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Symptoms of a weak IP?

6.5TD Burb

6.5TD Burb

Member
Messages
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Location
Wendell, NC
I think mine may be dieing but I'm not sure.
Problem:
Doesn't take much to set if off. I'll drive home from work (est. 20-35 minutes depending on traffic and route), let it idle for a couple minutes to cool down and shut it off. Eat some dinner and maybe leave for short drive, elapsed time from shut down to start up again: 45-60 minutes. While I'll be buckling up it will stall. I'll hard wire the lift pump (addition from p.o.) for a few seconds, hold the accel. pedal on the floor and crank it for maybe 10-15 seconds till it starts again. It did this twice tonight. Once to go to church and once leaving church.
A new lift pump has not helped this and the pmd is only a few months old. New hoses from the filter housing to injector pump (didn't see any tears/holes in hoses from lift pump to filter housing), freshly rebuilt injectors with new 60Gs, new Delco fuel cap and (and I still get a copious amount of vacuum, think filling up a gas tank with gauge sitting on or close to "E"), new fuel filter and CDR. Vacuum pump has been checked and is showing nice and strong.

Still drives fine, some days it seems to have more power than usual though. Other than the sporadic (it's always in the same spot/s but not necessarily consistent (wording?)...go fig) "fishbite" it runs just fine.

Sound like a weak IP?
 
Last edited:
If your ssd pmd is on the intake it may be causing your problem, mine lasted 3,000 miles.

Leo
 
NVM - Been relocated. Not to the bumper yet, the extension isn't long enough for that. Right now it's on the left side battery tray; it's off the motor so no more vibration but not sure about cooler air.

HighSierra - ??? Haven't read about that one yet. If I have any time at work tomorrow I'll do a quick search.
 
The RPM test can be done very simple. Start the engine and slowly accelerate to 2000RPMs. Hold it there for about 10sec and then slowly bring it back to an idle. Now you should be able to do this without seeing any spikes or drops in engine speed.
 
Engine need to be fully warmed up for 2000rpm check, and as you are moving the APP rpm should be linear to pressure applied to the APP, meaning if rpm stops traveling smoothly with the APP that indicates the IP is on it's way out.

But if you are still anywhere underhood with your FSD then that is suspect as well, I'd try another FSD 1st as it is less expensive than a IP, and if you do need a IP you can save some on it as you can buy one without a driver installed on it for about $200-400 depending on vendors discount without a driver.
 
Acesneights1 said:
When it's hot and your having trouble starting it pour cold water slowly on the IP. If it starts right up the IP is done.
Click to expand...

I thought that problem was only on the DB2 pumps? And if 94 and up if you pour water on the PMD, and it cranks then the pmd is dead and /or dying.

Was the "no start when hot" or "heat soaked" a problem on the electronic controlled pumps too?
 
Well did the RPM hold test (took the long way home to make sure it was nice and warm). Once I figured out how to keep my foot still long enough to keep it at a certain RPM it held rather steady at 2150. No RPM dropping/spiking during the slow revving.

I thought it was the PMD when it started doing this as well. Replaced the "old one" (2 months old when I took it off) with the one that is currently on there and it fixed the problem but for only a couple weeks (if even) and it started up again.
 
Odlaw said:
I thought that problem was only on the DB2 pumps? And if 94 and up if you pour water on the PMD, and it cranks then the pmd is dead and /or dying.

Was the "no start when hot" or "heat soaked" a problem on the electronic controlled pumps too?
Click to expand...

Yes. If the internals are worn the case expands when hot and the pump looses head pressure. I had a friend who had that problem in NY. Or you could just let the truck cool down. A badly worn pump usually does this when shut off very hot and then try to restart about 15 mins later. I actually thought I had that problem 2 summers ago but I put a Dtech on a heatsync in the front bumper and the problem dissapeared so in my case it was the PMD but a worn pump can also do that.
 
I bet you already considered this but could this be an OPSU problem? mine had a similar starting issue I could crank but it just stalled out unless I hit the gas.
 
There can be a rather large amount of vacuum in the tank and from the threads I've been reading on here from searching vacuum = a problem. I did read that some guys got a new cap but accidentally got one for gas instead of diesel which apparently caused some sort of problem. So I made sure to get one for diesel.

As far as I can tell OPS is fine, new AC Delco piece. It'll move with crank speed when trying to start it again.
 
6.5TD Burb said:
There can be a rather large amount of vacuum in the tank and from the threads I've been reading on here from searching vacuum = a problem. I did read that some guys got a new cap but accidentally got one for gas instead of diesel which apparently caused some sort of problem. So I made sure to get one for diesel.

As far as I can tell OPS is fine, new AC Delco piece. It'll move with crank speed when trying to start it again.
Click to expand...

Yes,

I think it was Rodd. Imploded his tank and bent the FSU in the tank. The guts in my fuel cap are gone. Drill it, hammer it, whatever you've gotta do!
 
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