Engine defueling when cold, P1689 code
12-05-2004, 04:24 PM
#1
Registered User
Thread Starter
Join Date: Aug 2004
Location: Ark.
Posts: 200
Likes: 0
Received 0 Likes
on
0 Posts
Engine defueling when cold, P1689 code
Had codes pulled the code P1689 is the only code that shows up. Engine defueling when cold and dies every now and then.
The problem shows up only when its sat over night or 8 hours at work. It don't matter how much fuel you give it, it picks different rpms to defuel. It has defueled at 1200 all the way to 2100 rpms. Once you have been driving 30 min or so it you shut the engine off, and let it set about 20 mins. It runs with no problem.
The IP has been replaced along with the CKP. There was a code P2016 when the IP was replaced. The problem stoped after the IP was put on for about 2 weeks then returned. The ecm was reprogramed after that, it lasted 2 days. I have reset the apps to many times to remember. I don't have gauges, but did check the pressure, it's fine. Also checked the boost its fine.
I have cleaned the connections on the, ecm, pcm apps, map, the 2 plugs on the fire wall and all ground wires I have found.
Can anyone tell me what is wrong, or anything that I've missed checking and how to check it.
Rodney
The problem shows up only when its sat over night or 8 hours at work. It don't matter how much fuel you give it, it picks different rpms to defuel. It has defueled at 1200 all the way to 2100 rpms. Once you have been driving 30 min or so it you shut the engine off, and let it set about 20 mins. It runs with no problem.
The IP has been replaced along with the CKP. There was a code P2016 when the IP was replaced. The problem stoped after the IP was put on for about 2 weeks then returned. The ecm was reprogramed after that, it lasted 2 days. I have reset the apps to many times to remember. I don't have gauges, but did check the pressure, it's fine. Also checked the boost its fine.
I have cleaned the connections on the, ecm, pcm apps, map, the 2 plugs on the fire wall and all ground wires I have found.
Can anyone tell me what is wrong, or anything that I've missed checking and how to check it.
Rodney
12-05-2004, 07:13 PM
#2
Registered User
Join Date: Jul 2002
Posts: 1,440
Likes: 0
Received 0 Likes
on
0 Posts
It sounds like the bypass valve in the lift pump is starting to fail. But, check your drain valve handle on the fuel filter assembly to be certain it is not barely open, or seeping a bit. The way to test is to pull a vaccum on the drain hose with the valve shut and see if it bleeds off. Also, check your filter cap and seal.
Also, if the fuel hoses are still OEM, they could well be leaking a bit of air, which will cause air to be trapped in the bypass on the lift pump causing to valve to stick open unit it gets warm fuel.
Even simpler yet, it could be a dirty fuel filter.
Also, if the fuel hoses are still OEM, they could well be leaking a bit of air, which will cause air to be trapped in the bypass on the lift pump causing to valve to stick open unit it gets warm fuel.
Even simpler yet, it could be a dirty fuel filter.
12-05-2004, 08:01 PM
#3
Registered User
Thread Starter
Join Date: Aug 2004
Location: Ark.
Posts: 200
Likes: 0
Received 0 Likes
on
0 Posts
RCW
The fuel filter and o ring seal has been changed 2 times in the last 3500 miles. On the fuel lines I don't know if there oem or not. I've only had the truck about 5 or 6 months.
! thing I forgot is, when this happens sometimes the transmission stops pulling when the engine gets power back. It's like the tranny is neutral, I just let off the go pedal then it shifts back in gear.
I checked the drain valve its not leaking it's been setting for 5 mins. with no drop in vacuum pressure (25 in.). It don't matter what the outside temp is, it's happened on an 75 deg day.
Rodney
The fuel filter and o ring seal has been changed 2 times in the last 3500 miles. On the fuel lines I don't know if there oem or not. I've only had the truck about 5 or 6 months.
! thing I forgot is, when this happens sometimes the transmission stops pulling when the engine gets power back. It's like the tranny is neutral, I just let off the go pedal then it shifts back in gear.
I checked the drain valve its not leaking it's been setting for 5 mins. with no drop in vacuum pressure (25 in.). It don't matter what the outside temp is, it's happened on an 75 deg day.
Rodney
12-08-2004, 10:23 PM
#4
Registered User
Join Date: Jul 2002
Posts: 1,440
Likes: 0
Received 0 Likes
on
0 Posts
What is happening is you are losing the communication between the ECM and the injection pump. Unfortunately, that does not mean that they are not communicating, but that during the sampling period the ECM called for some action that the VP44 failed to respond to, or visa versa.
When this first starts happening, it is nearly always the lift pump bypass valve sticking and the system is calling for more fuel and not getting a response. The pressure sensor says it is low, the computer has called for enrichment, and the ECM is stating the lift pump is correctly functioning. If you get sufficient quantities of air into the system, it will mimic the same condition.
Of course, there is always the ultimate, and that is your VP44 injection pump has started to fail. In that case the computer board in the pump itself starts giving up the ghost, and you will soon have a 1691 code, or it will simply quit running.
The wrinkle to this is your transmission acting up. I would pull the connectors for the ECM and the pump and clean them, then use dielectric grease to coat the terminals before you snap them back together. If you are having terminal problems the ECM will create confusion for the transmission, as on your truck the ECM and PCM are integrated. Then try a run and have the codes cleared and read again in a week. Have a tech use a good scanner, as you will want the instances and all the companion codes listed, which the cheapo scanners and "the twist on the key and dance three times to the right and then hop up and down" method will not reflect.
Look for fuel related codes, and if they are present start planning on an injection pump. If you get random codes, and no companion codes, then the PCM is starting to get unstable. You may get APPS codes, and then you have a sensor problem, and that will need resolution.
When this first starts happening, it is nearly always the lift pump bypass valve sticking and the system is calling for more fuel and not getting a response. The pressure sensor says it is low, the computer has called for enrichment, and the ECM is stating the lift pump is correctly functioning. If you get sufficient quantities of air into the system, it will mimic the same condition.
Of course, there is always the ultimate, and that is your VP44 injection pump has started to fail. In that case the computer board in the pump itself starts giving up the ghost, and you will soon have a 1691 code, or it will simply quit running.
The wrinkle to this is your transmission acting up. I would pull the connectors for the ECM and the pump and clean them, then use dielectric grease to coat the terminals before you snap them back together. If you are having terminal problems the ECM will create confusion for the transmission, as on your truck the ECM and PCM are integrated. Then try a run and have the codes cleared and read again in a week. Have a tech use a good scanner, as you will want the instances and all the companion codes listed, which the cheapo scanners and "the twist on the key and dance three times to the right and then hop up and down" method will not reflect.
Look for fuel related codes, and if they are present start planning on an injection pump. If you get random codes, and no companion codes, then the PCM is starting to get unstable. You may get APPS codes, and then you have a sensor problem, and that will need resolution.
12-17-2004, 02:44 AM
#5
Registered User
Thread Starter
Join Date: Aug 2004
Location: Ark.
Posts: 200
Likes: 0
Received 0 Likes
on
0 Posts
I finlly found the problem, the injector pump that was just replaced went bad. Replaced it today and it's has is running great again. You would think that for the money they cost these thing wouldn't go bad in 3K miles.
I was told by a Dodge mech how to quick check the ecm. With a volt meter, unplug the vp44, turn the key on, the top 2 should show the same as the battery minus .02 or so for wiring loss, the bottom 2 should show some 1.0 to 2.0 volts.
The Cummins dealer had put the vp 44 on and kept saying there was another problem and that they couldn't check the ecm. After telling them the ecm had been check and it was fine. Their question was how was it checked, I told them a volt meter. They finally found they had the info how their. They check the ecm and finally replace the vp 44 under warranty.
Thanks RCW for all your help, I did find 1 return fuel line fitting leaking.
Rodney
I was told by a Dodge mech how to quick check the ecm. With a volt meter, unplug the vp44, turn the key on, the top 2 should show the same as the battery minus .02 or so for wiring loss, the bottom 2 should show some 1.0 to 2.0 volts.
The Cummins dealer had put the vp 44 on and kept saying there was another problem and that they couldn't check the ecm. After telling them the ecm had been check and it was fine. Their question was how was it checked, I told them a volt meter. They finally found they had the info how their. They check the ecm and finally replace the vp 44 under warranty.
Thanks RCW for all your help, I did find 1 return fuel line fitting leaking.
Rodney
Thread
Thread Starter
Forum
Replies
Last Post
Timmay2
24 Valve Engine and Drivetrain
8
01-05-2020 04:54 PM