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erratic idle, lean code, hard start on 95 K1500 w/5.7


mongo108
10-13-2008, 10:42 AM
Working on a 95 K1500 w/ 5.7L, auto, air. Have gotten a 44 lean code. It is hard starting, long crank time. At idle it surges, occassionally stalling. The fuel pressure regulator was recently replaced, with no change in the condition. Already checked the IAC, appears to be operating properly, and no vacuum leaks have been found. Was told to check the ignition module. Cap and rotor are probably needing replacement, and some corrosion around the module. Being a former Ford mechanic, I don't have the resources anymore to check/test the module. I was told the pickup on the module can be problematic, and haven't been able to find any specs or testing procedure for the module itself, and I'm not to inclined to start throwing parts at a family members truck. Also, have not checked fuel pressure, don't have a tester to T into the TBI on this model. Any help would be appreciated so I can get this beast going for a family member. Thanks.

mwid73
10-13-2008, 11:50 AM
Definately check the fuel pressure. These are good symptoms of a weak fuel pump. If you can not check the pressure take off the air cleaner and watch the fuel spray in the TBI. It should be a nice cone shape in each side. If it slows down or starts to drip / or "spit" at the time the truck is idling poorly or starting to die I would change that pump. Try to find a parts store that sells Delphi pumps that's what GM uses in these trucks...

mongo108
10-13-2008, 12:44 PM
Have noticed the spray pattern. Nice conical spray, no drizzles, leaks, etc. I am trying to track down a tester, hopefully can find one. Thanks

2000CAYukon
10-13-2008, 02:02 PM
Factory Manual also suggests to test 02 sensor. If the pickup coil or module where bad, I doubt you would see a lean code since the lack of spark would cause a rich code.

//2000CAYukon

mongo108
10-13-2008, 04:43 PM
O2 sensor is switching properly, until the idle goes erratic. Then the voltage drops. Wasn't sure if that would be the cause, or the result of the problem. With the lean code, it's popping that code because it's correcting lean for a rich condition and has exceeded the parameters to what it can compensate for, but I could be wrong, been out of the business for a few years now.:banghead:

mwid73
10-13-2008, 05:06 PM
Unplug the MAP sensor and see if anything changes. If the problems go away the MAP is bad. If nothing changes then it's not. Also, it could possibly be a bad EGR valve. Is the only problem when it is at an idle? How does it react going down the road / accelerating?

jdmccright
10-14-2008, 11:02 AM
Before dropping big bucks on a new fuel pump, check the fuel pressure regulator. Of course, you'll need the aforementioned "T" to test the fuel pressure, but it could be worth your time.

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