Another case of the Stalls

[VA_GMC]

'97 2500 - It now has about 92k on it.

It died today after we had been making a few short stops. Right after the last stop, the truck died just like the key had been turned off after it was running about a minute. It started right back up so we kept going but it continued to stall at various times until we got about 3 miles from home - at this point it would start but as soon as we would try to take off it would die. I had it towed home and checked the fuel filter and lift pump. I changed the filter. The lift pump and relay were replaced just before I bought the truck in Jan. 2003. The seem to be ok. I have read a lot of the previous posts from doing a search and the OPS comes up often .. but doesn't this only control the lift pump? After installing the new filter, I let it idle for about 5 minutes and then put it in gear and hit the throttle a few times. Didn't take long for it cut off again. Then it began stalling even when idling (it was doing this on the road as well - before changing the filter). The SES light isn't coming on.

Any suggestions on the next step. I know the pump is under warranty and assume this would also cover the FSD. -? I typically never have any work done by a dealer.. but if it is under warranty this may be my only option. -? It is stalling when its cool, hot, makes no diff., so I shouldn't have any trouble demonstrating.

Anything else I should do before trying to "work" with the dealer?

Thanks.

12/20/2001 045699 # J4767 - BTH GLOW PLUGS RPL 71013 miles
12/06/2001 045434 # J5974 - PUMP MOUNTED DRIVER - RPL 70691 miles
08/30/1999 G29381 # J0960 - OIL FILTER BASE RPL 32850 miles
07/07/1999 G28418 # B5751 - LT TAILGTE SUPP RPL 31683 miles
02/12/1999 G25867 # F2003 - RR DIFFER GSKT RPL 27027 miles
02/12/1999 G25867 # J3177 - OIL COOLER HOSE RPL 27027 miles
01/27/1999 G25618 # J5430 - FUEL PUMP/GASKT RPL 26520 miles
01/27/1999 G25618 # J5805 - WASTE GATE SOL RPL 26520 miles
01/27/1999 G25618 # T2020 - WARRANTY TOWING 26520 miles
01/18/1999 G25444 # J5955 - FUEL INJECT PMP RPL 26131 miles

[Turbine Doc]

Sounds suspiciously like FSD but check wiring, and fuel filt, and lift pump pressure to IP

[VA_GMC]

I'll check the press. The filter is new as of yesterday. When looking at the wiring am I looking at the harness at the FSD? I looked around a little yesterday and check the voltage on the system. Everything looked pretty good. Charging system is putting out 13.7 volts.

If get a replacement FSD, can I unplug the factory unit and try it for a few days without voiding the warranty on my pump through the dealer (there isn't a seal or something that breaks is there?) or damaging the new one by not mounting it on a cooler, etc...?

I would feel more comfortable going in for a pump replacement knowing that the FSD is the problem. Plus I would have a spare when needed.

Thanks.

[ 07-11-2004, 12:14 PM: Message edited by: VA_GMC ]

[VA_GMC]

I checked the fuel press. at the inj. pump (put a tee in right at the pump) this evening and was suprised to find that there was essentially no pressure.

I was surprised becuase when I changed the filter yesterday, I also opened that water valve and fuel was blowing out of the line. But with the tee in the line and the engine running, there was only a dribble of fuel when I didn't have the gage on. -?? Book calls for a min. of 4 psi.

Possible lift pump problem? I thought it would run o.k. even with an inoperable lift pump.

http://home.earthlink.net/~themonroes/GMC/FuelPress1.JPG

[ 07-11-2004, 05:12 PM: Message edited by: VA_GMC ]

[tom.mcinerney]

VA--Sometimes they do run fine without LP. But system designed for ops with a rather specific LP, which maintains pressure 4-8psi.
You need to find out if problem is LP, OPS, or wiring (fuse?). Get power to LP [observe polarity, LP marked +/-], check pressure again. If OK wired direct, probably need OPS. Maybe try new LP+OPS....{Running engine at hot idle can cause OPS contacts to cycle/burn, possibly bringing LP down with it.} A relay in line can cure {is fitted in '96-up}. Kennedy Diesel has a kit.

[chuckf]

VA,
I have a 97 suburban with 203,000 miles. I had problems last week with stalling. No SES codes. The engine just shut off. I could hear the lift pump working on a restart. I didn't matter if the the truck had been running for a while or if it just started, it just died. The fuel filter is relatively new. After the stalling started it got progressively worse. I talked with John Kennedy and he suggested a new FSD module. I replaced the FSD - problem gone. I just drove over 200 miles pulling my 32' trailer, no stalls. Talk to John.

[DKeen]

Sure sounds like the FSD. I have a 96 and it did the exact same thing. FSD kit took care of it.

[VA_GMC]

Thanks for the replies. My LP is definitely running. Seems that the FSD may be the problem. I am a little puzzled by the low press. at the fuel pump from the LP but I know it really pushes the fuel out when the water valve is open. I called about a new LP today -- Borg Warner is running about $82.00 and Masters (never heard of them) are running about $90.00.

I guess I will call my nearest dealer tomorrow to get the truck on the road to recovery. I have a copy of the warranty, which I am guessing covers all parts of the IP including the FSD. I thought I read some horror stories a while back about others having difficulty with the dealer - not replacing the whole pump. Should I insist on an entire replacement if the FSD is the culprit? I have a feeling they will replace whatever they think is necessary while they have the truck and tell me when I come to pick it up. Not looking forward to it.

Thanks again.

[JohnC]

Originally posted by VA_GMC:
I am a little puzzled by the low press. at the fuel pump from the LP but I know it really pushes the fuel out when the water valve is open.Maybe the pressure relief valve in the injection pump has failed. this would allow volume with low pressure...