I have an 88 Dakota (V6) that I am trying to get running again (and running great). It's been sitting for 1.5 years, starts up, but won't idle (and runs rough). Looking for some direction on what components/areas I should be looking at to get it running like a top (it already has new spark plugs). I know the throttle bodies on these rigs are somewhat unique (double fuel injectors) and are known to have issues with the IAC (or IAC like apparatus), EGR malfunction and ports clogging, and leaking valve cover gaskets. I plan on doing the following -- what else would y'all recommend?:

New Cap and Rotor (wires are new)
New PCV valve
cleaning TB and IAC valve
Clean EGR ports and tubes
Inspect for vacuum leaks

Thanks!

 

Don't just inspect, replace ALL the vacuum lines.

For the PCV valve, use a genuine Mopar valve; the Fram and other aftermarkets will gulp the oil by comparision. Or if you run aftermarket, at LEAST add a catch can to keep the oil from being sucked into the intake.

Cats on these. At this age in years, the cats are probably non-functional at best and if it's been oil burning any, they're probably plugged.

GET A FACTORY SERVICE MANUAL! The one that says it's from Chrysler, not the Haynes or Chilton's.

RwP

 

Great advice Ralph. GREAT.

Are you aware of any online outfits that sell a "kit" with all of the vacuum lines in it? Also... how common is it for the IAC valve to fail without being recoverable from a thorough cleaning? And the same for the EGR valve. Lastly... what is the most common source for top engine oil leak on the back driver side of the engine (besides the valve cover gasket)? I will replace the oil pressure sensor gasket as well as I am aware they go commonly and create a big mess.

 

One last question... I notice smoke coming out of the oil dipstick tube with the engine running. A common problem at 160K plus miles? Or signs of something else (non-functioning PCV system for instance)? Thanks.

 

Non-functioning PCV can do that; so can worn rings (blowby). My Cougar has blowby - not that bad, but if I stomp on the gas, soon I have to stop and reseat the dipstick or it blows oil all over the driver's side of the engine bay via the dipstick tube ... *grins*

No, I'm not sure of anyone who sells a kit; I got lucky, found a nice low mileage rolled one with perfect plastic pieces and decent rubber, and used that. I did replace the rubber pieces; I used some 360* clamps to help make sure they sealed. If recycling the rubber, some Automotive GOOP on the outside of the plastic right before sliding the rubber on will help with sealing.

However, there's a nice diagram that once it clicks in what each item IS, it's pretty obvious how it runs. Or was to me. (Took a few weeks of head scratching for the AHA! moment, though.) My diagram was still on the inside of the hood.

I don't know how often the throttle kicker fails; it's not the IAC problem you usually read about, though, since it's not actually an IAC, but is a throttle kicker. I just replaced mine when I had the motor rebuilt back a few months ago (386,000 or so miles; it's now at 394,750+ miles and running great.) But previously it was working fine, so ... (Yes, along the lines of "If I don't do it NOW, I'll have to do it LATER when I might not have the cash ... so get'er dun!)

The EGR valve doesn't actually plug up that much; the EGR PASSAGES in the intake, however ... I paid an extra $50 to get the shop to boil out my intake and restore EGR functionality.

One more thing - if there's any doubt, replace the O2 sensor (NTK, Denso, or Mopar IIRC for the brands.) You'll be surprised how much better it runs when warm with that in good shape.

The Y pipe is Unobtainium now, so take good care of yours. (The rest of the exhaust is off the shelf for stock.)

I was too cheap to replace the three purge solenoids, though; that might make a difference on yours.

RwP

 

Wow! You just wrote a bestseller on the subject -- can't thank you enough Ralph. This is precisely the information I was looking for. You nailed it. I will post back with progress on this semi-restoration. Should have this thing running like a top shortly. Ralph -- do you still have your original fuel injectors?

 

Nope.

Don't even have the original throttle body - I had to replace my TB once and junk yarded it (no dosh), then when I had the money for the rebuild, I went ahead and ordered a reman'ed TB with injectors.

They are still available, and even new ... Motor Man claims to have them ( https://www.motormanfuelinjection.co...280150640.html but they don't list 1988 Dakota anymore); also, RockAuto lists them ( https://www.rockauto.com/en/catalog/...+injector,6224 ).

Take the OEM #s on RA, and you should be able to Google other possible sources.

BTW - Bona fides? I have a 1988 that by my notes I've put almost 200,000 miles on (and it's almost at 395,000 now!)

RwP

 

Almost 400k? Are you kidding me!?!? That's phenomenal. How many transmissions have you gone through? And was it just the one time you did an engine rebuild? This thing only has a few K north of 160. But it was neglected by the PO so I have some work cut out for me (lots of crud built up on the valve train and inside the valve covers). Do you have the factory air-filter and air snorkle or have you modified it (and if so, with what setup?)?

 

No kidding. And the original transmission I had rebuilt when the front pump let go at about 325,000 miles.

And AFAIK, that was the first rebuild on the motor.

I did several "Motor Medic Engine Flush" oil changes when i bought mine; you could hardly see the rockers in the valve cover through the oil filler hole when I bought mine, but after the fifth change, they were blackened and tarnished but you could see no gunk on them.

Factory air filter setup, yes. Don't forget, it pulls cold air from beside the radiator already; if you pay attention, most so-called "cold air intakes" are actually hot air intakes.

I do buy air filters 6 at a whack from RockAuto and change them every other oil change (will do that again in about another 1,000 miles).

I also am now running Rotella T6 synthetic and Motorcraft FL-300 filters (the FL-300 because it's bigger than factory, and it also fits the Cougar, so I buy those in 12-lot boxes ... )

Come 400,000 I'll be replacing the plugs - mechanic used copper plugs when he did the rebuild, so I'll be about time to at least clean and regap, and will probably go copper back in since they are a bit easier to fire than the longer life plugs. (OTOH, plats and iridiums don't erode like copper does ... so they can last longer. OTGH, longer lasting makes it easier for them to seize if not properly anti-seized on install. Le sigh.)

As to your oil leak - oil pressure sending unit and valve cover gasket are about it for oil leaks there. The design of the heads can pump up some oil, and the design also leaves oil sitting in the heads if the engine is not perfectly level on shutdown. If you park nose up, you'll have a life long battle on oil out the back.

Do pay attention when you change the gaskets - I took a few days extra last time I did mine before the rebuild, and cleaned and painted the valve covers. (Used Seafoam Blue; it's actually a pretty color, IMO. But pick one you like, and make it a lighter color so you can see the oil as it leaks. Or make it black and the oil leakage won't show up.)

My truck will never be a race truck; and with the 3 speed and a 2.92 rear end (2.94? Forget which offhand - 2.9sumpin') it tends to cruise town in 2nd (won't hold in 3rd until over 45MPH!)

Le sigh.

Not 2019, but in 2020, I'll probably upgrade to a 4 speed auto (42RH/44RH/46RH) and stiffen the rear end (3.54 is what I'm planning on, to match the Cougar's 3.55 it's getting this year.)

But that's slow time. I've still to finish putting the interior back in (between being tired after long weeks working, bad weather, etc. I've still got plastics to repaint and seal, a newly built headliner to go in, and now a shark's fin antenna to install on the roof. If it ain't one thing, 'tis another.)

RwP

 

One thing you can do is to start the truck and feel the exhaust manifolds as it warms up to make sure it is firing on all cylinders. If a few of the flanges to stay cold longer, then you should do a compression test. Or you could just do a compression test first. First while cold, then while warm. Does the engine run rough when it's cold and smooth when it's warm? If so then it could be a leaky intake gasket, or a seeping head gasket, check for oil in the radiator. Other things that can make it run rough 'consistently' are a worn out timing chain, or a bad distributor bushing. Pull your distributor cap, then rotate the crank clock wise then counter clock wise while watching the rotor in the distributor. If the rotor doesn't turn right away when you rotate it counter clock wise, then your timing chain is stretched beyond the tensioners. After that you can pull the distributor and wiggle the shaft to see if there is any side play. As far as the engine gunk, I've had great results using Seafoam.