Cold Start...Poor engine performance [Archive]

Spindrift

01-07-2005, 09:04

All was well during this past Summer and early Fall. Say hello to Old Man Winter.

After a cold start-up, and while driving under light acceleration, I started to feel real "fishbiting"; a severe hesitation, grab, bump, whatever you want to call it. When it's really cold, I feel this condition for about 12 minutes of driving time...until the engine is close to operating temperature. The hesitation/bucking is very pronounced upon acceleration and I feel the fishbiting once I'm driving the truck at a constant speed. I thought that the fishbiting and overall horrid cold engine running condition could have been caused by bad glow plugs and older injectors. I had always wanted to install new injectors so I thought this would be a good time to do it and kill two birds with one stone by installing the new glows at the same time. Unfortunately, the problem is still there, just as before. Again, this condition goes away as soon as the engine reaches operating temperature.

New IP last Summer, lift pump is one month old, TDC offset(-1.76). Checked operation of lift pump during glow cycle and once engine is running...pressure is good.

It appears as though this gremlin is entirely temperature dependent.

Any ideas? Thanks.

gmctd

01-07-2005, 09:35

So it heals after the wiring warms up\dries out - I'd suspect connectivity issues.

Harness grounding and connections - happens every fall\winter, all these electrical gremlins.

rjschoolcraft

01-07-2005, 10:02

JD, good to see your post. Hadn't heard from you in a while.

I was thinking fuel solenoid issues but hadn't come up with wiring glitches yet. Sounds like it might be on target.

Spindrift

01-07-2005, 11:08

Any possibility this might be in the OPS? If so, does it make sense to simply replace the switch or is there a good test procedure?

Ryan Colley

01-07-2005, 11:24

Hey Spindrift - I have the same problem with my 1988 K2500 (6.2 L mechanical injection) when it is VERY cold. Same thing with my (former) 1995 6.5 L. I was never able to trace down the problem before selling it (ate one too many PMDs for wallet to handle...). I had replaced the injectors, glow plugs, OPS and lift pump several times and no change. Only seems to happen when it is colder than -20 celcius (which happens quite a bit here in Canada. Using the block heater doesn't seem to have any effect. Let us know if you solve this problem.

Spindrift

01-07-2005, 11:47

Thanks for the good news. :(

gmctd

01-07-2005, 15:27

Still skirmishing in a never ending struggle for right, reason, and sanity over there, ronniejoe.

They seem to think I'm a Diesel Terrorist, striking at snake-oil and magic potion with swift strokes of the pen.
'but they would not listen, they're not listening, still.....perhaps they never will'

However, I pick up a little here, a little there, a little somewhere else in my quest to know the PCM and FSD - makes it all worth it.

Had a poster from the FSD design-house show up for a bit, but another poster, obviously still employed there, frightened him off.
PM'ed him, but by then they must have gotten to him and started him back on his 'medicine', from his sedate response.
He then faded back into the woodwork.

Alas, poor Yorick......

Or, perhaps - What, me worry?
;)

Kennedy

01-07-2005, 15:59

My 96 did this at one time too. Strange as it may sound, I've found that how cleanly it starts in relation to good glow cycles seems to be a factor. I have a 95 here that has been stalling cold. Went to start it today, and it just did not want to go. Finally started it and it went, sounded solid,but shut off like the key was turned off. Finally got it started and put 7 of 8 plugs in. If I have to pull the downpipe loose, it's not going back on in it's crushed form...

Anyhow, it passed the 3 hrs outside test. We'll see what the am brings...

On edit: I should add that it had perfectly functioning 60g's in it, but night and day improvement with the QH's...

Dvldog 8793

01-07-2005, 16:28

Howdy
I had the EXACT same problem this winter/fall. Posted here several times, other people had the same problem but no answers. I had this problem before and after a new longblock. The only things that were retained was the fuel system. Pump was only 15,000 miles old and the injcrs/GPs were about the same. GPS all checked good and they are QH's. They do work great BTW.
This is what I did to FIX the problem...
Blend my own fuel.
I now buy fuel ONLY at a truck stop and run about 10 gallons #1 and top off with #2 and a shot of additive in my 32 gal tank. This completly fixed the problem INSTANTLY. KNOCK ON WOOD!! :D That was 4 tanks ago. The only thing I can think is that I was getting a partial gel in the system and then once it warmed up and circulated enough fuel it would clear up.
Give it a try, what can it hurt.
L8r
Conley Janssen

Spindrift

01-07-2005, 17:13

What about that OPS? Cold temps not allowing the switch to close causing the lift pump to shut down for a spell. Got a new OPS laying around. Best to switch 'em, or is there an easier test?

gmctd

01-07-2005, 20:16

Connect a hose and ~15psi gage to the water drain valve, open it and check for same pressure when cold as when warm.

Kennedy

01-08-2005, 06:18

The lift pump on this one runs a LONG time after cold start attempt as there is a lot of residual oil pressure.

I'll be trying it shortly here.

Spindrift

01-08-2005, 06:23

JK,

Not quite sure what you're inferring from that last comment.

Kennedy

01-08-2005, 09:52

Residual oil psi keeps the OPS active so you will hear the pump run a long time after an attempted start.

Fired right off this AM, but one cylinder laid down so I shut it off reglowed, and it started on 8 again. We'll have to see about that #6 plug somewhere down the road.

Truck shut off on accelleration several times today. Just like a guy cut the key off. Started right back up though. I checked connections, jiggled everything etc and no stall. Removed optic filter harness and plugged in direct to pump. Snugged the battery terminals and went for a drive. Felt more responsive, and never stalled. Before, stepping into it was very lazy. Now the TCC seems to unlock and downshift response seems better. May have been the cables. Time will tell after it cools.

ECT on Tech 2 ran 200

markrinker

01-08-2005, 12:06

Obviously the cold brings out the worst in our rigs, and exposes inherant weaknesses in wiring, glow systems, injectors, etc.

My opinion is that the bucking first described here is probably fuel quality or quantity related.

Have you changed your filter recently? If not, I would first, then burn only winter blended fuel from high volume truck stops.

Spindrift

01-08-2005, 12:32

JK,
Are you suggesting that an electrical test of the OPS is in order?

Mark,
I originally thought the same thing, but wouldn't you think the conditions you describe would be present regardless of a change in temperature? I always fill at the same truck stop, summer and winter, except when I'm traveling. I'm religious about adding fuel treatment at every fill. I changed my filter 2,000 miles ago so I felt it was unnecessary this time. Nonetheless, you never know. It couldn't hurt to change it again.

markrinker

01-08-2005, 13:04

Hmmm...sounds like it may not be fuel after all...

One more theory...what if cold thick oil through the turbo was exaggerating slightly coked bearings, causing the turbo to 'surge' until warmed up?

Kennedy

01-12-2005, 15:53

Well, this one has revealed itself, and it's pretty nasty. When the truck was dropped off, I asked the usual questions about lift pump, filters etc. It has a new (recent) relay controlled lift pump, new OPS, and the filter was changed not long ago. Discussed whether it had been run on dyed fuel, cleanliness and quality issues etc.

So after getting my ass kicked by this behemoth, I decided to check the air filter. Pretty dirty, and definitely due for service, but not bad enough to creat the problems we are experiencing. Then I pulled the fuel filter because I just had a suspicion. The filter looked like you took the bluish rust from an exhaust pipe and ground it into a paste mixed with black paint! :eek: The media is kinda mushy, and there was a bunch of scum in the base.

I don't really care to or have the time to drop and clean or replace the tank so I replaced the filters, and took it in to Domine Chev. to have this part done. On the way in, the stalling was worse yet. You could step on it and it would seem to stall, but in fact it had gone back to idle. Time will tell. Starting was also difficult when cold even with the plugs. One time it would start, and the next time it wouldn't. I have a sneaking suspicion the pump will be junk after all that crap...

Spindrift

01-12-2005, 16:03

Originally posted by kennedy:
I have a sneaking suspicion the pump will be junk after all that crap... JK,

The answer may be obvious here, but do you mean the IP, not the lift pump?

Jim P

01-12-2005, 17:40

Last winter I was having problems with my truck quiting soon after startup. I would go out to start it and it would start fine but just about the time I would get back in the house, it would quit. I assumed it was the pmd,so I bought a new one but I left my old one on for a few more weeks.

I went to an auction one day and was there until evening and about half way out the driveway it quit but did start back up and run fine all the way home. One morning it started but never would restart so I put on my pmd and haven't had a single stall yet.

Mine would only stall shortly after starting when it was cold. If I just started the truck and did not let it warm up, it would try to stall about 1/2 mile up the road but the engine would always come back to life and keep running.

At work in the afternoon when the temperature was a little warmer, it never did stall.

Kennedy

01-13-2005, 07:18

Originally posted by Spindrift:
</font><blockquote>quote:</font><hr />Originally posted by kennedy:
I have a sneaking suspicion the pump will be junk after all that crap... JK,

The answer may be obvious here, but do you mean the IP, not the lift pump? </font>[/QUOTE]The return to idle thing kinda points at the injection pump. We'll have to see how it runs when cleaned up...

Govt issue

01-13-2005, 09:21

Does anyone know what type of problem the heater in the bottom of the fuel filter houseing causes when it goes out. Could this be some of the cold weather problems. Both of my 95s have this problem but my 96 dosen't.

Spindrift

01-13-2005, 10:33

As long as you're using a fuel additive with an anti-gelling component, I wouldn't think you would need to depend on the heater element.

joed

01-14-2005, 06:08

I have been experiencing this as well, most recently this a.m. - it was about 5 deg. overnight and my block heater seems to be on the fritz. It seems to be temperature dependent - only when it's below 20 or so.

This a.m. the truck fired after just a couple seconds of cranking, but ran about half speed for 20 secs or so, then smoothed out. The truck then sputtered on acceleration for a couple miles, or until it warmed up.

Odd thing is, in past winters I never noticed this cold sputtering before. Main difference is I have a new IP - it was replaced last June under warranty. I have recently replaced the fuel filter, and even broke down and installed Heath's remote FSD kit as I was also starting to experience an occaisional stall.

On a possibly related note, I've recently had APP codes stored in history, 0222 and 0226, and also a 0381 - Cyl. 7 balance. Could a flakey APP be causing this surging?

Joe.

Kennedy

01-14-2005, 06:27

Dealer says tank looks OK inside. Funny thing is the new PMD that I installed on a cooler is showing signs of possibly being bad. The old one on the pump worked when this one wouldn't (cold) but the one on the pump still acted up. Neither act up when the Tech 2 is plugged in though.

Looks like the grounds are haunting this thing...

Govt issue

01-14-2005, 06:45

both of my 95s have reman pumps. my 96 is original. i am going to try to plug in the 95s to see if they will run right cold. could the reman pumps be the problem, since my 96 dosen't do it.

BUZZ

01-14-2005, 12:03

My 94 has never started correctly after an IP replacement.
Buzz

Spindrift

01-14-2005, 14:21

joed,

Sounds identical to mine. Guess when my IP was replaced. June. This weekend I plan to get intimate with my grounds and connections.

Kennedy

01-15-2005, 08:41

Just a followup, this one turned out to be ground issues as suspected. The replacment engine was not installed very well, and items like the alt rear suppt bracket and wastegate solenoid mount bracket are missing. Wires zip tied to injector lines etc. Grounds were tied to a bell bolt and this was making poor connection as it was loose. I knew they were missing from the RR corner stud where they normally go, but when they got pulled down as they were, it pulled the main loom down and made it tough to see where they were. I had Domine's check while they had the tank out.

After seeing the inside of the tank, I will definitely suggest that when fuel contamination is suspect, LOOK FOR YOURSELF when the tank is out. I'd be willing to bet that a good many tanks that are replaced are not bad at all inside...