So, I fire up a jeep to pull it in the garage, only I have the coolant temp sender disconnected (robbed the part, long story), anyhow, it revs up to about 1800 rpm's all wild like, and then idles for a few seconds and dies. I repeated this a few times before I plugged in a temp sender, and then it ran fine.

I'm thinking if the wire for the sender was damaged, that you'd be dead in the water, and the symptoms would be this weird rev up and run for a few and die. FWIW, hopefully this helps someone someday

_________________
05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

I think that with the temp sensor unplugged the ECU thinks temp in like 0 deg Kelvin or something stupid like that

Also, I think I remember Yeti mentioning that unplugging the temp sensor will help the ECU keep the glow plugs on longer for improved cold starting. But it must be plugged back in to keep it running right.

Like everything else on this engine, if a sensor is unplugged the ECU will loose its mind.

_________________
U.S. Army Retired

Yeah, it's kind of strange that the ECU let it start, and then later decided that it's too cold, hot, or has no input, and shuts it down. Even stranger that the rpms jump so high. This is a GDE eco tuned jeep, I forgot to mention that detail, probably wouldn't matter either way.

_________________
05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

Yeah, it won't run right with the stupid sensor on the back of the thermostat unplugged.

Ask me how I know....

_________________
Silver 2006 KJ 2.8L CRD Limited:
GDE ECO Tune / Fumoto Valve / E-Tecno GX3123 7v Glow Plugs / 2nd Gen Fuel Head / Mishimoto RED Hoses / Rockers/Lifters @ 114k / Hayden FC + 11 Blade Nylon / Sears P1 Battery / Transgo 45RFE-HD2 Reprogramming Kit / Timken Front Bearings

Very interesting. Keith or Yeti would have to weigh in on how that sensor is tracked through the ECU programming. Obviously it goes open-loop right after starting and that *really* pisses off the computer if that sensor data isn't there.

2+2 suddenly divides by zero and equals bullfrog in the computer?

_________________
Proud supporting vendor of LOST Jeeps
TRAVELING CRD TECH. I come to you!
Need help? Just ask! I've taken it apart more than most.
Email jeep [at] maincomputer [dot] com - BOARD MESSAGING IS BROKEN
Over 225 CRDs currently driving with my valves, timing belt, rockers, or ARP Studs.
Bad noises = REALLY bad things.

We know for past forum comments (including Keith IIRC) that the coolant temp sensors feeds/produces real temps in degrees F/C to the ECU which in turn determines the temp gauge unmarked, in degrees, needle position. We also know coolant temp at least relates to AC and viscous heater operation and probably to fuel injection amount/timing. Hence it seems logical that a report of no temp to the ECU would cause the system to go nuts. That said I would have assumed a no start with code not a start/high rev/die.

_________________
Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs