gorms

Our 96 Dakota has 166k on it now, 3.9 V6/5spd has always been a strong running truck. Well my dad has had it for the last few months and its been running lousy intermittently, until lately its been stalling on long drives/bogging down/etc etc. Ultimatley it ended up getting a thorough tune up, each piece of the puzzle seemed to make it run better for a while. Kept getting cylinder 5 misfire and random/multiple misfire. Changed intake plenum/manifold gasket, every vac hose, whole ignition system, checked crank sensors, etc. Finally while it was running rough at idle (sometimes it ran o.k.) I pulled the injector plug off #5 and noticed no change. Any other injector made it run worse. The night before I thought it was fixed with a PCV valve because it was running very smooth, just a little low on power.

So we pulled the injector (all three on that side) and I attempted to clean it with a little homemade contraption. Basically just a piece of rubber hose that fit the nozzle of the injector, hose clamped to the injector. Filled the hose up with pb blaster, then carb cleaner, then injector cleaner, not all at once, and blasted it backwards through the injector with an airgun. Had to plug the injector in and turn the motor over to get it to open up.

But boy did it run better after getting it all together. I figured the most I had to loose was $8 for new o rings so why not. But is there a better way to clean them? Between the oil that was in the intake and the junk gas around here lately the varnish on the nozzle was pretty nasty. (Actually everything in that motor was pretty nasty, dad is doing "extended oil changes" again....) I also swapped the "bad" #5 injector for good #1 just in case it was something else.

Any harm in doing this? Or better way to clean them? I'm sure they all need a good cleaning, all the coils read the same resistance (around 15.3 ohm) and I'd hate to wreck 6 because I got lucky or something.....

madhat

I have taken the vacuum line off that goes into the intake and carefully poured sea foam in it slowly... Not sure if it would work on that your truck. I found the procedure on a hemi truck forum, it worked well for my wife's 08.

I'll see if I can find it.

madhat

The brake booster or PCV lines are the preferred methods for vacuum line introduction of Seafoam. If the BB enters the manifold at the rear, and the PCV the front, many people will perform 2 procedures to ensure the intake is fully cleaned. If you just do one on a setup like that then the area you use will be cleaned better than the other end.

Proper procedure for vacuum line Seafoam use...

1 - apply to an engine that is already at full operating temperature. Don't do it on a cold engine. Do it after driving or let the engine warm up a good 10 minutes before starting.

2 - do not rev the engine continuously while adding the Seafoam. That is sucking it through and burning it off before it has a chance to do any good. Seafoam should be added to an engine that is idling normally not being rev'ed. If it is starting to bog down back off on your pour rate, or stop pouring period, until it returns to a normal idle. If you must hit the accelerator to keep it running don't rev it just slightly bump RPM's until it is to a point it won't die. Again, serious rev'ing and racing of the engine is just going to burn it off before it can do anything. That may work when dumping directly into the throttle body because more is going in but through the vacuum source it is in a smaller quantity and more easily burned off.

3 - you only add 1/3-1/2 can through the vacuum source. Not a whole can. Adding a whole can is overkill and will also put you at a larger risk for hydrolock. Pour the remaining 1/2-2/3 can you have left into the gas tank.

4 - Use a small funnel in the vacuum line to make pouring the Seafoam in easier. It also helps to ensure that you don't add too much too fast. If you are pouring at a proper rate it is just a trickle from the can and will disappear instantly through the funnel without bogging the engine down too badly. If you pour too much too fast it will fill the funnel and the engine will start to bog and eventually die.

5 - once the 1/3-1/2 can has been added immediately shut the engine off. DO NOT REV IT! If you are near that 1/3 to 1/2 can point and the engine stalls out while pouring just stop there. Do not restart it if it stalls out at that point. Actually, many people prefer to use the Seafoam to kill the engine. They will dump a little extra to kill it. The theory is in doing so it keeps a little extra product in the cylinders for the 5-10 minute cleaning period( see #6 ).

6 - After the engine is off allow it to sit for at least 5 minutes. I personally feel 7-10 is better if it is an older vehicle with more miles on it. 5 minutes is fine on newer vehicles that do not need as much cleaning. This allows the product to do it's job( it sort of steams the inside of the intake/cylinders ). If all you do is rev the engine while pouring it in you have burned it all off before letting it sit.

7 - Restart after 5-10 minutes and NOW you can rev it. You should see some serious smoke if the engine has some miles on it. On a newer vehicle you won't see as much but you still should see some. Now go take a good strong highway run to burn it all off.

Fronty Owner

I usually run a bit less than 1/3 thru a vacuum line, and add about 1/3 to the oil somewhere around 500 miles before change. then dump the rest in a partial tank of fuel.

Hvytrkmech

Why didn't you check fuel supply pressure? There are a couple different way to clean injectors and as stated above you can try those. My recommendation would be purchase 2 20oz bottles of Chevron Techron fuel system cleaner.Then run you gas tank down to a 1/4, add 1 bottle of cleaner and put 15-20 gallons of super unleaded into your tank. Repeat the process once down to a 1/4 tanks.

Spooler

The only thing I have found to work is BG 44K. It is about $18.00 a can. I run it every 30k. It is the third part of the BG injector cleaning service. You should be able to pick a can up at your dealer. If they don't have it, the Nissan dealship probably will. Just poor it in the tank with a full tank of fuel. It is meant to clean the injectors the longevity of the tank of fuel.

railroaderone

The best way to clean injectors is the same stuff used at dealerships. NAPA sells a injector cleaning kit that hooks up to the sreader valve on the rail. You block the return line to the tank and remove the fuse of the fuel pump attach the can of cleaner and start he vechiel let it run untill the can is empty injectors are clean as the day they were new. Cost more but well with it

SIXSLUG

Isn't diesel a good solvent??

railroaderone

No diesel isn't

Dr.Dizzle

According to the folks at Chevron technical service,Techron Concentrate Fuel System Cleaner is their most concentrated and will clean combustion chamber deposits. There is approximately 100% more active ingredient in the Techron Concentrate than the Pro-Gard Fuel Injector Cleaner. The active ingredient is Poly Ether Amine(PEA) with a solvent carrier. PEA is highly regarded as a powerful injection system cleaner.

A bottle of Techron Concentrate Fuel System Cleaner, when added to gasoline according to the label instructions, results in an additive concentration roughly 10 times stronger than the dose in Chevron gas. I used Techron in the past on my personal vehicles and still do occasionally.

Redline SI-1, 3M Max Strength Fuel System Cleaner also contain PEA and work very well as does the 3M Fuel System Tune Up Kit, which is much like the system that automotive professionals use. I currently use the Redline SI-1 as it contains over 50 percent PEA. I purchase it at Pep Boys and I feel it offers me the best bang for the buck. They all work. BG-44K is also known to be a good one but I do not have experience with it.

Fronty Owner

there is a guy on the frontier forum that runs a quart of diesel every couple tanks of fuel in his gen1 truck.

gorms

I forgot all about seafoam...may give that a shot for all the other problems. When I had the intake manifold off everything in the valley was varnished up pretty bad, no clean looking metal inside. Pretty frustrating.

Hvytrkmech, I couldn't get my hands on a fuel pressure gauge. The injector that was clogged up was the first one in line to get fuel, and when I releive pressure on the fuel rail a few minutes after shutdown gas pretty much hits the hood, so I know it has some pressure (very accurate!). I would like to check it so I know, I think it's supposed to have 45-55 psi running?

For now it's got a pretty heavy dose of (lucas?) injector cleaner, will run another few tanks with additives, will check around for Chevron.

I do beleive that removing the injector was the only way to free it up, it has seen a few tanks with additives (not sure which types) since it's been acting up with little/no results. So with that I might just pull the rest of them and clean them out of the truck, I think back flushing it with cleaner might be the trick.

cougar

Berryman's Chemtool is a bit more aggressive than Sea Foam. I use the Chemtool for the initial cleaning and Sea Foam as a maintenance treatment.

timbo3500

When u had the intake off was there a pan on the bottom of the manifold? If there was did u change the gasket?

gorms

Yes there was, I did end up changing out the intake/plenum gaskets. At 160k it was in good shape though, not brittle and squishing out like you read about.

As a follow up I did end up getting it to run great with manually cleaning each injector as described above. Worked for about a month then the fuel pump died, Hvytrkmch was probably right all along. Had to wrap on the tank a few times on the way home to get it to fire up. I bet the failing fuel pump amplifyed the dirty injectors.

Now with a new fuel pump, clean injectors, general tune up it runs better then new, and mileage is back into the 20's.