Rich Idle and high oil pressure

97stanger

Legend
Joined
Mar 22, 2006
Messages
5,880
Reaction score
100
Randomly I started the car up after replacing the alternator and my wideband is showing that my car is idling extremely rich, in the range of 10.5-11.0. It normally idles around 14.5-14.7 if I remember correctly. I really haven't had the time to drive the car much the past 6 months or so, but has anybody ran into a rich idle and can give advise on quick things to look for? I just want to try a few things if they are quick and easy before getting the car on a dyno and see whats going on. Also, I run a cobra HO factory oil pump. Does anybody know what cold idle should be around? Today it was idling around 75-80, which sounds high to me but I don't remember if this is normal or not. Thanks in advance
 

96blak54

Moderator
Staff
Joined
Feb 21, 2011
Messages
9,982
Reaction score
2,817
Location
In the shop
Oil is normal cold start up. Thin oil = high pressure is good.

I would think a 6month start up would run a little different, but dang 10.5? Did it change once warmed up?
 
OP
OP
97stanger

97stanger

Legend
Joined
Mar 22, 2006
Messages
5,880
Reaction score
100
Oil is normal cold start up. Thin oil = high pressure is good.

I would think a 6month start up would run a little different, but dang 10.5? Did it change once warmed up?

ok, I didn't remember if oil pressure that high was normal or not even when cold.

and yeah, sat right in the 10.5-10.8 range for 2 minutes. Snowing today so I didn't take it for a cruise to see how it reacts to some rpm, but wasn't sure if anything quick I could check that might be common for such a rich idle. Just want to make sure this car is set up properly before I start hitting it with some nitrous
 

Wichers123

Well-Known Member
Joined
Apr 21, 2013
Messages
1,203
Reaction score
0
Location
Covington, louisiana
Do you have a battery switch that you turn off when the car sits and what's the temps out. Memory loss and low temps will change the afr's
 
OP
OP
97stanger

97stanger

Legend
Joined
Mar 22, 2006
Messages
5,880
Reaction score
100
Do you have a battery switch that you turn off when the car sits and what's the temps out. Memory loss and low temps will change the afr's

Well speaking of the battery, I did just get a brand new one because my other red top was stone dead, so I had the positive/negative cables off for a while. Shouldn't once the car idles a bit the ECU relearn the AFR's how it was tuned though? Here in NJ it was in the low 30's when the car was started, I haven't started it since. There is a race shop literally 5 miles down the street from me so to be safe I was planning on just bringing it there to strap it on the dyno and get a real idea of whats going on.
 

Wichers123

Well-Known Member
Joined
Apr 21, 2013
Messages
1,203
Reaction score
0
Location
Covington, louisiana
Ford ecu is slow to relearn sometimes can take a few drive cycles. To get right. Also 30 is pretty low for a stone cold no memory vehicle. Everytime I do a re flash to update/correct the tune in my car I start let idle for 5mins then I shut down and restart and they pretty much starts the drive cycle.
 
OP
OP
97stanger

97stanger

Legend
Joined
Mar 22, 2006
Messages
5,880
Reaction score
100
Ford ecu is slow to relearn sometimes can take a few drive cycles. To get right. Also 30 is pretty low for a stone cold no memory vehicle. Everytime I do a re flash to update/correct the tune in my car I start let idle for 5mins then I shut down and restart and they pretty much starts the drive cycle.

Thanks for the info, I'll give it a few restarts and let it idle a good 5-10 mins and see if it starts to relearn anything. Thanks again for the advice.
 
OP
OP
97stanger

97stanger

Legend
Joined
Mar 22, 2006
Messages
5,880
Reaction score
100
had some warmer weather today. Let the car idle a good 15 mins and put it in different gears. Like you said, it seemed to correct itself over some time and finally got to that 14.5-15 a/f ratio range once it relearned everything. One other question...I have an Autometer Vacuum/Boost gauge. What would be an expected vacuum reading @ idle without any load on the engine?
 

vermilion

Legend
Joined
Sep 15, 2007
Messages
6,300
Reaction score
158
Location
maryland
Usually 14ish but different cam specs. on Decel it's 20

Sent from my LG-D851 using Tapatalk
 

Latest posts

Forum statistics

Threads
77,440
Messages
1,502,189
Members
14,920
Latest member
marktuck99

Members online

Top