Running LEAN after upgrades

GC89

1J-THIS
Jun 13, 2007
938
3
18
38
Spokane, WA
Boost leak would be rich at WOT, and absolutely do not do anymore pulls at 14 afr. That is way past safe and will cause damage if it hasn't already.
 

supraficial

New Member
Mar 20, 2013
62
0
0
Southern MD
GC89;2080525 said:
Boost leak would be rich at WOT, and absolutely do not do anymore pulls at 14 afr. That is way past safe and will cause damage if it hasn't already.
I know I said boost leaks, but wouldn't a vacuum leak theoretically cause leaner conditions before any boost was introduced? The car would be sucking in more air post-afm than it is reading/supplying fuel for at the afm. Could be wrong, just thinking out loud.

I took off the filter and supplied a small amount of air (~5-10 psi) into the system insinuating the cars vacuum and it all dumped out of the back of the valve cover at the rear most bolt and showed a backed out helicoil which didn't let it sit flush. I fixed that bolt/leak and it didn't fix the rough, stumbling idle and seemed to make it a little worse on the afr. The car is reading 5.0 Vf at idle. The car doesn't hardly leave garage, let alone WOT pulls it's just at the tb cable
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,235
37
48
Atlanta
True, you would get a lean condition at idle and light cruise, but it would go pig rich at wide open throttle, since the leak point would be causing pressurized air to escape.

What diagnostic codes are stored?
 

supraficial

New Member
Mar 20, 2013
62
0
0
Southern MD
supraguy@aol;2080587 said:
True, you would get a lean condition at idle and light cruise, but it would go pig rich at wide open throttle, since the leak point would be causing pressurized air to escape.

What diagnostic codes are stored?

It doesn't throw any more codes at all.

To start off, I adjusted the fuel pressure regulator higher to ~40-50 psi and the afrs came back down to around 14ish like it's supposed to be, but the Vf's stayed pinned at 5.0. Then with the slightest touch of throttle it goes down to 0.0. I don't want to mask any bigger problems with that high of fuel pressure What I found strange was I had bought the newer replacement ECU (pt. #89661 14450) to see if that was a problem, and with that ECU the Vf stays locked at 5.0 even with any throttle blips. This afr only started happening when I installed a step colder copper plugs and the 550cc low impedance RC injectors. With the high impedance that were on before the afrs were all stoic and the Vf's were even normal, but now it's all lean. The injectors were a huge job so if it's another unrelated issue I would rather not take them all off again if possible haha.
 

supraficial

New Member
Mar 20, 2013
62
0
0
Southern MD
Update: so I took off the air filter of the lex afm during idle and the car died. So I figured the afm is the taking in too much air for the supplied fuel, i.e. The lean conditions at all throttle positions. So I took off the lex afm and put on the stock unit, which now idles perfectly, but under WOT pegs down at 10.0 starting at ~0-1 psi and until letting off. The lex afm does not have an adjustment screw as everyone says, so maybe I have too big of an afm? I'm happier now that the problem is too rich than lean, so I could live with this. I'm most likely going to get an SAFC in the near future, just posting because I was under the impression that lex afm + 550cc's would keep afrs perfect.