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Dodge Ram 12 Valve Diesel

94-98 PROBLEMS AND TROUBLESHOOTING

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Troubleshooting          Common Problems

Troubleshooting the DODGE CUMMINS 5.9L (1994-1998)

• Diesel Injection Service troubleshooting and tips page - CHECK IT OUT!
• Diesel  and  Turbocharger trouble charts, Hard Starting, stalling, smoke, etc,
• PCM fault codes from the '94 service manual (for 1994 - 1996 models)
• Turbocharger diagnostic tips - from the Star Center News
• Injection Pump Diagnosis Procedure Chart - TSB 14-01-89 for 89 models
• Fuel Pressure/Overflow Valve diagnostics - TSB 14-07-96
  • 1994-1998 12 valve fuel pressure should be 18-24psi at idle and 28-36 at 2000 rpm with no load.
• Turbocharger Diagnostics - see TSB 11-05-96
• Wastegate Troubleshooting - from a Holset pocket pamphlet
• overflow valve diagnosis info
• Intake Manifold Air Heater system testing

• Throttle Problems - NOTE: Recall 970 should eliminate these problems for 94-95 models
  • Frayed or Broken Throttle cable
    • Symptoms: High idle speed, loss of throttle control, low power
    • Look for broken strands on exposed steel cable at injector pump
    • Original cables had a 30,000 mile life
    • Replacement cable is a new design - life unknown
    • Throttle Cable Replacement instructions
  • Insufficient throttle travel
    • Symptoms: Low power, engine does not pull well above 2200 RPM
    • Caused by stretched throttle cable, throttle rod out of adjustment, worn throttle parts
    • Check by having someone hold the accelerator pedal to the floor while you see if the throttle bellcrank on the rear of the injector pump will move farther by hand.
    • Temporary fix: replace the small spring at the end of the throttle cable where it connects to the accelerator pedal under the dashboard. Unwind the short spring from the cable, install a longer spring, wrap it with a piece of tubing, and put a small hose clamp around the tubing to keep the spring from flopping over.
  • Broken throttle springs
    • Symptoms: Inadequate/No throttle return when pedal is released, high idle speed
  • There should be a double spring extending from the throttle lever on the rear if the inj pump to a bracket near the power steering pump.
  • Temporary fix: Use a generic throttle return spring from an auto parts store.
• Worn throttle rod parts - photos     parts diagram
  • Symptoms: Throttle binding, high idle speed, loss of throttle control
  • Temporary fix: Use tape or a tie-wrap to keep the socket on the ballstud.
• Foot pedal (throttle) tends to bounce resulting in bucking or jerking.
  • 1994-96: engines add a spring (part no 3933130) inside the existing injector pump throttle return spring.
  • 1997 engines replace the spring closest to the drivers side fender with part number 393131.
  • 96-98 engines TSB 18-29-97A replace throttle lever assembly (also, see below )
• 1995-96 vacuum component failure - brake system, A/C, cruise control problems may be caused by oil in vacuum lines. See D--97-10 for 7 year/unlimited mileage warranty extension for components affected by Recall 720.
• 1997 vacuum component failure - 97 models have a revised check valve, but they are failing after 4 years. No extended warranty coverage is offered for 97 models.
• 96 CA Diesel with "EGR SYS Failure" code - TSB 18-25-97 Reprogram PCM
• Erratic automatic transmission shifting,  truck jerking under load
• All pre 1998 models use a throttle position sensor
• The TPS connector can loosen or corrode. Check carefully, bend and coat pins with dielectric grease.
• The TPS is bad. Replacement is the only option.
• Low power and/or poor fuel economy
• Check first for a plugged catalytic converter , fuel filter, or air filter
• From:  DYNOOMAN@aol.com - I see a lot of low horsepower problems due to Excessive idle time's and plugged cat's... About 50%
• Check for loose or cracked boost line to the AFC housing on the Injector pump
• If diesel produces clouds of white smoke when first started, check fuel injection timing
• Defective Injector Pump Fuel Overflow Valve (Diagnosis tips) (TSB 14-07-96 )
• Defective fuel shutdown solenoid can restrict fuel supply.
• 1991-1992    TSB 18-11-92,   LDA  Starwheel adjustment
• 94 TSB 18-10-94A - check engine timing
• 94+ TSB 14-07-96,  Check fuel pressure
• Turbo diagnostics - Star Center Vol 29
• 94+   Check for a turbo/wastegate problem - TSB 11-05-96
• 94+ Wastegate testing and repair - TSB 11-08-98
• 96   Revised injection timing for CPL 2022, or 2023 - TSB 18-11-96
• 94-95 Acceleration tests, throttle linkage adjustments, fuel pressure tests - TSB 18-29-95
• Fuel pre filter screen clogged - screen should be checked every 24,000 miles.
  • Cleaning/Replacement procedure
• Rough Idle and low power.
  • 1994-1998 replace defective overflow valve in the fuel return line ( symptoms, diagnosis info )
• Excessive White Smoke
• 1994 engine s/n before 56148586,  TSB 18-10-94A correct timing to 12.5 degrees
• Low fuel economy and/or fuel leakage
• Fuel return hose behind the fuel filter has a reputation for failure and leakage
• Reported by several people including myself! Rams over 3 years old: beware!
• Regular fuel hose has a short life, use fuel injection line.
• Metal low pressure return line from the overflow valve cracked.
• Hard to start, no start, low power in cold weather:
  • All Ram diesel built before 01/01/98 - TSB 18-06-98 diagnostic table
  • Fuel shutdown solenoid adjustment - check for the correct position when the solenoid is activated
• 98 Diesel cold weather fuel heater wiring missing - Customer Satisfaction Notice #770
• 98 Diesel before 12/15/97 -   TSB 18-37-97
• Hard Start Diagnosis - Star Center News
• Whine or howl at highway speed
• TSB 11-01-97  - replace muffler with Part# 52019324AB
• Some exhaust brakes will produce a moaning sound at certain engine speed and load conditions
• Excessive Turbocharger Noise
  • Star Center News - Turbocharger Noise diagnostics
• Voltmeter jumps up and down - Normal, caused by intake manifold heaters cycling when engine temp is below 60 degrees.
• Voltmeter low, battery not charging
  • Intake heater stuck on (diagnosis page)
  • Engine speed sensor failed (the tachometer will also not be working)
  • Alternator failure
• Headlight intensity flickers or changes
  • Caused by intake manifold heaters cycling when engine temp is below 60 degrees.
  • If the problem continues at speeds above 18 mph, check for loose terminals on the manifold heater relays.
• Wide fluctuations of the temperature gauge
• the result of a large radiator, it is relatively harmless and normal
• Cummins has released a revised T-stat that does fix the "problem".  The revised T-stat Cummins part number is 3934373. (The old T-stat Cummins Part number is 3928499. )
• This solution has been reported by Gerry Willomtzer <dax@yukon.net>: 195 degree t-stat Dodge PN 3418459 intended for a 1973 or so gas engine (From Gene's Chrysler in Fairbanks www.geneschrysler.com).
• Engine overheating
  • Defective viscous fan clutch - if the fan does not produce an audible roar when the engine is hot, the clutch is not engaging.
  • 1994-97 all engines with snowplow factory prep code (AHD): TSB 07-05-97 Replace viscous fan with part # 52028837AA
  • Thermostat removed - the engine will overheat with no thermostat installed
• No crank with key held in start position - all 94-97 BR models & engines
  • TSB 08-21-97 check solenoid cable connection torque
  • dead battery - they die without warning
• 96-97 Speed control doesn't function or is intermittent
  • TSB 08-22-97 - leaking vacuum hose at the speed control servo
• Speed control overshoots the set speed when engaged -
  • Review procedure. Repeatedly engaging the speed control with little or no throttle confuses the speed control to the point that it thinks there is extra slack in the throttle cables, so it "takes up the slack" resulting in overspeed.  See TSB 08-16-95 Rev. A for procedure to "unlearn" the overshoot.
• Oil Leak at timing case, loud engine noise, engine miss, and (rarely) sudden stall - All engines built before March 1998: Assembly pin in timing case can fall into the timing gears. The pin bangs around inside the case until caught by a gear and thrown through the case. This can also damage the gears, camshaft, injector pump, or vacuum pump. This is a known problem that occurs infrequently. The simplest way to prevent this is to block the pin with a tab or bolt.
  Description of bolt in housing case to retain pin.      Description of tab to retain bolt.
  See TDR threads for additional details if you are a member. If not, google "killer dowel pin" for plenty of information.
  • "KDP" Killed today!
  • http://www.turbodieselregister.com/ubb//Forum1/HTML/000974.html
  • http://www.turbodieselregister.com/ubb//Forum12/HTML/000031.html
  • http://www.turbodieselregister.com/ubb//Forum12/HTML/000034.html
  • Preventative step to trap the pin before it escapes - TDR posting: Dowel Pin Pictures
• 98+ Ram speed control setting creeps upward - Replace faulty vacuum servo.

Throttle Linkage and Spring Problems

Subject:    Re: throttle spring
Date:        Fri, 20 Feb 98 07:34:33 CST
From:       kpenner@dalsemi.com (Keith Penner)
To:          cummins

 I looked through my receipts last night and only came up with the instruction sheet for installing the "reduced gain throttle lever installation procedure". It is kit # 3806215 with a bulletin #3887755-01. I do remember that it was packaged in Chrysler wrapping so it comes from them and not cummins.

 I hope this helps. The kit really fixes the throttle sensitivity problem. Also if you are able to get this done make sure that it is set correctly. My first test drive showed that I was not able to get full throttle range and they reset it.

Keith Penner  kpenner@dalsemi.com
 

Subject:    Re: throttle springs
Date:        Wed, 25 Feb 1998 16:47:31 -0800
From:       bernard rate <bernard.j.rate@tek.com>
To:           dfritz

The dealer performed TSB 18-29-97 on my truck today to cure the bucking  problem. They used p/n 5011726AA and 3806215. Driving home, I could tell that more travel is needed to get WOT.

Bernard.

Subject:   0 to 60 Times And Low Power
Date:       Sun, 1 Feb 1998 11:47:39 -0700
From:      "Matthew Stabnow" <homespun@btigate.com>
To:          cummins

Something you might check for your low power problems is the P7100 FIP overflow valve.  The Bosch P-type inline fuel injection pump is very sensitive to supply pressure variations.  If this pressure is low or pulsating excessively, the following symptoms can occur:

Low RPM miss / instability
Hard starting
Engine dies at idle (especially when hot)
LOW POWER
Fuel Filter cracking

You may not get all these symptoms, maybe just 1 or 2.  I have the Bosch technical repair bulletin which describes all the symptoms, testing and repair of the overflow valve.  The factory service manual also has a section on the Cummins fuel system with the location and replacement of the overflow valve, a simple and inexpensive procedure.  Your local Cummins dealer is probably your best bet for testing and repair of your low power complaint.

Matt Stabnow
homespun@btigate.com

 see overflow valve diagnosis info

Maximum Boost for stock Rams:
94+ 160, 175, 180 HP     15-18 PSI
96+ 215 HP                     21-23 PSI
1998+ ISB                       19-22 PSI

Page last updated: March 7, 2008