Stumbling and smoking white

[Blakers]

I just bought a beautiful 1995 2500 SLT A/T with 78,000 miles. The previous owner had a larger turbo housing installed, along with larger injectors and the pump turned up -- all Cummins parts and done by the Cummins dealer. The truck drives wonderfully and has lots of power, but when the engine is revved in nuetral it stumbles and misses at about 2200 rpm and above, plus belches white smoke like crazy. It will max out at 2700 full throttle. Is this the governed speed?

Different Cummins dealers have different opinions, but the shop where the upgrade was done says it is a charactoristic of these engines when the rpms are brought up with no load. It is caused by the compressed air in the cylinders being not hot enough to completely burn the fuel.

Does anyone have any other ideas or suggestions?

Thanks,
Blake

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1995 2500 SLT, Regular
cab, 4x4, Blue & Silver, a/t,
K & N air cleaner, 290 hp.

 

[Dieselnerd]

Mine will run up to 3000 with no problem, not only in neutral but on the road too. Maybe it's your mods causing the smoke and they are giving you straight information but I don't recall anyone else with the same complaint. As far as the 2700, check to make sure your throttle opens all the way when it's floored, it's a common problem.

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Ron

'96 Club Cab 2500 4x4, 4:10LS, Camper/Tow package, 3500 brake cyls. , Automatic, TST 230/605, Cat Test Pipe, Cummins Chrome, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, Rancho 9000's, All black. Tow 14k HitchHiker triple glide 5th Wheel. Also use 9. 5' Lance camper. NRA Life Member. KDP 61,000 NM-WT

 

[RHARVEY]

I had a lift pump installed by a Cummins dealer in Little Rock Arkansas last week. After they got the pump installed, the mech rev'd her up a few times and the way that you are describing it, mine did the same thing. I ask about it and they told me that when a injector pump starts to wear a little and it is running at stock timing that is what you get with a cold engine. I had never noticed it before, and the mech. said 'you don't stomp the throttle when she cold do you?'. He also said that when it warms up, it will go away. He also stuck his foot in it and rev'd it to 3500, I also ask about that! Justin(mech. ) told me that is why there is a governer on it.
Anyway it runs wonderful with no problems. .

Rick

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RICK
97 2500,CC,5 SPEED, 3. 54 Limited Slip,Psychotty System,K&N, Pre-Turbo ISSPRO 3" Pyrometer & Boost Guage,Silencer Ring Removed
15,000 RBW 5th Wheel Hitch,25' Excel 5th Wheel,Rancho RSX17000 Shocks,Amsoil Dealer,Straight Piped

 

[mikepvg]

Had the same stumble @2200rpm until I fixed the fuel delivery problem.

get a gauge on that thing & make sure you have 18-24psi @idle & 28-36psi @2000rpm & diagnose from there. Unless its cold, it should rev freely right on up (Loaded&Unloaded) to where you have the High Idle stop adj'ed. Oh BTW, congrats on your fine purchase!


#ad

Mike

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94 2500HD 4X4 5sp w/GearVendors O. D. 4:10 L. S. D. , K&N Oval w/ Pre-Filter, Straight Exhaust, Geno's Fumotovalve, AW-Direct Idle Controller, DiPricol Boost/Pyro/Fuel w/ Kevlar BSS line, Mag-Hytec Rear, 126K miles. Halon Protected, NRA Member. V1=Anti-"pinch" protection. KDP 125,700-NM-WT Insurance

[This message has been edited by mikepvg (edited 05-25-2001). ]

 

[Blakers]

Thanks guys! I have grown up with diesels in trucks, tractors, and cars and I have never heard of an engine that would do this. What is so weird is that under a load the engine does not stumble at all and revs to at least 2500 and does not smoke (unless I really get on it, it can leave a good black cloud). The new turbo housing does not have a waste gate - I wonder if that could be a cause? I'm gonna talk with the shop that worked on it again and I will test to see how high the engine will rev under load. It sure does not seem to have any power problems.

Blake

------------------
1995 2500 SLT, Regular
cab, 4x4, Blue & Silver, a/t,
K & N air cleaner, 290 hp.

 

[BushWakr - RIP]

I wonder??? I've read that the white smoke is often caused by the ksb solenoid not functioning properly. It advances 'timing' when cold to help elim. white smoke. Also timing in general will cause that if it is running a little retarded. Just a thought?
Bush'

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93. 5 W250 4X4,HD Spring Pkg, Rancho 7000's, Rear Swaybar,Dual Shock Front Stabilizer,BD 180HP Injectors,31/2" Mandrel bent exhaust,BD16cm 'Hot End',Modest Pump Tweaks(lock collar still on)Star Wheel@3oclock/Timed @ 1. 37mm,K&N Air,Isspro Pyro (Post Turbo),Tach,transmission Temp,Auto Meter Oil Filled Boost Ga. , 3:54's, 4 Speed Auto, Clubcab, Aftermarket Reclining Buckets w/ctr Drop Down seat/console, Black over Silver, 22psi,285-65R-16's,American Racing Clear Coat Mags, Amsoil 15W-40HD Marine,12,000 lb. Warn Winch,KC Spots. 103,900 Kms (64,600 mi's). NOT A VENDOR,Just an end user

 

[illflem]

Bush, I think you are speaking of a 24 valve.

 

[Blakers]

What is a ksb solenoid?

The guy I bought my truck from had the same problem with his 24 valve dually - it turned out to be a bad transfer pump.

So what do I need to check the pressure on my transfer pump (12 valve)? I have a gauge for testing fuel pressure on my fuel injected 302 Ford.
Are the fittings similar?

Thanks,
Blake

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"Blue Bomber" Blue & Silver 1995 2500 Laramie SLT, Regular cab, 4x4, a/t, K & N air cleaner, 290 hp, 3. 54 LSD, 265-75/16 (for now).

 

[Missouri Mule]

Blakers,
You couldn't be that lucky.
Pressure gauge should be alright but you mite need adopters.
I read where TST has the adopters if you need them.

------------------
Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

[This message has been edited by Missouri Mule (edited 05-26-2001). ]

 

[Blakers]

Thanks Missouri Mule,

I have been too busy to check anything out yet, but will soon. I talked with the guys who did my engine work - Diesel Injection of Pittsburgh http://www.dieselinjection.net/ and they said my stumbling/smoking situation was normal, but I can't really believe that. I will keep researching it.

Blake


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"Blue Bomber" ... Blue & Silver 1995 2500 Laramie SLT, Regular cab, 4x4, a/t, K & N air cleaner, 16 cm turbo housing, 290 hp/700, 3. 54 LSD, 265-75/16 (for now). Steam Engineer and NRA Endowment member.

 

['956Wheel]

Mine did simular stuff and it was the fuel drain valve, front left on the injection pump, when facing. $80. at Cummins, more at Dodge 1/2 that through Piers of BD. Your pressure will show a low reading if its bad. I replaced it, truck would not start, pumped the heck out of the primer button, fired up ran 200% better.

------------------
9535hundred

 

[SlyBones]

Just FYI,

Piers Harry
PDR ( Piers Diesel Research, Inc )
604-853-9396
PiersDiesel@aol.com

Lots of good stuff, besides just overflow valves.

------------------
1997 2500 4x4, CC, Auto, 3. 54 LSD, 70K, Everything inc Leather, K&N, 4" BD Exhaust, 230/605 Kit, PDR Pump Mods, DTT 91% TC, DTT VB, Mag-Hytec Double Deep, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Molded Side Steps w/ Ground Effects, Chrome Trim, Canopy, ProFlaps F&R, BedLiner, Aux. Lighting F&R, and tons more.

[This message has been edited by SlyBones (edited 05-28-2001). ]

 

[Hammer]

A cracked fuel return line will also cause this problem,,It allows air into the system and will lead to the white smoke problem and stumbling.....

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98, Flame Red, Quad Cab, 2500, 4x4, 5spd, Autometer and Cyberdyne gauges,Edelbrock Performer IAS shocks,TST#10 plate,16cm housing, B-D Exhaust Brake,Timing Advanced,K&N,Totally Amsoiled,Cat Muffler and Silencer ring ALL M. I. A. ,A BOMBING IN THE PROCESS!!

 

[Andy Redmond]

ck. your fuel psi. I suspect a overflow valve or weak lift pump, not to mention the infamous return line problem; however, most 94-95's may have had the return line changed by now.

Do we know if all the injectors are sealing well too?

Make sure you have a new fuel filter then take your fuel psi readings for best accuracy.

It can be in fuel psi "spec" and still suffer the condition you describe, usually a fresh overflow valve eliminates this problem.

I think you have the bosch number 2 417 413 086, this number has been superceded by the superior 2 417 413 093. Folks will argue this was discontinued in 94, but I've seen this on as late of models as a late production 96. The 093 will eventually lose some umph too over time, too requiring its replacement. The Bosch tsb on this is DSD SL 96-08.

Many of my customers have had good luck in submitting the invoice for replacement to DC and have rec'd a check back. . I know your 5 yrs is gone, but you have a little left on your 100k, doesn't hurt to ask, right?
800 992-1997

Finally, the Cummins tech makes a good point to an extent. When more fuel is added a cold engine will suffer more of these symptoms than the oem fueled engine.

Good luck, let us know how you make out with it.

Andy

 

[Blakers]

Which fuel line is likely to cause a problem? Is it a return line or a suction line?

Is the overflow valve easy to change or replace? If I test the pressure and it is low, how do I determine if it is the pump or the overflow valve?

Thank you!

Blake

------------------
"Blue Bomber" ... Blue & Silver 1995 2500 Laramie SLT, Regular cab, 4x4, a/t, K & N air cleaner, 16 cm turbo housing, 290 hp/700, 3. 54 LSD, 265-75/16 (for now). Steam Engineer and NRA Endowment member.

 

[DieselB59]

timing!

I am so surprised that nobody has yet even spoken of TIMING! All of the above symptoms are indicative of a problem with the injection timing being way too retarded. This is utmostly important in a Diesel engine as the injection of fuel must be as precise as a spark is to a gas engine. Timing for a modified engine should be at 14. 5 degrees BTDC.

 

[Smoker]

I totally agree with Chris. My 97' stumbled and white smoked so bad that I could not even use first gear. The reason... ..... a lot of fuel and timing was way too low. I recently set my timing up and my truck has not stumbled or white smoked once.

 

[Blakers]

Stumbles

Well I am finally able to get back on here to post something...



I took my truck in to Diesel Injection of Pittsburgh yesterday to try and find out why it stumbles, misses and belches white smoke at 2200 rpm.



They checked my fuel transfer pump pressure and it was on the low side of being in spec, so replaced the overflow valve to get the pressure back up. Then they checked the timing, which was right on, and adjusted the valves. What they did find wrong - and that was probably causing the problem - was there were several air leaks in the duct from the turbo to the intake. So I was losing boost.



Now she runs much better and will easily hit 30 psi of boost under a load. Last night I even went up a local hill and when the converter locked up and the turbo hit 30 psi the rear tires started to squeal a bit - and that was at about 80 mph at the time and still accelerating!



So it seems to run much better with more power and the stumble is gone. It was well worth drive 2. 5 hours and spending the day near Pittsburgh to have it looked at. I did not get to meet Tom P. , but I did meet his truck awaiting service there also.



Blake

 

[rhoads]

white somke

First time on new supplier/set up.

But in a nut shell-white smoke in a diesel is a sign of lack of fuel.

Now what is the cause$$$$$ filter,is there 90k on it??-10k ?NO way. the cause. . Did this happen just after the other guy's mod's

? before?

 

[The patriot]

Blake, when my fuel return line was leaking, it ran like that, but only when it was cold.

I replaced the line, and it was better, but still there. I found a fuel leak on the steel line that runs behind the injection pump, and my overflow valve was slightly out of spec.

After these two things, it was a different truck.

Eric