2.3l whipple 2005 mustang gt

[BrettB]

I’ve recently acquired a whipple mustang and I bought it knowing it had some tuning issues. Initially the car would run and drive fine, but as soon as you let off any throttle, the idle dips below target idle and dies. Half the time it would jump back up and idle fine, the other half it would bog out and die. Since I’ve replaced the bypass valve as it had a hole in the bladder and fixed another vacuum leak. Now as far as tuning goes, it could most definitely use to be cleaned up. Does anyone have any personal experience tuning anything similar to this that would be helpful to know beforehand? It’s got 52lb Bosch injectors, 400lph walbro sending unit/fuel pump that has been hardwired in, and Detroit rocker sc cams. On the drive home it acted like it was fouling plugs one by one until it hardly moved under its own power. Decided to do that less than a mile from my house too. But I pulled the plugs, cleaned them, threw them back in and she runs fine. I haven’t messed with the tune any, id like to get an idea of where to start before diving into it. I have noticed on cold starts the short fuel trims are everywhere, +\- 15, and at one point about 30 seconds in it will rise up to 66 for a decent period, and then back down to fluctuate. The afr also acts the same way, very fluctuant, 11-19, and one period for about 20 seconds will hang really lean, around 18. Then back to fluctuating. It bounces back and forth between 12-18. I’m too afraid to let it warm up to operating temps with those kind of readings. Is that typical? I have a couple cold starts datalogs and I was brave enough to get one brief cruising datalog. Any help would be greatly appreciated. I’m an automotive engineering tech student at Indiana state university and I’d really really like to tackle this myself, with some help of course.

 

[StockishS197]

I haven’t tuned a boosted 3v but the philosophy is more or less the same.

Has the car ever driven good? Do you have detail on who tuned it? If you dont, would recommend Lito.

If the STFTs are pegging, it sounds like the MAF Transfer Function isn’t scaled and needs to be cleaned up to get fueling right as a baseline. AFRs shouldn’t be swinging, it should be consistent near lambda, and STFTs should be +\- 5% correction.

The injector scalars could also be off in the tune which would greatly affect fueling. Tuner would likely request injector data sheet and/or the specific injector part number you have so they can get the injector flow data.

Without logs, it’s really hard to see exactly what’s going on but sounds strongly tuned related.

 

[BrettB]

I believe it’s tune related too. The guy I bought it off of did the tuning, he was a shop teacher over in Illinois. He was an intelligent guy but he said it was his first rodeo as well and was very honest. He’s helped me out quite a bit with it along the way. Like I said I drove it 3 hrs home and up until the point I fouled my plugs it was running fine besides I couldn’t come to an idle without aiding it. I’d have to catch it at idle with the pedal, pretty tricky but I got used to it in 3 hrs lol. Being a student I’m working on a fixed budget, ultimately I will take it to Lund or someone reputable if I need to but I’d like to put that money towards other things in the car and learn to tune it myself. It’s related to my major and it’s been a personal interest all my life. I’ve had many hot rods but I’ve never done any tuning myself and it’s always been something I’ve wanted to do. Right now I’m waiting on an analog cable so that I can tie my afr and boost gauges into the datalog. I’ve got some logs that I could share. I’ll get on my computer and attach them to this thread.

 

[BrettB]

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try that, no idea if that will work or not but i couldn't attach a csv file. I've been using hp tuning software.

 

[stkjock]

sounds like a dashpot issue from my limited experience.

 

[StockishS197]

I believe it’s tune related too. The guy I bought it off of did the tuning, he was a shop teacher over in Illinois. He was an intelligent guy but he said it was his first rodeo as well and was very honest. He’s helped me out quite a bit with it along the way. Like I said I drove it 3 hrs home and up until the point I fouled my plugs it was running fine besides I couldn’t come to an idle without aiding it. I’d have to catch it at idle with the pedal, pretty tricky but I got used to it in 3 hrs lol. Being a student I’m working on a fixed budget, ultimately I will take it to Lund or someone reputable if I need to but I’d like to put that money towards other things in the car and learn to tune it myself. It’s related to my major and it’s been a personal interest all my life. I’ve had many hot rods but I’ve never done any tuning myself and it’s always been something I’ve wanted to do. Right now I’m waiting on an analog cable so that I can tie my afr and boost gauges into the datalog. I’ve got some logs that I could share. I’ll get on my computer and attach them to this thread.

I would strongly suggest going with a known good 3v tuner (Lito) on a boosted 3v. On boosted cars, your margin for error is much more narrow than NA and even small fueling or timing errors can be catastrophic.

There are other options (I bought my SCT PRP tuning Software through LaSota and bought his tuning guide) where you can get an editable base tune file and they work with you are revisions so you learn as they tune, then you can fine tune everything you want.