starting issues
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The injectors receive pulses from the ECM through a fuse on each bank. The injectors have a coil and one coil wire goes to 12v and the other wire is pulsed to ground by the ECM. First check the fuses with an ohmmeter. Buy a noid light from an auto parts store or make one with an LED (light emitting diode) and a series 680 ohm resistor (both available from Radio Shack) and connect the light across the plug from an unplugged injector and see if the LED pulses during cranking. The homemade noid light must have the correct polarity on the injector plug. If you have spark, then you should also have injector pulses. If you have pulses to the injectors, spark, fuel pressure, then check for constant fuel pressure during cranking and check for fuel pressure holding for a long time after the ign is off. Also, try spraying starter fluid into the MAF during cranking to see it will start. Measure the resistance of each injector coil, they should be about 16 ohms. A better measurement would be to measure the inductance and Q of the injector coils, but this requires an impedance bridge. Very low resistance on only one injector coil on each bank will prevent all the injectors on that bank to pulse.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
An ohmeter is a very poor test, the impedance bridge will find a coil with a turn to turn short which will load the bank and prevent all the injectors on that bank to work. An ohmeter cannot find this kind of coil failure. A good test with the noid light is to first try one injector and if no pulsing, then unplug the remainder of the injectors on that bank and try it again. If you get pulses, then you have one or more defective injector coils.
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Drifting
Joined: Oct 2003
Posts: 1,594
Likes: 0
From: CALGARY ab
check fuel pressure on rail, first, if no, check fuse, then fuel relay, also listen for fuel pump start up with to on..then check fuses, INJECTOR
Pro
Joined: Feb 2010
Posts: 677
Likes: 3
From: Metairie LA
First off- is check engine light on with the key on? If not check fusable links by the battery they provide 12 volts DC to orange wire at ECM.
Another issue could be the VATS signal to the ECM. My vats module was bad but would allow the car to crank - just not sending proper signal to ECM to tell it to pulse injectors.
It would seem like it was trying to fire but then nothing. Made the 50hz signal generator - problem solved (for me).
I had both of those issues.
Another issue could be the VATS signal to the ECM. My vats module was bad but would allow the car to crank - just not sending proper signal to ECM to tell it to pulse injectors.
It would seem like it was trying to fire but then nothing. Made the 50hz signal generator - problem solved (for me).
I had both of those issues.
Team Owner
Joined: Jan 2003
Posts: 20,320
Likes: 248
From: Summerland B.C. Canada
Thread Starter
Cruising
Joined: May 2010
Posts: 12
Likes: 0
Ok i tried the light and got nothing... yes the check engine light is on but it stays on after all the others go off.. from sounds of it my ECM isn't getting signal from distributor or the vat is messed up .. I'm trying to find someone with a scanner for a reasonable price to see if they could tell me why the check engine stays on... Everything you all have told me has been helpful hopefully with these last few things i can get it running
Team Owner
Joined: Jan 2003
Posts: 20,320
Likes: 248
From: Summerland B.C. Canada
Is this a new problem, or did you buy it with this problem ?
Have you tried to retrieve trouble codes from the ECM ?
http://members.shaw.ca/corvette86/No...it%20Check.pdf
http://members.shaw.ca/corvette86/En...ButWontRun.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
Have you tried to retrieve trouble codes from the ECM ?
http://members.shaw.ca/corvette86/No...it%20Check.pdf
http://members.shaw.ca/corvette86/En...ButWontRun.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
Thread Starter
Cruising
Joined: May 2010
Posts: 12
Likes: 0
sorry i have been gone.... the service engine light has been on since i built it not sure if it was on when i bought from person it wasn't running at the time i don't figure it was... but i replaced ign module and it still doesn't give signal