IDI Guy Stumped

[IHdieselfan]

So I haven't posted here in a long time. Maybe 10 years. I have several IDI of my own and in the Family. I'm a Heavy Equipment/Diesel mechanic By Trade. I am having trouble with a project truck of mine. 94 IDIT. Pulled the motor out mainly to install type4 logger cam. wound up pulling the heads and had them redone(after the machinist is done he says that he found the valve springs 40 lbs to tight and replaced with normal ones. im thinking that was because of it was factory turbo motor, wish he hadn't done that) . new bearings in bottom end. engine had 280k on it but well kept and cyl bores were great. Upgrades: type4 cam, wicked wheel, banks down pipe. hypermax exhaust, IP Rebuilt + 10%(required New Housing), New injectors AND a new coat of DT466 Blue (just for a little extra oomff) . Now the Bad. I put it back in its home. It Fired Right up. But it sounds Wayyyyyy to advanced. I set the mark just like i have for the last 20 or so years ive been playing with IDI's. So i play with the timing, Better but not right. So i pulled the front cover off thinking ive got it a tooth off. nope dead on the money. so i take the pump back to the shop. They recalibrate. They say all good. put everything back together. still same sound, to advanded. so i check fuel supply and return. all good even by passed fuel tank selector valve. So i road test it. all good at first. but when i start to push it, good power till it gets high in the RPM's then it starts to stumble i mean stumble bad with white grey smoke and seems to die off. let off the pedal and it gets back to normal and runs fine as long as i go fairly easy on it. I guess my main question is can a IP calibrate on the stand but be to advanced on the motor?

 

[Big Bart]

Food for thought.

Does the new cam require you change the ip timing?
Do you have a timing device to confirm your timing is on or off?
Stumble because valves closing slower with softer springs?

I would start with the IP timing and go from there.

 

[IHdieselfan]

Type4 says no change to anything. Just put it in. No timing device. I thought the same thing about the springs.

 

[Booyah45828]

You need a timing device of some sort. The marks on these are for reference with the original pump. Your new pump needs timed correctly and a new mark made.

You need to have it timed sooner rather then later before you ruin something.

 

[subway]

I agree, the original timing marks on the pump housing do not mean much at this point. To properly time the truck it has to be checked with a timing meter.

 

[Big Bart]

Assuming is not going to help you fix this. Your challenge is many things where done at the same time. So it could be related to the pump, the cam, the springs, or your new exhaust. Or you bumped or broke something else during all this work. (30 year old trucks re easy to break, so not your fault, just how it goes.)

You mentioned you think the timing is off, too advanced. These trucks are very timing sensitive. A limited few, maybe 5% of the membership, had luck setting by ear at cold start. Some suggest they can get a pump +/- 2* but even they don’t know what theirs actually is. Since you are a mechanic by trade you know the importance of having the right tools. It‘s easy to be the cobbler without shoes as a tradesman but in this case you really need to start knowing your truck is 8.5-9.5 degrees BTDC at 2,000rpm. (Try to do that by ear.) Once you know the pump timing is on, you can move forward from there if your high rpm issue is still there.

Also make sure your timing advance is shutting off once the truck is warm or you might be fighting that too.

let us know how things progress.

 

[IHdieselfan]

Timing advanced was the first thing I unplugged.

 

[CBRF3]

I bet with the new pump your getting more pressure faster and at higher lvls than the old one causing injectors to pop early alot of hot pumps do this but stock they do just fine been there done that pull the injectors pop test them and set them to 1750psi-1850psi I like 1800psi myself for street use but for balls out i set higher nearing 1950psi which is rough on the injection pump but it really livens these motors up quickly but cuts the injector pumps life in 1/2.

worn injectors popping at lowwer pressure advances the timing old injection pump likely didn't build as much pressure as fast the new one being turned up and properly calibrated is overriding the injectors pop pressure making it advance timing and slobbering raw fuel instead of misting it that white grey smoke is raw fuel that was not vaporized and ready to be burned in the motor if you got good atomization of diesel fuel in combustion chamber and flame cup / swirl chamber in piston you get black smoke in place of the white gray smoke just a little IDI info for you the flame cup is the port inside the head where the injector and glow plug are if fuel is dribbling and not a hard stream to hit bottom of flame cup to turn to mist in a violent reaction from the pressure you get what you have now the white gray fuel smoke.


The issue with top end stumble and the white grey smoke is injectors are not misting but dribbling / squirting not misting again reset pop pressure and clean the injectors and make sure you get the good old injector chirp and if want to take it to next lvl simply have marine 370 5.9 cummins 12 valve 6bt injector nozzles machined to fit in your injector holes and install these on our injector body and this makes our motors run extremely good.

A video of my motor glow plug deleted and with nearly 500k miles on the motor which I have now swapped that motor out for one I rebuilt with nearly no miles on it yet but with same injectors / nozzles and hopped up injection pump and glow plug deleted literally removed glow plugs cut off the ends drove out the cores tig welded shut then machined in lathe to seat into the heads.

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[typ4]

Any machine shop with a clue would have asked you about the springs, the reason we use the comp 910 spring is because it has about 30-40 more lbs seat pressure.
As for higher pop cutting pump life, BS. JD and others use a DB pump that has pencil injectors set at 3200 ish IIRC. And they go 10k plus hours.
The cam does install straight up. How much boost do you have?

Sounds like valve float may be an issue also.
Keep in mind folks, some of us have found NON STOCK specs that work better than published machine shop specs.
Example, springs, valve recession, compression ratio, so on.

 

[IHdieselfan]

Typ4 thanks for responding. I'm getting 8psi boost.

 

[IHdieselfan]

The other thing that I've noticed is, when it's idling it sound more advanced. But if you give it just a touch of throttle say about 1000 rpms. It sounds more normal.

 

[IHdieselfan]

I'm going to buy a timing set up and set timing properly.

 

[typ4]

That would be the best thing to do because naturally the timing would be less noticeable as you rev the engine up. And they are finicky on timing and not all engines are the same.

 

[Steven Sochalski]

I'm going to buy a timing set up and set timing properly.

I purchased one of these units to time mine after a rebuilt ip install. It works great.