Ficm injector buzz test
Can anybody give me some advice on how to perform an injector 'buzz' test. I just completed replacing head gaskets, ARP Head studs, complete cylinder head overhaul, updated HPOP STC fitting, etc, and cannot get the engine to fire. Engine builds plenty of ICP: up to 2500psi cranking. I checked all injector connectors/pins, as well as ground wire connection at FICM...all seems well? Fuel pressure from FASS builds 62-64psi..no problem there...?
I have popped the little cover on the top of the FICM and tested the voltage at the far right screw: about 8.5 volts... I dont think that is right...shouldnt it be around 45Volts? I turn the key on and I get no initial buzz at all from the injectors without even cranking the engine.... When I do crank the engine the tach goes up to about 400rpm. The batteries are fully charged and the starter is brand new.
Unfortunately, I do not own a scanner, as the SCT2 programmer I have doesnt read squat!
I have checked the power fuses at the fuse box on the fenderwell and none appear to be blown...? The three wire harness plugs to the FICM are spotless (I never disconnected them until now to figure out if there was an issue there...everything looks perfect.)
I have to say, I precisely remember before I tore the top of the engine down to replace the head gaskets while trying to diagnose why the engine died, I recall the injectors buzzing as I cranked the engine over checking ICP pressure. Now, I did at some point disconnect the ground to the FICM/harness at the back and continued cranking the engine over...would this have caused damage to the FICM?
So, to recap, originally, while testing my truck with my replacement tranny a month and a half ago the engine just flat out died and would only crank... I thought I diagnosed the problem as being the HPOP STC fitting, as it definitely was bad (leaking-ruptured internal o-ring) ...so even though I thought that was why it wouldnt restart...I decided to take care of the puking issue and all is done, but engine still wont run! lol :bang :bang
Any help MUCH appreciated!
I'd say check your wiring, an injector going out won't cause your truck to not run but loose or chaffed wires will. A bad injector will cause rough idle and running conditions. The fact that your truck did this before being an intermittent issue wiggle those wires around and double check your connections.
It takes a good bit of cranking to get one to fire off after work like that due to air in the system. In fact, most shops will put a charger on them while they crank, simply because it will run the batteries dead before it has cranked enough to fire...
I have since ran down the wiring schematic to and from the FICM and right now it appears that there is no ground being sourced FROM the FICM to the FICM relay, to activate the relay. THERE IS however, 12+v input at #7 pin of FICM plug with KOEO and a constant 12+V at #27 pin whether the key is on or off..... ( :shrugs ) I can manually depress contact on FICM relay at fuse panel on fenderwell and I will then get a constant 48+ Volts at farthest screw to right on top of FICM...even when cranking engine..though the engine will still not fire!! Something is awry within the FICM IMO...whether its a synch issue or logic issue, I just dont know, as my head is spinning!
Eventually we'll get it figured out, even if I have to drag my truck to a Ford Dealer! :damnit
I will say though, she may not run, but she sure looks good! LOL
I appreciate everyone's input. :thumbsup
well according to the thing swamps posted elsewhere your FICM is putting out too low of volts
This is posted by Jonathan from swamps:
If your 6.0 will not start cold, the issue may be either the glow plugs or glow plug controller, or it can be the FICM (Fuel Injection Control Module). If after a long cranking with no start you get a lot of white smoke (raw unburnt fuel) out the exhaust, the problem is in the glow plug system. If you do not get any smoke, the problem is probably in the FICM.
The 6.0 injector has two solenoids on it; one turns the injector on (open) and the other turns it off (close). A few years ago, Ford came out with a new program referred to as inductive heating for the FICM, intended to combat issues with missing and rough-running during cold startup due to sticking spool valves in the injectors. This program works by running “extra” current through the close coil to generate heat and warm up the spool. On paper it was an excellent idea, and I advised a lot of potential injector customers to have their FICM’s reflashed rather than buy a set of injectors.
Based on my testing, it appears that the early models of FICM’s only used the inductive heating when the EOT was less than 48*F or so. The “first” updated heating strategy turned it on any time the EOT was less than 184*F, meaning every time you started the truck if it was shut off for more than 10 minutes! Ford’s newest update to the heating strategy has it coming on below 148*F; better, but that’s still a lot of current draw.
Unfortunately, there have been some very serious consequences.
Although the FICM on the 6.0 is way more “intelligent” than the IDM on a 7.3, its basic job is to convert 12VDC to 48VDC and deliver this to the injectors at the proper time. Under normal operating conditions, the FICM typically draws 6-7 amps at 12V into the FICM power supply, which is well within its design limits. However, with the inductive heating active this current draw increases to 24-32 amps—it pegs the 30 amp meter on my test bench! Although the FICM power supply is capable of sustaining this load for short periods of time (1-2 minutes) it eventually gets very hot.
If this was all that happened, things wouldn’t be too bad, but there are several components on the printed circuit board that were not properly soldered during the manufacturing process, and as the PCB heats up and expands, the solder under these components cracks and they lose their electrical connection. The FICM’s 48 volt power supply is actually four separate or independent units; if one of the four goes down, the other three can supply enough current to run the truck, even with the inductive heating active. If two of the four go out, the truck will start and run normally as long as it is warm out, i.e. as long as the inductive heating does not turn on. If three of the four go out, the truck will probably not start or run unless it is at full operating temperature, and even then it may not start. If the injector voltage is over 35 volts, they run OK, although not as well as when it is 48 volts. If the voltage drops below around 24 volts, the injectors cannot fire. While most scan tools will display the FICM voltage, they do not always show the correct value. For instance, AutoEngenuity can only display voltages between 40 to 56 volts, so if the voltage is 35, it will display 40.
How to check your FICM for proper voltage output.
(Perform this check when the engine is completely cold.)
1. Remove the two bolts that hold the coolant reservoir to the cowl and push the reservoir out of the way forward and to your right. You do not need to disconnect any of the hoses.
2. On top of the FICM is a small cover held on by two #20 Torx screws; remove these two screws and pry the cover off.
3. On 2003 and early 2004 trucks, you will see 7 screw heads under the cover. On 2004 and later trucks you will see 4 screws.
New Page 1
4. Take a multi-meter set on DC volts and connect the ground lead to battery negative, and with the key ON measure the voltage at the screw on your right—closest to the driver’s side fender. Do not let the probe short against the case! The voltage should be right at 48 volts. Anything between 47 and 49 is good.
5. Have an assistant cycle the key and measure the voltage during the initial key-on buzz test. Voltage should not drop below 46 volts.
6. Next measure the voltage while cranking the engine. If voltage stays at or above 45-46 volts, the FICM is fine. Abnormally low battery voltage can give a false low FICM voltage reading, so make sure your batteries are good.
The procedure is the same for FICM’s with 7 screws, except that you will be checking voltage at a different screw, as shown in this picture.
New Page 1
If the voltage is above 46 volts in all the tests, your FICM is in excellent condition. If it is between 36 and 45 volts its OK, but not great. If it is between 25 and 35 volts, you have serious FICM problems.
I am coming to understand that the FICM relay is not activating/closing its contact due to the fact the supplied GROUND circuit that is suppose to be provided by pin#27 at the FICM isnt happening...hence, when the key is turned on, there is no main FICM power being supplied to the FICM! :damnit
Also, as I understand, pin#27 will measure B+ voltage at FICM connector WHEN CONNECTOR IS DISCONNECTED FROM FICM, but when connected and key is turned on, pin#27 actually becomes a GROUND circuit for the FICM RELAY BY THE FICM ITSELF.... :bang
OH ERIC (ID) AND JOHN G...would you Ford geniuses care to help a fellow 6.0 owner out??? lol
Thanks Outlaw, I appreciate your response. :thumbsup
no problem, beyond that you are beyond my smarts. Hopefully one of the 6.0 geniuses will help ya
anyone have a picture of which screw to check with the 7 screw version?
Make sure you have all the connectors on the driver side fender plugged in good.
Also, the screw for the 7 Pin FICM is in the row with 4 screws and is closest one to the center of the motor, if anyoen finds this thread and needs to know
|All times are GMT. The time now is 02:45 PM.|
Powered by vBulletin®
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.