hugger 6933

In my 89 c1500 I'm ready to crank up but no spark. The coilpacks are hot but no spark at the plug. scan tool reads no codes, can hear the fuel pump run each time the key is turned on. All grounds have been double checked . The orange [constant voltage] and the Ingition wire[red] is hot with the key on and cranking. Any body got any Ideas? Jim

Gen3Benz

iTrader: (4)

Do you have injector pulse? put a test light on the ground side of the injector and crank.
Also watch cranking rpm and cam hi and low.

I broke one of the grounds on the back of the head....had inj pulse but no spark.

hugger 6933

no injector pulse no mil no spark. ckecked the grounds again . Still nothing. Jim

hpmotorsports

iTrader: (5)

sounds like you missed a power or ground somewhere, or losing power while cranking , make sure you have 12 volts at the coils & injectors while cranking

LS1MCSS

iTrader: (18)

What harness are you using?

hugger 6933

I have the factory wiring harness reworked by lt1 wiring in PA. The cranking voltage is 12.4. The fuel pressure is 56psi[Iknow tht does'nt have anything to do with the fire] The pcm was also reprogrammed by the same people at the same time. I have two grounds at the back of the motor one at the front drivers side. I went around the harness agian to ckeck the grounds. I replaced the crankshaft sensor. Still at a loss. Jim

hugger 6933

lots of lookers ,no helpers? I plead for someones help! Jim

Rodder

iTrader: (2)

Are you sure the MIL works?

Are you seeing RPM jump up on the scan tool during crank? (you are using HP Tuner/EFI Live/etc and not some dumb code reader, right?)

hugger 6933

nope, just some dumb code reader. Jim

crainholio

iTrader: (2)

Check your INJ1 and INJ2 fuses, or whatever the harness guy put in their place. Each of those two fuses feeds one bank's injectors and coils.

If the fuses are good, whip out your volt meter and check for 12VDC at the injectors...just one injector per side will tell you what you need to know.

Report back with findings.

LS1MCSS

iTrader: (18)

There should be three ground wires bult into the harness. If you only have two at the back of the head, that could be the problem. The guy that reworked the harness may have tied two of them together, but if he didn't that may very well be the problem. If all three wires aren't grounded, it will probably not start. I have a spare harness in my garage, at home, and if I can remeber it tonight, I'll take a picture so you will see what I mean about the grounds.

fast377

iTrader: (52)

Agreed. I know I have 3 grounds on the back of the driver side head (I want to say there is one on the back of the passenger head, but I cant remember). I just went through a similar problem (I was getting spark but no fuel.)

hugger 6933

I do have battery voltage at the coils and injectors. I do have three grounds. Jim

crainholio

iTrader: (2)

Time to invest in a scantool that can read RPM and injector pulsewidth during cranking.

In the interim, I'd go back and verify connection at the crank position sensor.

crainholio

iTrader: (2)

PS: easy test to see if the PCM is seeing you crank the engine...verify the fuel pump is operating during cranking. Watch your fuel pressure guage during cranking and/or have someone listen to the pump with a mechanic's stethoscope.

You're getting the 2 second prime from the PCM, which is good. Now just test to see if the PCM spins the pump up during cranking.

If not, then you know the PCM isn't seeing the crank turning during starting.

hugger 6933

The fuel pump is NOT running during the cranking. That means crank sensor or crank sensor curcuit doesn't it? Jim

crainholio

iTrader: (2)

It's a good indicator. Check the crank sensor connector and wiring for damage, ensure it's connected tightly.

MrDude_1

iTrader: (4)

yes.

make sure the crank connector is fully plugged in. its right behind the starter and very easy to miss.

of the last 3 builds i helped with, every one of them missed that until i pointed it out, so dont feel bad if thats it.

hugger 6933

I have had someone tell that it sounds like a vats problem W ould'nt it start and die if it were? Jim

crainholio

iTrader: (2)

Have you gone over your crank sensor yet?