Ok new member here, been using this form for several years to diagnose and solve problems that arise. Respect to disco mike and Spike as they have been alot of help. thank you all.

Ok now to the meat of it. Im currently stumped and so is my mechanic, and after searching these forms i could not find a answer to put this issue to light.

2003 disco. Just installed a used motor from a 2001 range rover. it was a 4.6 Bosch just like the disco. i did some research on several forums and the consensus was just drop in and go. We did the swap, new plugs, wires, hoses, thermostat, used the Disco's wiring harness and resealed the engine as well. However upon finishing up i run into several issues.

First. the engine will not idle right. i believe this is controlled by the ECU, which i had flashed and re calibrated about a yr ago. the MAS is also fairly new mabe yr old as well. So it leaves me to believe there is a computer issue. when i create a vacuum leak and it runs better but still not right.

Second. The ECU is not connecting to the scanner. i plug it up, the scanner receives power, but it goes on to read unable to connect. computer issue again?

Third. have a flashing green M and S. which i have found can be conclusive to low power. the battery is brand new not 2 days old. tested battery and cleaned linkage, test was around 14. battery also wont hold charge as its new and the alternator tested good, leads me to believe that something is drawing the battery.?

Me and my mechanic and several opinions later have not been able to troubleshoot this problem. Are these issues all related to the ECU, in which case should i get a used one or send this one to LR to re calibrate?

If anyone has any ideas they will all be welcome. please. Thank you for the help just at a genuine loss here

 

Battery could have a dead cell.

 

a two day old battery with a dead cell? But if he tested the batter and alternator and the results indicated they were both good then I would doubt the battery has a dead cell.

 

Did you accidentally swap the IACV connector and one of the coil connectors?

Also the m & s light is easier to troubleshoot with a scanner that can read the transmission codes. Anything else is just a guess. When you put the shifter in park or neutral or drive, etc does the indicator in the gauge cluster show the correct gear?

 

Hola que tal?
OK I have read your post and it raises more questions than I have immediate answers for and so I have to ask more questions some perhaps impertinent !
Question 1
The engine that failed was it a 4,00 litre or a 4.6?
Question 2
Was that engine the original build ex factory or did someone do a 4,6 upgrade .
Question 3
Why did you change out the original engine?
If it was changed due to a failure dictating a change, was it running OK with no faults just prior to failure?
Question 4
Why was the ECM re-flashed; factory updates or some aftermarket tune?
Question 5
What scanner are you using to access the PCM?
Question 6
At any time have you been able to access the PCM prior to past engine change or is it only with this engine installed?
Have you ever pulled the scanner connection at the mil plug during a scan procedure?
Question 7
As a point of interest did you hear the donor engine running before you revised it and base lined it ?
Question 8
The M&S lights suggest poor primary circuits and perhaps bad grounds, are all these verified and not crossed with a chassis sourced positive?
Question 9
This brings me to another query; with parasitic draw somewhere you might be creating a "live" ground. Bosch PCM's do NOT LIKE live grounds and will shut down to protect various sensitive circuits. I would eliminate the parasitic draw before doing anything more. Focus in on the alternator /starter circuits/fuse box etc & primary circuit wiring insulation.
Question 10
Going back to your mechanic who is apparently stumped on this; does he have the ability to access the various positive and negative pins in the MIL connector and confirm continuity and good grounds. Both are essential for access to the PCM and other modules on the car!
The equipment he has can he access modes 6 through 10 and use an oscilloscope to access module/sensor wave forms ?

With some of these big issues answered I might be able to help.
Saludos
T/V

 

Did you put the grounding strap back on the engine?

 

Ok guys thanks for the feedback

Jafir. as far as the IVAC connector-not to my knowledge. will check to be certain. also shifter on indicator gauge shows correct gear

Tuercas Viejas. massive imput thank you. have answers to most here, a few i cannot be certian
#1 its a 4.6
#2 original build
#3 the old engine had massive oil leaks with a suspected dropped sleeve, was cheaper to replace.
#4 ECU was flashed and re-calibrated because it was believed to be fried by a incompetent mechanic. factory re calibration. was working great before replacing engine
#5 PCM (power train control module) same as ECU? if so i have a obd2 scanner and the shops got a $8000 scanner not sure specifics on make neither will connect
#6 if PCM is the same as ECU then yes i could access it fine before engine change. (MIL plug)? unsure not the best with acronyms.?
#7 donor engine ran smooth
#8 as far as i know the grounds have been checked not sure if they have been crossed with positive chassis (how to tell).?
#9 looking for a parasitic draw is what we are currently looking for, what are some signs of such.
#10 im afraid your going to have to expand on this question. ( does he have the ability to access the various positive and negative pins in the MIL connector and confirm continuity and good grounds)how to due such? (The equipment he has can he access modes 6 through 10 and use an oscilloscope to access module/sensor wave forms ?) i dont believe this garage has that equipment.

Im sorry i am unable to answer all of these in detail. im not as knowledgeable in electronics as i should be. i am i quick study tho if you can break it down.

thanks for your response

 

grounding strap to be honest cant be certain. should be, where is its location

 

It is a silver mesh looking strap that bolts from the firewall to the engine. Should be to the left of the brake booster behind the engine. At least that is where it is at on a 4.0L.

 

did replace the booster, will check.