Jacob's Exhaust Brake Problems???

[HBarlow]

I had the dealer install a Jacobs "eBrake" exhaust brake on my Ram before I took delivery. The brake is a great accessory and I have been very pleased with the additional braking it provides. I use it all the time whether towing or simply driving around town. It allows me to descend steep grades with a trailer in tow without using the service brake.



The truck now shows 66,000 on the odometer and for the last several thousand miles I've been experiencing intermittent problems with the exhaust brake. The brake works perfectly around town but when I hook up my travel trailer (16k# gcw) the brake occasionally fails to operate. When I back out of the throttle to take an exit ramp after pulling at highway speeds for an hour or two the exhaust brake won't close. After the truck cools for a few minutes it will usually operate normally again... ... for a while, then the problem repeats.



On a couple of occasions when I have lifted my throttle foot to slow, the brake has engaged for a brief time but then it cycles between closed and open as the truck slows, with no throttle input from me.



Has anyone had a similar experience? Any suggestions?



I reviewed the MOPAR/Cummins/Jacobs warranty book that came with the brake. The brake housing and valve are covered by a 100k mile warranty but the solenoid, switch, and wiring harness are only covered for 36k miles. I'm not anxious to take the truck to a local Dodge dealer who doesn't have any experience with the Jacobs brake. I don't want to pay them for several hours of labor to (possibly) diagnose the problem and then tell me it is not covered by warranty.



I talked to the service manager at a local big truck dealer and Cummins repair service today. He told me he can repair it but, of course, the cost will not be covered under warranty.



I sent an e-mail to Jacobs a couple of days ago asking them for advice but have not received a reply.



Any information will be appreciated.



Harvey

 

[Sticks]

Originally posted by HBarlow

The truck now shows 66,000 on the odometer and for the last several thousand miles I've been experiencing intermittent problems with the exhaust brake. The brake works perfectly around town but when I hook up my travel trailer (16k# gcw) the brake occasionally fails to operate. When I back out of the throttle to take an exit ramp after pulling at highway speeds for an hour or two the exhaust brake won't close. After the truck cools for a few minutes it will usually operate normally again... ... for a while, then the problem repeats.



On a couple of occasions when I have lifted my throttle foot to slow, the brake has engaged for a brief time but then it cycles between closed and open as the truck slows, with no throttle input from me.





Harvey

As far as the brake not closing, it might be the solenoid is getting too hot, and is suffering some sort of electrical issue.



With the throttle issues, it sounds like you pressure switch on the pedal needs adjusting... unless you don't have one, and it is taking it's commands from the computer. If that is the case, you may want to try re-calibrating the TPS. This could actually be causing both problems.



Worth a shot anyways.

 

[Whitmore]

Harvey, I am thinking you may have a not so good connection into pin #20 on the ecm, I have installed 3 Jacobs brakes around here and a guy came back in a week and said his was intermittent just like yours is doing, anyhow I re did his connection and he hasnt had any problems since



cheers, Kevin

 

[HBarlow]

Sticks and Kevin:



Thanks to each of you for your suggestions.



Sticks, how do I get the TPS recalibrated? Is that something the dealer would have to do?



Kevin, your suggestion sounds like a quick and easy check that even I can make. I'm going to get my Ram Service Manual out this afternoon and see if I can find the ECM and pin 20 as you suggested.



Harvey

 

[dresslered]

Harvey-

I would have to go along with Kevin's suggestion being a loose connection into pin #20 on the ecm (when installed properly, there is a definite "snap" to the connection. Also, if the dealer did not provide a "drip loop" on the wire, it could be that liquids (oil, moisture) may have entered the contact area.



Another thought is that you have lost a vacuum line or you have a bad check valve. Do your heater controls work properly? Otherwise, yours is the first instance that I have ever heard with the Jacobs. I have almost 50k on mine used all the time.

 

[GAmes]

The 12 valve set-up is different I know, but I had the same problem once when the microswitch on the throttle worked out of adjustment and didn't fully close when depressed.

 

[Sticks]

Originally posted by HBarlow

Sticks and Kevin:



Thanks to each of you for your suggestions.



Sticks, how do I get the TPS recalibrated? Is that something the dealer would have to do?



Kevin, your suggestion sounds like a quick and easy check that even I can make. I'm going to get my Ram Service Manual out this afternoon and see if I can find the ECM and pin 20 as you suggested.



Harvey

Disconnect batteries for at least 30 minutes, then reconnect batteries, then key to on position do not attempt to start, then push peddle down slowly to floor then back up slowly, do this three times, then turn key off, then turn back on and start your engine.



I don't have a manual, but the proceedure in numerous threads follows this pattern. Some say to disconnect the ECM/computer for the time the batteries are disconnected also.



I would try Kevin's fix first. Seems to make a little more sense.

 

[HBarlow]

Thanks again for additional good information and advice.



I'm going to publicly confess my ignorance. I tried to find the connectors on the ECM this afternoon but wasn't successful. I'm offering a weak excuse but I was trying to find the ECM and connector(s) in a dark engine compartment with the glare of the sun working against me. I could see what I think was the ECM, at least it looks like the drawing in the Dodge Service Manual, but I couldn't see well enough behind the lift pump, fuel filter, fuel lines, and various rubber hoses and wiring harnesses to locate the connector.



Is the connector visible and accessible without removing parts to gain access? Should I be able to see and identify pin# 20 while standing beside the left fender?



From the suggestions offered on this forum and a mechanic I spoke with, it makes sense that the problem I'm experiencing is electrical. It sounds right that either the TPS is not sending the proper signal or the signal is being interrupted by a bad connection.



Maybe I can locate the connector tomorrow if I get the truck inside out of the sunlight and use a drop light. I'll try resetting the TPS as well.



Harvey

 

[Sticks]

Harvey... Write down your radio stations numbers. Makes it a lot eaiser to re-program when you get done.

 

[Whitmore]

Harvey, tomorrow when the sun is out and addequate light is available to you take the 2 bolts out of the mount for your fuel filter housing, this will allow the filter housing to tip foward so you can see what you are doing, then you will see the ECM behind and lower on the side of the block, there is I think 1 allen bolt in the center cover of the ECM, take it out and pull the cover off just a few inches and you will see the wire comming from the brake harness, I think it will be on the right and towards the bottom, simply wiggle a puch it in as tight as you can get it. bolt the cover back on and put the 2 bolts back in for the filter housing and you should have it, when I did this I had the brack activated and the wiggle worked precisley.



cheers, Kevin

 

[HBarlow]

Sticks,



Thanks for the radio reminder. I only have two stations programmed and their frequencies are easy to remember --- Rush Limbaugh and a local AM station that plays the music of the '50s.





Kevin,



Thanks for the detailed instructions. I'll park the truck tomorrow so I can see in the engine compartment and follow your instructions. Would it be useful to disconnect the connector, visually inspect and shoot it with electrical contact cleaner, or should just pushing it tight resolve my problem?



I sure appreciate this TDR discussion forum!



Harvey

 

[Whitmore]

Harvey I wouldnt worry about cleaning it, the ECM connection had a silicone plug in it that you must push out with a drill bit so you can install the connector to and the whole affair is in a sealed unit once the cover is on.



good luck, Kevin

 

[HBarlow]

Thanks Kevin.



I'll just try to push the two sides of the connector together hard enough to hear the click.



Harvey

 

[SWC]

I have a Pac brake and have been having problems with my brake not engaging. I purchased my brake from PDR. Al figured it could be the #20 pin connector on mine as well. When I was around Vancouver Al said to stop in and they replaced the connector. Then he suggested the recalibration thing. I am still having problems. My problem seems to be tied into when I use the cruise control. If I don't use the cruise the Pac brake will always work. Sometimes the engine will idle higher then normal when the Pac will not engage. If I turn off the engine, wait 15 - 20 seconds start the motor, the Pac brake works and the idle is normal.

I have taken the truck to the dealership to see if there is a code and they could not find anything on the ECM.

When the Pac will not work there is no 12 volt signal at the solenoid valve. My solution: bypass the ECM. I put in a relay which I can switch from inside the cab which will take the 12 volt signal from the ECM or the battery. I have a BD brake switch on the shifter. Now when I pull on the switch I have instant brake rather then wait three seconds to find out if the ECM is in idle position. I used the toggle switch that came with the brake to switch the relay to ECM or battery. I have had this solution in place for 20,000 miles with no problems.

The only down side is that the brake can be engaged at any time including full power. If the brake is engaged with power I KNOW IT. I have never had the EGTs get high if the Pac is accidentally engaged. If some one else drives the truck I switch the Pac to normal operation.

Stan

 

[HBarlow]

Kevin,



Today I got out a drop light and some metric tools and, emboldened by your good instructions, removed the two bolts that attach the fuel filter cannister to the engine. I pulled the cannister away from the engine and let it hang on the rubber fuel line exposing the large ECM connector.



Like you suggested, there was an allen head bolt in the center of the connector which attached it to the ECM. I was able to rotate the allen head bolt about 3/4 to one full turn in the clockwise direction. I don't know if it was loose enough to cause my problem but it was loose enough that I was able to tighten it.



I won't know if that cured my problem until I hook up and pull my TT at highway speeds for a couple of hours. That has been the only situation when the exhaust brake failed to operate normally.



I am optimistic that it will be cured because with the benefit of the suggestions received on this forum I've convinced myself that the hard parts, the brake itself, is probably not causing the problem unless heat expansion and binding is involved. It makes more sense that the problem is related to the TPS sensor signal through the ECM to the brake solenoid. Anyway, I'm hopeful.



Thanks to each of you who offered helpful suggestions.



Harvey

 

[Whitmore]

Hope it helped Harvey, was the wire loose when you took the cover off the ECM?

 

[HBarlow]

Kevin,



OOPS! I wasn't smart enough to pull the cover. I guess I didn't understand my instructions.



When I saw the connector on the outside cover of the ECM I thought I was just supposed to push it in tight. Should I have removed the cover and checked the wires and another connector inside the cover?



I appreciate your guidance.



Harvey

 

[Carlton Bale]

What is being experienced here is not a problem with the exhaust brake or the wiring to the exhaust brake. The issue occurs only with 2001. 5 engines (which have electronic cruise control) and an exhaust brake. The way to resolve the issue is to replace the Throttle Position Sensor. There are newer sensors being sent to Mopar that have been revised.



I'm not in the product engineering group and I do not have all of the details as to when the newer-style TPS will be available. Also, I don't know exactly what the issue is.



If you have a 2001. 5 or 2002 truck and the exhaust brake won't come on after using cruise control, the situation may be resolved by replacing the TPS.



Hope this helps!

 

[HBarlow]

Carlton:



Thanks very much for the information you provided.



I have an appointment with the dealer who sold me the truck and installed the Jacobs E-Brake.



Could you possibly refer me to any documentation that I could present to the dealer's service manager when I get there? It would be helpful to convince them that I got this from an authoritative source.



I think I'll print out your message and take it with me as well.



Thanks again.



Harvey

 

[Bill Stockard]

Harvey,



Bring your truck by here and I'll check out pin number 20 on the ECM for you. Been there--done that!!



Bill