Secondaries not functioning - ZR-1 Net Registry Forums

TexasZR1 · 06-15-2019

My secondaries started acting up with the heat lately.

They work fine when cold, then after warm-up (anywhere from 5 miles to 20 miles) they stop functioning.

I first replaced the fuel pumps (they were original). Fuel pressure test shows ~40psi at idle and ~50 at WOT.

Injectors were replaced by the prior owner.

The vacuum pump is functioning properly (runs for about 10 seconds to build vacuum; cycles for about 1 second every 3 or 4 minutes).

When jumping the pink wire at the ecm to ground, i get intermittent function of the secondary butterflys when warm. When it's cool, everything works great.

I'm thinking it's the vacuum solenoid?

Wiring diagram shows only one vacuum solenoid for the secondaries. Is this correct?

I need to start ordering other parts (gaskets, etc) to pull the plenum.

As a sanity check, any other diagnostic I should do first?

Also, anyone have a parts list for stuff to order for the plenum RR?

Do I need to remove the throttle body to pull the plenum?

Do I need anything other than Jerry's "36 pc Fuel Injector Maint"?

I've also seen recommendations to block some coolant ports?

06-15-2019	#1
TexasZR1 Join Date: Oct 2018 Location: Houston Texas Posts: 40	Secondaries not functioning My secondaries started acting up with the heat lately. They work fine when cold, then after warm-up (anywhere from 5 miles to 20 miles) they stop functioning. I first replaced the fuel pumps (they were original). Fuel pressure test shows ~40psi at idle and ~50 at WOT. Injectors were replaced by the prior owner. The vacuum pump is functioning properly (runs for about 10 seconds to build vacuum; cycles for about 1 second every 3 or 4 minutes). When jumping the pink wire at the ecm to ground, i get intermittent function of the secondary butterflys when warm. When it's cool, everything works great. I'm thinking it's the vacuum solenoid? Wiring diagram shows only one vacuum solenoid for the secondaries. Is this correct? I need to start ordering other parts (gaskets, etc) to pull the plenum. As a sanity check, any other diagnostic I should do first? Also, anyone have a parts list for stuff to order for the plenum RR? Do I need to remove the throttle body to pull the plenum? Do I need anything other than Jerry's "36 pc Fuel Injector Maint"? I've also seen recommendations to block some coolant ports? __________________ 1990 ZR1 #2184 BLK/BLK. Essentially stock. Plug-in Skip Shift Eliminator.