car pulsates under load when in power mode

[| 1990 ZR-1 |]

I'm acutually exeriencing a similar issue where I can't tell much of a difference between "Normal" and "Power" modes. If the issue lies in the secondary injectors, would that throw of a code, or a warning light? Is there a way to check if the secondary injectors are bad without pulling the plenum?

[tccrab]

From Marc Haibec's website:

http://zr1specialist.com/HAT%20Web/a...Resistance.htm

A word of caution, DO NOT force your volt meter probe leads into the female pins of the ECM plug.
Save yourself the agony that only took me 2 years to diagnose and repair on my ZR-1.
Shoving the probe leads into the pins serves to stretch out the female connector and then they won't make good contact with the male pins in the ECM.
Causes all kinds of mysterious intermittent problems.

Back-probe the pins instead, simply pull the rubber plugs out with needle nosed pliers.
When you look carefully at the ECM plug you will see what I mean.

Good luck!!!

TomC
'Crabs

[tomtom72]

Hi and welcome to our corner of the asylum!

I would ask do you know when the fuel filter was last changed out? They are out of the way & get overlooked. No SES light when you try to make it accelerate? Then the light goes out when you relent? Check CCM as it may store that soft DTC.

It sure sounds like it's starving for gas when you want the secondaries, but why?
2* injectors check Ohm readings hot. Ohm okay = good coils, but could be clogged tips.
2* injectors for fuel flow, could be injectors or fuel pumps. 55 PSI on rail is top of the range, FSM says 48 - 55 PSI. Check regulator hose for fuel, if fuel present regulator is N/G. Pump socks clogged?
2* vacuum system could have: a vacuum leak or bad actuators.
Collapsing air intake duct from filter housing to air horn.
These are some of the things you could look at. Not trying to make work for you. Are the injectors OEM, if so they maybe the most likely cause of the trouble.


Tom