Z34 problem (Crank no Start)

[maybe2fast]

1991 Z34

crank no start- We don't know what to do next any Ideas fellaz

has 40 lbs fuel pressure

has spark

runs on carb clean

weak injector pulse

powers and grounds good

new PCM did not help

[maybe2fast]

come on fellaz I need some ideas!

 

Thankz Don

[Slade901]

Check the CTS (Coolant Temperature Sensor). If the CTS is failing and giving out very high temperature reading, the computer will tell the injectors to open and close very quickly. When engine is cold, it needs more fuel to initially start it.

When a good CTS works, it gives the computer the right cold temperature reading and so doing, the computer tells the fuel injectors to stay open longer to initially start the engine and then slowly goes to normal operation when the temperature goes up.

[maybe2fast]

I'll check it, any other possibilities? Fellaz?

[maybe2fast]

any?

[EurosportZ34]

LOL, this is wierd. My Z34 is actually in the shop now and it's going to stay there over night for them to work on it 2morrow yet. But anyway...it has the same symptoms. I'll post here again once they find out what's wrong with her.

[Zboy]

Will it start when partially opening the throttle? was the weak injector pulse on ALL the injectors, or just the harness? If you checked just the harness, Check each injector individually for a pulse. Then ohm the injectors, mine ohmed out at 12-12.3 ohms at 30 degrees fahrenheit. 92 lumina Z-34, sitting for days without running. Engine ice cold. The actual ohms arent as important as the spread. Below 11 ohms is bad above 12.5 is bad. any variance of more than half an ohm is bad. Ususally you will see something like 12, 12.1, 12, 12.1 13, 12.1. As long as all the injectors are between 11 and 13 ohms and grouped close together, they are probably fine. Did you check the injectors with a noid light or DVOM? Also check the harness and terminals for corrosion, damge to wires, slightly broken/ cracked wires.

[DaveFromColorado]

I had one bad injector do that to me on my old 3.1 beretta, it'd kill the whole system if I was over like 4000 rpm's or more then 3/4 throtle.

 

--Dave

[maybe2fast]

the thing with the injectors is that if you ground the individual injector it will spray just not on its own

[maybe2fast]

come on guys any ideas

[Slade901]

What do you mean It runs on carb clean?

 

Remove the intake hose to the throttle body. Spray some starting fluid in the intake of the throttle body and crank the engine to see if the engine starts for few seconds. If it does starts you got fuel related problem.

 

 

You might have 40 PSI but you might not have enough volume over time.

 

Try by-passing the fuel pump relay and manually supply 12 volts to the fuel pump. There is usually a wire hanging down near the fuel pump relay/fuse area and just put a 12 volt source there to active the fuel pump. Try cranking the engine to see if it works this time.

 

Try replacing the fuel filter and test it.

 

Check all the fuse inside the vehicle and check the fuses on the side of the engine bay.

[maybe2fast]

I'll try :!: any other ideas would be awesome thank you guys

[maybe2fast]

the vertic is.... one bad injector makes the entire car not start thank god it is the middle front one! thanks for the help guys

[EurosportZ34]

The shop finally figured out why my Z was having problems starting and with the battery draining. It was the passive restraint module or something like that located inside the glove box. I'm guessing that module locks your seat belts in once the doors are closed and gives power to the courtesy key locks outside, etc. New news to me!