Engine/Transmission (1998.5 - 2002) ECM - new ,rebuild or other problem

[Mike B.]

Dan, If it were me I'd swap the ECM's out again just for ****s-n-grins. I really don't see how a faulty ECM would take out the VP. I've swapped out at least 3-4 different ECM's between my two 99's without any pump issues at all.

On a side note: Last Friday I finally got around to sending my ECM core to Auto Module Services for a rebuild. It will probably be another week or so before I'll have the opportunity to swap ECM's but I will post the results here.


Cheers

Mike

 

[JR]

If the truck runs fine, no miss throughout power/rpm range, no cel, etc, I think your fine. It is possible (but rare) you got a defective pump from Chip. Have you persued that to see what they found? Might fill in some of the blanks you have. Or maybe you had the previous pump mis timed? It's as simple as drawing the gear up onto the shaft key slightly out of wack.

 

[DMorris]

If the truck runs fine, no miss throughout power/rpm range, no cel, etc, I think your fine. It is possible (but rare) you got a defective pump from Chip. Have you persued that to see what they found? Might fill in some of the blanks you have. Or maybe you had the previous pump mis timed? It's as simple as drawing the gear up onto the shaft key slightly out of wack.

I didnt rule out pump timing until I pulled it apart, It was correct, no marks or sign of improper installation. I was super careful installing and really examined it prior to pulling pump out and the gear was on right for sure. Great suggestion to send pump to Blue chip and see what their find is. I have it boxed ready to go.
I feel no miss or issues with it, it will put out a bit of black smoke , more then in the past. It is so cold here (-18 this morning) that it is hard to tell on start up and idle. Even when first driving it runs fine and seems good. I am just worried that some how the information to the pump could do damage. At the same time it runs ?
What I want to do is cancel payment to GoEcm on the last computer and let them keep it. At the same time there is a certain amount of comfort with knowing the ecm is the correct one. Then again - does it really matter as along as it runs. After all that ECM ran that truck long before I got it. But it also had a new pump in in not too long before I got it- looked pretty fresh when I pulled it out. Not more then a year or two old. Guess I am probably letting the past inter"fear" with my current decision making.

 

[DMorris]

More.
So I get the new computer in, decide to swap. Starts runs fine - BUT - I had to do a double key bump to get lift bump to run.
Seems like a lot of white smoke until engine gets warm ? Then on a restart - had to bump key twice for start ? Then again this morning. I take it for a drive anyhow, low and behold I get a check engine - pump low circuit error ? Battery high voltage, and companion module. Battery high- is that stored in the PCM ? says "old" in the scanner.That pump low circuit I think is what I got with the other ECM in too.
The original ECM gave me the least problems. But please tell me this pump low circuit error is not a problem with the new just replaced pump ?
I am going back to the original ECM and they can keep the POS they sent me and give me the $300 back I paid for that one.
God I am out of my mind with this truck !!! What do I do now ?

 

[DMorris]

The code is "injection valve low/open circuit" both ECMs gave check engine, same codes. But runs o.k. ?
Also I check my voltage at battery- 14.9 to 15.5 volts running- bounces around a lot between the two ?

 

[DMorris]

Any thoughts on my 0253 code ?
I was wondering and this is probably way out there. But would it behoove me to get a smarty and just reprogram to one of their settings for my 98.5 ? Or am I just throwing more bad dollars after bad dollars chasing the dream of a properly running truck ?

 

[JR]

15.5 volts is too high of a charge, that could possibly set some erratic codes in itself. Did you erase the fault to see if it returns? A Smarty or similar tuner will not correct a faulty ECM. What did you do with the unit from GoEcm?

 

[DMorris]

one is sitting on my desk, would not start the truck half the time. Usually had to crank, then recrank to get the lift pump to fire.
The current one that they originally rebuilt is running the truck, I still do not drive it (much). Both ecms I had 15.5 volts running. Do all these trucks have a external regualtor ? I have a box mounted on the fender that has wires leading to the alternator. I may be wrong but I dont remember seeing that on a 02 I had or my 03 ? I know my womens grand cherokee controls voltage through ECM and has no external regulator ? Is this a possible problem leading to all these problems I am having ? Funny I know they put a new alternator in it not too long prior to me buying it.
I did erase the fault and with maybe 20 minutes of running now - no check engine light.
I am going to send this ecm on my desk back and get a refund (I hope)
I have to say it seems like a lot of blueish white smoke on cold start up and idle, but once driving seems like its fine.

 

[DMorris]

Sooooo,
Please tell me this makes sense. I pull the external regulator, looks like the epoxy is warped , go grab a new one, throw it in start truck.
Seems like no more white blue smoke, and charge is at 14.4 V. I know the 14.4 volts running makes sense, but the white smoke gone make sense ? Could this be my problem all along ? High voltage output ruined my original ECM, and maybe then ruining my pump ? Could I actually have this fixed ? Would high voltage give me all these problems ? Maybe the truck is good for another 240K ? Drove 6 miles and no check engine. I am starting to feel like there is light at the end of this tunnel !
BTW still no excuses for GoEcm , they screwed me on the second ecm for sure, it never ran the truck.

 

[Mike B.]

Dan I could certainly be wrong here but I'm pretty sure both of my 99's are internally regulated at the alternator. Did the External regulator you removed appear to be an OEM installation, just curious more than anything I guess.

BTW: I'm planning to install the ECM I received from Auto Module Services in one of my 99's over the weekend to testing. According the AMS they replaced what they call the "main chip" and reprogrammed the unit. Considering they got the thing back to me in under 3 days makes me think they had a repaired unit sitting on the shelf & just took mine as a core. Hopefully I'll come back with a positive report.

cheers
Mike

 

[JR]

Voltage regulator is integrated into the PCM on the firewall. You may not have used a regulator rated for enough amps? How did you wire it?

 

[Mike B.]

That's interesting because the alternator I installed last month was internally regulated to 14.4v as was the one I removed. I wonder why there's two regulators?

 

[DMorris]

two wire hook up - then grounded through the mounting screws. has the old style chrysler plug. I think this was converted long before I got it.
So - do you guys think this was my problem ?

 

[JR]

That's interesting because the alternator I installed last month was internally regulated to 14.4v as was the one I removed. I wonder why there's two regulators?

They are an open field externally regulated type altenator. If they were internally regulated then fixing a charging issue would be as easy as replacing the altenator. The reason people do an external regulator is because the real fix is replacing the PCM which is a several hundred dollar venture.

 

[WUrbowicz]

hello MB
been reading up on ur posts for 2 days now/ thank u for all ur info. and perseverance/ have been having loss of power @ highway speed and loss of tach intermittently for past 6 months with all the improper start up sequence before ignition/ now,no start/ pin #6 @ vp is 12V and ground is good/ only 8.5V @ lift pump/ surmised it's the ECM/
??? is, How and with what specific tools can u replace the engine mounted ECM, behind the fuel filter in 15 min.??/TIA/ Warren

 

[Bob Wagner]

there are 3 10mm bolts and the wiring connection take a torx 25 .

 

[WUrbowicz]

thank u BW
Next question is do I go @ it from the top and remove the fuel filter housing or do I go @ it from the bottom and remove the starter/ I'm 5'3 and my reach is suspect/ TIA /Warren

 

[WUrbowicz]

Hello TDR
Ended up removing fuel filter housing to make easier access to Engine mounted ECM, for removal/ except for the need for use of a breaker bar to extract the (3) 10mm bolts,ECM removal went well/ Replaced it with one from 2000 year truck/ No change in lift pump function/ Still no 12V to lift pump/ installed a remote ignition switch powered relay to run the lift pump/ works w/ key on now/opened fuel filter drain line and good flow with Key On/ need to bleed the injectors and give her a Kick.
Will keep u posted/W