losing sleep over P1693
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From: Armstrong B.C.
losing sleep over P1693
I now realize P1693 is a companion code but i can't figure out to what. Using a solus pro scanner, it tells me to delete the code and then go to the other module to find another. Well i delete it and then there's nothing anywhere, will any OBD2 scanner work on my 99 ctd. Truck has started sputtering at high RPM since the weathers getting colder. Also after deleting the code it comes back everyday. anyone deal with anything like this.
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Unless you have a professional scanner you cannot get all the codes, and you cannot sequence the code scripts to look for associations. That is not bad, as most people do not need that level of detail.
What the P1693 is telling you is that you have a code that is coming from the PCM that is telling the ECM it is failing a checksum from one of the powertrain components. The main problems that are issued from the PCM are cruise control errors, TPS/APPS failure errors on automatic transmissions only, low charging system voltage, or the VP44 computer is failing to detect a reset to idle timing or is seeing low fuel pressure after the throttle is closed.
Given you are seeing the problem occur in colder weather I would look to the fuel filter or the lift pump as the culprit. I would also expect that you have some miles on the OEM VP44 and the erosion around the timing shuttle is probably to the point that your internal pump pressure is a bit low at idle.
Get a reading on the fuel pressure from the lift pump and after it is through the filter, and if it is over 9 psi, then it is an internal VP44 issue. If under that you either have a dirty filter or the lift pump is starting to go.
What the P1693 is telling you is that you have a code that is coming from the PCM that is telling the ECM it is failing a checksum from one of the powertrain components. The main problems that are issued from the PCM are cruise control errors, TPS/APPS failure errors on automatic transmissions only, low charging system voltage, or the VP44 computer is failing to detect a reset to idle timing or is seeing low fuel pressure after the throttle is closed.
Given you are seeing the problem occur in colder weather I would look to the fuel filter or the lift pump as the culprit. I would also expect that you have some miles on the OEM VP44 and the erosion around the timing shuttle is probably to the point that your internal pump pressure is a bit low at idle.
Get a reading on the fuel pressure from the lift pump and after it is through the filter, and if it is over 9 psi, then it is an internal VP44 issue. If under that you either have a dirty filter or the lift pump is starting to go.
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From: Armstrong B.C.
I just changed the filter and have a gage on the lift pump (inlet of housing) and has never gone below 6psi wot and 12 at idle, also am wondering about my TC it has stayed locked up a couple times while trying to stop. I don't have easy access to the solus pro i was using so would one of those cheaper scanners pick up the other codes or should i spend the cash at the dealer to use their scanner. Thanx guy's. Havent checked codes since i did the filter and it's a 99 so can't do the odometer trick.
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If you have 5 psi any day of the week the VP44 is ruined! They absolutely must have a minimum of 9 psi to circulate enough fuel to keep them cooled at WOT.
The difficulty with any scanner is that the VP generally fails without any codes whatsoever. It is the nature of the beast and why it is so important to make certain that you have a good quality rebuild with the proven updates. Also ran rebuilds will have you back here in short order, and sometimes they do not even last through the first filter change.
That said, the hundred dollars or so you spend at a decent dealer to have the system scanned may turn up IAT, MAP, or some other sensor with a failure pattern. That would be a lot cheaper than a new VP.
The difficulty with any scanner is that the VP generally fails without any codes whatsoever. It is the nature of the beast and why it is so important to make certain that you have a good quality rebuild with the proven updates. Also ran rebuilds will have you back here in short order, and sometimes they do not even last through the first filter change.
That said, the hundred dollars or so you spend at a decent dealer to have the system scanned may turn up IAT, MAP, or some other sensor with a failure pattern. That would be a lot cheaper than a new VP.
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From: lyman, utah
If you have 5 psi any day of the week the VP44 is ruined! They absolutely must have a minimum of 9 psi to circulate enough fuel to keep them cooled at WOT.
The difficulty with any scanner is that the VP generally fails without any codes whatsoever. It is the nature of the beast and why it is so important to make certain that you have a good quality rebuild with the proven updates. Also ran rebuilds will have you back here in short order, and sometimes they do not even last through the first filter change.
That said, the hundred dollars or so you spend at a decent dealer to have the system scanned may turn up IAT, MAP, or some other sensor with a failure pattern. That would be a lot cheaper than a new VP.
The difficulty with any scanner is that the VP generally fails without any codes whatsoever. It is the nature of the beast and why it is so important to make certain that you have a good quality rebuild with the proven updates. Also ran rebuilds will have you back here in short order, and sometimes they do not even last through the first filter change.
That said, the hundred dollars or so you spend at a decent dealer to have the system scanned may turn up IAT, MAP, or some other sensor with a failure pattern. That would be a lot cheaper than a new VP.
A lot of people now know about bad lift pumps and think they are the cause of VP44 failures; NOT SO! Starting with the early 98’s, not only were they weak pressure wise, but also had exposed terminals on the bottom that corrode off in salt environments. The way to tell if you have a corrosion sensitive pump is to see if the electrical connection is a plug on a 6-inch pigtail coming from the bottom of the pump. If the plug is on the top cover of the pump you’re all set!
If the lift pump fails the truck stays running because there is another vane pump in the front of the injection pump, which keeps the fuel flowing AND THEREFORE LUBRICATION to the rotor. As long as there is return fuel flow from the injection pump there is lubrication to the rotor.The existence of the vane pump in the front of the VP44 is why these trucks keep running with a bad lift pump! The only accurate way to test a lift pump is to monitor pressure UNDER LOAD and if it is above 5 PSI, no performance is lost and the pump is OK. If pressure is less than this, a drastic reduction in horsepower can be felt, especially when pulling a trailer. The usual scenerio is a customer puts a performance box on his truck and the lift pump can't produce enough fuel to make more horsepower, and the performance product gets the blame.
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From: Armstrong B.C.
I'll try to get it to the dealer, one other thing i noticed is my exhaust manifold is cracked (supprised). so i can see the lack of power but not a stumble, and it's getting worse so for now i'll blame the cold. Thanx for the input.
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Johnh, lubrication is not the issue. It is plain and simple - heat.
I have had hundreds of VP44's apart, and the failures are nearly always the front bypass port diaphragm, the rear housing, and the computer. The temperature failures occur when the pump body exceeds 280 degrees F, and the front diaphragm softens and then bursts letting fuel pressure drop too low at the timing puck to allow it to work properly, or the heat destroys the computer, and you have inadequate fuel pressure to compensate for the excessive clearance on the timing puck in the rear case, or as some refer to it as the timing rotor.
Yes, some early pumps lost computer connectivity, but the vast majority of the problems are from inadequate supply of fresh cooling fuel. But, it really makes no difference, if the computer is toast then the pump is toast; if the diaphragm is blown the pump is toast; and if the rear timing port has eroded such that there is inadequate internal fuel pressure to shift the timing, the pump is toast!
I do agree that a perfectly good pump with a close tolerance rear housing will safely run at 5 psi at WOT. However, I have yet to see a used pump with some mileage that has not had that rear housing replaced with the linered version get enough cooling fuel at 5 psi.
The big witch on these pumps is that rear housing that blows out the center section of the "timing slot" for the bypass solenoid puck. That blows out from cavitation, which is the result of excessive fuel pressure from the pump itself eating away the alloy on the housing. Heat destroys the front diaphragm, and then you end up with inadequate internal volume and pressure to get the puck to move in the blown out bore!
I have had hundreds of VP44's apart, and the failures are nearly always the front bypass port diaphragm, the rear housing, and the computer. The temperature failures occur when the pump body exceeds 280 degrees F, and the front diaphragm softens and then bursts letting fuel pressure drop too low at the timing puck to allow it to work properly, or the heat destroys the computer, and you have inadequate fuel pressure to compensate for the excessive clearance on the timing puck in the rear case, or as some refer to it as the timing rotor.
Yes, some early pumps lost computer connectivity, but the vast majority of the problems are from inadequate supply of fresh cooling fuel. But, it really makes no difference, if the computer is toast then the pump is toast; if the diaphragm is blown the pump is toast; and if the rear timing port has eroded such that there is inadequate internal fuel pressure to shift the timing, the pump is toast!
I do agree that a perfectly good pump with a close tolerance rear housing will safely run at 5 psi at WOT. However, I have yet to see a used pump with some mileage that has not had that rear housing replaced with the linered version get enough cooling fuel at 5 psi.
The big witch on these pumps is that rear housing that blows out the center section of the "timing slot" for the bypass solenoid puck. That blows out from cavitation, which is the result of excessive fuel pressure from the pump itself eating away the alloy on the housing. Heat destroys the front diaphragm, and then you end up with inadequate internal volume and pressure to get the puck to move in the blown out bore!
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From: lyman, utah
Johnh, lubrication is not the issue. It is plain and simple - heat.
I have had hundreds of VP44's apart, and the failures are nearly always the front bypass port diaphragm, the rear housing, and the computer. The temperature failures occur when the pump body exceeds 280 degrees F, and the front diaphragm softens and then bursts letting fuel pressure drop too low at the timing puck to allow it to work properly, or the heat destroys the computer, and you have inadequate fuel pressure to compensate for the excessive clearance on the timing puck in the rear case, or as some refer to it as the timing rotor.
Yes, some early pumps lost computer connectivity, but the vast majority of the problems are from inadequate supply of fresh cooling fuel. But, it really makes no difference, if the computer is toast then the pump is toast; if the diaphragm is blown the pump is toast; and if the rear timing port has eroded such that there is inadequate internal fuel pressure to shift the timing, the pump is toast!
I do agree that a perfectly good pump with a close tolerance rear housing will safely run at 5 psi at WOT. However, I have yet to see a used pump with some mileage that has not had that rear housing replaced with the linered version get enough cooling fuel at 5 psi.
The big witch on these pumps is that rear housing that blows out the center section of the "timing slot" for the bypass solenoid puck. That blows out from cavitation, which is the result of excessive fuel pressure from the pump itself eating away the alloy on the housing. Heat destroys the front diaphragm, and then you end up with inadequate internal volume and pressure to get the puck to move in the blown out bore!
I have had hundreds of VP44's apart, and the failures are nearly always the front bypass port diaphragm, the rear housing, and the computer. The temperature failures occur when the pump body exceeds 280 degrees F, and the front diaphragm softens and then bursts letting fuel pressure drop too low at the timing puck to allow it to work properly, or the heat destroys the computer, and you have inadequate fuel pressure to compensate for the excessive clearance on the timing puck in the rear case, or as some refer to it as the timing rotor.
Yes, some early pumps lost computer connectivity, but the vast majority of the problems are from inadequate supply of fresh cooling fuel. But, it really makes no difference, if the computer is toast then the pump is toast; if the diaphragm is blown the pump is toast; and if the rear timing port has eroded such that there is inadequate internal fuel pressure to shift the timing, the pump is toast!
I do agree that a perfectly good pump with a close tolerance rear housing will safely run at 5 psi at WOT. However, I have yet to see a used pump with some mileage that has not had that rear housing replaced with the linered version get enough cooling fuel at 5 psi.
The big witch on these pumps is that rear housing that blows out the center section of the "timing slot" for the bypass solenoid puck. That blows out from cavitation, which is the result of excessive fuel pressure from the pump itself eating away the alloy on the housing. Heat destroys the front diaphragm, and then you end up with inadequate internal volume and pressure to get the puck to move in the blown out bore!
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From: Armstrong B.C.
get this now, if i nose her downhill and torque stall it at 1500 it spits and sputters in rev and low. but not on the flat wont do it till yer moving at 1500 locked up and light peddeling it. 2200 to 2500 it stars again when moving up a slight grade. and are there any other problems with the "53" other than coolant cracks (not that there good) just wondering.
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From: Austria Europe
Sounds like a fuel problem to me- on my 98.5 one of the screws of the in tank module had rubbed a hole into the fuel pickup line in the tank. The result was aerated diesel to the IP, it di hate it. It would run decently if I kept the fuel above 3/4 or 7/8 full, but the problems would start if I had it nose up or nose down on a less than completely full tank.
I replaced the line in there with a 10mmID line that goes straight to my frame rail mounted pump. No more troubles since then.
PS: more than 200 k miles on the stock VP44
I replaced the line in there with a 10mmID line that goes straight to my frame rail mounted pump. No more troubles since then.
PS: more than 200 k miles on the stock VP44
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From: Armstrong B.C.
the fuel pressure gauge never skips a beat unless it sucks air and doesn't make it change. and it doesn't seem to matter if the tanks full or empty. just driving me nuts, i'm sure i will figure it out when it's on a tow truck, can't wait.
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From: Armstrong B.C.
ok so i ran fuel lines from the lift pump to a gerry can today, pressure and return, and guess what does the same **** thing. also replaced the line from LP to IP no difference at all. i see a fire in it's near future.
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From: Monkton, MD
I had the same problem with my truck. it had a bunch of codes including P1693 and my fuel pressure never went below 5 psi. at high RPM it would shutter and blow white smoke. I changed the fuel filter and checked the connection for lift pump and vp44. turned out to be the lift pump so i replaced it with an airdog 150 which comes with a bigline kit to eliminate the stock filter housing. now there is no more shutter and the code is gone. One of the best systems and an easy install. It fixed mine. GOOD LUCK!