Back story... bought a 93 dakota sport 2wd 3.9l 5 speed with 320k on it. Originally i was going to simply re-seal the top end. Well you know how that went. I tore the heads off and did some mild clean up of the ports and bowl. That snowballed into a full out of frame rebuild. Eventually it got to the point of the machine shop not getting my engine machined (who would blame him? It's just a v6 after all) so I picked up another used 3.9 with 170k on it. Same deal for the most part. Everything new above the deck.

Mods and/or upgrades and replacements

• Fuel injectors (used eBay Best Bosch upgrade injectors 19lb)
• hughes valve springs, retainers, and keeps
• Harland Sharp 1:7 roller rockers
• Egr delete
• Everything vacuum except brake booster removed (to try to isolate vacuum leak that I may or may not have)
• A/c present but not in serpentine
• Powersteering delete (I know, not recommended or wise. It will get added later when I repair it, it leaks like a siph)
• Pretty sure I used copper spark plugs. Will have to confirm later.
• Kegger mod
• Shorty headers
• Both Coolant sensors
• Intake air temp sensor
• Mechanical oil pressure gauge... oddly says 60-70psi at idle if I remember right. Also will confirm later.
• Double roller timing chain

Retained stock cam, pushrods, lifters, throttle body, air filter housing.

Now for my problems.

• So far, it idles at 1200ish, much better than before with open headers and o2 plugged in. That was a 3200 idle.
• Glowing red headers

From my exhaustive google research over the last couple days. I've read that it could be super lean or rich and retarded. I have not pulled the plugs yet to find out how they are holding up. I will be doing that once I get off work.
I'm wondering if my intake pan gasket didn't hold and thats my high idle. I am aware that turning the distributor doesn't really change my timing. But it does change the fuel spark sync?

For the timing chain install I put #1 cyl at TDC since the heads were off that was easy. I used the dots as cam @6 and crank @12. That points the dizzy at the passenger front tire area.

Cranks no start at any dizzy position except max clockwise rotation. Turning the dizzy counterclockwise revs it up and then kills it down to a crank no start.

 

Check firing order, I believe number 1 is marked on the cap, and it is kinda/sorta pointing the rotor toward the passenger front, however, I seem to recall that when the cam dot is at 6, and the crank dot is at 12, it isn't number 1 at firing position, its whatever is fourth in the firing order on a six cylinder..... (Don't remember the firing order on those.....)

 

So, upom reading about indexing the dizzy, which i probably havent read enough about, since i just skimmed through the service manual. I concluded that the dizzy wasn't indexed and needed to be reindexed. Which i did, runs like a top minus the glowing exhaust.

I will pull the valve covers and triple check the wires. seems like it wouldn't run as well as it does if the wires were all a mess like you're saying. I mean other than it idles high (vacuum leak that I think j found but didn't have time to fix tonight) and the headers glow.

I've pulled the plugs. 1,3,5 were all blackened (non oily and not wet) and starting to turn ashy. I assume this is from initial start where it had way too much fuel. And now whatever is causing super lean burn and glowing exhaust.

2,6 were the same as 1,3,5. 4 was wet but not oily.

Also to note, after messing around with the dizzy index. Cylinders 1, 4 do not glow. The rest still glow. So mostly at this point, I'm concerned about the fine adjustments to the injector timing via the dizzy. And if my refurbished ebay injectors are actually compatible with this engine.

Like I said. I will check timing to rocker movement tomorrow after work or this weekend.

Another note on injectors, my worry caused me to lookup injectors for the 5.2l at autozone verse the 3.9l. Not the same. The injectors i bought were for the 5.2l but 19# with 4 holes instead of the single hole. Im also thinking that 92-93 injectors were 21#? Id have to find the link again.

 

For 1992/1993, according to Five-Oh Motorsports,

[QUOTE]Flow Rate: 19.2 lbs/hr at 43.5 PSI, 205 cc/min at 3 BAR/QUOTE]

For 94/95,

They DO list the same injectors 3.9/5.2, though, for both years.

Then again, these are the 4 hole ones; originally they may have been different, haven't checked.

RwP

 

[QUOTE=RalphP;3509437]For 1992/1993, according to Five-Oh Motorsports,


But when you go and check vehicle fitment. It will be only for the 5.2 or only for the 3.9. at least for my web browser. Rock auto is the same way, separate part numbers.

I found the problem was the intake manifold bolts didn't hold torque. Even after multiple torque sequences. I must not have fully or properly 1. Torqued them. Or 2. Heat cycled them. Either way. Retorqued them and let it run for a good while. So far seems to have held after 12hrs.

Other vacuum leaks I found were the injector o-rings didn't seal to the intake side for some reason. Fixed that by simply removing the upper reatainer clips and pushing the injectors down far enough to seal both top and bottom o-rings.

I also found that the brand new intake manifold temp sensor leaks through the plug. Will try one more new sensor before I say forget it.

But yeah. Massive air leak causes glowing exhaust.

 

Good to know.