bucking in drive and OD

[mossyoak71]

I have been trying to get the bucking out of my truck. It is driving me crazy and i just found out how to do a datalog. It seems to be getting worse over time, and I'm at a loss for what to do. Can someone look at this datalog and tell me 1) what is going on and 2) how to try and remedy it. Thanks for any help.

iQuad-2018-03-18-07.06.211972471670.csv

[Me78569]

less timing in those situtations.  Please post your tune and narrow down the datalog so we know where the bucking is happening.  

 

 

[mossyoak71]

I will get more info and tune tomorrow. I used the tune builder tool, and they started out ok, it would buck a little, then it just started getting worse. It will also buck ever so slightly in the stock tune.

[Me78569]

At what condition does it happen?  light load only? if so under what load %.  what rpm does this happen at?  

[mossyoak71]

Ok, so I took some pictures of when it does it. This is the tune that you sent me, which I had to start it at 80 instead of 70 because it would die when I pressed the pedal. Also cruising along at 70+ and stab the pedal and when the wire tap comes in it really bucks. I attached the pictures and the tune.  Now the street tune that I attached will buck at all rpms above 1500. But when you stab the pedal, it will get up an go. Wiretap will cause slight bucking. This is the tune I made with the tune program. All the tunes that I have done with it will buck. So I just want to know where I am going wrong.

iQuad-scott1-2017-12-07-04.06.45608484781.json

streettune.json

[Me78569]

Both of those images have TPS at %20.  Is it bucking in the images?

 

It sounds like too much timing,  try adding 1* of timing to fuel load timing

 

also drop your 1500 rpm timing setting to 16* and the 2k down to 18.5* and reduce you light throttle timing down to 1 or 1.5 *.  You are ending up with a ton of timing at light throttle in the 1500, 2k area

 

I dont think your truck likes timing as much as most do.  Was there something "special" about your setup?  pistons or somehting?

Edited March 20, 2018 by Me78569

[mossyoak71]

Nothing special, just what is in my signature. Like I said, I have been banging my head, and it hurts. So I will try that. The only thing special is the fact that it's in a Ford, mated to the 5R110W, and 3:73 gears. I just wonder if the ratios in the transmission have anything to do with it. When you say fuel load timing, what is that, cause I don't see it in the quad?

Edited March 20, 2018 by mossyoak71
Question

[Me78569]

Do this

[mossyoak71]

I will, thanks

[Mopar1973Man]

I would drop the 1,500 position to at least 15*.

[Dieselfuture]

9 hours ago, mossyoak71 said:

When you say fuel load timing, what is that, cause I don't see it in the quad?

Max load timing offset

[mossyoak71]

Well by doing the things you said to do, it has helped the 1st  tune alot. I will try 5he other this afternoon.

[Me78569]

bucking is nearly always too much timing.  Backing off the rpm timing settings normally solves the issue

[mossyoak71]

So the other tune seems to be working good. Could it also be that the gear ratio in the Ford automatic is different than the Dodge. I know when the engine gets lugged down in slow traffic it will buck. I'm still working with DCS on the tranny tuning. 

[Mopar1973Man]

On 3/20/2018 at 7:32 PM, mossyoak71 said:

I know when the engine gets lugged down in slow traffic it will buck.

Between working with the 1,500 RPM timing band, max load timing offset, and low psi timing reduct these 3 setting can get rid of most of the bucking. 

 

Max load timing offset - 3*

Low psi timing reduct - 2*

1500 RPM - 14.5*

 

That's what I'm running. Very rare to see bucking. The thing is you need to get a fair amount of retarding at low RPM's to able to pull in a lugging state. 

[Me78569]

I like ot set Timing reduction to 5* then timing reduction scaling to %50.  That way you get a very fast pull in timing when you try to pull in a lugged state.

[Mopar1973Man]

3 minutes ago, Me78569 said:

I like ot set Timing reduction to 5* then timing reduction scaling to %50.  That way you get a very fast pull in timing when you try to pull in a lugged state.

 

Hmmm... I might try that on my performance tune I'm playing with. 

 

A matter of fact my Stealth Plate is on its way and be here on Thursday...

Edited March 22, 2018 by Mopar1973Man

[Me78569]

Yep you will still get a max of 2.5* of pulled timing, but it will happen at %50 throttle rather than %100 throttle

[Mopar1973Man]

Still very marginally understanding on the timing reduct setting. That's one of the settings I've not got my head wrapped around good. 

[Me78569]

scaling sets a max amount based on the timing reduct

 

So 5* timing reduct and %50 scaling gives you 2.5* max timing pull.

So 5* timing reduct and %30 sclaing givees you 1.5* max timing pull. 

So 5* timing reduct and %70 sclaing givees you 3.5* max timing pull. 

 

The key is how fast timing hits that point. in this example we have 2.5* timing reduct %100 scaling vs 5* timing reduct %50 scaling.  same total pull in timing, but the 5* %50 scaling hits peak timing pull at %50 tps input