99 Tahoe 5.7

[khayle35]

I've had this truck for about 8 months. Had 148k on it, has 155k. Went ditch hopping once about 5 months ago, with nothing but having to replace the torsion bar mounts. May have a radiator/cooling system leak, but it only red-lined once. I was driving on the highway, about 65, no cruise, when her RPM'S nose-dived. I goosed the gas, but she only responded to light pressure, with RPM'S only going to 1100-1400. No check engine light, and she wasn't overheating. I turned her off and now she's not starting. She's cranking, the battery's fine, the fuel pump and filter are good, the air filter is good. I have yet to check the throttle body/injectors. Any ideas where to proceed?

 

[khayle35]

*UPDATE. Tried puttingva few drops of fuel on the butterfly valve, amd theres's some strange, rapid clicking noise coming from near the battery. I tried cranking her again, and she lost some battery power, and there was a bad *CLUNK. Still no start-up

 

[Tex99Tahoe]

Sounds pretty bad. My first 'shotgun' tricks would be to disconnect battery ground, pull/inspect all fuses from all 3 zones, then after 30 minutes of disconnect, rehookup the battery and try to start it.

Things like this are the reasons I always get a set of the factory manuals...

 

[lesterl]

So? Does it crank but not start? If it is cranking, then spray a good ammount of carb cleaner into the intake. If it fires off that suspect a fueling issue. If it wont start from there, then possible ignition.

Lets start there, post back results.

 

[lesterl]

If you are getting clicking could be a bad battery (not enough voltage, have it tested.)

 

[Tex99Tahoe]

I'm still going thru my `99, looked around the battery area, found 2 engine grounds. The upper, at the thermostat, was tight but renewed it anyway. The lower, ahead of the starter, was finger tight, renewed that too. But thinking about the clicking, if it's not the starter solenoid, like from a discharged battery, then all I could find that could click and clunk like that could be the air conditioning compressor clutch. The clutch is controlled by the Vehicle Control Module (VCM), and the HVAC module, computer stuff. If they're messed up, other computers could be messed up too.

 

[lesterl]

Do you have a temp knob with #'s or with a red/blue ramp on your hvac head? ramp only would be an analog system and no computer control of the clutch, the clutch is controlled by a switch on the dash and the cycling switches in the system.