Throttle response help needed

PVD04 · Jan 7, 2006, 12:55 PM

I've set this weekend to get my MAFTpro working on speed density and am running into some issues. So far I've been using it in AFC mode, however I found that when I would do quick shifts the car would hit what felt like fuel cut in the next gear. I didn't have a computer with me to log so I'm not sure what was happening. Now, with the car in speed density mode, when I hit the throttle the engine hesitates and then accelerates. The air fuel ratios jump to 21 and then drop to where they should be and the engine revs as it is supposed to. I have played around with TPS Enrich and Decay, but this hesitation doesn't seem to be affected. My settings are now at 0.5 enrich and ~1.5 decay, but I have had it as low as 1.00 without much help. Does anyone have any suggestions?

Thanks,

Paul

Sap12687 · Jan 9, 2006, 09:31 PM

bump for some help...interested

PVD04 · Jan 11, 2006, 06:49 AM

To update my status, I did a lot of data logging over the weekend and was able to get the car mostly drivable, however it seems to be getting worse on a daily basis. I adjusted my low load fuel settings based on the data log, however I'm not sure that it was very effective. I'm thinking it will probably be in my best interests to tune via the VE table. Does anyone have any suggestions regarding which way would be most effective?

My throttle response is still pretty bad. If I'm already on the throttle slightly and tip in, the response is great and as expected. The issue is when I'm completely off the throttle and the ECU has gone into decel mode (no fuel or spark). When I get back on the throttle I feel a moment of acceleration followed by a complete loss of power for approximately 0.5-1.5 seconds and then the car accelerates as expected. With my throttle decay set at 0.15 to get the car somewhat drivable, I'm not sure where to go next. I'm at work, so I can't post any log information right now, but if anyone that could help could tell me what situations and what parameters need to be logged to provide assistance I could get those posted tonight.

Thanks,
Paul

TurboBob · Jan 12, 2006, 09:17 AM

you should not have to do that to the throttle decay, there may be a lean spot in the fuel map you are hitting. The momentary acceleration is from the TPS or MAP response fuel, and then you have a lean spot for a moment.

If you can post or email me a log, I will dive into it.

What RPM does this occurr at?

Bob

PVD04 · Jan 12, 2006, 10:49 AM

Quote:

Originally Posted by TurboBob

you should not have to do that to the throttle decay, there may be a lean spot in the fuel map you are hitting. The momentary acceleration is from the TPS or MAP response fuel, and then you have a lean spot for a moment.

If you can post or email me a log, I will dive into it.

What RPM does this occurr at?

Bob

Bob,
It's typically worse at low RPM, but it does happen at almost all RPM. I began editing my VE table last night and it seems a little better, but not a whole lot yet. The log file I have is fairly long. I have done 3 logs, the most recent with the new VE table and I believe it has almost 14000 data points. I have attached a few samples of that log that illustrate my problems.

The problem happens at pretty much any RPM point, especially during tip-in after decel in gear. There is a ~1/2 second pause after I push the throttle. It also happens when I heel-toe during downshifts. I have to hold the throttle for ~1/2 second before there is any engine response.

In the log, you can see the response while upshifting following sample #2200, the heel-toe response following sample #2440, ~3000 RPM tip-in response following sample #3350, ~3500 RPM tip-in response following sample #4020, and a ~2300 RPM tip-in response following sample# 7130.

Thanks,
Paul

PVD04 · Jan 13, 2006, 05:26 AM

Also, here is my bin file.

-Paul

TurboBob · Jan 13, 2006, 01:37 PM

emailed a couple files to you.

Bob

PVD04 · Jan 15, 2006, 12:15 AM

Update:
Bob sent me updated firmware and software, but the problem still seems to be there. I tried switching to AFC mode and turning of the TPS and MAP enrich, but there is still a ~1 second delay before anything happens. I'm just wondering if anyone else has run their MAFTpro in AFC mode and had throttle response issues with the TPS and MAP enrichment turned off. It seems that if the MAFTpro is just passing the MAF signal straight through to the ECU it should work as though the MAFTpro were not connected. If anyone could confirm for me that the MAFTpro in AFC mode does not require and TPS or MAP enrichment I would appreciate it. Thanks,

Paul

dryad001 · Jan 15, 2006, 12:35 AM

I actually just turned down my TPS enrich and decay a little bit today, my current settings are enrich .40 and decay is at 1.40. I don't have the slightest hesitation at all.

PVD04 · Jan 15, 2006, 12:42 AM

My response is awful unless my decay is down around 0.1. I'm wondering if there is something wrong with my MAFTpro.

-Paul

dryad001 · Jan 16, 2006, 07:51 PM

Try starting over again, and go slowly when turning everything down. I had to do this 2 times to get everything right, now my car runs like stock. Also make sure your tps enrich and decay are turned off.

TurboBob · Jan 16, 2006, 09:43 PM

I'm still working with you direct, but I have been experimenting with the decays set low like your car, and it works pretty well on my car down to .25

B

TTP Engineering · Jan 20, 2006, 07:37 AM

I have an idea.... PM me Paul, we'll get it worked out.

trinydex · Jan 28, 2006, 11:17 PM

so what happened?

PVD04 · Jan 28, 2006, 11:56 PM

Quote:

Originally Posted by trinydex

so what happened?

I'm actually in contact with Bob on close to a daily basis figuring out ways to solve various drivability issues. I'm to a point now where my part throttle drivability is almost as good as stock, but I have a few WOT problems. Part of it is that I'm still tuning and don't have my VE table perfect just yet. Based upon some recent emails with Bob the rest will be resolved very shortly.

-Paul