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View Full Version : surging idle when at a stop...did tune cause it?



Youngblood
05-01-2010, 09:40 PM
so i recently installed a lidio tune. and i absolutely love it. car performs great.. but i noticed after a day or two..as i come to a stop..my idle bogs down and goes up..and it may do this 2-3 times then even out. never did this before the tune..or maybe i never noticed. but what can this be? i did the plugs..and im about to do all 8 coils because i do have a rough idle and im up there in miles. it looks like some one replaced some of the coils at some point but im gunna just do all of them. probably accel or msd coils. i know this will help my rough idle..but what about the surging...could it be the iac? or posisbly a dirty maf

also at one point i did advane the global spark by 4 degrees because ive spoken to a few people and they say it makes the marauder a lil more powerfull. and i def did notice a increase in pull. but i have the same problem with both spark settings.. although it is more noticeable and severe with the advanced timing as well as running a lil rougher. so at this point im not sure. i set the spark back to normal. and just tryign to figure out whats causing this surge

justbob
05-01-2010, 09:50 PM
The IAC and the MAF could cause this. You sure you don't have unmetered air entering?

Youngblood
05-02-2010, 08:16 AM
i dont beleive so. i do have a kn intake. im going to check it today to see if its leaking. but i really did notice the idle problem after the tune..as well it being much worse with the extra 4 degrees

guspech750
05-02-2010, 08:19 AM
Put the stock tune back in and see what it does.

boatmangc
05-02-2010, 10:22 AM
Put the stock tune back in and see what it does.
+1 eliminate the other change

Ktorres1
05-02-2010, 10:49 AM
What's your drive idle rpm set at?

Youngblood
05-02-2010, 11:43 AM
not sur eill have to check. its whatever lidio set it at. but when stopped it just bogs down below 500 and shoots up and down and up and down then up..lol then to normall

LeoVampire
05-02-2010, 11:45 AM
not sur eill have to check. its whatever lidio set it at. but when stopped it just bogs down below 500 and shoots up and down and up and down then up..lol then to normall

This may be a stupid question but is the AC on when this is happening?

The PCM is supose to raise the idle a bit when the compressor turns on. Is there is a chance it is surging each time the clutch for the compressor turns on and off?

Youngblood
05-02-2010, 11:46 AM
i thought about that too. but it does it with the ac on and off

LeoVampire
05-02-2010, 11:49 AM
i thought about that too. but it does it with the ac on and off


Okay cool one thing down that could be a cause too many more to go:lol:

Youngblood
05-02-2010, 11:52 AM
lol at first i figured it was the iac..but ive had iac motors go and the car reacted much different. also it looks as if its been replaced. so im ruling outt he iac for now.. next im think its the maf but once again this happened after the tune. if the idle was just rough it would be a dead give away. cause i ahve to do coils anyways. but this constant surging is driving me nuts

LeoVampire
05-02-2010, 12:07 PM
lol at first i figured it was the iac..but ive had iac motors go and the car reacted much different. also it looks as if its been replaced. so im ruling outt he iac for now.. next im think its the maf but once again this happened after the tune. if the idle was just rough it would be a dead give away. cause i ahve to do coils anyways. but this constant surging is driving me nuts


I would still clean the IAC and the MAF and then check it and see how it does.

If it still surges remove the tune bring to stock and see what it does. If you have to disconect the battery after removing the tune to make sure the PCM resets and then see how it runs. It may take a bit for the notice to come around seeing it has to relearn again.

ctrlraven
05-03-2010, 06:42 AM
I agree with Leo, try cleaning those to parts. If it still does it then return the car to stock and see how it is. Instead of buying "CRC MAFS Cleaner" get some "CRC OD Electronic Cleaner", it's a dollar or two cheaper and is the same stuff pretty much, also noticed it dries faster.

Zack
05-03-2010, 06:56 AM
Lisio sets the idle in drive to around 575-600 IIRC.
raise the idle to 650 in drive.