6.5 TD Intake bolts - rough and smokes until warm

[Splitrimz]

I have two of the six bolts that hold the "L" shaped intake from the Turbo to the top of intake that won't snug down. Is it critical that the interface between this "L" shaped intake and the top of the motor intake be air and vacuum tight? I remember on gassers that a leak in the intake would cause all sorts of rough stuff. My truck starts and smokes, black and grey, until it warms up and then it smooths out. I can't even drive it until the rough stuff goes away, I press the throttle when it is in this rough mode and it really bogs down. Is the "L" intake tube a possible culprit? Any other suggestions? Thanks. '94 6.5 Dually. Stock

Splitrimz

[DmaxMaverick]

An intake leak on a Diesel won't effect starting and idle. Your cold engine problem isn't related to the intake hat. Sounds like you have an issue with your glow plug system and/or air in your fuel system.

A leak in the intake on a turbo Diesel will leak charge air under load, while making, or trying to make boost. Very different than a gasser, and not at all comparable. All 6 of those bolts are critical. They must be torqued properly, or you risk engine damage. If they won't tighten, they are either stripped, or you are using too small a bolt. A Heli-Coil is an easy solution for a stripped thread. Any machine shop and most auto shops can help with that. Or, you can get a kit and do it your self. If the leak becomes more significant, turbo overspeed and/or excessive EGT's will be the result. Not to mention power loss and decreased fuel mileage.

[Robyn]

I agree with Maverick on the bolts.
These can be tapped oversize and US standard bolts installed or the helicoils done to restore the threads.

The clouds of smoke can be caused by several issues.
Be sure your fuel filter is clean.
Be sure air filter is clean and that some little creature has not built a home in the inner fender air tube and set up house keeping.

The injectors can be worn and causing issues too.

Glow plug problems generally will result in Blue to white smoke upon startup but will clear out and be ok within a short time.

Bad injectors can cause poor running all through the power range.
Poor smokey starts and smoke at idle even when warm.

Having the injectors tested would be a good idea.

Keep us posted.

Robyn

[Splitrimz]

Thanks for the tips: The bolts on the intake will get the attention they need.
Regarding the rough Idle and smoking, I will check the glow plugs first. I recently installed a set of the long duration plugs, I'll make sure that are all still burning. Injectors are certainly on the list, 170,000 miles on the originals, but that is last on my list due to the cash outlay.

The glow plug dash light goes on and off like it should, that should indicate that the relay is cycling. If the relay was bad and the glow plugs stayed on, would glowing plugs after startup cause problems?

The Air path is not a problem, I'll check the fuel filter. Ive checked the fuel lines from the tank to the lift pump and from the lift pump to the injector pump, all seem OK.

Any thoughts on the Encoder Sensor that is mounted on the injection pump? Can a failing one cause my sort of problem, or would that be a more permanent symptom?

The phenonema of the problem going away when it warms up has me puzzled. The warm up time till smooth running is much longer on colder days than warmer.

Again, thanks for the tips, I'll keep plugging at it, I'll certainly report back any findings.
Splitrimz

[Splitrimz]

Oh Silly me, Injectors run about $320.00. Just two tanks of fuel at my local. I got to keep things in perspective.

[DmaxMaverick]

Definitely time for injectors. Don't bother with testing them.

Your glow controller sounds OK. If it's cycling before starting, and for a little while after (afterglow), it's doing what it should. Glow plug quality is somewhat subjective, so checking them is a good idea. Unfortunately, it may not tell you much. Short of taking them out and looking at them while they glow, a meter test will only confirm continuity. Usually, continuity indicates a good plug, but not always. While you are messing around in there, it's easy enough to pull them and throw 12V at them. They should glow bright orange within only a couple seconds, or at the very least, within the time you see during a cycle.

The optical sensor in the IP could be causing problems, but leave it for now. Eliminate the easy, most common stuff first. It's not likely to cause cold start only problems, anyway.

[Robyn]

If the plugs are in reasonably good shape things should be fine there.
Even having one or two that are not working will generally not make a big issue, just a few seconds of smoke except in COLD weather.

The injectors lose pop pressure over time and the nozzles wear out along with the valve geting sticky.
They will start popping at lower pressures sometimes very low and instead of a nice fine mist in a cone shaped pattern they will pee a stream off into the corner of the precup.

Often the injectors will dribble after the injection cycle is finished.
Dribbling causes excess smoke and can also contribute to high exhaust temps.

Poor injector function is a leading cause of poor fuel economy, high exhaust temps and lower than nominal power output.

It cant be stressed enough to get these little buggers working properly.


Glow plugs are a necessary item but they stop influencing the issue very quickly after startup.

Once the glow plugs have been offline for about 20 seconds or so they are not doing much.

If your optical sensor was having issues you would be seeing the ses light coming on and there would be DTC's

When the engine first starts the systems are all set via the different sensors relating to engine coolant temp, air temp and so on. The advance is set depending on the temp too.
As the engine first fires and comes to life there are a lot of things going on. The ECM is monitoring the engine speed and if it does not reach the target speed then adjustments to fuel, timing and such are applied to try and stabilize things.

During this process there are cylinders that may not be firing well or at all and this contributes to the shaking, huge amount of smoke and other not so lovely behavior you are seeing.

The cylinders that are firing reasonably well are carrying all the load at that time trying to get things going. If the engine speed is slow and all cylinders are not firing, when the ECM adds fuel to get the speed up to spec then you may see some black smoke and more white smoke.

Black is an overly rich condition but is burned fuel. White to bluish white is unburned fuel and is coming from cylinders that are not firing as yet. As the internal temp increases from compression heat and the heat from surrounding cylinders working the remaining holes will eventually pick up and start working one by one.

As this happens the white/ blue smoke will clear out with some puffs of black and then the stack should be clean.

Once the engine is warm a very good indicator of bad injectors is a visible light blue haze coming from the stack (tail pipe) this can be dribbles or just poor injection at low speed.



Best

Robyn

[Splitrimz]

Wow, thanks for the analysis Robyn..All the pieces of that orchestra have to be playing in harmony after startup. My orchestra is having some disagreements.

I had some time to look at the beast yesterday. Checked the glow plugs on driver's side. Lo and behold the back two are not working. Heaven's knows what I'll find on passenger side. These were replaced within the last year with a long burn style. That doesn't seem like good longevity to me. I'll post further as I get into the passenger side.

After reading your description of the start scenario, I'm convinced that I have several problems.
I do get codes, have been for years, the two that indicated advanced timing and then retarded timing, that have gone away with warmup. I'm talking four years of that one.

Injector's are on my list after I get the glow plugs sorted out. I'm usually strapped for time, the only reasons that the beastie is getting attention is #1, it's demanding attention and #2, I'm on vacation this week.

Thanks for all the help and more to come.

Splitrimz

[Splitrimz]

I had some time to look at things, Here is an update.

Replaced two glow plugs on passenger side, it is starting better.

Still ran rough, really rough and smoked as usual. Disconnected the water temp sensor to the computer I think it's called the ECM. The truck runs fine, a little fast on the idle with the sensor disconnected but smooth as silk and lots of power and no smoking. I get down the road and when it warms up I connect the sensor back up, it idles back, and it runs fine.

Ah Ha I say, get a new sensor at Napa, drop it in, litteraly (It's in the bowls under the intake), <groan>l Back off to the parts store for sensor #2. Grasp it tightly in both hands and install it. It doesn't fix the problem.

Where next, the ECM?

Thanks, Splitrimz.

[BamaChief600]

Hate to bump this but Robyn is describing most of what is happening to my truck. When I first start it it is a hard rough start with lots of smoke. When I add some fuel it gets rough and alot of shaking. I let off of the fuel and it smoothes out. After it gets warm it is ok but at lower rpms it surges and when I let off the fuel I get a puff of smoke. This I do know: I need glow plugs they are original and I feel I need injectors as they are original. The truck has 138K on it. I have not run any codes ( got to get me a reader or go to my buddies shop. Any thoughts?

[DaveBr]

Check your lift pump to see if it's still working. My truck belched white smoke and shook bad untill I changed the pump. The colder it got, the more it shook.

[BamaChief600]

I have one of the kits for lift pump from Kennedy so I hear it when I cut on the switch....Im starting to lean towards injectors. Got it good & warm and it ran like a champ.

[rhsub]

Since your truck is a 93 it should have a mechanical injection pump?
Check the housing pressure cold advance (HPCA) system, the purpose of this system is to advance ignition timming when cold (up to 80'F) to reduce white smoke and engine missing
To check system;
check for power to small pink wire (could also be a green/black wire, been a long time since i worked on one, anyway it is the smaller wire going to the terminal on pass side of injection pump), key on, engine cold. Should have power until engine reaches approx 80'F
if no power check temp sensor switch rear of pass side head or fuse and wiring
if you have power check operation of HPCA solenoid by unplugging pink wire and running a jumper wire from bat+ to pump terminal when engine is idling hot. You should hear alot more diesel rattle (you are advancing the ignition timing). Solenoid can be replaced without removing ip
Hope this helps and Merry Christmas
Let us know how you make out
Ron

[DIESEL5]

i also have a 93 and last year was experiencing similiar issues and i ran the gammit of starting with the least expensive stuff first and graduating to the really expensive stuff. After talking to the local dealership diesel mechanic (while my 06' was in for tranny lines) he explained to me that the injection pump has little nozzles in it (think of a rotary gatlin gun) that wear and as they wear they leak fuel and or dont hold line pressure to the injectors. So when i did the head job I replaced the injection pump and all that smoking and rough idle went away like magic oh yeah i had already replaced the injectors and glow plugs before doing the head job and they had little affect if any on the problem. Any way it sounds to me as if your injection pump might need to be overhauled/replaced. Good luck

[BamaChief600]

i also have a 93 and last year was experiencing similiar issues and i ran the gammit of starting with the least expensive stuff first and graduating to the really expensive stuff. After talking to the local dealership diesel mechanic (while my 06' was in for tranny lines) he explained to me that the injection pump has little nozzles in it (think of a rotary gatlin gun) that wear and as they wear they leak fuel and or dont hold line pressure to the injectors. So when i did the head job I replaced the injection pump and all that smoking and rough idle went away like magic oh yeah i had already replaced the injectors and glow plugs before doing the head job and they had little affect if any on the problem. Any way it sounds to me as if your injection pump might need to be overhauled/replaced. Good luck

Just got a new pump last year, I have power to the HPCA so tomorrow Im going to try and jump it when I have time.

[BamaChief600]

Well I finally got my smoke problem fixed. I finally bit the bullet and got a new set of injectors and glow plugs. It took me longer than I wanted to change them. Drivers side I had done in a couple hours, well the passenger side was just a nightmare. Couldnt get the turbo from the manifold as the bolts kept trying to round off. So I took the manifold/turbo off together. Well after getting injectors popped in the last one by the firewall was a bugger. My socket was to long and kept hitting the heater core lines. Finally broke down and moved the core back and all went well from there. No smoke on start and good healthy smoke on mashing the motor.

[Robyn]

Injectors are a much overlooked issue when it comes to hard starting and smoke.

The little buggers lose pop pressure over time and the spray pattern goes south too. The Pee a stream rather than a fine cone of mist.

When this happens the glow plugs can't ignite the fuel very well and the things miss and belch clouds of smoke.

Another indicator of injector problems is whisps of bluish smoke at idle even when warmed up.

If the rig needs glow assistance to fire when warm, its an even better indicator of poor injectors.

As long as the IP and injectors are good, these engines should pop right off even after sitting a couple hours (After good run)

My 94 Burb will start after sitting all night without glow if the outside temp is up close to 85 or so. A little rough but still great for a no glow startup.


The coolant temp sensor controls the advance. unplugging it on a DS4 system tells the Puter that its extremely cold outside and the thing advances as far as it can.

This is a trick to get one going but not the answer to the issue.

Step up and get a fresh set of squirts and some glow plugs.

MGW