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TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
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It's getting cold in Iowa. I'm ~2 months into owning an 06 Liberty CRD Limited. Got the GDE tune ~ 1 month ago. Really enjoying it.

I've noticed a significant increase in crank times with the colder weather. When the jeep has been cold soaked in ~35-45F air temps I'm having to crank for ~3-4 seconds to get it to start. This is up from ~ 1 sec when warm. The cold start takes longer than any of my other diesels vehicles (Cummins, VW TDI). Is this normal for the CRD? Is it a function of the GDE tune? I've got a lift pump installed and no indication there's air in the filter. I plugged the MAF back in after getting the GDE tune. Fuel Filter is less than 1 month old. Got the V6 Airbox with the Amsoil airfilter and it's less than 1 month old. Not getting any glow plug errors. I do have the fuel heater and viscous heater disabled but don't think that would cause this issue.

Thoughts or suggestions?

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
Ripster
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Joined: 19/07/2009 08:05:49
Messages: 15
Location: UP of Michigan
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I have found nothing that starts like a TDI, even the old ones. The CRD just seems to have to crank, even before the tune. It may have
gotten a shade better, but it is not the explosion that the TDI does, it just fires. You hear the starter and the engine is running.

2005 Silver Limited CRD
GDE Eco Tune
PML Differential Cover/Crankcase Mod
Tal & Hadas Grill Guard/TransGo Shift Kit
V-6 AirBox/Lunar Boost & EGT
Lund Cold Weather Grill Insert
Cat 2 Filter, Cummins Lift Pump
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GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 350
Location: Southeast Michigan
Good question. We have noticed this on both of our vehicles as well. In warm conditions the start is very quick, then in the range of 40-50 F the crank times are about 3 seconds. As the temps get lower, the starts begin to improve again. We saw 1-2 seconds at 30 F a few days ago. The temperature range you are having issues with is when the glow plugs stop having pre glow or it is so short the glow light barely flickers. We have not modified the glow calibration yet, but the longer crank times in mid-ambient temps may justify seeing if we can have the glow plugs on for a second or so to get some heat in the chamber. With a cool engine block the start ability is not the best without any preheating of the glow plugs. Let us know how the start times change with varying temps as the winter rolls in...it should improve.

The other issue with the KJ CRD when comparing to other diesels on the market relates to the starter and cranking speeds. The gearing and torque of the starter is only producing cranking speeds of about 105-110 rpm in very cold conditions. Other products will have cranking speeds of 120-140 rpm in the same condition. This difference in speed is huge when we want to compress the air in the chamber. The faster the cranking speeds, the more heat build-up due to compression and less leakage past the rings.

If anyone else has noticed this or other variance in cranking times, please let us know.
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MrMopar64

Joined: 07/07/2009 08:09:33
Messages: 2
Location: Southeast Michigan
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Don't forget also that the Jetta (from 2006 and prior) had a higher compression ratio - 18.5:1 in the 2006 1.9L, upwards of 19.5+ in older engines. This combined with a higher cranking speed (especially with a smaller engine) makes cold start-ability much more improved over the KJ engine with its wimpy starter and 17.5:1 compression.
95BadBoy

Joined: 19/07/2009 06:48:47
Messages: 9
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I have noticed an increase in cranking time also. Though not as bad as posted above. At 40 degrees and above - it is almost instant. Lately been seeing about a 2 sec delay to start at 19 to 20 degree am start temps, and upon start it will very briefly run up to about1300 to 1500 rpm and just as quickly settle to 750.

Also have not seen the glow plug light stay on - just the little blip as the dash goes through it's startup proceedure.

05 KJ CRD Sport - Lt Khaki with GDE Tune
05 TJ RME - Silver with stuff
GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 350
Location: Southeast Michigan
There is another factor that makes the Jeep take a little longer to start when compared to the older VWs. The KJ is a common rail engine and the first 2-3 engine revolutions are used to fill the rail with fuel and pressurize it to the proper pressure. During this time, the injection is not yet even activated. The older VW had unit injectors that are capable to fire immediately.

The tune added the rpm flare right after the start to assist with a stable idle and to help build vacuum slightly quicker than the stock calibration.
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TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
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Has anyone experimented with other starters that would offer higher crank speeds?

GreenDieselEngineering wrote:The other issue with the KJ CRD when comparing to other diesels on the market relates to the starter and cranking speeds. The gearing and torque of the starter is only producing cranking speeds of about 105-110 rpm in very cold conditions. Other products will have cranking speeds of 120-140 rpm in the same condition. This difference in speed is huge when we want to compress the air in the chamber. The faster the cranking speeds, the more heat build-up due to compression and less leakage past the rings.

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 350
Location: Southeast Michigan
We have not tested other starters, but there are several on the market that would provide faster cranking speeds. It would be important to make sure the pinion is matched for the flywheel and the alignment is correct. We are not aware of any off-the-shelf starters for the KJ and some manufacturer design work might be necessary.

During our cold start tests the last few days, we have noticed significant variance in start times based on battery voltage. The red top in our 06 is starting to go...fast. With the coolant temps around 5 C the 2006 KJ started in 2.35 seconds and the battery voltage was at 10.7V. In the 2005 KJ the start only took 1.0 seconds and the battery voltage was at 11.2V. The lower system voltage affects the glow plug temperatures and the voltage supplied to the injectors. This reduces the engine's ability to have optimized combustion. Once the engines started and the alternators kicked in, the voltage on both vehicles stabilized at roughly the same point. We are replacing the battery today in our 06 KJ and will post results in a few days.
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TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
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Thanks. I'll be checking my battery . . .

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
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Was your battery voltage data points during the start (while spinning the engine) or just sitting there without a load? My battery voltage is dropping to around 12.1 V after sitting for about 8 hrs. On the other vehicles I've had this usually means needing a new battery. Looks like I've got a new battery in my near future. Do you guys recommend the Optima's or do you have a better alternative?

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 350
Location: Southeast Michigan
We measured the voltage during the first second of "key-on" before starting a cold engine. There is some draw from the glow plugs during this period. Today with the new optima red top we measured 11.2 V and the engine started in 1.35 seconds. The battery voltage seemed to have a strong positive effect.

12.1 V is not a bad number with no loads, try measuring it with a load from the glow plugs in the morning. A failing battery will have a larger voltage drop, ours was down in the 10s V.

We trickle charged it for 10 hours and measured voltages around 11.7 V, then after three days of sitting the voltage would drop to about 10.7 V.

Here is a rundown on the 06 with new battery voltage measured at the terminals from this evening after sitting all day at 55 F.

key off 12.17 V
key on 11.75 V during glow phase, steadies out after several seconds at 12.05 V
cranking 9.70 V lowest visibly seen on hand held meter
running 14.30 V
shutdown 12.50 V trickled down to 12.2 V after 30 seconds

Colder temps will drop all these numbers. We have seen cranking voltages drop down in the 7s at -15 F.

The optima has very high power density. A good battery for this application. It would be interesting to know how many people with failed batteries ever charged their battery for any reason? The gel batteries require a specific charger designed to charge in a specific manner to promote battery life. We only have a regular/deep cell charger and have a feeling this contributed to the demise of the battery. Time to go shopping for a new charger...
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GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 350
Location: Southeast Michigan
Yesterday after driving our 06 with new red top, the voltage after shutdown was 12.8 V (warm battery). This morning the voltage (with key off) read 12.3 V. The readings vary wildly depending on the conditions.

We also measured the current draw inherent with the vehicles after sitting overnight. Both the 05 and 06 measured almost 1.7 amps of current across the terminals, not sure how this compares with other vehicles yet. Most vehicles have some sort of leak rate for current, usually low enough to be able to start the vehicle after a few weeks of sitting (in a perfect world).
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TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
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Good info. Went out and checked 3 of my vehicles. I disconnected the negative terminal of the battery for a minute and then put the amp meter between the battery and the vehicle cable.

2006 liberty CRD. Current drain starts out in the ~1.5 mA range and after about 15-20 seconds stabilizes at 290 mA.
2001 VW TDI. Current drain starts out in the ~300 mA range and after about 5 seconds stabilizes at 30 mA.
1990 YJ. Current drain starts and stays at ~28 mA.
Didn't do the big Cummins as its 2 batteries and its raining . . .

Seems like my Liberty has a substantially higher steady state current load in the off condition than my other vehicles. No wonder it has the lowest battery voltage of all my vehicles after sitting overnight (my other vehicles still have ~12.6-12.7V on the battery after sitting overnight while the CRD is down to ~12.1). If you let it sit over the weekend (Friday afternoon to Monday morning) that's ~60 hrs and 18 Amps of its capacity lost. Yikes.


GreenDieselEngineering wrote:Yesterday after driving our 06 with new red top, the voltage after shutdown was 12.8 V (warm battery). This morning the voltage (with key off) read 12.3 V. The readings vary wildly depending on the conditions.

We also measured the current draw inherent with the vehicles after sitting overnight. Both the 05 and 06 measured almost 1.7 amps of current across the terminals, not sure how this compares with other vehicles yet. Most vehicles have some sort of leak rate for current, usually low enough to be able to start the vehicle after a few weeks of sitting (in a perfect world).

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
Offline
That above estimate of mine is pretty rough. There are several battery drainage calculators on line that should give better info. Here's an example.

http://www.gizmology.net/batteries.htm


2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
TDIwyse

Joined: 01/10/2009 06:58:20
Messages: 54
Offline
Does anyone know the impact of this TSB and the battery drain issue? GDE, does your tune impact this TSB?


http://www.allworldauto.com/tsbs/NHTSA__JEEP_LIBERTY_technical_service_bulletin_10498.html

2006 Liberty Limited CRD
2004 Ram Quad Cab 4x4 Cummins
2001 VW Jetta TDI
1990 YJ with 2006 Cummins B3.3T
 
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