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IP replace time?

B

bshull

Member
Messages
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1
Location
Buhler, KS
On my 95 burb it is getting a real hard cold start. Lots of white smoke that last 15 or more seconds and it does not sound right, the sound is too "soft" for a diesel cold start, also the engine has the diesel "rattle" but it is not as loud as it used to be when warmed up. The sound change has been a gradual thing that started last summer.

I was in Minnesota a month ago and it started in cold weather -5 deg F without being plugged in with lots of white smoke. This morning it was 1 deg and it would not start, put jumper cables on and it started after a lot of cranking.

I have tested the glow plug system (duratherms) and it is working. Plugging it in will make starts a little easier but still a lot of smoke.

The truck will fail the 2000 rpm test. I hooked up gmtd scantech to check timing and it was 10.5 deg for actual, 10.4 for desired and -1.54 for TDCO. Looking at idle fuel rates I noticed the rate was 2 mm. i thought this should be higher, around 8 mm.

I have most of the reliability upgrades; diamond eye exhaust, walbro lift pump, duratherms, new batteries (two weeks old), and remote mounted PMD. All modifications are less than 1.5 years old. Truck mileage is 195,000 miles and I do not think the pump has been changed.

I think everything else is up to snuff, is there anyway to check the ip further?

Thanks

Brian
 
You said that you checked the GP system, but did you actually test each individual GP? Mine starts hard with white smoke, but I only have 4-5 GPs working. My IP only has about 10,000 miles on it.
 
I am getting about 5 to 6 psi out of the ffm at idle.

I did check all the easy to reach glows, driver side and the front three on the passenger side. All checked out just below 1 ohms. I am also getting power to the glows that I was able to check.

Thanks

Brian
 
bison said:
Pop test the injectors,you could have some pissers
Click to expand...

x2

Also if your idle fuel rate is 2mm3 that could cause you to fail the 2000 rpm test, it makes the throttle really touchy. You may have to take the cover off the IP and re adjust the OS.

The best way to check a glow plug is to remove it and watch the thing heat up.
 
The #9 will actually probably bring the mm value down, because it offsets the fueling, so right now its offset like 6mm3 from an OS that wasnt calibrated correctly, a higher resistor will offset it a litte more to make the same fuel seem like less to the PCM.

The 2mm3 at idle is too low, need to adjsut the OS until it is around 8mm3
 
Thanks for all the help

it is running a 9 resistor, I replaced it when i moved the pmd off the pump.

I agree the injectors need tested. The opti adjust has always scared me a little. I will read on the forum to see what I find about this procedure. I have had this burb for almost two years, most of my problems have been the previous owner trying to tweek something, perhaps he tried to get a bump from the optical sensor and moved it too far.

My main concern is it seems to have gotten worse within the last two months.

It should warm up a little this weekend so i will have a look then,

Thanks for the help!

Brian
 
After some consideration and thoughts of traveling to the frigid north in a week or two I did not feel I had the time to tinker with the IP so I bit the bullet! Purchased a freshly rebuilt IP and installed it. This was a tough decision and I know I probably would of gotten it fixed if I had more time to experiment on the IP however the previous owner was a bad mechanic who had to "touch" everything in an attempt to make it bigger, better, stronger. I have no idea what else he might of done.

I use this truck for work and breakdowns cannot happen, not to mention when it is sub 0 and you are 800 miles away from home you really do not want a breakdown.

Everything seems better, much better. Once all the air was bled from the system and timed it pops off really well (now I want it to get cold to see what happens). I also noticed no smoke at idle, before the ip switch I had a little haze in the exhaust while the truck was idling. No more haze. The throttle has better snap and the engine sounds much better.

I suspect as mentioned above the previous owner tried an optic bump and moved it too far. I also suspect the pump was on its way out anyway. As far as I am concerned I think a refreshed pump was a good way to go, I wonder if it will yield better fuel mileage?

Thanks for all the help guys!

Brian
 
For less than a new IP and no hassle messing with the current one I could also program an EPROM to correct for the uncalibrated OS. Although then it would not work quite as well on a replacement IP if ever in the future without the Optic bump. Although it would certainly still work, just show an oddly high idle fuel rate, rather than the erroneous low rate which was likely causing the haze, as it hunted for a fuel rate up and down to make it idle at the right RPM.

The good thing is that if you got an actual new rebuild from a real Stanadyne shop it would be a 5521S model, with the S having upgraded hardening and coatings on internal wear items, and it should prove to be more reliable and consistent for you.
 
Yes I did get a 5521s pump. I did not think of reprogramming the eprom, but as you said if I had to change it later it might not work as well on a new ip.

Thanks

Brian
 
Sometimes, we just have to bite the bullet and change the IP. The time of experimenting and troubleshooting is probably going to cost more, considering the possibility of down time when the truck is needed.
 
If something is making me money I won't hesitate to spend money on it.
 
For those that can do it themselves and have access to scanners its not so terrible on the wallet. My kind of troubleshooting is a weekend or less, so thats also not always really a drawn out process. Knowing what to look for or what to try and having all the tools to do it is another thing as well though. I have worked with 4 other people to unbump an OS either because of their own or PO bumping or they received a rebuilt IP that wasnt calibrated. Afterwards they said it never ran so well, just from that change. So although its not yet mainstream, wouldnt want to shy people away from giving it a shot.

You'll have to let us know if it helped the cold start situation, did anything else get changed since? Batteries, starter, glows, ect...
 
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