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Lb7 Glow Plug Feedback Question

1117 Views 5 Replies 3 Participants Last post by  MaxRoadArmor
2001 LB7 HARD STARTING WHEN COLD (UNDER 5 f) I just replace all 8 glowplugs and the metal rails that deliver the power. I put it on the scan tool and it shows 10.9 V for the glowplug feedback. Should this be down around 5-6V?
The other question is on the intake air heater---It also shows 10.9 volts and the element bench tested fine. On the scan tool the intake air temp does not change as you cycle the intake heater. Should it?
Using the scan tool and volt meter I verified that I had power to both the plugs and the intake heater during the wait to start period.
I also put in 2 new batteries just to make sure---I have no codes now or in the history.
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might be the glow plug controler or the 175amp glow plug fuse. the glow plug and air heater circuit are connected i believe. do you plug it up when its cold? my SES light is on, the glow plug feedback curcuit A code comes up so i think my problem is a bad plug or 2. how hard are the plugs to change? they look like a pain in some areas.
The Fuse is fine. I'm unsure on the controller. I do have power to both the glow plugs and the intake heater when the wait to start light is on. The glowplugs were easy to get to after i removed the inner fender wells. I broke 2 off on each side and had to drill and use the easy out to remove them. Tried about everything---heat etc, but they would'nt budge. When I plug it in overnight the wait to start light only stays on for a few seconds. It was -22F here last night and I needed to cycle it about a dozen times before it finally fired. The real odd thing is that there is no big puff of smoke when it fires ao when it is cranking. I'm starting to lean towards a fuel delivery problem. I have good fuel pressure at the fuel rail and am running straight #1 with a new filter. Anybody ever hear of anybody having a crankshaft sensor or fuel switch act up in cold weather? I have no codes coming up and nothing in history. Frustrating.....
Had injectors replaced now glow plugs are bad. GM doesn't want to cover the cost of replacing them under the warranty. I say they went bad do to the injectors failing
same here my injectors were replaced before i bought the truck and afterwards the P0380 code was throwing. theres a whole buncha stuff covered under the emisssions warranty that should be covered 5/100,000. bring up article 1.2 page 15&16 of GM warranty manual, tell um to look it up and see what it says.
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