Can't get a smooth steady cruise, car jerks trying to cruise

s300 and SManager software questions & answers
Post Reply
InTheZone
Posts: 8
Joined: Sun Mar 10, 2013 1:42 pm

Can't get a smooth steady cruise, car jerks trying to cruise

Post by InTheZone »

Car isn't tuned but I have a basemap from a tuned vehicle with a similar setup. I'm not sure if they changed anything for my car since it needs to be tuned, maybe it runs richer than it should when under acceleration...

Most acceleration feels fine, steady smooth throttle response.

My problem is during any steady cruise, whether at 20mph in 3rd gear or 50mph in 5th gear, I get a steady pattern of the car feeling like it hesitates then picks up, resumes, repeat.

Under acceleration my wideband gauge shows rich conditions, but under cruising conditions I go from sometimes rich to around 14.7 to lean. And when in a constant cruise it hovers on the lean side.

To keep it from being lean while giving it gas I usually accelerate, then let off, repeat.


I just calibrated my tps again yesterday as I noticed one of the screws fell out and the sensor was reading all over as it was loose. I set it to 0% closed and max open reading was around 97%, same reading even if I manually open the TB by hand. Every now and then the closed position will read .12% and fluctuate between that and 0%.

This datalog was pulled this morning on the way to work while the car was warmed up.

car setup:
-d16y8, sleeved
-crower stage 2 turbo cam
-crower springs
-crower chromoly retainers
-crower steel billet rods
-wiseco pistons
-wiseco heavy duty wrist pins
-stock cam gear, timing set to 12*
-skunk2 intake, ported to TB
-skunk2 70mm throttle body(forgot to mention I had inconsistent cruising speed ever since I installed this on my last build with crome. I never had a re-tune before I cracked the stock sleeves so I assumed it just needing tuning to smooth it out.)
-2.5" piping(I bought the 70mm TB thinking I was getting 3" I/C piping
-omni 4 bar map sensor
-id1000 injectors
-walbro 255 fuel pump
-FPR steady around 42psi
-s300 v2 w/boost by gear(mac solenoid)
-cast manifold(has longer runners than typical log manifolds)
-turbonetics bb turbo, similar to gtk-500 turbo
-full race I/C
-mishimoto radiator and oil cooler
-greddy thermostatic sandwich plate
Attachments
test.skl
basemap, running plx wideband v2 and I wired both narrowband and wideband inputs into hondata s300 v2
(37.51 KiB) Downloaded 121 times
jerky cruise.s3d
50mph cruise, jerk/hesistation/lean condition
(478.71 KiB) Downloaded 120 times
Last edited by InTheZone on Tue Jun 03, 2014 5:14 pm, edited 4 times in total.
User avatar
Hondata
Site Admin
Posts: 10434
Joined: Thu Aug 15, 2002 12:13 pm
Location: Torrance, CA
Contact:

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by Hondata »

TPS is all over the place, but it seems you've fixed that. Don't worry about the maximum being 97%.

The lambda input is going to 4.98 V. This causes the short term trim to run negative. So it is either the lambda / lambda sensor, the wiring or the closed loop settings in SManager.
Hondata
excaliburcombo
Posts: 44
Joined: Fri Mar 07, 2014 4:23 pm

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by excaliburcombo »

please post your current calibration as well.
InTheZone
Posts: 8
Joined: Sun Mar 10, 2013 1:42 pm

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by InTheZone »

Hondata wrote:TPS is all over the place, but it seems you've fixed that. Don't worry about the maximum being 97%.

The lambda input is going to 4.98 V. This causes the short term trim to run negative. So it is either the lambda / lambda sensor, the wiring or the closed loop settings in SManager.
yesterday when I was reading I was getting a huge range of random % for TPS. I fixed the bolts yesterday and every time I read the close and open % it stayed at the correct values.

The datalog is from today, this morning, after I re-calibrated.

I'll do another run tomorrow with the car slightly accelerating and post the datalog, the tps will be steady.

It is very hard for me to keep the throttle steady while cruising as the car makes me decelerate/accelerate suddenly and it's only moving a percent or two throughout the log because of that. Only under acceleration does it run smooth.

I'll edit my original post with my basemap.
excaliburcombo
Posts: 44
Joined: Fri Mar 07, 2014 4:23 pm

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by excaliburcombo »

please check as Hondata said. So it is either the lambda / lambda sensor, the wiring
Hondata wrote:TPS is all over the place, but it seems you've fixed that. Don't worry about the maximum being 97%.

The lambda input is going to 4.98 V. This causes the short term trim to run negative. So it is either the lambda / lambda sensor, the wiring or the closed loop settings in SManager.
InTheZone
Posts: 8
Joined: Sun Mar 10, 2013 1:42 pm

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by InTheZone »

excaliburcombo wrote:please check as Hondata said. So it is either the lambda / lambda sensor, the wiring
Hondata wrote:TPS is all over the place, but it seems you've fixed that. Don't worry about the maximum being 97%.

The lambda input is going to 4.98 V. This causes the short term trim to run negative. So it is either the lambda / lambda sensor, the wiring or the closed loop settings in SManager.
don't know if it changes anything, but any slight load, even the slightest incline I can get a steady afr, steady rpm, steady throttle position. But as soon as the road levels out or I'm on a decline it's impossible for me to maintain the same speed without it jerking.

Does it hurt driveability that I'm running 2.5" piping into a 3" TB?
sympak
Posts: 5
Joined: Sat May 17, 2014 10:50 pm

Re: Can't get a smooth steady cruise, car jerks trying to cr

Post by sympak »

Sounds a lot like the problem I am having. I made my car drivable by adding fuel to the bad area. It runs rich but it drives smoother. I am running in open loop though.
Post Reply