car together, injectors not firing
10-03-2008, 07:23 PM
#1
car together, injectors not firing I've got an LS6 in a 944. Got the whole thing together and the injectors are not firing.
I check all the simple stuff, power, ground, batt charge, ect.
I have power at both sides of the injector. Niether goes to ground when I crank it.
I purchased a standalone ECU so there is no VATS.
Ideas?
I check all the simple stuff, power, ground, batt charge, ect.
I have power at both sides of the injector. Niether goes to ground when I crank it.
I purchased a standalone ECU so there is no VATS.
Ideas?
10-03-2008, 09:19 PM
#2
Launching!
iTrader: (1)
Join Date: Jun 2004
Location: VA
Posts: 223
Likes: 0
Received 0 Likes
on
0 Posts
Your injectors are stuck closed. Happened to me. What I did was applied power to one terminal with the other grounded the other one to a spare battery. Put a fuse in line with the wire you are applying power too. I tapped it on and off with the fuel rail under pressure and off the intake manifold. Make sure the wires you are using are long enough and away from when the injector that you are trying to fire. All 8 of mine were stuck. I also added some atf to the fuel to lubricate the injectors. Like 3 tea spoons to one gallon of fuel. Smokes alittle but add more fuel to dilute. Worked for me. If your injectors are shot I have a set of 98 vette injectors in great shape! Good luck!
10-03-2008, 10:09 PM
#4
On The Tree
iTrader: (2)
Join Date: May 2007
Location: ARIZONA
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
I agree probably stuck injectors. Did the motor/injectors sit for a long time as you built the car or are they new injectors? We just finished a rock buggy with a 5.3 from a yard and every one of the 8 injectors was stuck. We were able to get a few of them functioning by tapping on the sides of the injectors with a tool. Something fairly heavy but not to heavy....just to enough to unbind the discs inside. If this doesnt work then pull you rail and take injectors out, remove the o rings then soak them in chemical of choice for few hours. Will be fine after this most of the time. Dont use anything too crazy to soak em in.... dont wanna ruin em with aircraft stripper. LOL
10-05-2008, 01:04 AM
#8
http://carprogrammer.com/Z28/PCM/LS1/Holden_LS1.pdf
Good reading! Check the section on the Crank Position sensor. It has a diagram of the sensor. If you happen to have an O-scope, it would work best, but a DMM will work. Look for voltage fluctuation on the signal wire.
Jack
Good reading! Check the section on the Crank Position sensor. It has a diagram of the sensor. If you happen to have an O-scope, it would work best, but a DMM will work. Look for voltage fluctuation on the signal wire.
Jack
10-05-2008, 11:42 AM
#11
You shouldnt have power at both sides. Sounds like you have a bad harness or something. One side should be hot all the time, but the other side should be pulsed to ground to get the injector to fire. Measure the resistance between the two terminals to one of the injectors, if there is very low resistance, i would say you problem is either harness or pcm
10-05-2008, 12:23 PM
#12
http://carprogrammer.com/Z28/PCM/LS1/Holden_LS1.pdf
Good reading! Check the section on the Crank Position sensor. It has a diagram of the sensor. If you happen to have an O-scope, it would work best, but a DMM will work. Look for voltage fluctuation on the signal wire.
Jack
Good reading! Check the section on the Crank Position sensor. It has a diagram of the sensor. If you happen to have an O-scope, it would work best, but a DMM will work. Look for voltage fluctuation on the signal wire.
Jack
Thanks for the link
, I think I have a bad Crank sensor. With a good quality analog meter I have no fluctuation in the signal wire. Do the coils usually fire from the cam sensor 'cause I have spark?
10-05-2008, 12:25 PM
#13
You shouldnt have power at both sides. Sounds like you have a bad harness or something. One side should be hot all the time, but the other side should be pulsed to ground to get the injector to fire. Measure the resistance between the two terminals to one of the injectors, if there is very low resistance, i would say you problem is either harness or pcm
10-05-2008, 01:08 PM
#14
I have very little resistance across the injector. All 8 injectors open when powered with 12volts manually. By my analog meter I am getting constat power on the signal wire from the crank sensor.
I have 12v at both sides of the injector when any injector on that bank is plugged in. Since there is almost no resistance across the injector that makes sense to me. From this I am assuming the LS is a batch fire motor, is that correct?
I have 12v at both sides of the injector when any injector on that bank is plugged in. Since there is almost no resistance across the injector that makes sense to me. From this I am assuming the LS is a batch fire motor, is that correct?
10-05-2008, 01:54 PM
#15
I have very little resistance across the injector. All 8 injectors open when powered with 12volts manually. By my analog meter I am getting constat power on the signal wire from the crank sensor.
I have 12v at both sides of the injector when any injector on that bank is plugged in. Since there is almost no resistance across the injector that makes sense to me. From this I am assuming the LS is a batch fire motor, is that correct?
I have 12v at both sides of the injector when any injector on that bank is plugged in. Since there is almost no resistance across the injector that makes sense to me. From this I am assuming the LS is a batch fire motor, is that correct?
Jack
10-05-2008, 08:52 PM
#16
Disconnect the injector and stick your two leads into the two pins. You should have 0v across the two. Then ground one lead and check for voltage on the two pins. One should be 12v, the other 0v.
It does seem like a crank position sensor problem, not an injector or injector wiring problem.
10-05-2008, 09:21 PM
#17
He's going to chassis ground with his negative lead, and checking both sides of the injector harness with it plugged into the injector. He should have 12v on both sides.
Disconnect the injector and stick your two leads into the two pins. You should have 0v across the two. Then ground one lead and check for voltage on the two pins. One should be 12v, the other 0v.
It does seem like a crank position sensor problem, not an injector or injector wiring problem.
Disconnect the injector and stick your two leads into the two pins. You should have 0v across the two. Then ground one lead and check for voltage on the two pins. One should be 12v, the other 0v.
It does seem like a crank position sensor problem, not an injector or injector wiring problem.
10-06-2008, 09:39 AM
#18
He's going to chassis ground with his negative lead, and checking both sides of the injector harness with it plugged into the injector. He should have 12v on both sides.
Disconnect the injector and stick your two leads into the two pins. You should have 0v across the two. Then ground one lead and check for voltage on the two pins. One should be 12v, the other 0v.
It does seem like a crank position sensor problem, not an injector or injector wiring problem.
Disconnect the injector and stick your two leads into the two pins. You should have 0v across the two. Then ground one lead and check for voltage on the two pins. One should be 12v, the other 0v.
It does seem like a crank position sensor problem, not an injector or injector wiring problem.
10-06-2008, 03:03 PM
#19
Thats with the injector plugged in, right? Disconnect it and check that you have 12v on only one side.
There are three wires on the crank position sensor. 12v, ground, and the signal to the ECM.
Disconnect the sensor and check for power and ground. Then disconnect the ECM and ohm out the signal wire.
There are three wires on the crank position sensor. 12v, ground, and the signal to the ECM.
Disconnect the sensor and check for power and ground. Then disconnect the ECM and ohm out the signal wire.
