Plenum removed. Change coils pack or not

[Siwir]

Hi,
I'm quiet new owner of 1990 Zr-1 corvette and I just decided to pull off the plenum due to first injectors change after 28 years
My question to more experience members is do I have to change coils on 50k miles car or not. Dont know if current oem products are as good as factory coils.
Thanks for some advice
Btw Car run ok on normal power even on high rpm, just on full power mode lose power and hesitate to accelerate

[Demps]

I'm not a fan of throwing parts at a problem. It's not too hard to pull the plenum once you've done it so here's my technique:

I assess ignition wellness by monitoring for a miss, wire integrity, coil resistance, plug condition...to start with. I've found: drive the car a gear high in steady cruise and gradually/slowly add throttle. If it misses, odds are you have an ignition issue--Plug condition or gap, wires or coils.

So, if you suspect any ignition problems you could change the coils...but you may find it's the wires or plugs. A free check is to check resistance across the coil posts and then across the wires paired over the coil. Plus change the plugs.

Ted

[Siwir]

Hi,

Thanks for quick replay. So I’m going to just exchange vacuum solenoid (arrives tomorrow form USJ) and will measure resistance on all coils. (I’ll compare to new / one spare I have). If resistance would be ok then I will not change coils pack this time. I hope new injectors and new vacuum solenoid solve performance issue. I have never felt like she run on full power mode. It seems based on injector housing inspection that secondaries throttle where not used long time… A lots of carbon on the walls.

[jss06c6]

Originally Posted by Siwir

Hi,

Thanks for quick replay. So I’m going to just exchange vacuum solenoid (arrives tomorrow form USJ) and will measure resistance on all coils. (I’ll compare to new / one spare I have). If resistance would be ok then I will not change coils pack this time. I hope new injectors and new vacuum solenoid solve performance issue. I have never felt like she run on full power mode. It seems based on injector housing inspection that secondaries throttle where not used long time… A lots of carbon on the walls.

Just FYI, it's not uncommon for the secondary ports to be dirty since they aren't always used, dependent on your tune..

Sent from my XT1585 using ZR-1 Net Registry mobile app

[Siwir]

Originally Posted by jss06c6

Just FYI, it's not uncommon for the secondary ports to be dirty since they aren't always used, dependent on your tune..

Sent from my XT1585 using ZR-1 Net Registry mobile app

Ok good to know.👌
I just received vacuum selenoid from rock auto and it seems that this unit keeps vacuum worst then my old😞. Is this normal ? When you apply vacuume on one site of this selenoid there is slow leak.

[XfireZ51]

At the very least, I wouuld disconnect all the harness connectors, pull plug wires from coils, and coils of coil mount brackets. Clean up any oxidation and apply dielectric grease where appropriate. Save urself some headaches later.