Plenum pull and injectors in my near future... - ZR-1 Net Registry Forums

ram_g · 11-08-2020

So I've posted elsewhere about taking back my new Nittos to Discount Tire and replacing them with a set of Michelins. The newfound ride smoothness has highlighted a bit of roughness elsewhere - specifically a bit of vibration on hard acceleration, felt primarily in the shifter but also pretty much everywhere. The Nittos masked that so I hadn't really paid it much attention these last few months.

I've been mulling over this vibration the last few days until I made a chance discovery last night. I normally drive everywhere with the power key turned on, but last night I forgot to turn it on and immediately noticed that there was no vibration on acceleration. Turned the power key on and turned on the vibration as well.

Today I did several back to back runs and confirmed the finding. The secondaries are definitely working as there is definitely increased power at the higher RPMs, but the vibration is absolutely correlated to the secondaries coming on.

Back at home I did a couple of Haibeck's tests - checked the amp draw of the fuel pumps (~10 amps, good) and grounded pin 17 of the green ECM connector (yes, both secondary actuators move). And there are no error codes.

So all this leaves me with the injectors and hence a forthcoming first plenum pull. I have Haibeck's DVD and have just placed a substantial order at Jerry's.

(My car is a 1991 that I purchased 4.5 months back with 12,850 miles on the clock. It now has almost a 1000 more, and that is despite pandemic-induced inactivity! The car sat for many years before I bought it but is generally in very good shape and almost completely original. I have been using non-ethanol gas thinking the injectors would be fine, but alas it looks like that is not going to be the case...)

If anybody thinks I am NOT on the right path, please let me know!! (And wish me well for the plenum coming-of-age-ceremony!)

11-08-2020	#1
ram_g Join Date: Jun 2020 Location: Houston, TX Posts: 183	Plenum pull and injectors in my near future... So I've posted elsewhere about taking back my new Nittos to Discount Tire and replacing them with a set of Michelins. The newfound ride smoothness has highlighted a bit of roughness elsewhere - specifically a bit of vibration on hard acceleration, felt primarily in the shifter but also pretty much everywhere. The Nittos masked that so I hadn't really paid it much attention these last few months. I've been mulling over this vibration the last few days until I made a chance discovery last night. I normally drive everywhere with the power key turned on, but last night I forgot to turn it on and immediately noticed that there was no vibration on acceleration. Turned the power key on and turned on the vibration as well. Today I did several back to back runs and confirmed the finding. The secondaries are definitely working as there is definitely increased power at the higher RPMs, but the vibration is absolutely correlated to the secondaries coming on. Back at home I did a couple of Haibeck's tests - checked the amp draw of the fuel pumps (~10 amps, good) and grounded pin 17 of the green ECM connector (yes, both secondary actuators move). And there are no error codes. So all this leaves me with the injectors and hence a forthcoming first plenum pull. I have Haibeck's DVD and have just placed a substantial order at Jerry's. (My car is a 1991 that I purchased 4.5 months back with 12,850 miles on the clock. It now has almost a 1000 more, and that is despite pandemic-induced inactivity! The car sat for many years before I bought it but is generally in very good shape and almost completely original. I have been using non-ethanol gas thinking the injectors would be fine, but alas it looks like that is not going to be the case...) If anybody thinks I am NOT on the right path, please let me know!! (And wish me well for the plenum coming-of-age-ceremony!)