ocliffie

Help....My 99 24V has been occasionally loosing power at cruising speed (70mph) for the last 3 or so weeks but not every day. I drive about 80 miles a day. Usually slows down to about 55 mph and within 2 minutes everything is beautiful and back up to 70. Last night I wasn't sure I would make it home. RPM dropped to around 1200 and I was going up an incline at about 40 mph. Did this every 5 minutes for about 20 miles. Once I got onto the secondary roads (speed limit under 40) no problems. The first time it happened I drained the fuel filter...clean and no water. The 40 mile trip this AM was uneventful. I am loosing my sense of humor real fast. Note: Injector pump replaced at 99,000 and truck has 122,000 now. I use a fuel additive religiously after the injector pump incident.

tool

Do you have a fuel pressure gauge???

Have you had it checked for codes????

Have you tried a APPS reset?

ocliffie

No, I don't have a FP gauge but it sounds like I should get one. What pressure(s) should I be getting? This is probably the best place to start.

I haven't checked for codes yet

No, I haven't done a APPS reset

Mike Perez

After you do all the things Tool mentioned....fuel pressure, code's, and APPs......And that doesn't fix it. Change your MAP sensor (Boost Sensor). My truck had the same symptoms and the problem got worse as time went on. It became an everyday consant problem, so I checked for codes and fuel pressure; no codes and fuel pressure was good. MAP sensor fixed it.

MP

ocliffie

Thanks Guys

I ordered a fuel pressure gauge and fitting yesterday

Mike, I see you also have a 99 so if the pressure is OK the MAP sensor seems like a good possibility

Mike Perez

ocliffie,
Did you ever find the problem?

just curious,

MP

ocliffie

Mike,

No I didn't fix it yet. Had to spend some time on my son's s10 blazer replacing the worn balljoints. The bottoms ones were ready to let go. Just got the FP gage installed this weekend and am getting 13 psi at idle, 10-11 at cruise and around 9 with the peddle to the floor. This morning cruise shifted down to 9-10 and 8 at full throttle. I read something on dodgeram.org which says 8 should be min under any condition. I guess the lift pump is ok?? The next thing they mention on the same site is a carboned up IAT sensor so I will take care of that next then on to the MAP if that doesn't work. Somewhere in there I am going to check the codes. Where did you get your MAP. I found one on Heathdiesel.com for around $115.

Mike Perez

I didn't get any super deal like I have seen some guy's on the DTR site, but I wanted it that day. I payed $97.00 at the dealer, I called around and found it for $85.00 to $116.00 with a two to three day wait.

My IAT sensor did not look dirty at all; MAP sensor was dark compared to the new one.

My truck never showed any codes, I think the "check engine light" would come on, but I'm not sure. I did check my OBDII scan tool by disconnecting the wire to the MAP sensor, and it did give me a code for that.

I just installed the Chevy One ton rear wheel cylinders, like I read about on this site. Both of the originals were leaking and the shoes had almost no wear. I do feel the difference.

Good luck, I still want to know the conclusion.
MP

ryanofire

Hi ocliffie I also I'm having the same problem with my 99. Just not real familiar with working on diesel motors. So exactly where would the map sensor be located and what function does it play. I hate to ask dumb questions but this problems is getting out of control and sometimes dangerous on the interstate.

gamiller31

MAP(Manifold Air Pressure), It deterinies how much boost or the lack of boost, thus telling the computer how much fuel can be injected, based on throttle position. The MAP is located just to the rear of the fuelfilter canister on the 99.

Valv

I found this dealer in Dallas with excellent prices:

https://www.dodgeparts.com/oe_parts_catalog.html


A MAP sensor is $ 80.00

ocliffie

Mike,

I changed the MAP sensor this weekend. No change. I just found out how to do an APPS reset today and that's the next step. Can you tell me more about the wheel cylinders. I blew one out recently when some idiot pulled out in front of me and haven't replaced it yet. I think it sealed itself back up although because it seems to work now. No time for that problem now but I would still like to hear about the brake deal because as you know this isn't the best machine when it comes to stopping.

ocliffie

ryanofire,

What's the latest on your problem. I haven't been active on this site for a few days. Read my last post for how I am progressing.

muddybeast

How did you guys get the MAP sensor off? I looked at it and it looks like it is gonna be a PITA. Plus it would require a huge deep socket.

tool

It is no sweat it's like a 5 minute max job to change. You need an 1 1/4" deep socket, just unplug the connector (put your hand on it and pop the tang off the little tab on the sensor and the connector will easily come off) careful not to loose the grommet/seal inside the connector.

Use said deep socket and about a 4" extension, easily comes out. Pop new one back in (check specified torque) reconnect, I coated my connector prongs with diecletic first and voila, it is done. That easy.