brokegenetic

I have a 95 vert z28 stock it was running perfectly and one morning would not start.

Original opti with newer cap rotor(riveted & sealed), the motor cranks and sometimes starts
I can get it to start if pedal is wot, but idles as if its lean and dies if i punch it and get rev it up slowly though.

At the beginning it was getting no injector pulse(when it was not starting) now it gets a weak pulse (with noid light), injectors get full voltage.

Fuel pressure has been constant whether car started or not, 41 prime and 37-38 running constant pressure.

Check gauges light is on, gauges work, light was on before I removed waterpump.

I tried replacing opti with a good used unit and same symptoms.

Today I will be checking and cleaning all grounds.

Is there any way to check ignition switch without replacing it yet?

I don't have a scanner but will be hunting my neighbor down so I can use his

Any ideas?

d2stephen

I'm having just about the same exact problem. Did you happpen to find a solution?

Hal Fisher

Weak battery or bad coil or IC module maybe?

Hal

brokegenetic

Okay its been a while cause I've been working but finally got my hands on a snap on scanner the car no longer starts, still cranks,

tried one used opti and one new, same symptoms; sparks, cranks, no injector pulse, the scanner gave me a code 18(no crank signal) everything else checks out.

Scanner states it might be an ecm problem and to check all grounds, I have cleaned the ecm ground on the block, the one on the driverside/coil stud area, new strap, cleared codes and still no go, same code pops up

Any ideas?

brokegenetic

scanner just started going into mismatch communication/no communication to spitting out just about every code there is like 52 53 then it went back to normal just sending code 18 and 48( but thats cause I have the maf off)

Injuneer

DTC 18 is a problem with the injector circuits. Use Shoebox's LT1-specific code list, not the generic one in the scanner.

http://shbox.com/1/Dtcs.htm

brokegenetic

What would cause a dtc 18? Any test I can do to verify pcm is good?

Injuneer

The PCM is seeing the wrong voltage on one (or more) of the injector circuits when it tries to fire the injector. PCM supplies a ground to fire.

Key on, check the pink wire to each injector connector, measuring against a good engine ground. Should have 12V on each pink wire.

Connector off the injectors, measure the resistance across the two pins on the injector. Should be 12-15ohms,

Get a set of 'noid lights, crank the engine and verify that each injector is getting a ground pulse from the PCM, to fire the injector.

That will verify all parts of the injector circuits, including the PCM.

brokegenetic

With key on I'm getting 12.99 to 13V

injectors are from 12.5 to 12.8 ohms

got the noid lights and the injectors are not pulsating, lights just stays on

monday I'll take the pcm to a place that supposedly can check them,

anything else I can do till then?

brokegenetic

Got another pcm in and still no good, same symptoms and still dtc 18, I guess I'll tear the plastic covering and check every wire tomorrow

brokegenetic

Double checked everything, replaced terminals on ground wires due to some corrosion and nothing.

Decided to go with the code the snap on scanner gave me which was no crank signal and started checking found that there was no juice going to the crank fuse by the driver's side door and then traced it lower

I think its the ignition switch and connector

brokegenetic

http://s308.photobucket.com/albums/k...tionswitch.jpg

http://s308.photobucket.com/albums/k...hconnector.jpg

meissen

Yikes! That doesn't look too swift at all!

brokegenetic

Installed the switch and connector on saturday and runs like a champ. Starts on first crank everytime!!!

95mysticta

im having the exact same issues! sent you a PM