Revs drop to 700 when come to a stop

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Hey all!

2006 crd with weeks 1 and 2, in take fuel pump and gde eco tune.

What controls the revs in the crd? When i come to a stop my revs drop down to 700 then after stopping it revs up to about 800 then settles around 750. Sounds like it's about to stall.

Thanks all.

Chris

WWDiesel · **Posted:** Wed Jan 25, 2017 8:58 am

The PCM controls all engine speeds including idle using inputs from all the various engine monitor sensors and input from the accelerator petal and crank speed sensor...
It does this by the amount of fuel that is injected via the injectors based on input from all the sensors!

First thing I would recommend in your case is to pull and clean your MAP sensor or replace it.
Also, are you getting any DTC's (check engine lights) and if so what are the "P" codes?
:SOMBRERO:

flash7210 · **Posted:** Wed Jan 25, 2017 9:22 am

undrgnd wrote:

Hey all!

2006 crd with weeks 1 and 2, in take fuel pump and gde eco tune.

What controls the revs in the crd? When i come to a stop my revs drop down to 700 then after stopping it revs up to about 800 then settles around 750. Sounds like it's about to stall.

Thanks all.

Chris

Does it do this every time you come to a stop or only when cold after you first start it up?

What you describe sounds like the torque converter lockup clutch not being fully disengaged when coming to a stop. This is a common problem that is related to the transmission fluid drainback issue. But it only occurs when trying to drive away after first starting the engine and can cause the engine to stall.
Some easy things to do:
Make sure the trans fluid level is at the full HOT mark +half a quart
Let the engine idle in N for a minute after starting before driving off

If its happening at every stop no matter how long you have been driving it, then I dont know. We need some sensor data to help figure it out.
Maybe one of the accessories is dragging, like the AC compressor or power steering pump or viscous heater. Whenever one of those items is actively engaged idle speed should bump up slightly to compensate for the load.

WWDiesel · **Posted:** Wed Jan 25, 2017 10:53 am

Actually, I understand from my transmission expert; the torque converter stall issue right after starting up and driving for a short distance is wear issues in the front pump assembly with a plunger sticking causing the TC to lockup and stall out the engine. :roll:

Not really related to the drain back issue when first starting and experiencing poor TC engagement when placed in "R or D"...which adding an additional qt. of ATF+4 will help solve..
:SOMBRERO:

flash7210 · **Posted:** Wed Jan 25, 2017 12:29 pm

WWDiesel wrote:

Actually, I understand from my transmission expert; the torque converter stall issue right after starting up and driving for a short distance is wear issues in the front pump assembly with a plunger sticking causing the TC to lockup and stall out the engine. :roll:

Not really related to the drain back issue when first starting and experiencing poor TC engagement when placed in "R or D"...which adding an additional qt. of ATF+4 will help solve..
:SOMBRERO:

Not wanting to get into a pissing match over little details, but...

I believe the two are related.
In that both instances are related to a valve in the pump being lazy and not wanting to wake up and do its job. Idling in N for a minute helps wake it up, so to speak.
And slightly over filling the transmission just keeps it...
...fat and happy.

WWDiesel · **Posted:** Wed Jan 25, 2017 2:34 pm

flash7210 wrote:

WWDiesel wrote:

Actually, I understand from my transmission expert; the torque converter stall issue right after starting up and driving for a short distance is wear issues in the front pump assembly with a plunger sticking causing the TC to lockup and stall out the engine. :roll:

Not really related to the drain back issue when first starting and experiencing poor TC engagement when placed in "R or D"...which adding an additional qt. of ATF+4 will help solve..
:SOMBRERO:

Not wanting to get into a pissing match over little details, but...

I believe the two are related.
In that both instances are related to a valve in the pump being lazy and not wanting to wake up and do its job. Idling in N for a minute helps wake it up, so to speak.
And slightly over filling the transmission just keeps it...
...fat and happy.

No problem, think we on same page!

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Thanks for all your replies.

This happens all the time cold or hot.

My map is maybe 1000 miles old so that should be sweet.

No codes or lights at all.

I'll have a look at the fluid and go from there.

Thanks for the advice.

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Ok so I have some more data. Again no codes no stalling no check light. Oil levels are correct.

When coming to a stop cold and at temp engine, my load reading shoots up to circa 50%. My fuel rail psi flactuates between 4600 to 4900 psi. This I belive may be causing the engine to idle low and sound bad like almost wanting to stall.

What could cause the above??

Thanks

flash7210 · **Posted:** Tue Feb 07, 2017 4:30 pm

Rail pressure seems normal.
Load is too high.
Something is engaged that shouldn't be.
What happens to load when you pop it into neutral?
Does load change with the AC on or off?

On a hot summer day, electric cooling fan on HIGH, AC-ON, and stopped with foot on brake and trans in D, my load reading is about 33-38.

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Cold engine. With just in nuetral 36 no brake 36. With brake 36.

In drive stopped with brake on 53..with ac on 56 to 58...

What could be engaging??

Edit..I just popped it in N and the transfer case in N and it still does it...the car also revs a little bit on its on...on then off like it's hunting. No ac on.

WWDiesel · **Posted:** Wed Feb 08, 2017 3:29 pm

Please read:
Transmission front pump 68009879AB (RL009879AE)
Severe wear of the TC limit valve bore in the front pump housing results in loss of converter release oil pressure. Reduced release pressure at low speed and idle can drag the converter linings, causing engine surge, pulsation or stall.
The torque converter limit valve spring in the 45RFE, 545RFE front pump can often break. This valve limits converter release pressure. A broken spring can cause the valve to become stuck and result in converter clutch release issues including engine stalls at low speeds.
Chrysler vehicles equipped with 45RFE, 545RFE and 68RFE transmissions often experience TCC related troubles. These may or may not include trouble codes accompanied by TC clutch slip, no lockup, overheating and / or loss of fuel economy. In some cases, the TC clutches may be unable to release TC lockup, resulting in improper lockup functions and / or complete engine stalling. Problems such as these can be caused by excess wear in the TCC switch valve bore, which allows vital control pressure to escape the circuit. Replacing the complete transmission oil pump assembly with a new updated assembly or reconditioning the bores with the proper tools and installing an oversized TCC switch valve kit can restore crucial clearances for renewed TCC control and operation.

A good transmission shop should be able to diagnose the problem... :roll:

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Ouch. Thanks all. Appreciate the input.

rankom · **Posted:** Wed Feb 08, 2017 8:39 pm

if you can , do the return fuel flow at each injector just to see if they are returning same amount of fuel , may not be problem in this case but hey why not check it , personally i like them to be balanced out same

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

rankom wrote:

if you can , do the return fuel flow at each injector just to see if they are returning same amount of fuel , may not be problem in this case but hey why not check it , personally i like them to be balanced out same

Hey rankom

Do u do this by putting a tube in the top of the injectors (ie remove the line with the little clip) and letting the car run. Is this called the fuel spill return line?

Do u think an injector can cause this problem?

Cheers

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

rankom wrote:

if you can , do the return fuel flow at each injector just to see if they are returning same amount of fuel , may not be problem in this case but hey why not check it , personally i like them to be balanced out same

Hey rankom

Do u do this by putting a tube in the top of the injectors (ie remove the line with the little clip) and letting the car run. Is this called the fuel spill return line?

Do u think an injector can cause this problem?

Cheers

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

rankom wrote:

if you can , do the return fuel flow at each injector just to see if they are returning same amount of fuel , may not be problem in this case but hey why not check it , personally i like them to be balanced out same

Hey Rankom

To do the above do i remove the clip and hose from on top of the injectors and let the car run a bit. The fuel should flow in bottles to measure the difference between the injectors. Is this what you mean?

flash7210 · **Posted:** Thu Feb 09, 2017 8:42 am

undrgnd wrote:

Hey all!

2006 crd with weeks 1 and 2, in take fuel pump and gde eco tune.

What controls the revs in the crd? When i come to a stop my revs drop down to 700 then after stopping it revs up to about 800 then settles around 750. Sounds like it's about to stall.

Thanks all.

Chris

I take back what I said earlier about your engine load being too high.

Lets take a step back and review what happening...

You have a GDE tune.
Engine starts up normally but has a somewhat low, rough idle.
Cold engine, in gear, and when viewed with TorquePro shows engine load of about 50%.
Fuel rail pressure is normal.

First, if its only doing this while the engine is cold and the engine never stalls then I think you have nothing to worry about.
Second, this symptom might be a "feature" of the GDE tune. So if you are really concerned you may want to contact GDE.

My observations on my CRD:
Cold engine, idling in gear, rpm is 725-750.
Engine load is about 50%.
I occasionally get a rough idle when cold, but after I've started driving it it becomes smooth and normal. And once things have warmed up engine load (at idle, in gear) returns to its normal ~35%.

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Thanks flash. I will go for a solid drive this weekend and re do the test with an at temp engine. I will also do the flow test and come back with an update.

rankom · **Posted:** Thu Feb 09, 2017 8:14 pm

yeah , that is the test ,remove clip and small hoses from top of injector solenoid , i have proper test kit , you can make your own , with some clear empty water bottles and 4 small tubes (MUST BE SAME LENGTH) so 2ft each or so. if your alternator pulley or TC is not loading your engine , it is possible something is going on with fuel supply, check all basics first low pressure side Filter , when you fill up them small test bottles (IDLE ENGINE ) about 2min and check fuel level in them should be almost same 2-3 mm up or down . some fuel injector shops are friendly and can give you an honest answer if you can find one , to be honest real and only accurate test is the bosh bench test.

undrgnd · **Joined:** Sat Mar 26, 2016 4:47 am **Posts:** 194

Is there a way to remove the hose from the t peice that come out of the injectors with out breaking them or will it not break?? I assume I need thr t peices to put my own hose in.

Cheers

Revs drop to 700 when come to a stop

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