Is this cam surge?
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Is this cam surge?
Hi guys. I started from scratch with my tuning on my '85. So far I've tuned everything myself with the advice from a few forum members. Everything is turning out a lot better now that it did before.
I'm running the factory timing tables and everything.
But my problem is when I'm in fourth gear until 3000 RPMs while just cruising, I get a slight buck every 2-3 seconds. It's just one buck.
Is that cam surge? If not, what is it?
Thanks!
I'm running the factory timing tables and everything.
But my problem is when I'm in fourth gear until 3000 RPMs while just cruising, I get a slight buck every 2-3 seconds. It's just one buck.
Is that cam surge? If not, what is it?
Thanks!
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Drifting
Joined: Feb 2013
Posts: 1,465
Likes: 12
Hi guys. I started from scratch with my tuning on my '85. So far I've tuned everything myself with the advice from a few forum members. Everything is turning out a lot better now that it did before.
I'm running the factory timing tables and everything.
But my problem is when I'm in fourth gear until 3000 RPMs while just cruising, I get a slight buck every 2-3 seconds. It's just one buck.
Is that cam surge? If not, what is it?
Thanks!
I'm running the factory timing tables and everything.
But my problem is when I'm in fourth gear until 3000 RPMs while just cruising, I get a slight buck every 2-3 seconds. It's just one buck.
Is that cam surge? If not, what is it?
Thanks!
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Bucks back and fourth slightly under 2000 RPMs with light load in the lower gears.
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Pro
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From: Milwaukee Wi
Have you disabled hyway mode? It may be run too lean if in HM.
Also during cruise (low load) you may have too much spark advance(45+). Take 2 deg out of table where that occurs and blend surrounding cells.
Also during cruise (low load) you may have too much spark advance(45+). Take 2 deg out of table where that occurs and blend surrounding cells.
Last edited by Rohn; Oct 23, 2014 at 02:17 PM.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
And okay. I'll play around with timing. I'm using the stock timing table. Is this a common problem on stock timing tables?
Pro
Joined: Jul 2002
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From: Milwaukee Wi
If your car is not "stock" then you need to make the tune fit. I added timing just where you are experiencing issues. I went from stock table to LT4 table. That added timing at cruise big time. No issues.
Are you using stock injectors and stock FP?
Are you using stock injectors and stock FP?
Melting Slicks
Joined: Aug 2003
Posts: 3,401
Likes: 397
From: Lakeville MI
To combat surge, you want to take out a lot of timing to try and kill the low speed torque in the region, so that more throttle is required to produce the same road load torque.
This will help pull more air (and less exhaust) into the cylinder that is on the intake stroke while the 90 degree adjacent cylinder is in overlap.
This will help pull more air (and less exhaust) into the cylinder that is on the intake stroke while the 90 degree adjacent cylinder is in overlap.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Thanks.
Safety Car
Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
To combat surge, you want to take out a lot of timing to try and kill the low speed torque in the region, so that more throttle is required to produce the same road load torque.
This will help pull more air (and less exhaust) into the cylinder that is on the intake stroke while the 90 degree adjacent cylinder is in overlap.
This will help pull more air (and less exhaust) into the cylinder that is on the intake stroke while the 90 degree adjacent cylinder is in overlap.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Oh I forgot to mention. I haven't driven it under those conditions WITHOUT the ALDL cable plugged in recently, so I don't know if it will do it without the cable plugged in. Every time that I have taken it out I have been doing data logs. bjankuski mentioned in another one of my threads that the ALDL cable being plugged in will add 8* of timing advance. So could that be why it's doing it? Is the whole timing table advanced by 8*?
Safety Car
Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
Oh I forgot to mention. I haven't driven it under those conditions WITHOUT the ALDL cable plugged in recently, so I don't know if it will do it without the cable plugged in. Every time that I have taken it out I have been doing data logs. bjankuski mentioned in another one of my threads that the ALDL cable being plugged in will add 8* of timing advance. So could that be why it's doing it? Is the whole timing table advanced by 8*?
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Okay well I took it under the same conditions without the ALDL cable plugged in a it was hardly, hardly, hardly even noticeable. I had to give 100% of my attention to it to feel something that's really not that noticeable.
Guess it's fixed
Good thing to, because I'm usually the one who fixes things that are not broken, and end up breaking other things. Lol.
Thanks guys!
Guess it's fixed
Good thing to, because I'm usually the one who fixes things that are not broken, and end up breaking other things. Lol.
Thanks guys!