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Cold start surging?

Old 12-05-2010, 07:33 PM
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Default Cold start surging?

Its not really a "problem" yet, but it has become an annoyance.

On first cold start of the day, especially in the cold, the car takes some slight effort to actually start (cranking it over). Once the car starts it has this surging that it does until either I pat the throttle or I let it work itself out which takes about (6-7 sec). After this it doesn't surge anymore for the rest of the day as long as I don't let the car sit for a prolonged amount of time.

I included my cranking PW and ASE settings. Fuel setup is 190HP Walbro, rx7 460s, stock rail. Stock 1.8 w/ MS1 and COPs, T3 Garrett...blah blah blah..


Cranking PW
-40 F 6.6 ms
-20 F 6.2 ms
0 F 6.0 ms
20 F 5.7 ms
40 F 5.5 ms
60 F 4.7 ms
80 F 3.8 ms
100 F 3.1 ms
130 F 2.6 ms
160 F 2.4 ms


ASE Settings
-40 F 55%
-20 F 50%
0 F 45%
20 F 40%
40 F 35%
60 F 33%
80 F 28%
100 F 21%
130 F 17%
160 F 15%

I am figuring I just don't have enough fuel on startup, but before I went and started changing anything, figured I would check with some experienced heads. Any suggestions?
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Old 12-05-2010, 07:41 PM
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Increase cranking fuel in small increments til it starts fast.
The surging not sure I understand: the rpms jump around or what? what are your afr's when it does that? My adaptronic did that and it was because of a poorly tuned fuel map around the idle cells.
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Old 12-05-2010, 08:02 PM
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Originally Posted by 18psi
Increase cranking fuel in small increments til it starts fast.
The surging not sure I understand: the rpms jump around or what? what are your afr's when it does that? My adaptronic did that and it was because of a poorly tuned fuel map around the idle cells.


Yea as far as surging, it just surges from about 500-1000rpms nearly stalling when it surges down. The afr is around 14.7-15.0 but once the surging clears out the AFRs go to around 13.5-13.8, and idles around 1300 till it warms up.

I should just increase fuel in small increments in the cranking setting only correct?
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Old 12-05-2010, 08:06 PM
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u got 2 different issues.
Yes increase cranking fuel for your start problem.
And smooth out the cells around the cells that it surges in, so your afr's don't jump around causing the car to bounce rpm.
just my .02. It worked for my car anyway, and it did the same surging bs
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Old 12-05-2010, 08:10 PM
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Originally Posted by 18psi
u got 2 different issues.
Yes increase cranking fuel for your start problem.
And smooth out the cells around the cells that it surges in, so your afr's don't jump around causing the car to bounce rpm.
just my .02. It worked for my car anyway, and it did the same surging bs
Awesome I appreciate it, ill try that out.

Just curious what kinda plugs and gap people are running here with COPs, would you mind sharing yours with me?

I still havent pulled my plugs since doing my COP conversion. I am still running BKR7Es gapped at around 36-37. No hiccups or misses, runs GREAT, but I really want to take advantage of the coils.
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