Jump to content

Poor Performance on a 24 valve.


Guest 04Mach1

Recommended Posts

Guest 04Mach1

I am new to the forum and joined due to Mopar1973man presence in many other forums. With that being said I hope I am posting this in the right place.

 

I have a 2001 4x4 quad cab short bed auto that I purchased about 2 years ago with 86k on the clock and appeared completely stock with 3.54 gearing. It now has 114k on the clock with an Airdog 100 with .5" fuel lines running 16 psi idle and I have not seen it drop below 14 psi with throttle and also has a K&N CAI. The VP looks to have been replaced sometime before  I purchased as it has a reman sticker on it. The issue I am having is low performance. The truck idles great with no smoke. When driving it seems the engine pulls strong until about 2000 rpm then seems to slow in rpm climb and pulling. Max RPM is about 2600 RPM right now. Turbo seems to be spooling great and I don't feel any misses. There are no codes present in the ECM (stored or active). I have cleaned the IAT. I can not find any boost leaks. The stock exhaust seems to have adequate flow. Two local Dodge dealers say ECM and PCM are up to date. I have not been able to get better than 13.2 MPG (hand calculated) cruising I-25 at 65 mph from Denver to Albuquerque. Also I have had the truck emissioned at 2 separate shops and they both stated opacity was far less than most trucks my year which in my mind means the truck is running too clean. I have sought advice from these 2 shops and they say everything checks out good mechanically.

 

I am out of ideas on improving performance and fuel economy. I have thought about going the tuner route but until I feel the truck is running as it should in stock form stay away from tuners fearing I may cause more damage. I'll also add that I am comparing performance to my 1997 4x4 quad cab long bed auto with 3.54 gearing completely stock with 220k on the clock. I thought the 24V was supposed to be more powerful than the 12V.

 

Any ideas where I can look?

Link to comment
Share on other sites

Is it possible the APPS is giving the ECM a low reading (meaning low fueling)? Has it ever ran like you think it should since you have owned it? Possible wrong key in the pump or maybe the pump gear is off one tooth? I know of one truck that the pump gear was off by a couple of teeth and it still ran. Not good, but it ran.

  • Like 2
Link to comment
Share on other sites

I'd  double check the injection timing.   Seeing it's been  replaced (injection pump)   Sounds  a  tad  late.

 

your   97  had  the same  hp as  the  SO  24 valve..   

 

BTW!   Welcome to the  family! :thumb1:

Edited by rancherman
Link to comment
Share on other sites

Guest 04Mach1

Thanks. I just read the APPS calibration procedure so I'll try that. I've had the batteries disconnected at least twice since I've owned it and have not ever done the APPS procedure. How would I verify timing? Or if the correct key was used on the VP? Yes the 24v has always felt weak compared to the 12v. The 24v shift points seem different (higher) too so maybe that's part of it.

Link to comment
Share on other sites

Guest 04Mach1

No modules. She is completely stock with the exception of the K&N CAI and Airdog 100 with .5" fuel lines.I'll try to post a full throttle video.. if I can figure out how.

Link to comment
Share on other sites

Guest 04Mach1

The above video is one I just shot going full throttle at 1500 rpm in first through about half way of second. Noticed my mileage is a tad lower than I had stated. Oops.

Link to comment
Share on other sites

The only way I know to verify timing is to pull the front cover and line up the timing marks. That K&N CAI is not helping you at all. Personally I would throw it in the garbage. It has been proven that these engines get better mileage with warm air entering the cylinders. Mopar1973man can explain that better.

Link to comment
Share on other sites

Guest 04Mach1

I've noticed no difference in mileage with the air filter. The original air box was broken from mis-installation of air panel. Temp runs at about 190 on the gauge. I had her idling about 15 minutes with 40 temps before I made the video. The lull above 2000 rpm is the same no matter temp. The video was full throttle and there was not a hint of smoke from the exhaust.

Link to comment
Share on other sites

Guest 04Mach1

Well more sniffing around and I know for a fact that my truck does not high idle even in below 0 weather. I am leaning towards a software causing the issues. There is little documentation on my truck before I bought it. I am printing the tsb for high idle to discuss with stealership.

Link to comment
Share on other sites

Guest 04Mach1

I just watched a vid of Mopar1973man on YouTube for fan clutch. I think that may be part of my fuel mileage draw. Mine was locked up when I bought it so I put a cheapo Imperial brand from Advance Auto Parts on. It has always been very stiff no matter radiator temp, hot or stone cold. Sounds like a plane on take off which maybe can be heard in the video.

Link to comment
Share on other sites

Guest 04Mach1

I often wondered about the transmission too. Fluid shows no signs of getting hot but I don't have a gauge to confirm. Fluid has at least 20k miles and is still bright red. However driving normally the transmission shifts about 2k rpm. I feel it shift every gear. Overdrive at about 45 mph and tcc lock shortly after.

Link to comment
Share on other sites

 I know you said you have 16 psi  fuel pressure.... is it  measured AFTER the filter??     Just  eliminating  some  possibilities here.

a partial   plugged filter  will do  the exact same thing too.    poor  motor spin up with no smoke...   Actually will run  fair  up to a  certain  rpm or   fuel  requirement..  then  it hits a wall.    

Your  lack of  smoke  makes  'late timing' seem  not so  certain..

Link to comment
Share on other sites

Guest 04Mach1

Ok. I just pulled the codes from the cluster.

For P PCU:

P0500 - No vehicle speed sensor signal

P1693 - DTC in companion module

For P ECU

P0234 - Turbo boost limit exceeded

P1693

For some reason my generic scanner wasn't pulling codes from the truck and I have no check engine light so I assumed no codes. Guess I should add the wastegate to the list of things to check.

Link to comment
Share on other sites

×
×
  • Create New...