Question under plenum!

When I was checking my secondary actuators the other day on my 90 zr1, I was very surprised to find two connections hanging loose above the ignition coils under the MAP. Can anyone tell me what they are for?

Looks like they would fit above the starter back at the fire-wall...I´ll attach some pics. Appreciate any help!!

Can´t send the pics, don´t know whats wrong! They are only 17k

Here is another picture..

[Jeffvette]

Two possibilities

1) The wire connecting the Coilpack frame
2) The wires that plug into the DIS module.


Based on the two pictures together it's the coilpack frame connectors.

[Jeffvette]

Also let me add, based on the way you removed things, you need to be a bit neater with it. Removing the map sensor from the plenum is not necessary. Leave it on and just unplug the vacuum line and the harness plug.

This is just an observation....no personal attack.

Coilpack frame ok! What´s the function of this? I believe previous owner must have forgotten to plug these back in when they changed the starter or something, also find some loose bolts in the valley...Strange that no codes were set, it´s impossible that they could have come loose when I pulled the plenum....Guess they have been loose for quite a while. Unfortunately I can´t get in contact with the previous owner and ask since the car is an import from Spain and the original owner has moved.

Would sure like to know the function before I plug them back in...

PS had to get a little rough to get a decent picture

Regards

[Wegone]

I beleave Jeff is right..I also don't think it will run with them lose..

[Jeffvette]

Originally posted by roadster
Coilpack frame ok! What´s the function of this? I believe previous owner must have forgotten to plug these back in when they changed the starter or something, also find some loose bolts in the valley...Strange that no codes were set, it´s impossible that they could have come loose when I pulled the plenum....Guess they have been loose for quite a while. Unfortunately I can´t get in contact with the previous owner and ask since the car is an import from Spain and the original owner has moved.

Would sure like to know the function before I plug them back in...

PS had to get a little rough to get a decent picture

Regards

They should be plugged up. As this controls the way the engine starts. The computer tells which two plugs to fire upon startup. If you remember, that is why it may take a while for the ZR-1 to start. The computer is trying to find the optimum sequence.

Also if you remove the coilpacks there is a metal frame and then there is the base which the coilpacks plug into. This is what those connectors go to.

Here is the passage from the book.

Once the ignition module determines the position of the crankshaft, it must select which of it's four ignition coils to charge. Each coil has two secondary towers for two spark plugs.

The coil secondary windings are wired such that two cylinders are 6 degrees BTDC when a crankshaft notch is aligned with the magnetic crankshaft sensor. For instance, on a typical eight cylinder, engine clylinders one and six are paired. When cylinder one is at 6 degrees BTDC exhaust, cylinder six is at 6 degrees BTDC compression. This pairing allows one coil to fire two spark plugs in series simultaneously. One cylinder requires a higher voltage for spark ionization to occur (compression), and the other requires a lower voltage (exhaust). The module can then charge and trigger each coil in firing order based on progam logic, wheras a distributer would use a rotor and a cap; hence no moving parts to wear.

I have no clue as to how your car ran with out this plugged up.

Thanks guys for the info!
This is a mystery to me...Plugged them back just to test how good they would fit, and they were pretty tight, wonder how they came loose in the first place. My tach reading has been off, maybe this has something to do with it. Should be real interesting to se what´s happening when I fire it up in the spring...

BTW both my actuators were upside down, but no problem with the valves they open and close fully, and no binding. Only 8 Hg to fully open, so I guess this is an issue that differs from Lt5 to Lt5. No need to correct mine anyway. Just ordered a new solenoid and cleaned two checkvalves that were leaking vacuum, then back in business..I have some pictures if somebody is interested!

Regards

[Jeffvette]

Roadster, I can dig through my box of parts and show you what all is comprised in this area. The Coilpack base, the frame and the coils.


Let me know.

[FrankUrbinati]

See Jeff going the extra mile to be good to a fellow ZR1er ! That's part of what's so great about owning these car's. The people !!
To You Jeff !!

Couldn´t have said it better!!!
Great forum Great people Great cars...

Yippie.. the snow is melting and temperature is rising...-18 to+6 degrees C in 2 weeks.

My new solenoid has just arrived from the US, so I´ll fire her up soon. Did some investigation and according to the electric diagram these connectors supply power to the coils, so it shouldn´t be able to run without these plugged up, as already mentioned by Jeff. But I´m 99.9% sure it´s been unplugged....4 lead connector supply each coil, and 2 lead supply all 4 coils..strange...

I´ll let you know how it goes!!

[Jeffvette]

Here you go.


http://www.corvetteforum.net/c4/jeffvette//img_0343.jpg

http://www.corvetteforum.net/c4/jeffvette//img_0344.jpg

http://www.corvetteforum.net/c4/jeffvette//img_0345.jpg

http://www.corvetteforum.net/c4/jeffvette//img_0346.jpg

http://www.corvetteforum.net/c4/jeffvette//img_0347.jpg


Might have to cut and paste links into your browser window.

Thanks Jeff nice pics!! Are those demon coils any good?

[Jeffvette]

Yes the demon coils rock. I was having problems passing emissions. I guess the spark wasn't hot enough to burn all the fuel. After putting in the SD coils I passed. NP on the pics. I got parts everywhere since the engine is being punched out.