m915a1 jake brake quit working

Hello everybody again truck been sitting for 2 months
just finished main job season.time to fix truck and drive .jake brake doesnt work.couple weeks ago i spun around the block and tried to jake it on highway,it worked but responded about few secs after i pressed pedal.now it quit at all.
also,how do i fix fuel level gauge bouncing in the middle and same with oil pressure.kinda erratic.both getting 12v.
what steps do i need to reduce coldstarting time,it was 24f today,it took me about 15-20sec and 3 times to start truck.
Sorry for so many requests at once.i jsut dont want to hijack.ive looked up online about those issues havent found or wasnt smart enough to comprehend anyways .

they take awhile to start when cold. And they will huff and puff for awhile till they get warmed up... it takes a minute for it to spin up and create enough head and compression to start. A block heater is the only way to reduce cold starts really.

Fuel gauge is probably a bad ground. Clean the ground at the tank and on the frame and re attach it and go from there. Oil pressure could be a sender

On your Jake's you need to see if you have power to your pedal. If you have power then make sure you have power across the switch when it is pushed. Could be just the floor switch. If you have power across both floor switch connectors when you push it then go up to the switch on the engine throttle. If you do not have power there but had it at the floor switch I would suspect a bad wire or transmission switch. If you have power at the engine switch on both terminals with your throttle off then your Jake's should work.

I guess it is not working on any mode select setting?

Thank u man gon try today.
I've seen pics av8or posted about air ride ,I haven't seen joint between cab and firewall.as far as I know.i need some pivot bushings instead solid mounts in front of cab as I want to slap 2 airbags in back of cab.
Do u have any idea how to go around fixed valves in firewall to cab and steering wheel shaft.
.

akita91 said:

Hello everybody again truck been sitting for 2 months
just finished main job season.time to fix truck and drive .jake brake doesnt work.couple weeks ago i spun around the block and tried to jake it on highway,it worked but responded about few secs after i pressed pedal.now it quit at all.
also,how do i fix fuel level gauge bouncing in the middle and same with oil pressure.kinda erratic.both getting 12v.
what steps do i need to reduce coldstarting time,it was 24f today,it took me about 15-20sec and 3 times to start truck.
Sorry for so many requests at once.i jsut dont want to hijack.ive looked up online about those issues havent found or wasnt smart enough to comprehend anyways .

Click to expand...

Sometimes you can simply tap the jake brake pedal a few times and it will make contact after truck sitting awhile.

nope,jake doesnt work at all

cleaned ground at tank for sender,still bouncing little bit ,right in the center.
oil pressure says 40psi after turning on light climbs up to 70psi.

Then swap your sender. It is a normal Tectran unit. Can be found on ebay.

which one do you think ?

akita91 said:

95-3120	49229​	240-33 ohm​	Compatible with most brands​
95-3121	49230​	0-90 ohm​	AC type gauges​
95-3122	49231​	78-10 ohm​	Ford or Chrysler​
95-3124	49595​	10 - 180 ohm​	matches response of VDO models​
95-3123	49594​	-​	Replacement float for 95-3120, 95-3121, & 95-3122​

which one do you think ?

Click to expand...

95-3120

Can you guys please help to understand,im looking right now in manual and found out current transmission has *speedometer gear cable* which hooks up somewhere behind to actual speedometer ,so how new allison 4500 does it,they mated this old cummins with 4070p. assuming trans sends speed to tcm,tcm shifts and simultaneously sends numbers to speedometer.? if my speedometer right now mechanical,does it mean i have to buy electronic ?

okay 6hours later figured it out .
1. put in new trans (find out if they can be mated with engine)
2.cut or add driveshaft length
3.convert speedometer to electronic as 4500 doesnt have tachograph provision,only electronic sensor(output speed sensor goes into speedometer,where goes input speed sensor?)
4.add turbo speed sensor to make trans shift correctly
any steps im missing?

How are you going to add a turbo speed sensor?

Check the switch on the foot pedal for the Jake. That was the culprit for erratic operation on ours. Sometimes the Jakes would only kick in after standing on the pedal for a few seconds, sometimes they wouldn't work at all. New switch solved it.

I had a jake stop working on a 915a1 because the throttle shaft switch took a dump, I just wired around it till I could replace it.

i dont know,im newb.just found that allison has 3 sensors and thought that i can tap something in turbo .maybe i cant.

ill try now thank you

Does anyone have used or new PTO for this truck? chelsea listed them for 2k which i think is little bit high.
Ive read all PTO posts on this forum via google search.