Engine/Transmission (1994 - 1998) Little to no boost on 12V

[weshope]

I don't think I have any leaks in the ducting between the intake side of the turbo and the engine intake. The flex couplings look good and the intercooler appears to be good. I pressurized and sprayed everything down with soap solution to look for bubbles. I'm going to double check it tomorrow or Saturday.



I'm interested in this diaphram in the AFC. Does anyone know what it does and how it would prevent me from getting boost?



My turbo is not coming alive like it used to. It's like someone flipped the switch and took all the power from me. There is no way I can pull anything with it in this condition. I can't even get it to put out any black smoke. Use to, if I got on it in 2nd and 3rd, the turbo would start to spool, the smoke would roll, and when the turbo came up to speed, the smoke went away and it would set you back in the seat.



1998 2500 4x2 QuadCab, Banks Stinger Plus Kit, Banks Brake

 

[kenny61]

I'm interested in this diaphram in the AFC. Does anyone know what it does and how it would prevent me from getting boost?

It is what senses the boost and allows the motor to fuel if it is torn it will not allow the motor to fuel no fuel = no boost

 

[weshope]

I just found this link discussing the AFC and the diaphram.



Turning up the pre 94 Ram diesel injector pump

 

[weshope]

Thanks. This sounds like my problem. If I could get the EGT to rise abnormally or if I could get it to smoke, I would think it was something else. It's just not getting the fuel.



To get to the diaphram for inspection, do I remove the flat head screws holding the cast housing where the pressure line for the controller T's in? The screws I'm describing are the ones facing the firewall. Where can I get a replacement diaphram if this one is bad? Thanks.



I have pics but don't know how to paste them in my post.

 

[weshope]

Here's pics of the AFC housing I'm referencing and my test tool.





View attachment 71513



View attachment 71514

 

[kenny61]

Yes thats the afc. I never changed one so I don;t know. It is probably available from cummins or dodge

 

[MLee]

I just found this link discussing the AFC and the diaphram.



Turning up the pre 94 Ram diesel injector pump

The go-to diagraham/instructions you have referenced is the 89-93 pump. you need to go to the 94-98. 5 lay out for the info you want. As stated pull the top off the pump and work your way inside till you get to where the diagrham shows the RED washer that is shown in the cut-a-way. There is more to it than meets the eye.

 

[surfbeetle]

In post 21 you mention no smoke... Maybe I missed it prior to that, but typically no boost=lots of smoke provided you are fueling the engine. I think you are now on the right track looking at the injection pump and AFC (Air Fuel Control).

 

[PToombs]

I don't want to seem like a wise guy, but have you changed the fuel filter lately? I went back thru the thread, and nobody mentioned fuel. The filter may be plugged, or the LP may be getting bad. The no smoke condition should be the 1st clue.

All this monkeying around and you just may not have the fuel you need from the start.

Just my 2 cents worth.

 

[weshope]

I too thought of the fuel filter. I pulled it today hoping to find something, but it was fine. I went ahead and installed a new one.



I think I may have found the problem. If not THE problem it is a problem. I stopped by the local diesel supplier in town today and talked to the counter guy. He said he sees the fuel shutoff solenoids get lazy and not open all the way. He suggested reaching down on the bottom of the solenoid after starting to see if it was making full up travel. I checked this and my solenoid would move another 1/2 inch or so up with the engine running. This would explain the lack of fuel to the motor but it showed no other symptoms other than no making full power. I didn't have time to do a test drive this evening. I will check it out tomorrow. If it gives me back my power by manually placing the lever all the way up, then I'm buying a new solenoid and relays.



An easy way to test the diaphram on the AFC is to take a Mighty Vac hand pump vacuum tester, attach to the barb fitting where the pressure line for the wastegate controller is normally located, remove the intake reference line from the T-fitting and place your finger over the opening while you pull a vacuum on it. I did this on mine and it held rock solid, so the diaphram is good.

 

[PToombs]

If the shut off isn't going all the way off, that could be the problem! A little lube on it sure wouldn't hurt anything, from the sounds of it. Let us know what the results are.

 

[weshope]

I'm feeling pretty good right now. I started the motor today and checked the lever arm attached to the solenoid. It moves at least 1/2 " upward after the engine is started. What a difference this makes. My power is back. I can make 20" boost in 2nd gear with it matted with no weight on the truck. This is what I'm used to. I'm glad it's something simple. I think the solenoid is shot. The boot is torn and it feels like the inner shaft/spring of the solenoid is detatched from the housing. At any rate, I'm going to get a new one and replace the relay(s) associated with it. Does anyone know where the relays are located? I found 2 located on the firewall just to the left of the valve cover (as viewed from the driver's seat). One of the relays has a connector hooked to it and the other does not. I don't know if this is normal for a 1998 with a 12v motor. Does anyone have a good supplier on the solenoid? I think my source at the diesel shop had one in stock. I will probably buy it from him since he led me in the right direction. I like returning favors.



At least I have a better understanding of how the turbo works on my truck now. Thanks for the continued support and advice.

 

[surfbeetle]

I think Geno's sells them. Also I believe that Larry B also has them. Last year, I bought a new rubber boot from Genos, $35. 00 delivered. I removed the rotten boot, cleaned out the solenoid and greased it. Works great. I think the new solenoid would costs around $200.

 

[BigPapa]

The spring and the shaft aren't connected to the housing. They just kinda "ride" in there. Mines been without a boot for over 200K miles and I've never lubed it, just wiped it clean (it's never very dirty) the 2-3 times

I've had to have the solenoid off.



Scott

 

[weshope]

I pulled the solenoid off today. The boot is pretty much gone. I took some pictures. This one appears somewhat worn, but I'm not sure what a new one looks like on the inside. From what I can tell, the plunger (part that big spring goes around) kind sits at the mouth of the magnet until the starter is engaged. Once engaged, it gets pulled into the magnet housing and is held there as long as key is in the run position. Does anyone know if the rod end shaft is supposed separate from the plunger assembly easily. If you look at the pics, the bell-shaped end of the rod end assy goes into the plunger and is held there by a conical-shaped steel spring clip. I pulled mine out to inspect the bore of the plunger and found a spring under the spring clip. I can push the rod end assy into the plunger with hand pressure. I can also pull it apart with hand pressure. I don't feel like this is normal, but like I said, I don't know how a new one is supposed to be. It looks like the bell-shaped end of the rod end assy has a pretty good wear mark around it where it has been hitting the spring steel retaining clip. Does this sound right to anyone?

 

[Dave M]

I don't know the answers to your questions but I'll share my experience. I had an intermittant no start. When I pulled the plunger on the solenoid manually it would start. I finally pulled the solenoid and the parts fell out as I remember. I cleaned everything with brake cleaner and sprayed it with silicone spray and worked for a year. Then I replaced the relay.



If cleaning it up doesn't work I'd replace the solenoid. Geno's (www.geno'sgarage.com) and Larry B's (Foster Truck) for around $200.



The relay is 70 amps and is on the firewall. There are 2 relays next to each other on drivers side below the cowl rubber. It's the relay nearer to the fender... . or on the right if you are in front of engine looking at firewall.



Look at post #3 of this thread for photo of relay location and solenoid adjust procedure:



https://www.turbodieselregister.com...51-fuel-shut-off-solenoid-best-way-stall.html

 

[RIVIRRAT]

also check or clean the small wires on the + post of the battery if bad connection would also cause your problems mine did about the same thing and that took care of it

 

[BigPapa]

weshope,



The parts in your 2nd and 3rd pics are supposed to be connected. You may be able to clean them up good and use some super glue or maybe an epoxy to put them back together. Someone else may have a better solution.



I've already decided that when my solenoid goes out I'm going back with a cable instead.



Scott

 

[weshope]

I got my new boot and solenoid saver diode from Geno's today. I'm also replacing the 70amp solenoid relay. I did notice some corrosion on the battery terminals, so I'll clean them as well.



The parts pictured in the 2nd and 3rd picture look like they are held together loosely by the conical shaped spring clip that you can see in the 3rd picture. I think mine is worn, but we'll see how it works when I get it bolted back on.



I'll let you know how cleaning the terminals and the solenoid works.

 

[weshope]

Little to no boost problem fixed. During all this I learned that it takes burned fuel to spin the turbo first and then you get boost and then controlling from the wastegate controller. I'm sure this is obvious to most, but I had to learn it the hard way.



I took the red scotchbrite pad and cleaned the bore of the solenoid and applied some ACF-50 (lightweight lubricant used on aircraft that eats corrosion but not plastic or rubber) and installed a new dust boot. Re-installed solenoid and tested using the old relay. I also bent the spring steel retaining clip that holds the spring in the bore of the plunger. This will hold on to the rod end shaft a little tighter now. I turned the key to start position and it snapped right up like it was supposed to. I also installed the solenoid saver diode. Boot = $27, Diode = $24, new relay = $20 from Geno's. Fixed problem and now have protection and spare relay for solenoid. New solenoid is $190 if the starter contacters weld together without the saver diode installed. I thought about doing the starter contacters as well to save the starter if this happens. Has anyone else done these? Can it be done with starter installed?