89TII engine swap in his FB and a couple weeks ago he did the wiring harness and everything

hornbm

I'm not sure if it would make a difference or not, because of the trailing coil actually consisting of two coils. The FB only uses two coils instead of the three coils that the FC uses.

Since you are talking about using the existing leads on the FB for the coils, are you refering to cennectin the lead to the coil itself (with the screw) or crimping it onto the connector that normally comes from the main relay? The reason why I ask is that the wire going to the FB coils is about 8 times thicker than the wire comming from the main relay to the coils on the FC.

NZConvertible

This may or may not be related to the problem, but how are you planning to use a S5 ECU (which must have the S5 electronic OMP plugged in) on a S4 block (which has a mechanical OMP)?

jrx13

iTrader: (3)

Well in your first post in this thread, you said all of the EGI circuit is losing power during cranking. Why don't you just run a jumper wire straight to the battery positive terminal then crank the engine and see if it fires up. Then you'll no for sure if that is the problem.


-Jack

Thaniel

Prove that it runs first.

Also does the voltage drop to 1 volt anywhere else in the car when cranking. Maybe the battery just isn't cutting it or there is corrosion on the cables etc.

HAILERS

I probably should have kept my mouth shut about this. On the 82 there was a lead and a trail coil. A black/white (memory says black/white, could be wrong) fed each original coil assy. So I used that as the 12v switched source for the series four coil assy and ran a trigger wire from the ECU (copy catted the wiring diagram by stringing wires from the coils to the ECU). I was just using the standard carb. Just wanted to see if I could string wires and use a series five ECU for ignition and ditch the 82 ignitors and coils assy. One of my unfinished projects that got sold to make room for another car.

Your's is a 85 and probably fuel injected, so it may/probably is different. I didn't have any problems starting the car. Just had to string some tps wiring, pressure sensing wiring. I'll butt out now. Sounds like you're going to have a pretty good little car there once it starts up. Hat's off to you for having a go at it.

Oh, pay heed to what the NZ said about the series five ECU and the series four omp. Thats another obstacle to overcome. I believe the car is not going to run very good except at idle until you do something about that combination. Shouldn't be an issue just starting up though. I be gone now.

hornbm

Well by 85 was carburated, but the IG2 thing was exactly correct!!!

I got the thing to fire, but I still have problems.

I'm sure my timing is really off which I'm going to go fix in a minute.

I cant get the thing to idle. I he the thing dire up and the it dies immeadiately. After quickly looking over the motor, I noticed that there were many coolant leaks around the engine, one is from a screw that I forgot to put back in the throttle body, ('doh!) and the rest seem to be from my USED water pump. I'll be ordering a new one today.

Now heres the big one, I've got a intake manifold leak around where my S4 lower manifold meets my S5 upper and mid.

The reason is because one of the studs do not line up on this combo, and everyone I asked told me that I can just remove the stud and be fine, but its leaking around where the stud is missing. How should I close this leak?

Any other reasons why it might be dieing like this?

hornbm

I'd like to add about the OMP. I have a modified 12a front cover to accept a S5 metering oil pump. So I'm not using a mechanical one. I've allready heard the horry stories of the infamous "limp mode"

I also pulled off the intake manfiolds, and there was a nice leak present in the intake lower to mid intake manifold gasket, right where that missing stud is. So does anybody have any ideas on how to tighten that up?

The last important detail, is about the lower S4 manifold. My origional idea was to use the S5 port acutators on the s4 manifold, and then make a custom stopper plate for the rods that turn the sleeves. Well after I designed the whole thing and bolted it all up, I discovered that for my design to work the S5 acutator would have to move a fraction of an inch more to get over the top of the rod swing. So I just left it like that, (5th and 6th ports not working) and figured since I have to break in the engine in anyway, I cant go above 4000 RPM so the aux. ports wouldnt even be helping me.

I just figured that after I pass emissions I'd go get a s5 lower manifold, block off the port air, and have working 6 ports again.

Now the problem arises being that to fit the S5 acutators on there, I had to grind a little off the lower intake, right where the vacuum supply to the S4 acutators are. Since I'm not using them I dont think it will be a problem, but what I dont know is if that vacuum is a closed one.

Correct me if I'm wrong, but in an S4 setup, vacuum enters the side of the lower intake and goes to the acutators. With the vacuum line for the brak booster also being there, do I have a gaint vacuum leak on my hands here? Or am I ok?

hornbm

bump

Thaniel

The attached pic is from a guy who put a S5 upper on a S4 lower. You can see the SHCS he added to fix the problem I think you are having.

Thaniel

HAILERS

*****Correct me if I'm wrong, but in an S4 setup, vacuum enters the side of the lower intake and goes to the acutators. With the vacuum line for the brak booster also being there, do I have a gaint vacuum leak on my hands here? Or am I ok?*******

The actuators on both series use.......Pressure.

HAILERS

***How should I close this leak?****

I'd try some red RTV. Put a smear of vaseline on the lower gasket, and using your judgement, put a bead of RTV on the mating part, and put it together. You don't want to use too little, nor too much. Too much and you'll have squezze out of RTV in the intake area. And while that might not cause problems if it breaks off later in the intake, it should be avoided. I think I'd torque the studs on either side of the missing stud first then the rest. It should stop the leak if there is nothing else holding the manifolds apart.

hornbm

What does SHCS mean? I've never seen that one before. I looked at the picture and I cant quite make out what the guy did to the manifolds, If I had to take a stab at it it looks like he drilled a new hole in the intake, but I'm not sure thats correct.

Ok thanks Hailers, I'll try both of your ideas, as soon as I figure out exactly what the first one is, lol.

The last thing I have to worry about is the short running time of the engine. I recently found out today after I had pulled my intake manifolds off, that starter wire that connects to the circuit opening relay had come loose. Could that be why it only ran for a half a second?

hornbm

also you said tighten the bolts around the missing stud first, but the missing stud is the one on the end of the manifold (clossest to the firewall) Is that still going to be ok?

hornbm

bump

Thaniel

Sorry, SHCS is a Socket head cap screw (bolt that uses a hex wrench to tighten it not a hex head bolt). I guess the idea is to drill an additional bolt hole closer to the runners. Using a SHCS lets you put it gainst the runner and still tighten it.

hornbm

ok, cool. For now I'm going to try just some RTV, and if that doesnt hold then I'll go that route. I assembeled the intake yesterday anyway.