1988 RRC 4.6L Conversion - Need some assistance
- Thread starter CassidyN3555L
- Start date
jymmiejamz
Adventurer
I don't think changing the ECU is going to make all that much of a difference. I would suspect it to make more of a difference from a cold start. The injectors are the same for 3.5/3.9/4.0/4.2/4.6. The fuel injection ECU should be able to adjust the fueling to account for the 4.6.
proper4wd
Expedition Leader
Jimmy and I disagree there - but with regards to to the ECU itself a 14CUX box will plug in to and work directly in place of your 13CU with no changes to the wiring or sensors. This means you can buy a 4.2 ECU (from a 1993-1995 Range Rover LWB 4.2) and plug/play.
Based on your description it sounds like everything is functioning properly (it starts, idles, runs, etc) but is delivering extremely poor performance and fuel economy. This leads me to believe it is a tuning issue rather than an actual hard fault in the system.
That being said - double check the basics. Fuel pressure, timing, etc.
One other thing that can lead to poor performance/economy on these things are the O2 sensors. Do you know how old they are?
Based on your description it sounds like everything is functioning properly (it starts, idles, runs, etc) but is delivering extremely poor performance and fuel economy. This leads me to believe it is a tuning issue rather than an actual hard fault in the system.
That being said - double check the basics. Fuel pressure, timing, etc.
One other thing that can lead to poor performance/economy on these things are the O2 sensors. Do you know how old they are?
CassidyN3555L
Cassidy
Back from hunting and working on the Rover again (did not take Rover).
Correct on the running and poor performance. Tuning could certainly be off as I was unable to get a good tune based on the timing light / TDC and my tachometer doesn't work, so I tuned it based on sound and idle position that it didn't stall out on but still allowed it to fire back up again. The idle sounded higher than it should be. The tach wire is connected to the alternator but doesn't seem to work and I'm not sure why or what exactly else I should look for.
The Y-Pipe has O2 Sensors with wires but I can't seem to find anywhere for them to plug into? If I recall correctly, before I brought my truck into the shop for this project I don't believe the 1988 with the 13CU had O2 sensors. The guy shuffled a lot of parts around while he had his shop and I believe he mentioned swapping the Y-Pipe out for some reason, which could explain why I can't find anywhere for them to plug into.
If I could get the tach working I might be able to better tune it. If in fact this thing is supposed to have 02 sensors maybe there is a way I can hook them up.
Yes, the crankshaft, connecting rods, and pistons were swapped to 4.6 as well.
I'm pulling the injectors out today to see what they're like.
Any other thoughts?
Thanks again!
Correct on the running and poor performance. Tuning could certainly be off as I was unable to get a good tune based on the timing light / TDC and my tachometer doesn't work, so I tuned it based on sound and idle position that it didn't stall out on but still allowed it to fire back up again. The idle sounded higher than it should be. The tach wire is connected to the alternator but doesn't seem to work and I'm not sure why or what exactly else I should look for.
The Y-Pipe has O2 Sensors with wires but I can't seem to find anywhere for them to plug into? If I recall correctly, before I brought my truck into the shop for this project I don't believe the 1988 with the 13CU had O2 sensors. The guy shuffled a lot of parts around while he had his shop and I believe he mentioned swapping the Y-Pipe out for some reason, which could explain why I can't find anywhere for them to plug into.
If I could get the tach working I might be able to better tune it. If in fact this thing is supposed to have 02 sensors maybe there is a way I can hook them up.
Yes, the crankshaft, connecting rods, and pistons were swapped to 4.6 as well.
I'm pulling the injectors out today to see what they're like.
Any other thoughts?
Thanks again!
Steve Polychronopolous
New member
So you don't have the o2 sensors hooked up and you have no idea where the timing is set or if the advance is working. Problem solved. Don't mess with the injectors. Still not the problem.
ProvinceOverland
New member
Your 13 CU defiantly had o2 sensors .
Here is a schematic of what the O2 Sensors should plug into thats ....if you have the right y pipe and or O2 sensors !
97 D1
01 D2
94 RRC
https://www.facebook.com/provinceoverland/
PS I found this link too
http://www.seriesdefender.com/manuals/1314CU_14CUX_Systems.pdf
Last edited:
CassidyN3555L
Cassidy
Finally had some time to work on the Rover recently.
After all your comments about the 02 sensors, did some additional searching.
We found the O2 sensors, they were taped up out of the way and hiding. I'm not sure why.
Engine seems to be timed and running much smoother now.
Also figured out the weird tapping sound. It appears the power steering belt is slapping/rubbing the block. I've tightened it a few times and the noise goes away or reduces for a short period of time then comes back. The belt doesn't appear to be excessively worn or stretched out and before the engine was worked on, I went through belts periodically. I'm not sure if I just need to replace the belt or if there is some kind of spacer for the power steering pulley to clear the block. Any thoughts?
Thanks again.
After all your comments about the 02 sensors, did some additional searching.
We found the O2 sensors, they were taped up out of the way and hiding. I'm not sure why.
Engine seems to be timed and running much smoother now.
Also figured out the weird tapping sound. It appears the power steering belt is slapping/rubbing the block. I've tightened it a few times and the noise goes away or reduces for a short period of time then comes back. The belt doesn't appear to be excessively worn or stretched out and before the engine was worked on, I went through belts periodically. I'm not sure if I just need to replace the belt or if there is some kind of spacer for the power steering pulley to clear the block. Any thoughts?
Thanks again.
jymmiejamz
Adventurer
There is a spacer that goes behind the steering pump pulley. You can just put some flat washers behind it if you lost the spacer.
proper4wd
Expedition Leader
You need to get that tach fixed also. The ECU relies on the same signal for RPM. I went through this like 15 years ago with a 13CU and it would run ok on start up and for the first few minutes until the engine switched from open to closed loop and then it all went to hell.
Steve Polychronopolous
New member
Does a 1988 Range Rover not get its tach signal from the alternator like the rest of them do?
Steve Polychronopolous
New member
13 and 14 gets the reading direct from the coil. White wire with a black stripe. With an Inline current limiting resistor