|
|
|
|
| Author |
|
|
Registered
Join Date: Feb 2020
Posts: 31
|
930 idle drop during warm up
My 87 930 had perfect idle of 950 rpm but suddenly the idle is dropping during the first couple of minutes of warm up from 1100 rpm to 500rpm and them even 200 rpm. Obviously this leads to the engine stop running. After 5 min warm up the engine idles perfectly at 950 rpm.
I had suspected the WUR (installed a fully rebuild unit) and then the auxiliary air valve (rebuild and cleaner it and it seems to work fine). My next attempt to find the problem was rebuilding the distributor but nothing has been identified as a problem there as well. Checked for vacuum leaks without any finding and have changed out all black and red and yellow relays. Any other components I should look into to diagnose the problem. Thanks |
||
05-29-2025, 12:44 PM
|
|
|
Registered
Join Date: Jul 2008
Location: Central Washington State
Posts: 4,396
|
You may want to confirm you've got power to the WUR. Kind of sounds like it's staying in cold start mode, i.e., rich, until it gets warmed up by the engine heat alone. Power comes off the rear fuel pump relay circuit. Pull the plug from the WUR and check voltage. If voltage is OK, then put an ohm meter across the WUR to make sure the internal heating element isn't an open circuit.
The WUR and AAR work in concert with each other to set up a cold rich high idle for the first 3 minutes or so.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ. |
||
|
05-29-2025, 01:20 PM
|
|
