L
lionrover88
Guest
luvs2getmuddy said:
It's not for the "have to" these adjustments are your choice. If you want to fine, if you don't, fine too.
:victory:
It's not for the "have to" these adjustments are your choice. If you want to fine, if you don't, fine too.
:victory:
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.
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.
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
'91 RRC 3.9
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.
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.
ptschram
Well-known member
ptschram
Well-known member
L
lionrover88
Guest
ptschram said:
OK PT, GIVE US SOME INSIGHT OF YOUR KNOWLEDGE I KNOW YOUR GOOD AT THAT. YOU HAVE ELABORATED FOR ME A BUNCH. WHATS THE DEAL WITH ADJUSTING THE MAF AND TPS?????
atriot: :victory: LADIES AND GENTLEMAN, MR. PT SCHRAM:applause: :applause:
1.3-1.5 volts for the not cat tune? I am not sure there is any TPS adjustment on the 14CUX trucks.
L
lionrover88
Guest
rover4x4 said:
my truck doesn't have cats anymore due to PO and those r the settings i use.
if ur tps has slotted holes it will be adjustable. if not then no, it won't be adjustable.
:victory: