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MikeC
10-13-2003, 22:48
While on a recent 750 mile trip (without our camper) I had the following occur about 50 miles from the destination, then all was well for a week while driving only locally. It then happened again as we left to come home.

What my Burban did on the way there was that it seemed to lack power, but still had boost as normal. Seemed like the truck was out of fuel. Along with this came the trans not wanting to lock the converter, or at least I assume so, as the trans temp rose. The "service engine soon" light came on the first time but reset after the truck was off for about an hour, it did not come on the second time.

The lack of power started on the highway when I used the cruise to accelerate from about 60mph. Normally the truck will just pull harder and speed up gently without any change in the trans. During this episode the RPM's came up about 500 (not normal) but the truck seemed flat and didn't accelerate. After pulling off the highway it did'nt want to accelerate normally to even 35 and I had to watch my foot to keep trans temps down.

Here's what I've checked so far.
Lift pump works, ?? pressure, it pushes fuel out vent on filter
Fuel filter
Trans fluid level and condition
SES light out since initial episode

What is wierd is that it started to do all this again as we left but it only began after we got on the highway and then only lasted about 5 - 10 miles. During our stay it ran normally in mixed driving.

My questions are:

Do I have an intermittent lift pump pressure problem? OR do I have signs of an impending injector pump failure?

AND, Would codes still be in the system to check even though the light is out?

Sorry for the length but glitch is hard for me to describe.

Thanks!!
Mike

StephenA
10-14-2003, 05:04
How about using John Kennedy's paper clip method to read the codes... It's on his website under tech tips, as I recall.

MikeC
10-14-2003, 08:23
I think the paper clip trick only works for OBD-I trucks, not sure. Have a scanner in the area, going to try that.

Mike

ucdavis
10-14-2003, 18:30
Mike- Lift Pump circuit trouble sets a DTC 0231 in later rigs at least (98 for sure, but don't know if it started in 96). Sets the code if ign volts minus LP volts > 4V for two consecutive starts (basically when LP isn't running but is asked to). 0231 turns on MIL; MIL turns off after 3 consec. starts w/out the failure & DTC clears after 40 consec. warm-up cycles w/out this or other emmission related trouble.
W/that said, if you were not towing, I don't think LP trouble would cause your symptom as an unloaded rig can usually get enough fuel from IP suction alone (I know I did for ~2K mi. till the IP caved). You can test further by running engine & opening fuel bleed by coolant crossover; if it sucks air LP isn't running, if it pumps fuel LP is pushing IP demand plus the bleed flow. BTW, cracking filter bleed is much less prefered to the front bleed petcock cuz you can suck air into filter that must be purged so it won't get in the IP.
Sooo, the likely culprit is in the IP assembly, though the whole http://www.thedieselpage.com/members/tt99-9.htm Stalling checklist is your next process. It's gotta be fuel or grounds and it could easily be the fsd. You didn't mention #miles, etc. on the Burb, IP, fsd, etc. which could be useful info. Some local parts shops will do a code scan for free; Autozone in NorCal apparently quit doing it, but you can call around or buy a code reader for 'bout a sawbuck (IP itself is likely to throw codes 251, 370, 1216, 1217 when on its way out). Did you put a magnet down into filter to see if you have metal shavings? That'd be the IP grinding itself to junk.

MikeC
10-15-2003, 12:26
ucdavis,

Thanks for the info so far!

I checked the LP with the Ign on, engine off so as to not pull air into filter housing prior to pulling filter to assure it wasn't plugged.

Truck has 98K
IP has about 60K
FSD has 35K and was new when mounted to intake on the FSC cooler

I haven't tried the magnet or checked the fuel pressure at the bleeder, both of which I want to do soon. Also, I'm going to call my local Auto Zone, where I get most of my auto related stuff and who know me, to check about scanning for codes.

THANKS again,
Mike

MikeC
10-23-2003, 09:45
:confused: Well..........I went to Auto Zone and their scanner will only pull engine codes. It showed no codes.

This morning I had a friend with a Snap On scanner pull codes for the tranny, none.

Now I have no idea other than the possibility of a bad batch of fuel.

Lacking other ideas I will drive it and hope it doesn't fail while towing the camper somewhere near BFE.

Mike

Tough Guy
10-23-2003, 17:59
When is the last time the tranny filter was changed?

MikeC
10-24-2003, 21:10
Tranny filter was changed with the install of the deep pan, probably 25K ago.

The truck is due for oil, oil filters & lube in about 600 miles. I am considering dropping the trans pan and changing that filter too. Air filter (Amsoil) cleaned and oiled about 5400 miles ago.

Mike