crank no start

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10-07-2016, 03:09 PM
beaver50

crank no start

About a month ago my car started to crank for 10-20 seconds befroe it would start.I got over at a friends and it wouldnt start back after turning it off.I checked the fuel pressure and it was low so i replaced the fuel pump.I replaced it with a racetronix pump.It started up fine for a few times and started doing it again.So while having the trans rebuilt.they checked it for me.Codes came back MAF,O2 sensor and knock sensor.So Monday I brought it home and ive not tried to started it until today.I put the maf on.Now It just cranks,it tried to hit 1 time then nothing.Now it just cranks and will not start.Its getting fuel and fire to the opti.Anybody have any ideas whats going on.
10-07-2016, 03:13 PM
Camaro96

Check the wires that run to the MAF , I believe it should be 5v and I know for 96 the power wire is pink. Double check the fuel pressure.

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10-07-2016, 03:25 PM
beaver50

My car is a 94 Z28,Ive checked them.i also put the old one back on to see if it would start.Still no start.fuel pressure is 42 lb.
10-07-2016, 04:03 PM
Injuneer

The power supply to the MAF is 12 volts on the pink wire (all years 94-97), when measured to the black/white wire. The signal wire (yellow) is a variable frequency, about 2,000 Hz at idle.

Have you ever run a data log? I know I've helped you with at least a 1/2-dozen problems over the past few months, but can't recall if you logged it.

When the fuel pump primes and shuts off, how fast does the pressure drop?
10-08-2016, 10:24 AM
beaver50

No ive never data logged it.Im not sure on how fast the fuel pressure drops.Ill check it.I know its 46lb then when I crank it.It drops to the 42lb.I dont know whats going on with it.It just started taking time cranking before it started.A few times,I would crank it and let the key off.It would start running.like you cranked it too long or something.Thats how it tried to start 1 time yesterday.
10-08-2016, 02:08 PM
Injuneer

You indicate you "have fire at the Opti". Does that mean you pulled the coil wire off the Opti, held it near a ground and it sparked? If so, did you then check for spark at several plugs?
10-08-2016, 03:25 PM
beaver50

injuneer,You have give me alot of help and I do thank you for it.Ive had nothing but trouble out of this car sense I bought it.But I hope to have everything on it replaced(I HOPE).Im getting fire and fuel.Thats why im confused.If you have fire and spark it should start.
10-08-2016, 06:47 PM
Injuneer

But.... did you check for spark at the plugs? You said to the Opti. What if the rotor came loose? No spark, or incorrectly timed spark to the plugs.
10-09-2016, 02:48 PM
beaver50

Ill have to check it.
10-10-2016, 02:59 PM
beaver50

Im getting fire from the opti.I have threw the plugs.i have no idea why it will not start.I need help!!
10-10-2016, 04:37 PM
Injuneer

Have you checked the fuel pressure since the problem started? I know you posted the PSI numbers, but those look like what you measured in one of the earlier posts. I helped someone about two weeks ago who installed a new pump, and the flex pipe for the fuel pump, in the tank had fallen off.

Try starting it with the MAF disconnected.
10-13-2016, 03:36 PM
beaver50

IVE checked everything i know to check.Everything is good i have fire and getting plenty of fuel.I cant figure it out.IM going to send it too a mechanic.They know more than me.ILL let everybody know what happens.