Hi guys (and gals?)- I have a 1985 Ram 50 with the 4D55. It was well-used when I got it, but seemed to run well, delivering 30-32 mpg no matter how I drove it. Now I am having a problem with the glow plug system. Last winter I had some starting problems so I replaced the plugs with some good used ones, and the improvement was dramatic. Now, when I turn the key, there is no relay "Clunk-Clunk" and no diesel "Rattle-Rattle" when I crank the starter. Just a little bit of stinky gray smoke and eventually a dead battery.
I have an '85 factory Ram 50 manual that has some good diagrams and it tells how to check a few of the components, but nothing about troubleshooting the whole system as such.
Can anybody point me in the right direction?

I think maybe the best way to fix the whole system is to check the components one by one to find out where the problem is. If you can find your glow plug relay, see if it is getting power when you turn the key.

I believe there is a fat wire from the battery to the relay, and another fat wire from the relay to the glow plugs. There should be thinner wires on the relay that control it. Just work your way through the system with a test light.

Sounds like you glow controller took a crap on you. It's not very common that both solenoids would stop working at the same time.

Like was stated before, you need to check each component individually but I am guessing you need to have the glow controller rebuilt. It's a common problem.

Hey, i am in seattle, and we have parts for these things. We are doing some conversions on monteros to the 4d55, and have about ten of the engines laying around. we run a for starter selenoid with a voltage regulator and a manual button for glow plugs on the conversions. Super simple, as the factory set up tends to give up the ghost and no replacement parts are readily available. Feel free to email me at urbandwelling@gmail.com or call at 206-999-3619.

Marty

I just did a 4D56 conversion into an '89 raider. I put a small push button on the steering column cover in front of the ignition key. It runs a starter solenoid mounted to the firewall so it is easy to hear it engage. Works like a charm!

I had a bad glow plug and ordered a set from England on ebay. I ordered them two weeks ago and got them today. I just did a pop test and spray pattern test and my injectors need shims and nozzles. The piston rings seem a little worn too.

Did you say you can get parts?

Yep. thats the easiest way to do it, but put a voltage regulator in front of the selenoid to make sure your only running about ten volts, or you will bake the glow plugs. On glow plugs and parts, most everything is available thru Napa. Timing belts, replacement plugs, gaskets, seals, the whole noine yards. Some special stuff like oil pick up tubes are a bit trickier, but i have been running stuff down for the 4d55/6 into montero trick, and its pretty easy. Feel free to drop a line with needs. NAPA man!

Thanks, everyone. Looks like some good advice. There are still a few details: Voltage regulator? What kind of unit would you suggest (brand, model/part#)? I guess it would have to be able to handle the amps that those four little hotties draw.
I've heard tell of an NGK plug that fits the 4D55 but is designed for 12V. Anybody know the part# for those?
It looks to me like the OEM system is MEANT to deliver full system voltage (should be somewhat more than 12V) through one of the relays.
How about this- A "normal-OFF" toggle switch with two "ON" positions in the dash, with each "ON" terminal wired to its own OEM relay (assuming they're good). That way you could manually select full or reduced voltage, depending on air and engine temperatures. Yes? No?

I'm definitely NOT the Go-To guy for 4D55 parts. I squeak by, and hoard whatever good used stuff I can find/afford. You wrote that you pop-tested your injectors. Do you have your own tester? Where did you source the shims and nozzles?

I purchased an injector tester for Mercedes diesels on ebay ($190). I found out I need shims and nozzles. Cord at Sun Diesels is checking with his Australian division to see what they can get. The nozzle has a number on it, NP-DN0PDN112. The pop pressure is supposed to be 2200 psi (2134-2276 psi). My injectors 1-4 tested at 1700, 1800, 1700, 1800. The shims 1-4 were 1.37mm, 1.25, 1.32, 1.25. The nozzles were all dished on the combustion chamber end, and the spray patterns were awful.

Glow plugs come with different voltage specifications. I don't know why. I found an NGK part number for 4D56 glow plugs: NGK CY57. Don't know if it's the right number. 4D56 glow plug prices seem to vary from about $8.50 to $40.00. Don't know why. I got some from GB that were claimed to be genuine Mitsubishi. They were not. They took two weeks to get here and they look cheesey next to the OEM's. I tested them in the air. The OEM plugs glow along the entire 3/4" tip, the replacements only glow for about the first quarter inch.

Seattleraiders said to use a voltage regulator ahead of the solenoid to protect the glow plugs. I spent a little time looking for one but sort of struck out. There are some Ford and GM controllers for about $150 on ebay. I wonder if they would work. I wonder if a voltage regulator is necessary. The plugs take a while to start glowing with 12v, say about 5-7 seconds. It's not like they snap to attention and look like they will melt. I wonder if the extra volt does damage. I would worry more about it after the engine starts and the alternator ups the system voltage to 14v.

Buy new glow plugs! When they are totally shot they will not send the resistance signal back to the glow controller . This will prevent clicks clunks etc from relays. By the way the controllers can be rebuilt like any other auto ecu. If you live in a real cold area I would highly suggest maintaining the original system.

Mike Warme 818 268 3012