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1989 - 1993 Ram 5.9L Cummins

1ST GEN RAM WITH A CUMMINS: A BRIEF HISTORY OF THE RISE OF THE CUMMINS MOTOR 1989 was the start of a beautiful thing, the marrying of Dodge and Cummins. When the Dodge-Cummins pickups came on the sce ... read more

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1989 was the start of a beautiful thing, the marrying of Dodge and Cummins. When the Dodge-Cummins pickups came on the scene, the light-duty truck market was changed forever. Its true that GM had diesel pickups in their line since 1978 and Ford since 1983. And that's all fine and dandy, but those who know diesels, understand the major difference we're talking about here. The smaller Cummins engine produced more torque than either Ford or GM (400 vs. Ford's 345 ad GM's 246). And with a manual transmission, the Dodge's GCW rating was 16,000 pounds, which was two tons greater than its closest competitor!

The Cummins engine used in the Dodge lineup first went into production in late 1984 for such heavy-duty applications as combines, tractors, road graders, loaders, cranes, and crawlers. Thus, the Cummins engine had been tested on the job for 5 years and more than 11 million miles before the first one was installed in a Dodge pickup, allowing them to really work out any of the kinks that Ford and Chevy owners had to discover themselves. Was the 1st Gen a perfect truck? No, not necessarily, but it was a solid powerplant that many would pinpoint as the beginning of the diesel performance industry.


Any automotive enthusiast has an era of vehicles they deem a “classic,” many times evoking memories of a vehicle they once had, or dreamed of having one day. For some, it’s a 50’s Chevy, for others, muscle cars of the late 1960’s and early 1970’s. Some of us, its 1980’s square body trucks. There’s the C/K Chevy’s, Bullnose Fords, and the first iteration of the heavy duty Rams unveiled in 1981. Now, if you take someone with a passion for these trucks plus an interest in diesel performance, there’s really only one truck in your eyes, the 1989-1993 Rams with a 12 Valve Cummins. This first iteration of Rams with a factory diesel option were very mechanical in nature, meaning they’re relatively simple to work on and parts are fairly inexpensive. Compared to the newer vehicles, there’s no computer to allow for a “chip” or “programmer,” just good old mechanical performance by means of injectors, an upgraded fuel pin and governor spring, turbo, and so forth. The 1989-1991 models were not equipped with a factory intercooler to keep your exhaust gas temperatures (EGT’s) down, so a very popular upgrade is to upgrade the truck with an intercooler. Overall, you can make plenty of performance parts upgrades on these trucks to bring the power levels to the same levels of the newer vehicles, and honestly, do it for a whole lot less money! Will you have the creature comforts of auto-dimming headlights, proximity sensors, and a tire pressure monitoring system? No, but not everyone really wants all of that anyways.

Look through all of the options we carry for your truck, and as always, if you have questions on how to best achieve your goals, feel free to give us a call, send an e-mail, or start a chat and we would be happy to assist.

Products in this section are designed to work on 1989, 1990, 1991, 1992 and 1993 model year Dodge trucks equipped with the 5.9L Cummins unless otherwise noted.

Diesel Power Products is not affiliated with Cummins or any of its subsidiaries or related companies. Unless a product is specifically identified as a Genuine Cummins product that has not been remanufactured, modified, or refurbished, Cummins makes no representation or warranty about the product and has not authorized, tested, or approved the parts for use in genuine Cummins brand products.

We get a lot of calls and e-mails each day with various product, vehicle, and installation questions. Some are completely off the wall and can even catch us off guard at times, but many others are fairly routine, so we thought we'd post some of the most popular questions that can hopefully be a good resource for you.

Q: I'm looking to add some more power to my 1st Gen and some people have told me I can slide or remove a fuel plate on a 12 valve to accomplish this, but I can't find what they're looking for.
A: This would only apply to the P7100 equipped trucks in the 1994-1998 model years. The 1989-1993 1st Gens have a VE injection pump that does not feature a fuel plate. That said, it does have a fuel pin and governor spring that can easily be upgraded to both add power, but also widen the power band by allowing the pump to fuel at higher RPM's than factory.

Q: I have the 518 automatic transmission and I've recently added larger injectors and turbo, so its time to address the transmission. Ideally, I would make this transmission capable of torque converter lockup, is that possible?
A: The 518 and 727 transmissions, unfortunately, are not capable of torque converter lockup. For anyone with an automatic and not wanting to convert to a manual transmission, a popular upgrade is to swap out for a 47RH transmission that would have come from a 1994-1995 Ram and will allow for lockup.

Q: I'm in need of gauges and looking at the Edge Insight monitor, can I use that in my 1st Gen?
A: Yes and no. The Insight is intended to be plugged into the OBDII port under the dash, at which point it gathers information from the ECM and displays it on the screen. Well, your truck doesn't have any of that. However, Edge realized the demand for this and has an optional "12 Volt Kit" that supplies power to the monitor in instances when there's no OBDII, and then you can use Edge's EAS System to add sensors to anything you'd like to monitor, such as Exhaust Gas Temperature, Boost, Transmission Temperature, and Fuel Pressure. Its a similar process as if you were to install analog gauges, but with a simplified wiring process.

Q: Is it possible to install a P-Pump on my truck to get more power than I'm able to get out of my VE Pump?
A: The simple answer is yes. There are conversion kits that include the necessary fuel lines and adaptation pieces to accomplish it. The hardest or most expensive part typically is getting the P7100 injection pump itself.

Q: What kind of turbo comes on the 1st Gens? A: The factory turbo on these trucks is manufactured by Holset and is most often referred to as an H1C. Depending on the truck's configuration, these came with either an 18cm or 21cm turbine (exhaust) housing. Most would say this is too larger of a housing for these trucks and attribute slow turbo spool to this. A very popular upgrade is to exchange the housing for a smaller 16cm housing for noticably faster spoolup.

Q: What are EGT's?
A: EGT stands for Exhaust Gas Temperature, which is the temperature of the exhaust leaving your engine. This measurement is typically measured before the turbo to ensure you are not overheating components. For most applications, we recommend not exceeding 1300 degrees.

If you've got a question about your 1st Gen Cummins, feel free to give us a call at 888-99-DIESEL and we would be happy to assist.

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