FSD failures and hard starts

[sbigos]

My '94 6.5TD 2500 Chevy has had the injector pump replaced several times under warranty. Now the warranty is out and I'm having the same issues, DTC 35, hard smoky starts while cold. From the Diesel Page, I've figured out maybe I need a new FSD and should try the FSD cooler. Warm starts are fine and there are no problems other than hard cold starts and DTC 35. Fuel always seems clean when changing the filter, which I do about every 15k miles. My questions are as follows:

1. How can I isolate the problem to the FSD?

2. How does an FSD failure cause hard cold starts?

3. Why are some vehicles more susceptible to FSD failures than others? Maybe it's the heat in Florida.

Thanks for any help.
Steve

[DmaxMaverick]

Your problem sounds more like glow plugs or HPCA, rather than IP/FSD.

DTC 35 (pulse width error) shouldn't cause the symptoms you describe, but should be addressed.

[gmctd]

DTC-35 is pulse width short, can be caused by fuel supply problems - lift pump, oil pressure switch (OPS), lift pump relay, leaky rubber seals in fuel supply system. Open lift pump fuse.
Anything that results in air bubbles in the Inj Pump.
Fuel will pump slower in cool\cold weather - requires supply system be fully operational.

[ucdavis]

Try the checklist for Stalling at:
http://www.thedieselpage.com/members/tt99-9.htm
and you'll be able to find the trouble or isolate it to the FSD.

[moondoggie]

Good Day!

Can't speak to hard starting except glow plug & battery connection issues covered MANY times in the forums. You might want to look at DTC 35 - Help! (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=004386#000000)

Blessings!

Brian Johnson, #5044

[sbigos]

Thanks for the help so far. I'm in the midst of digesting the DTC 35 forum info and started cleaning the ground connections. Still confused on how an FSD failure can cause hard starts though, as the FSD cooler manufacturers state, unless a set DTC 35 does not clear at shutdown. Anyone know if a DTC 35 active at shutdown can cause a startup in limp-home mode?
sbigos

[moondoggie]

Good Day!

During my period of DTC 35 causing SES to light, on the few occasions when I shut down with the SES lit, it started just like it did everything else during this time: perfectly. As I said, the ONLY symptoms I had were: 1) SES lit; 2) cruise wouldn't work when SES was lit.

Good Luck & Blessings!

Brian Johnson, #5044

[ucdavis]

I concur w/Moon- starting in limp mode is was no different than any other by-the-book start. But I did have occasional hard starting w/35's & 36's. Mine turned out to be the pump, not FSD, but yours could be either or just bad connections needing cleaning, or grounds fritzing up the fuel solenoid circuit.

[DAVE FERENCZ]

Hard start could also be failing solenoid on starter. How is the cranking speed.This is not likely your problem because you have fine warm start.I bet it could be a bad glow plug.

[Scooby]

A clamp on dc ampmeter can be used to locate a bad glow plug. If you have access to a dc clamp meter, it would be easy to find bad plugs by cycling the key switch with the clamp on each wire and check for current draw.

[madjack]

moondoggie,
I am having the same thing that you stated in an earlier post. I will just be cruising down the road in cruise and the SES light will come on and the cruise quits. After a few minutes the light goes out and everything works again. Did you ever figure out what was causing this. Any help would be appreciated.
Thanks Jack