car doesn't like A/C
Thread Starter
On The Tree
Joined: May 2004
Posts: 133
Likes: 0
From: Dallas
car doesn't like A/C I recently rebuilt my motor due to a blown piston/head gasket, and during the rebuild process I decided to slap an F1 cam in my 2001 A4 Z28. Of course then I decided to purchase LS1 Edit. So...upon reading the inordinate amount of information here on ls1tech, I got my car to idle and start up without the A/C on. I've increased the idle rpms to respond to the A/C being on, but that didn't help. I've increased both the IAC and Idle Air tables 20%, and the 400 column in the VE table is at 60%, 800 and 1200 are at 70%. When I start it up with the AC on, it drops to 300 rpm, then kicks back up over 1200...then settles out...but once I put it in reverse, the RPMs just drop and surge and then the engine dies. The Idle RPM table goes from 1100 down to 800 in gear depending on the temp. In park it's 1100-855. With the AC off...it will surge a couple of times on a cold start but after it warms up a bit it's great. I know something's not right.
Another thing it was doing was slipping. I have a 3000 stall so I found the thread describing to change the misfire tables...that seems to have fixed the slipping problem. Except that with my stock internals...on the highway I used to cruise at 70mph at 2000 rpms...now at 70 mph I'm at 2200. With the bigger cam I'd figure it should be less right? I know the converter is locking like it should...
I'm still trying to figure out the shift point thing too. But that's another issue.
My main concern is getting my car to idle right. If NoGo, Chris, or Joe could chime in and give me some pointers I'd appreciate it greatly. I'll be happy to send people my edit files or log files too. Many thanks up front to all.
Another thing it was doing was slipping. I have a 3000 stall so I found the thread describing to change the misfire tables...that seems to have fixed the slipping problem. Except that with my stock internals...on the highway I used to cruise at 70mph at 2000 rpms...now at 70 mph I'm at 2200. With the bigger cam I'd figure it should be less right? I know the converter is locking like it should...
I'm still trying to figure out the shift point thing too. But that's another issue.
My main concern is getting my car to idle right. If NoGo, Chris, or Joe could chime in and give me some pointers I'd appreciate it greatly. I'll be happy to send people my edit files or log files too. Many thanks up front to all.
Thread Starter
On The Tree
Joined: May 2004
Posts: 133
Likes: 0
From: Dallas
well this morning I logged my drive to work...and it jumps around a lot. The lowest I saw it was 19, and the highest is 199. I'll post some entries.
First starting the drive this morning:
72
70
67
110
96
118
130
132
121
127
125
135
137
113
114
114
110
110
110
142
149
133
115
114
113
109
105
104
102
79
75
132
141
148
136
Mid-drive:
172
173
175
176
170
160
159
167
177
171
166
171
171
169
170
170
170
170
170
169
169
169
169
160
158
158
157
155
155
140
124
145
123
116
115
135
125
when I stopped logging:
40
39
35
30
31
29
28
27
84
88
88
79
61
63
50
31
31
31
31
31
30
30
30
28
28
80
33
29
29
29
29
24
22
21
23
23
55
46
39
Sorry for the long post.
First starting the drive this morning:
72
70
67
110
96
118
130
132
121
127
125
135
137
113
114
114
110
110
110
142
149
133
115
114
113
109
105
104
102
79
75
132
141
148
136
Mid-drive:
172
173
175
176
170
160
159
167
177
171
166
171
171
169
170
170
170
170
170
169
169
169
169
160
158
158
157
155
155
140
124
145
123
116
115
135
125
when I stopped logging:
40
39
35
30
31
29
28
27
84
88
88
79
61
63
50
31
31
31
31
31
30
30
30
28
28
80
33
29
29
29
29
24
22
21
23
23
55
46
39
Sorry for the long post.
TECH Apprentice
Joined: Nov 2001
Posts: 387
Likes: 0
From: South Elgin, IL
I have a gut feeling your VE values are off. I had the same issue and adding to the lower values to richen things up fixed the problem. I ended up in the range of 75-85-90. I'm running a TR230 w/10.5 LSA.
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Did you change the VE's at 400rpm's by 40%? That affects 400 to 800rpm's. Raise the base spark in drive and in park from 0 to 1200rpm's and up to .52gms/cyl by 2.0. Then, raise your IAC table by a high number, like 2.0 and see what effect that has. Judge the next change in IAC's from there. When you get rid of the surge, if you have cruise effect lower the RAF's. Let us know what you get.
Thread Starter
On The Tree
Joined: May 2004
Posts: 133
Likes: 0
From: Dallas
thanks for the tip. I'll give that a shot. I know I have adjusted the base spark tables but I'm sure I didn't go to .52 gms. Went to .24 I believe. I'll be sure to post up the results later. I'd do it now but I'm kinda stuck at the office. Stupid job...always getting in the way of things.
Yes, I adjusted the 400 column down to 60%.
Will this help fix my car from running so rich? It's going through gas like mad.
Yes, I adjusted the 400 column down to 60%.
Will this help fix my car from running so rich? It's going through gas like mad.
Will this help fix my car from running so rich? It's going through gas like mad.[/QUOTE]
I'll bet your spending a lot of time at idle and at slow speeds.
The suggestions are to let you judge the results to determine what's next.
I'll bet your spending a lot of time at idle and at slow speeds.
The suggestions are to let you judge the results to determine what's next.
Originally Posted by TIMMEH
actually quite the opposite. I tend to stick to highways when driving around town. That being said I spend a lot of time in the low RPM range (2-3K) cruising.
Thread Starter
On The Tree
Joined: May 2004
Posts: 133
Likes: 0
From: Dallas
Okay everyone, I did just as gojo suggested. I sat outside and logged different things sitting in place (idle). It still surges a few times without the AC on during the start, but then smoothes out. If I try and start the car WITH the AC on, big surge then falls on its face and dies. I opened up the set screw a tad more to help as well. So the throttle reads at .4
Once I started it, I began to log at different intervals. I'll be glad to go log during a drive but I thought I'd start with this data while not moving.
In park, NO AC:
IACs went from 115 to steadily decline to mid to low 40s and stayed in that range.
In park WITH AC:
IACs jumped to 109 and fluctuated between 114 and 106 with one low point of 95.
In Gear without AC:
IACs declined again beginning with 104 dropping to high 20s low 30s and resting there.
In Gear WITH AC:
IACs jumped up to the low 80s, high 70's.
I was told that with the AC turned OFF...you want your IACs in the 70's for an A4 with the cam I have. Is that correct? And if so, what do I do to get them there?
On a side note, how do I get my Ltrims to stay in the negatives? Reduce the IFR table right? (version 1.4 of edit.)
Once I started it, I began to log at different intervals. I'll be glad to go log during a drive but I thought I'd start with this data while not moving.
In park, NO AC:
IACs went from 115 to steadily decline to mid to low 40s and stayed in that range.
In park WITH AC:
IACs jumped to 109 and fluctuated between 114 and 106 with one low point of 95.
In Gear without AC:
IACs declined again beginning with 104 dropping to high 20s low 30s and resting there.
In Gear WITH AC:
IACs jumped up to the low 80s, high 70's.
I was told that with the AC turned OFF...you want your IACs in the 70's for an A4 with the cam I have. Is that correct? And if so, what do I do to get them there?
On a side note, how do I get my Ltrims to stay in the negatives? Reduce the IFR table right? (version 1.4 of edit.)
Last edited by TIMMEH; May 18, 2004 at 08:25 PM.
http://www.ls1tuning.com/iboard/index.php?showtopic=9
Try this method.
Reduce IFR's is right.
You have an IM.
Try this method.
Reduce IFR's is right.
You have an IM.
Last edited by gojo; May 18, 2004 at 09:03 PM.
Thread Starter
On The Tree
Joined: May 2004
Posts: 133
Likes: 0
From: Dallas
PM sent. Thanks for your advice. By adjusting the IFR to 90%, I got the LTrims down to an average of -2.24 and -1.9 respectively.
I tried nogo's recommendations but I can't get it to quit surging using his method unless I unplug the IAC. With the IAC unplugged it fires right up. I even tried adjusting the IAC table to 9.2 like he suggests, and that didn't help. Should I reduce the VE table by 5%?
I tried nogo's recommendations but I can't get it to quit surging using his method unless I unplug the IAC. With the IAC unplugged it fires right up. I even tried adjusting the IAC table to 9.2 like he suggests, and that didn't help. Should I reduce the VE table by 5%?