DiscoWeb Message Boards
 

Go Back   DiscoWeb Message Boards > DiscoWeb Technical Boards > Range Rover - Technical Discussions

Reply
 
Thread Tools Display Modes
Old 05-04-2009, 06:25 PM   #1
lionrover88
Guest
 
Posts: n/a
Default TPS and MAF adjustment

Here are the pics for the adjustments of the TPS and MAF. This should be easy to do.
These adjustments should be made with a warm engine, ignition on, motor off.
Attached Images
File Type: jpg May03_001.jpg (42.5 KB, 132 views)
File Type: jpg May03_002.jpg (36.8 KB, 173 views)
File Type: jpg May03_003.jpg (41.9 KB, 115 views)
File Type: jpg May03_004.jpg (44.3 KB, 164 views)

Last edited by lionrover88; 05-05-2009 at 10:24 PM.
  Reply With Quote
Old 05-13-2009, 10:36 PM   #2
Diggaz
Guest
 
Posts: n/a
Default Re: TPS and MAF adjustment

I could be mistaken, but those pics just look like the values. How do you do the actual adjustment?
  Reply With Quote
Old 05-14-2009, 06:09 PM   #3
luvs2getmuddy
Member
 
Join Date: Oct 2006
Location: Aurora, Ontario, Canada
Posts: 492
Default Re: TPS and MAF adjustment

I never had to adjust either of the two, and I've swapped them out a handful of times.
__________________
2002 P38 4.6HSE Borrego Edition
1990 RRC - "Camel Trophy inspired" SOLD
1991 BMW M5 SOLD
luvs2getmuddy is offline   Reply With Quote
Old 05-14-2009, 08:12 PM   #4
green
Member
 
green's Avatar
 
Join Date: Apr 2005
Location: Broomfield,CO
Posts: 200
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by Diggaz
I could be mistaken, but those pics just look like the values. How do you do the actual adjustment?
I agree wheres the adjustment. I see values
__________________
89 RRC-35's
97 DI-35's
green is offline   Reply With Quote
Old 05-15-2009, 02:19 AM   #5
92rrrandall
Member
 
Join Date: Jul 2004
Location: Cary NC
Posts: 316
Default Re: TPS and MAF adjustment

If the TPS has two mounting holes then it is non-adjustable. The earlier TPSs used on the 13CU system had mounting slots on it and the mechanic has to adjust the base setting.

When you install a TPS on a 14CU or 14CUX or GEMS or Bosch system, the computer adapts to the new one after a few minutes of driving. No adjustment is required by the mechanic.

Regarding the air flow meters used on the 13CU, 14CU and 14CUX: These Hitachi made AFMs are labeled as 3AM or 5AM and are completely interchangeable so long as they came off a Land Rover. They are adjustable for idle mixture only. The idle mixture adjustment feature has no bearing on air mass measurement.

The engine actually does not have to be warm to make the idle mixture adjustment. However warming the engine is part of the procedure for checking the output of the mass sensor. I would not worry about the mass sensor too much because these AFMs rarely fail. You can also clean the hotwire with a quick blast of electronics cleaner.

It is easy to adjust the idle mixture: Turn the ignition to ON, but do not start the engine. Leave the connector on the AFM and pull back the rubber boot so you can see the wires(just like the picture on the far right in the first post of this thread). Set your volt meter to DC volts and put the probes on the two outside wires(just like the picture on the far right in the first post of this thread). These AFMs on NAS engines were set at the factory to ~2.0 volts. Most non-NAS engines had this AFM set at ~1.0 volts.

If you want your engine to idle better and burn much less gasoline while idling do this: Remove the tamper proof cap. There is a potentiometer under the cap which turns like a screw. It is not a actually a screw so you will have to experiment with different small screwdrivers to get it to turn. The potentiometer can be adjusted anywhere from 0 to 3.5 volts. It is very easy to set it at precisely whatever voltage you want. More volts mean richer idle mixture. You can also use an exhaust pipe sniffer to fine tune the CO content if you are so inclined.

Randall
92rrrandall is offline   Reply With Quote
Old 05-15-2009, 04:41 AM   #6
Discoinjapan
Member
 
Discoinjapan's Avatar
 
Join Date: Feb 2006
Location: Yokosuka Japan via PA
Posts: 2,504
Default Re: TPS and MAF adjustment

good write up except you state that these mafs never fail.
__________________
93 D1 a couple of mods(now parts truck)

94 D90 ST Red

95 RRC County LWB

96 D1 a few mods (tsunamied)

01 D2 SE7 Another RHD

06 RR Supercharged
Discoinjapan is offline   Reply With Quote
Old 05-15-2009, 10:23 PM   #7
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

I still have no figured out how to "tune the maf" for a non cat configuration.
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Old 05-16-2009, 07:48 AM   #8
kk88rrc
Member
 
Join Date: Mar 2007
Location: Portland Maine
Posts: 625
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by rover4x4
I still have no figured out how to "tune the maf" for a non cat configuration.
RPI recommends between 1.0 - 1.5.
http://www.v8engines.com/carbs-2.htm#setting-up
__________________
Kevin
88 RRC "Audrey" now a parts donor
88 RRC "Daphne"
kk88rrc is offline   Reply With Quote
Old 05-16-2009, 08:21 AM   #9
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

I was under the impression that you did something to the MAF itself but it seems you adjust with the screw under the tamper proof plug.
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Old 05-16-2009, 12:11 PM   #10
Diggaz
Guest
 
Posts: n/a
Default Re: TPS and MAF adjustment

Very good explanation Randall, thanks.
  Reply With Quote
Old 05-16-2009, 05:47 PM   #11
landrovered
Member
 
landrovered's Avatar
 
Join Date: Nov 2006
Posts: 4,277
Default Re: TPS and MAF adjustment

rover4x4,

You are simply adjusting the gain (for lack of a better term) of the MAF, there is nothing else to do with it. It has a wire that heats up and the amount of current needed to heat it determines the mass of the flow, that is why it is called a hotwire MAF.
__________________
That's MISTER Liberal Commy Pinko to you asshat.
landrovered is offline   Reply With Quote
Old 05-16-2009, 06:44 PM   #12
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by landrovered
rover4x4,

You are simply adjusting the gain (for lack of a better term) of the MAF, there is nothing else to do with it. It has a wire that heats up and the amount of current needed to heat it determines the mass of the flow, that is why it is called a hotwire MAF.

This is the explanation I have been needing for months. It sort of spells it out in the RAVE but I wasnt clear that the allen screw under the plug really did. Why did Land Rover program the trucks to run rich, to keep the cooler? Does a hotter plug with the pretuned rich mixture make more "power"?
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Old 05-17-2009, 09:44 AM   #13
landrovered
Member
 
landrovered's Avatar
 
Join Date: Nov 2006
Posts: 4,277
Default Re: TPS and MAF adjustment

As far as I understand it, they did it so the cats would get hot enough to complete the combustion and pass emissions, also reduce pre-ignition.
__________________
That's MISTER Liberal Commy Pinko to you asshat.
landrovered is offline   Reply With Quote
Old 05-18-2009, 08:25 AM   #14
green
Member
 
green's Avatar
 
Join Date: Apr 2005
Location: Broomfield,CO
Posts: 200
Default Re: TPS and MAF adjustment

"Remove the tamper proof cap." by this you mean the brown plastic square piece that is glued down to the top of the MAF that has the LUCAS name on it?
__________________
89 RRC-35's
97 DI-35's
green is offline   Reply With Quote
Old 05-18-2009, 08:40 AM   #15
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

no its a little black round plug on the intake plenum near the throttle body.
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Old 05-18-2009, 08:41 AM   #16
kk88rrc
Member
 
Join Date: Mar 2007
Location: Portland Maine
Posts: 625
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by green
"Remove the tamper proof cap." by this you mean the brown plastic square piece that is glued down to the top of the MAF that has the LUCAS name on it?
Nope... it's the little round thing on the upper right corner circled in red.
Attached Images
File Type: jpg 10-west-air-mass-setup.jpg (56.5 KB, 139 views)
__________________
Kevin
88 RRC "Audrey" now a parts donor
88 RRC "Daphne"
kk88rrc is offline   Reply With Quote
Old 05-18-2009, 08:46 AM   #17
landrovered
Member
 
landrovered's Avatar
 
Join Date: Nov 2006
Posts: 4,277
Default Re: TPS and MAF adjustment

Mine was aluminum, if you use a drill bit and turn it by hand you can open it up without damaging the pot under the cap. After the adjustment, I plugged mine with a plastic plug that came on a set of brake calipers that I had, it fits just right.
__________________
That's MISTER Liberal Commy Pinko to you asshat.
landrovered is offline   Reply With Quote
Old 05-18-2009, 08:53 AM   #18
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by kk88rrc
Nope... it's the little round thing on the upper right corner circled in red.
ahh, so there are two of these. I guess the other one is for the base idle adjustment?
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Old 05-18-2009, 10:26 AM   #19
green
Member
 
green's Avatar
 
Join Date: Apr 2005
Location: Broomfield,CO
Posts: 200
Default Re: TPS and MAF adjustment

I thought it was the red circle one, just checking. AND THANX! I have been searching for this for a long time as well!
__________________
89 RRC-35's
97 DI-35's
green is offline   Reply With Quote
Old 05-18-2009, 04:24 PM   #20
lionrover88
Guest
 
Posts: n/a
Default Re: TPS and MAF adjustment

I'm Sorry People, i have issues with my PC, Please forgive me if i was not very clear with the pics.
The MAF is adjusted with a #5 allen wrench the red circled location in Kevins pic is the only location that has a screw hidden under a aluminum cap/plug there is no other adjustable screw on the MAF.

The throttle position sensor is adjusted by loosening up the two screws and turning it untill the desired value is reached, after that hold it in place and retighten the screws.

This information is for the 3.5ltr Gems motor, that is in my 1988 RRC. I played around with these adjustments after reading a thread on discoweb that talked about these adjustments for a 14cux ECU. The 3.5ltr uses a 13cu ECU but i experienced bettter performance as i did the adjustments. Even though DO NOT EXPECT THESE ADJUSTMENTS TO BE A WAY TO MAKE YOUR ROVER A RACE CAR IT IS NOT!!!!!! ALL IT DOES IS, IT MAKES THE ROVER MORE EFFICIENT!!! It is advisable that you write the original values down BEFORE making any adjustments, so you can go back to the original settings in case you experience problems.
  Reply With Quote
Old 05-18-2009, 04:36 PM   #21
lionrover88
Guest
 
Posts: n/a
Default Re: TPS and MAF adjustment

Quote:
Originally Posted by luvs2getmuddy
I never had to adjust either of the two, and I've swapped them out a handful of times.
It's not for the "have to" these adjustments are your choice. If you want to fine, if you don't, fine too.
  Reply With Quote
Old 06-01-2009, 09:30 AM   #22
kalahari
Member
 
kalahari's Avatar
 
Join Date: Jul 2005
Location: Pulaski, TN
Posts: 284
Default Re: TPS and MAF adjustment

Lion - Thanks for the thread.

I finally fixed my issue. The 88 ran fine and normally idled well, maybe a little low but well. Sometimes when it was at operating temp it would die at a stop sign or red light.

These are the steps I took to resolving the issue

Cleaned the MAF
Cleaned the Throttle Body
Cleaned the IAC valve
Tested and adjusted the TPS and MAF to Lion's settings
Adjusted the Base Idle Speed
Replaced the IAC valve

Still had the same issue. Given I knew the CATs were bad and going in for replacement next week. I also noticed that my battery light was getting that dim glow again. You really couldn't see it in the daytime, just at night.

Saturday I swapped out all the old belts and installed the 140 amp Alt I purchased from Will a couple of months ago. Bingo! Problem solved. While all the other stuff probably needed doing and possibly contributed to the problem, I believe the underlying problem was a dying Alt.
__________________
Jeff Hibdon

88 RRC 40th Anniversary Edition
01 DII SE
04 DII SE7 - Sold
02 DII Kalahari - SMASHED!
kalahari is offline   Reply With Quote
Old 06-01-2009, 02:32 PM   #23
j_button
Member
 
j_button's Avatar
 
Join Date: Apr 2004
Location: Dallas, TX
Posts: 64
Default Re: TPS and MAF adjustment

Kalahari, I did everything you did except for the base idle speed. My problem was the same. It would idle way to low and stall once running in closed loop. Tried 1.6V 1.7V same crap. I put the MAF back to 1.88V and all is good. How do you adjust the idle speed? I assumed the ECU controlled this? I really don't think I'm having alternator issues, no signs. Battery voltage is 13.8V at idle, no dim lights and what not.

'91 RRC 3.9
j_button is offline   Reply With Quote
Old 06-01-2009, 02:55 PM   #24
kalahari
Member
 
kalahari's Avatar
 
Join Date: Jul 2005
Location: Pulaski, TN
Posts: 284
Default Re: TPS and MAF adjustment

This is the procedure for an 87-88 RRC copied from AB's Tech Section :

Routine idle speed adjustment during maintenance services is not necessary not desired. The bypass air valve (stepper motor) located at the rear of the plenum chamber receives signals from the EFI's electronic control unit and automatically corrects hot idle speed within a range of 665-735 RPM. Use of air conditioning will raise the idle speed slightly above the normal range. This is acceptable.

Complaints of idle surge, excessively high or low idle of off idle hesitation can usually be traced to one or more of the following:

Incorrect throttle plate/throttle lever position
Incorrect potentiometer adjustment
incorrect accelerator cable adjustment
Defective/disconnected road speed transducer
Ignition timing not within specification
Vacuum leaks
Incorrect fuel pressure
Loss of crankcase seal at oil filler cap or dipstick
Defective stepper motor or other EFI fault
Carbon build-up in throttle housing passageways
Basic engine condition - compression or leak down problems

Use the Workshop Manual, Lucas handheld tester and other shop diagnostic equipment to isolate and correct any of the above problems.

If the above checks, repairs or adjustments do not solve the problem, the base idle speed should be adjusted. IMPORTANT: All steps must be followed in sequence exactly as listed below. DO NOT attempt this procedure unless the basic throttle/timing/potentiometer adjustments have been made (see Workshop Manual - Section 19).

With the engine at operating temperature and an accurate tachometer connected:
Center punch and drill (1/8" bit) the tamper proof plug located on the throttle housing.
Remove the plug with a sheetmetal screw and pliers.
Discard the plug and clean up any metal chips.
Switch the ignition on - DO NOT START THE VEHICLE.
Disconnect the stepper motor plug
Switch ignition off
Listen for click from EFI main relay (under the right front seat).
Reconnect the stepper motor plug.
Switch the ignition on - DO NOT START THE VEHICLE.
Disconnect the stepper motor plug.
Start the vehicle in neutral without touching the accelerator
Adjust the base idle speed with a 3/16" Hex wrench to 550 to 650 RPM by turning the base idle screw. Turning counter clockwise will raise the speed and vice versa.
Reconnect stepper motor plug.
Switch ignition off.
WAIT for main relay click
Switch ignition on, start the engine and rev briefly to 2000 RPM
Idle speed should stabilize at 665-735 RPM
Install new tamper proof plug.
__________________
Jeff Hibdon

88 RRC 40th Anniversary Edition
01 DII SE
04 DII SE7 - Sold
02 DII Kalahari - SMASHED!
kalahari is offline   Reply With Quote
Old 12-10-2010, 12:41 PM   #25
rover4x4
Member
 
rover4x4's Avatar
 
Join Date: Apr 2004
Location: North Carolina
Posts: 4,767
Default Re: TPS and MAF adjustment

Is there any advantage to the 5AM MAF?
__________________
poor gas mileage gets you to the best places on earth
rover4x4 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Checking the TPS voltage. FatMcNasty Discovery - Technical Discussions 0 04-13-2009 10:41 PM


All times are GMT -4. The time now is 03:20 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ?2000 - 2013, DiscoWeb LLC. All rights reserved.