Go Back   DodgeForum.com > Dodge Trucks > Dodge Dakota > 2nd Gen Dakota
Sign in using an external account
Register Forgot Password?


2nd Gen Dakota 1997 - 2004 Dakota's

2.5 4 cylinder engine

Reply
 
 
 
 
Thread Tools Search this Thread
  #1  
Old 04-07-2013, 06:35 PM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default 2.5 4 cylinder engine

"I have a 1998 dodge dakota 4 cylinder 5 speed. The engine is new with 40 miles on it. The head is totally rebuilt new valves, guides, springs etc., new pistons, new cam, lifters, pushrods, rocker arms, new injectors, new crank sensor, new distributor, new cap, new rotor button, new plug wires, new ignition coil, new timing chain, new timing chain tensioner, This engine is new except for the crank and rods... This engine still does not have any more power then it had before it was rebuilt? I'm lucky if I get 15 miles a gallon! It still cuts out or kinda of like a surge or something when you give it gas to get going? The check engine light works but it is not on! Any ideas what the problem could be? Could it be the oxygen sensors or what?
This ad is not displayed to registered and logged-in members.
Register your free account today and become a member on Dodge Forums!
Reply With Quote
  #2  
Old 04-08-2013, 12:34 AM
magnethead magnethead is offline
Champion
 
Join Date: Feb 2005
Vehicle: 01 Dako 3.9 4x2
Location: Fort Worth, TX
Posts: 4,920
Send a message via AIM to magnethead
Default

Why was it rebuilt?

The 4 cylinder only had ~140 HP if even that much.
__________________

68 Camaro (sold): 5.318@128 / 8.568@155 ; 2014 Dragster: 4.79@143, 2014 2X Champions!
Magnethead494.com Web & Computer Maintenance
McDermott Family Racing
Reply With Quote
  #3  
Old 04-08-2013, 09:45 AM
00DakDan's Avatar
00DakDan 00DakDan is online now
Section Moderator
Dodge Forum Moderator
 
Join Date: Dec 2010
Vehicle: 2000 Dak Sport CC 4.7 5 speed 4x4
Location: MA
Posts: 3,418
Default

I moved your post into the Dakota forum.

It does sound like you have a fuel problem if it's cutting out or surging. O2 sensors can get "lazy" and slow to respond. How's the exhaust, any restrictions? How's the cat?
__________________
http://dodgeforum.com/forum/signaturepics/sigpic158370_10.gif
Reply With Quote
  #4  
Old 04-08-2013, 06:49 PM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

Everything checked out fine fuel pressure, exhaust, cat. Converter, sensors everything! Gonna pull the front cover its possible I may have gotten the cam a notch out
Reply With Quote
  #5  
Old 04-08-2013, 07:01 PM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

http://www.allpar.com/mopar/amc-25.html

Did you over size the pistons you should have its worth the extra Hp?

The 2.5 is not a pusher engine its a curser engine even though my 2.5 is faster off the line than most cars the way its geared.

The way its geared its a great freeway flyer at 85 to 95 also... she loves 95 in 5th gear.


http://www.shop.505performance.com/c...?categoryId=40
__________________

Last edited by 98DAKAZ; 04-08-2013 at 07:04 PM..
Reply With Quote
  #6  
Old 04-25-2013, 07:08 PM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

Yes the engine was bored .030 regardless this engine still has a miss to it....a code keeps coming up that says catalyst is bad but I had that checked out there's no restrictions
Reply With Quote
  #7  
Old 04-26-2013, 02:47 AM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

That would mean your cat may be bad or even plugged up/old

It could be an O2 problem also or even MAP sensor

Pull the air temp sensor and clean it... it may need replacing they get covered in oil at times.

Just testing sensors doesn't mean everything is ok sensors get lazy and show up as good all the time I say replace all your sensors at the 120 to 150K mark even if still running good

If your cat is not welded in just clamped in take it off and take it for a drive see what happens you may get a dash warning but if it runs way better its the cat

Don't forget to reset the PCM so it starts blank

Also taking it off gives you a chance to inspect it you may find its plugged up good if you cant see inside give it a few good whacks with a hammer then shake it if you hear things rattling inside its toast
__________________

Last edited by 98DAKAZ; 04-26-2013 at 07:17 AM..
Reply With Quote
  #8  
Old 04-26-2013, 07:37 AM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

The exhaust was tested they don't think it's stopped up because it blows real hard out the exhaust tail pipe.... I had the cat off a few months ago it looked brand new I could see thru every pin hole. The computer is throwing code for a bad cat I just can't see the cat being bad considering how good it flows. I replaced the upstream oxygen sensor but not the down stream I was told the down stream didn't control the engine it was there to tell when the cat was bad
Reply With Quote
  #9  
Old 04-26-2013, 07:57 AM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

Then I would jump on the down stream O2 $35 I think NTK is best I have Bosch and have no problems but everyone says they are bad but so far my Bosch have been ok for me I think the V8 and V6 don't like the Bosch
__________________
Reply With Quote
  #10  
Old 04-26-2013, 08:05 AM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

Have you replaced the air temp sensor yet they are cheap $15 to $30 I think or just pull it and clean it inspect it.

KEEP all your old sensors they may come in handy at some time label the old ones so you know what they are

Click the image to open in full size.

Click the image to open in full size.
__________________

Last edited by 98DAKAZ; 04-26-2013 at 08:12 AM..
Reply With Quote
  #11  
Old 04-26-2013, 10:49 AM
sxrsil3nt's Avatar
sxrsil3nt sxrsil3nt is offline
Record Breaker
 
Join Date: Dec 2010
Vehicle: 2002 Dodge Dakota Sport 4x4 3.9L
Location: Ontario, Canada
Posts: 1,075
siX-x
Default

Wow Dakaz you could practically eat off that engine bay.

If only I could keep mine half that clean.
Reply With Quote
  #12  
Old 04-27-2013, 10:32 AM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

The only reason I haven't replaced the sensor by the cat is because I was told it has nothing to do with how the engine runs?
Reply With Quote
  #13  
Old 04-27-2013, 07:51 PM
00DakDan's Avatar
00DakDan 00DakDan is online now
Section Moderator
Dodge Forum Moderator
 
Join Date: Dec 2010
Vehicle: 2000 Dak Sport CC 4.7 5 speed 4x4
Location: MA
Posts: 3,418
Default

You were given BAD information. Change the downstream sensor. This is from the factory manual:

Downstream Sensor: The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content). The downstream oxygen sensor also provides an input to determine catalytic convertor efficiency.
__________________
http://dodgeforum.com/forum/signaturepics/sigpic158370_10.gif
Reply With Quote
  #14  
Old 05-10-2013, 04:48 PM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

I have now replaced upstream and downstream sensors and the truck still does the same thing
Reply With Quote
  #15  
Old 05-10-2013, 05:10 PM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

Have you pulled out the air temp sensor and look at it? Its on the intake manifold cant miss it check your spare vacuum port make sure its plugged up.

Have you checked the distributor ignition pickup? Its under the rotor remove the plastic cover that's it.

Sometimes its as simple as the coolant temp sensor

Only other is the crank position sensor

Click the image to open in full size.
__________________
Reply With Quote
  #16  
Old 05-10-2013, 05:36 PM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

The 2.5 engine has a flaw that's irritating but easily avoided and you listed it the take off from a dead stop to acceleration burp/hiccup the only way to avoid it is feather the clutch and gas it this gets you past the burp/hiccup that's why I'm always fastest off the gun green light.

You may have put the timing chain on wrong or a bad or misaligned distributor.

The 2.5L is a very simple engine

By the way I have talked to many 2.5 owners and everyone has the burp/hiccup problem

Check the intake manifold gasket you should never use a thick gasket only the thin ones why they develop air/vacuum leaks after a few months... use the OEM thin gaskets only
__________________
Reply With Quote
  #17  
Old 05-11-2013, 12:05 PM
Joey4u9's Avatar
Joey4u9 Joey4u9 is offline
Registered User
 
Join Date: Apr 2013
Posts: 13
Default

I'm about to check the IAT sensor the engine already has a new crank sensor... I'd like to think it would show up if the IAT was bad? Ill most likely just go get one real quick
Reply With Quote
  #18  
Old 05-11-2013, 12:38 PM
Tom A's Avatar
Tom A Tom A is offline
Section Moderator
Dodge Forum Moderator
 
Join Date: May 2012
Vehicle: 1997 Dakota Sport 4x4
Location: Concord, CA
Posts: 1,473
Default

You're going to go broke if you keep throwing parts at it. Buy/borrow/rent/steal a scanner so you can see what the sensors are doing instead of just replacing them randomly.

If you have an Android phone, you can buy a Bluetooth OBDII adapter for 25 bucks and the Torque app for another 5. That will actually give you a halfway decent scanner for the money.
__________________
http://i286.photobucket.com/albums/ll101/OldFatGuy_photos/DodgeAvatar.jpg
Reply With Quote
  #19  
Old 05-11-2013, 01:57 PM
98DAKAZ's Avatar
98DAKAZ 98DAKAZ is offline
Champion
 
Join Date: Jul 2011
Vehicle: 98 Dakota 2.5L 5 speed AX-15
Location: Gilbert, Arizona
Posts: 3,605
Default

Well I look at it this way those parts needed replacing anyway I say replace all sensors after 150K. But I do say keep the old ones as backups they come in handy at times.

Its still way cheaper than a shop at what $100 to $200 an hour

Sometimes a code never comes up
__________________
Reply With Quote
  #20  
Old 05-11-2013, 02:21 PM
Tom A's Avatar
Tom A Tom A is offline
Section Moderator
Dodge Forum Moderator
 
Join Date: May 2012
Vehicle: 1997 Dakota Sport 4x4
Location: Concord, CA
Posts: 1,473
Default

I guess I'm weird because I don't replace parts that are still functioning properly. And I'm not talking about checking codes. I'm talking about reading the data stream.
__________________
http://i286.photobucket.com/albums/ll101/OldFatGuy_photos/DodgeAvatar.jpg
Reply With Quote
Old 05-11-2013, 02:21 PM
 
 
 
Reply




Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Join DodgeForum
Advertising

Featured Sponsors
Vendor Directory
Our Sponsors
All times are GMT -4. The time now is 09:43 AM.

Internet Brands, Inc.


Contact Details & Emails