If the EGR is blocked, you'll have worse fuel economy.

Fix that, the plenum, and clean the throttle body. You might be very pleasantly surprised.

Oh, and remember, our trucks are about as aerodynamic as a brick wall ... so they don't get exceptional fuel economy at all.

RwP

 

Quote:

Originally Posted by tbugden

When I took it out I decided to do a 0-60 run just to see if I really was as down on power as my butt dyno says I am. Well I didn't have the greatest launch but it wasn't too bad. It took me over 10 seconds to get to 50 mph...50. I stopped there, no reason to continue.

.

With a 318 magnum? and a 0 to 50 over 10 sec? That is waaaaaay down on power, IMO. FWIW I recently purchased a used Gtech...... Even with my 125hp V6 I would be disappointed if it is over 10 sec. to 50. I would think you should be between 6 and 7 seconds.....

 

Yep I know. I gotta get this thing fixed man. Maybe now I should pull the injectors and see if they're working properly.

 

I put in some rebuilt injectors a couple years ago thinking the old ones I had in were part of the issue. There was no perceptible change. I now wonder if getting new would make a difference?

 

I don't think the EGR is blocked, but it's failing. Problem is that back on my B250 I had the same thing, occasional CE light for EGR valve and I replaced it and my MPG went down, so I'm reluctant to do anything with it at the moment.

The plenum fix is a guess. I can see some oily substance in the intake but I don't know that it's leaking, but it has some idle / stall / overpowering problems so I assume it's plenum related. When the engine is cold and you're in reverse it behaves properly, if the engine is warmed up it will bear down and push hard against the brakes. When you knock it into neutral the engine rpms pop up close to 2500 before settling back down around 500.

As for driving a brick the Dakota is not nearly as much of a brick as a the B250 or VW Vanagon / Eurovan or countless others, but if I continue to use this I'm likely going to dump the 3.9L in favor of a 1.9L or 2.0L TDI coupled to a MT. And since it's already been done here the road to do this has already been paved. In fact it's already been paved twice in a Dakota and several times in a Ranger. And while some friends have suggested a 4BT I would prefer the TDI since it has electronic controls and can be easily tuned. Heck if I could find a 3.0L V6 tdi I'd go that route but those are at present few and far between.

My budget can't live with a sub-20 mpg truck at least not if it's driven often, my Chevy 6.5L TD got 20-25 and that's a K1500 4x4 and a larger truck. I didn't expect the 3.9L to be that big of a guzzler but I guess they are.

Since I have a spare 1.9L TDI and all the electrics, it's basically just a matter of buying the adapter kit to mate to the MT and doing the refit. But all this right now is off into next summer sometime when it's not cold and nasty outside, so I'll be spending part of the weekend doing the plenum and tb cleaning and we'll see if that makes the situation better.

EDIT: second Dakota tdi conversion is here if anyone is interested. It's not as thorough as the prior one.

Steve

 

Okay guys I figured it out. Well, sort of. I found my IR temp gun and found that #6 and #8 cylinders aren't doing anything. They're getting spark and fuel (I swapped injectors today to be sure), but not firing.

#8 was the cylinder with lowest compression (105 PSI), but #6 had good compression (well, same as the others). Therefore, I'm guessing this is a valve issue or perhaps camshaft? Intake valves not opening all the way?

I'm quitting out of frustration with it today but I'll probably pull it all apart this weekend.

 

Got an air compressor? Do a leak down test. that'll tell ya where compression is going.

 

I do but I gotta borrow a leak down tester.

 

You remind me of the tagline one poster on the TCCoA forum has:

"I really love my Thunderbird! I'd love it more if all eight cylinders worked!"

RwP

 

So you've really been driving a V6 truck then?

Steve