Engine/Transmission (1998.5 - 2002) To Marco or Bob, ECM question

[azpete]

For the last couple winters when the morning temps were 60 or below my truck on start up would have a rough idle and white smoke for just a minute or two. Check engine light and 1690 code would set. Around the beginning of this year I installed the Catcher ECM. Still had the same symtoms on cold start up but no codes or light have shown up since. Just wondering why the Catcher ECM won't show a trouble code.



Cured the morning start up troubles by plugging in the engine heater every night. Replacing the crank position sensor next week to see if that is the cause of the 1690 code.

 

[Bob Wagner]

Pete is your wait to start light working? The 1690 code may be an indication of a failing injection pump especially when you mention white smoke.



That may be the problem but lets talk before you make a move

 

[azpete]

Wait to start light is there and the Catcher works just great. Just wondering why it won't set a code. Will give you a call Monday if I can.



Thanks

Pete

 

[Marco]

Several softwares that have been used by DC don't trigger the CEL for the same fault codes. Most likely, you went from an older SW revision to a newer one. Where the newer one does not set the CEL for that code. Any way, the fault is still stored in the ECM even without the CEL.



Helps?



Marco

 

[azpete]

Thanks Marco, That explains it and by the way I enjoy all the years of your hard work to develope this ECM everyday. Keep up the good work.

 

[catoiler]

Marco,How are you doing on the 3rd gen stuff?Any news as to when you will have one for us "plug n go"guys. :-laf

 

[rivercat]

Marco, as an electronics guru you seem the best person to answer this enigma



I don't have a voltmeter and cant check my MAP but I do have a scanner and in data mode I get like 58. 3 inches of mercury= 29. 13 p. s. i by conversion at idle and it moves right up to 75 inches of mercury = 36. 8 by conversion and stays (pegged) at any thing greater than 8 p. s. i onthe boost gauge. This is with the MAD ecm installed does this mean my MAP is bad is there like a spring that could be weak making it peg at only 8#s of manfold pressure? or a air leak that bleeds the air off and makes it think it has more air behind it than it does. Thanks Marco

 

[Marco]

Rivercat,

There's been some confusion about the MAP readings with them scanners.

( Software problems )

Are you SURE that your scanner reads the MAP right?



Most simple way would be to take voltage readings. A cheap DVOM will do.

Otherwise, a dealer with a DRB... ...



Marco

 

[rivercat]

just wanted to add that I get the same #s with stock ecm and no box of any kind attached.





Another anomoly is in data mode with key on engine off I get o % TPS on the 15$ reading and on the D1$ reading I get 8. 2% without touching the petal

 

[Marco]

Well... I'd say it's the scanner.



Marco

 

[Partyat33]

Can I ask a different ECM question. I put a 47RH in my 2001 HO replacing the six speed. When the engine is warm it seems to fight the transmission and the engine revs up and down and really sounds bad. Not that good loping sound you might think of. When cold it does not do this. If I get a 'catcher' can you somehow tell it to behave with my trans ?The 47RH does not have any electrical hookup to the ECM or PCM.

 

[Marco]

The only thing the ECM has to do with the transmission is a different low idle governor for AT or stick. Well a little simple but you get the picture. The ECM couldn't care less what kinda AT transmission is behind the engine.



So to come to your question, yes I can provide your stick ECM ( which it has to remain because of the HO engine ) with the AT low idle governor.



Marco

 

[Partyat33]

Would this be different than just lowering the idle. ?

 

[Marco]

Would this be different than just lowering the idle. ?

.



Actually the AT idle is higher than the stick idle, not lower.



Maybe you misunderstood or I didn't explain enough.



Diesel engines have two "governors". High Idle ( Redline ), and Low Idle which is just that, the idle speed without load. When I mentioned the "Low Idle governor" that's what I was referring to, not lower idle speed.



Helps?



Marco

 

[Partyat33]

Partially, If the idle is higher, won't that make the problem worse ? Or is there some kind of feedback loop involved.

 

[Marco]

If the idle is higher, won't that make the problem worse ? Or is there some kind of feedback loop involved.

Well, the AT low idle governor is a little higher because when you drop into gear the there's a "peak" in torque demand. If the low idle governor is not matched to that situation, you know what happens...



Marco