Hey everybody,

I live in Charleston which is unusually 40 F in the mornings. I will run the car to the stop light about a 1/4 mile down the road where I sit for 5 minutes for the light to cycle. About a minute of waiting, and the car will fluctuate +/- 200 rpm at the light. It will bog down rather quickly and then over rev to compensate for the low RPM. Once the car is warm the problem and roughness of idle goes away. Am I looking at bad glow plugs? I have GD eco tune if that helps.

Glow plugs have exactly nothing to do with your problem, as they aren't on while you sit at the light. The only symptom of completely burned out glow plugs would be an inability to start the engine at temperatures below about 40 degrees F. Within about 30 seconds of startup, they go off and stay off.

It sounds to me like you might have an air leak in your fuel line, but there are other possible causes.

The two cheapest fixes for your issue is either:

A. 2nd Gen Fuel Head (Possible but unlikely honestly because we're talking about already running/starting fine)

B. Temperature Sensor - I just rebuilt my top end and when I didn't have the temperature sensor hooked up at the back of my Thermostat it idled like crap. Does it idle way up (like 900-2000 rpms) when you start it? This is another possible rough idle area.

IS it throwing any codes at all? Is there a CEL or is the Red Thunderbolt on the left side of your gauge display lit?


The most likely culprit, although I"m loathe to mention it because I don't want you to think another possible real problem is this simple, is the quality of winter diesel fuel. Make sure you are adding additive at every fill up, or the proper amount of additive for the amount of fuel you add. It helps keep water out of the lines, makes life easier on the fuel/water seperator, etc.


IT wouldn't hurt you to upgrade to the 2nd gen fuel filter head if you have not already, if you have, then change the fuel filter every 2 oil changes and your life will be simpler as well.

Hope some of this helps!

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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

It is the low idle governor fluctuating during the transition from 2 pilot to single pilot injection. Nothing wrong with your CRD, it is a slight instable idle due to the tune. I do not have a fix for it. It occurs with coolant temps between 30F to 110F.

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Providers of wholly developed aftermarket solutions for the KJ CRD.
(248) 977 - 9531

Would there be a transition between two injectors to one injector going into a stoplight at normal operating temperature, or is this my torque converter not unlocking? Engine drops 200 RPM on a somewhat agressive breaking. Car has stalled 3 times from a stop.

Quick off topic, but is that the difference in sound and power I feel when the temperature gauge is about 1/4?

Sent from my DROID BIONIC using Tapatalk 2

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2006 Sport, GDE FT Eco Tune, Custom Trans Tune
2015 Ram 1500 Big Horn EcoDiesel, GDE Hot Tune

That would be the viscous heater disengaging, I believe, at 140F.

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
RL super sliders, Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.

I'm not saying glow plugs are the problem but they stay on 'post start' for more like 160/180 seconds at that temp. More than enough time to drive 1/4mile and idle for 1min and still should be on.

So this only occurs with CRDs with a GDE tune? It's not a problem, I just wanted to know. Mine has done it for years, and it's more noticeable in the winter. You told me a long time ago that it was fine.

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2005 Black KJ Sport CRD,
GDE Full Torque ECO TUNE, GDE Transmission ECO Tune,
Samco British Racing Green Hoses
Build Date 1/05
200k miles.
Original Owner

Interesting, maybe I should pay attention to the tach when at a stop sign/light during warm up. If mine or stoutdog's fluctuate it's not enough that I've ever noticed by feel or sound with either the EcoTune or the turbo tune.

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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

Mine is almost unnoticeable. It sounds like the ac kicks on and off, maybe 50-ish rpm down than back up. Also with gde Eco. I wouldn't worry about it, even though before knowing this about gde, I was wondering if the ac still kicks in even though was off and the heating knobs in a position it was not supposed to start.

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.