IDM's what a waste. : )

[Marauder]

Thought I share a lesson I learned today.

I've been chasing my tail for the last two weeks trying to find the source of an engine miss at part thottle as well as some extremely rich conditions.

So I started running things down. My AE hates my laptop so that was useless point of information. I do have a scan gague and it showed the ICP pressures bouncing around from 550 to 630 at idle. So I replaced the IPR and ICP sensor at the same time. Things became better but the miss went away when the engine was cold and as it warmed the miss became worse. I'd say it made the truck run about 40% better. But I still had the miss and smoke from hell. So I started reading again!

Wiring harness and UVCH came to my mind. Although I have no CEL.
It idles fair runs strong without a the miss. Check my sig for engine specs.

So now I'm thinking I have a bad TS chip from Beans. What else could it be?

I see the post here about Swamps IDM and head over to their page and read up on their product and what a complex black box it is. The thing that struck me the most was they noted that the IDM units got slower as they aged!

Mine had 244,000 miles on it. The truck started right up every morning and ran strong with my GQSSB....but my 250/200 are asking for a pretty narrow window to fire in.....I wonder?

So I head over to Strictly Diesel here in Phoenix and to my surprise they stock the Swamp Modded IDM...Cool!

After the install......

I still have the off load eratic miss when hot, but it a lot less and the smoke is about 70% gone. Which now means I don't have people making lane changes behind me when leaving a stop light. The engine runs in a much more precise manner. It was like going from points to and digtal igntion system.

The lesson here is that if your going with a injector that requires a better quicker signal, don't over look the IDM. My IDM was a 120 it ran my stage II injectors fine and I bet you could put it in a stock 95-97 and it would run great. It was when I changed the injectors and turbo that the **** hit the fan!

I read that IDM's never fail or rarely did. Water wasn't an issue either as my truck resides in AZ. No one ever mention that they grew weak over time....just the guys over at Swamps. Thanks for doing your homework!:thumbup:

Now I need a new Clutch!!!!!!:wtf:
Along with some live tuning!

Whew!!!!

 

[CSIPSD]

Ahhh shut up... I want one of these more and more every day...

 

[Cody]

:whs: i knew i shouldnt have opened this lol

 

[TARM]

Now here is the thing that gonna have you up wondering. As its not gone but only helped is it really addressing what the issue really is or is doing what is likely the case and just covering up what the real issue is by the compensation it offers?

But looking at what the hopped up IDMS do differently that the stocker even a worn older stock IDM as yours is might help point you in the right direction to narrow things down some.

 

[co04cobra]

Have you ran a cct test and buzz test. Compression numbers? Fuel psi? The swamps IDM is a very worth while upgrade. I commented over in another thread about them recently. However, Im with tarm. It sounds like you have just masked a problem. I would dig a little deeper.

 

[Marauder]

Now here is the thing that gonna have you up wondering. As its not gone but only helped is it really addressing what the issue really is or is doing what is likely the case and just covering up what the real issue is by the compensation it offers?

But looking at what the hopped up IDMS do differently that the stocker even a worn older stock IDM as yours is might help point you in the right direction to narrow things down some.

True Tarm, not only did it mask some aspects but defined the miss even more. Like the firing of the injector when under load you can clearly hear all of them clattering. During the miss you can hear them shutting on and off as a whole. so it's not just one injector or "A" wire that is failing.

Have you ran a cct test and buzz test. Compression numbers? Fuel psi? The swamps IDM is a very worth while upgrade. I commented over in another thread about them recently. However, Im with tarm. It sounds like you have just masked a problem. I would dig a little deeper.

My motor has about 27,000 miles on the clock same for the injectors before they were modded to 250/200. Fuel psi is 62 and holds steady at wot. The only thing left is the PCM, chip, or the oil temp sending unit and it reads fine with my scan gauage. My CPS has the same mileage as the motor as it was replaced during the build....

and when you put your foot to it pulls hard without any issues other than it running a tad too fat fuel wise. Go figure?

You are right though.....I need to do some more digging.

 

[neverkickn]

Hmmm. I am guessing that you don't have an open injector circuit since you haven't mentioned it. If you dont have any codes and you have a miss it has to be mechanical right?

 

[neverkickn]

True Tarm, not only did it mask some aspects but defined the miss even more. Like the firing of the injector when under load you can clearly hear all of them clattering. During the miss you can hear them shutting on and off as a whole. so it's not just one injector or "A" wire that is failing.

Oh, not one injector missing, all of the injectors dropping out at once.

Sounds like a fun problem to fix.

 

[co04cobra]

What color cps?

 

[Marauder]

What color cps?

I'll have to crawl under the truck to find out this afternoon.

Although.......

Last night I took the truck out for a spin on the freeway, hooked up to my scan gauge. All readings where in the ballpark for what I have. with a few exceptions. Under WOT in my DD tune I saw injector pulse width as high as 3.1 MS for 250/200 injectors. The other thing was the reading for the "injector timing" function reading was stuck at 1.1-1.2 degrees BTDC. something is fubar with the chips ability to communicate to the scanner and I would guess the IDM.

I have Dennis at Strictly Diesel burning me a DP single 80E program chip to swap out the TS chip. If all goes good after the swap I guess I'll be golden.

Electronics....it figures... LOL.

 

[TrailerHauler]

The truck runs perfect before its up to temp huh?

 

[Marauder]

The truck runs perfect before its up to temp huh?

Very True!
To a point, as the motor warms it's fueling requirements change noticablely.

Another thing I've noticed at speeds of 65-75 mph on the freeway the engine shakes and shutters, without any cylinders missing. Sort of like a out of balance drive line, when I push in the clutch and get out of the throttle the truck continues on smooth as silk. The higher the speed the worst the shutter gets at part throttle. In 115 degree weather it was at it's worst.

When it's doing it's shaking thing at part throttle on the freeway, then roll fully in to the throttle the engine smooths out and runs like a smoke belching raped ape.

The best way to describe the engine miss around town is like a flickering light bulb, the injectors come on to operater perfectly then drop to a sub par setting that induces the engine missing. Then it goes away only to come back again. The more I think about it, it has to be a bad chip.

Thanks for all your input guys.

 

[skylinedan]

Did you watch oil temps as you drove it from cold to hot on the freeway ? Wonder if you have a sensor that is giving scude readings, and causing your problem.

Dan

 

[Big Bore]

If the tuning is based off EOT, it will change the fueling and injection timing. Since fueling is based off ICP and PW...

 

[onebad7.3]

My truck runs fine until the oil temp gets to 130ish then it has a miss, but after the temp gets over 175ish then its fine once again.

 

[Marauder]

Did you watch oil temps as you drove it from cold to hot on the freeway ? Wonder if you have a sensor that is giving scude readings, and causing your problem.

Dan

That's what I considered as I started to learn more about the fueling system.
Temps ran 188 -195 around town, then when on the freeway it would run 203-204 cruising to 209 running it at night.

All sensors function well and responded to load and rpm. The injector timing data is in the tank. I think this speaks volumes to what is going with the firing of the injectors.

If the tuning is based off EOT, it will change the fueling and injection timing. Since fueling is based off ICP and PW...

I agree but not in a manner were it runs good then tanks, then comes back to runnig good again 45 mins into a drive in the middle of the day in 100 degree temps.

 

[TrailerHauler]

Sorry if I missed it but whats the ICP and duty cycle doing?

 

[V-Ref]

Marauder

You're not the only one out there seeing this....

I've surmised it's a oil aeration issue...one that can be masked/aggravated by tuning, and one that hasn't been tackled by the 7.3 tuning community.

If somebody knows the secret, you can have my 6 pos chip, and I'll be glad to make it worth your time.

I wish somebody coulda saved me the hassle, expense and effort of doing multiple compression checks, uvchs, VC gaskets, IPR, ICP, CPS, IDMs, and bunch of money tied up in tuning in a attempt to sort it out. In the end...live tuning is the answer IMHO.

In other words I wouldn't tear your motor apart anymore looking for a problem that can't be fixed, and in the mean time you set yourself to chase after boost leaks, fod in your motor, etc...but that's my truck/experience...yours may be different.

Just for curiosity sake...what PCM?

DPC-421 XPC4 here.

 

[Tom S]

I'll have to crawl under the truck to find out this afternoon.

Although.......

Last night I took the truck out for a spin on the freeway, hooked up to my scan gauge. All readings where in the ballpark for what I have. with a few exceptions. Under WOT in my DD tune I saw injector pulse width as high as 3.1 MS for 250/200 injectors. The other thing was the reading for the "injector timing" function reading was stuck at 1.1-1.2 degrees BTDC. something is fubar with the chips ability to communicate to the scanner and I would guess the IDM.

I have Dennis at Strictly Diesel burning me a DP single 80E program chip to swap out the TS chip. If all goes good after the swap I guess I'll be golden.

Electronics....it figures... LOL.

I believe that timing reading is false.

 

[TARM]

TO see if this is the same as the issue V-ref is speaking of as if it is like he said you are looking at a very different approach:

Does it only do this after a hard run or romp?

When it idles rough etc does a good romp on the throttle seem to help clear it up?

I do not think your issue is EOT related

If I had to guess and its not the issue V-ref is speaking of I think IPR ICP is where I would be looking. This seem to be something related to HPOP oil IMO

BTW what oil are you using and how many miles for OCI?


I actually had a very similar issue as yours with my Dual stealth HPOP and it ended up being the IPR ICP. When it got warmed up it would seem to have a miss on front drive side injector which is #2 in firing order. The rest would idle loud and rough. It seemed fine when you gave it heavy throttle and was surgy under light throttle. Upon checking codes I had none.