BAD Idle

[FD5]

My truck is a 95 2500, Cummins, Auto, 231K. I bought is used after my 94 was totaled. My problem is that it has a bad, rough, idle that shakes the entire truck. I carried it to DC dealer and they adjusted the valves and replaced the fuel filter. It still had the problem but I was told to run an injector cleaner and the problem would go away. I used the Howes One Shot injector cleaner, problem did not go away. Went to the Cummins shop in town and they said my injectors were bad, so I had them replaced. Problem is still there. I need your input and suggestions before I go broke trying to figure out what is wrong. Thanks guys.
John

1995 2500 Ram CC, auto, 3. 54, Amsoiled, cat & muffler fell off, if anybody finds them they can keep them.

 

[Joe G.]

Is it idleing too slow?

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

['956Wheel]

Try bleeding the injectors, you may find a line that does not make a difference could be air in the line. #ad
Also check valve clearance. Water in fuel?

These are the things I would check. Lets face it, not much goes wrong with the ENGINE on these trucks! #ad


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9535hundred

 

['956Wheel]

Originally posted by Statland:
Try bleeding the injectors, you may find a line that does not make a difference could be air in the line. #ad
Also check valve clearance. OOPS DISREGARD THAT! Water in fuel?

These are the things I would check. Lets face it, not much goes wrong with the ENGINE on these trucks! #ad

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9535hundred

 

[FD5]

Idles between 650 and 750. Rebuilt injectors were installed about 3 weeks ago at a local diesel shop. They said problem MIGHT be the injector pump and I don't have that kind of money right now to MAYBE correct the problem.
John

 

[Paul]

Could be a bad overflow valve.

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Paul A. Schmidt
95, 4X4, SLT 2500, 5 spd. , 4. 10, 270 hp. ,675ft. lb. TST, AFC spring kit,215hp. injectors,16cm2 turbo housing, Pacbrake, Walker muffler,
GearVendor O. D. , CenterForce Dual Friction clutch.
Eastern PA.

 

[Joe G.]

That is just an attachment screw so it shouldn't be a problem. However, dirt may have got in that way. I'm not sure if the screw hole goes thru into the innerds or not. It needs to be replaced because it's one of two that attach the fuel solenoid bracket to the pump.

 

[LarryB]

Screw missing may indicate that someone has been in there messing with stuff. Is it the break off screw that is missing? Whats your smoke situation? Have you done the "loosen one injector line at a time to find missing cyl" routine yet.

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1972 Chinook class C with 96/215 5spd, 4/5" exh, 4"BD, MagHytec, 85gal fuel, K&N RE0880, AutoMeter, 370's, BD gov kit, BD afc kit, 16cm, 16%btdc, yada-yada-yada
www.fostertruck.com/cummins

[This message has been edited by LarryB (edited 01-07-2001). ]

 

[Kunze]

I agree that the screw isn't right especially since you aren't the orig. owner but those symptoms are exactly like when my overflow valve went bad. I hope you find the problem (and soon)

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'94, 2500, 4X4, SLT, 3. 54 gears, Prime Loc, Silencer ring in the tool box, DeeZee bright tread running boards, side box boards and mud flaps. Alpine CD player. I cleared 100K mi while the board was down. Jardine Performance 4" exhaust (sounds just like a Pete, it's great) Schied Diesel put timing to *15 (by timing light), put gauges in on the A pillar (trans temp, boost, and egt) They also set my stock plate up (40 hp 150 ft/lb gain) OH, what a difference a day makes

 

[Joe G.]

The book calls for 800 with the transmission in drive with the AC on at normal operating temps for the automatic. As Paul says, the overflow valve is also a prime suspect. If my idle is to low the thing rocks and rolls.

 

[FD5]

Is the overflow valve located on the pump? How much to change it out?

 

[FD5]

About the idle speed. Between 0 and 1000 RPM on my tach, there is a mark around 300 RPM and another around 700 RPM. With the engine at normal op temp, A/C on in drive it idles right at the 700 mark. If this is to low, how do you adjust the idle speed. Thanks again. John

 

[Joe G.]

The overflow valve is on the engine side of the pump even with the forward delivery valve. It looks kind of like a banjo fitting. Before you take it out, cram some rags between the pump and the engine to catch the flat washers. If you drop them they never be heard from again. The idle is adjusted by a verticle adjustment screw on the back of the pump. It has a 10mm head and a 10mm lock nut. It's a good idea to stick a screwdriver in the throttle linkage where the throttle cable attaches to open the throttle a little so that there is no pressure on the adjustment screw. It's kind of a PITA to reach so you don't need to fight the throttle spring pressure while you're adjusting it.

 

[FD5]

Could this be the problem?

Standing on the drivers side looking at injector pump, there is a box attached to the rear of the pump with 4 bolts holding the top on. The bottom right bolt is missing, could this cause my idle problem?

 

[DieselB59]

Indeed that shaking does point my diagnosis towards the overflow valve. It's a simple ten minute repair, and when bad it'll shake the engine like crazy. You can even pull yours out and loosen out the 14mm bolt from the banjo bolt and give the spring a stretch just a hair and re-install it (being careful about the check valve position). Then see if the engine shakes after the minor tweaking.

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Chris Timochko
AUTO WURKS DIESEL R&D TEAM
1997 5sp 4X4, Espar Heater, A. W. D. HX40 turbo, ATS 3pc Manifold, BD 4" Brake, Marine Compression, A. W. D. Custom Tuned Injection Pump, A. W. D. Intercooler, A. W. D. 370B Injection Nozzles, Delivery Valves, Governor & AFC Spring Kit, Psychotty Air, A. W. D. Water Injection, NOS Diesel Kit, A. W. D. 6" Chrome Exhaust System, BD No Smoke Valet Switch, McLeod Dual Disc Clutch, Mag-Hytec Rear Cover, Cummins Chrome Kit, Optima Red Tops, Hadley Bully Horns, Hurst Line Loc, Goodyear Wrangler AT/S 305/70/16s.
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Project U96 - 1996 3500 2WD racer. A. W. D. Marine Ultra Low Compression, A. W. D. Teflon-coated Pistons, A. W. D. High Lift Camshaft, Ported and Honed Cylinder Head, Intake and Exhaust manifold; A. W. D. HX40 Turbocharger, ATS 3pc Exhaust Manifold, A. W. D. Water Injection, A. W. D. Custom Fabricated Fuel System, Race Spec A. W. D. /BD P7100 Injection Pump, A. W. D. Custom High Flow Fuel Injection Nozzles, BD Auto transmission and Custom TC, Weld Draglites, Goodyear Eagle Drag Slicks, 5" Single Stack Through The Bed, Mag-Hytec on Rear and Transmission.