pikey7

I'm just trying to evaluate why i've never got my car to run totally correctly. I've currently got a set of uprated chips in, along with the rest listed below, and I always seem to have a small hiccup at sometime or another in the rev range. Even though I am using a MAF, i take it that the chips still contribute something to the running of the engine, and so I thought it may be an option to use some sort of piggyback to basically dump the DME/KLR.

I've seen that so far Link (Guru etc...)and Vitesse(not sure if that's also the link system) do something similar, but what's the options here??

Any advice gratefully received! Thanks

fast951

Mike,

Vitesse PiggyBack is not a Link system.

If you are using a LR MAF, you already have a signal massager (box with 4 *****). The function of this box is to modify the MAF signal to look like a AFM signal so the DME can understand it.

A PiggyBack, Vitesse, Link or whatever works in conjunction with the DME/KLR. The only way to get rid of the DME/KLR is to go to StandAlone.

Your supplier should be able to assist you withe hickup problem. Work with them! Much easier & cheaper to fix what you have first.

pikey7

Thanks Fast,

I know it's always easier to work with Dave & Mike than go some other way.... I was I suppose wondering if it is the function of the MAF controller to effectively replace (or lie, for want of a better word) to the brains. Is that the case??

I suppose then it's time to get back down to the dyno (I don't suppose the oil that i had in No.1 helped with the mixture settings!), and redo it again. Oh well!!!

fast951

The Box you have is modifying voltage curve to be interpreted correctly by the DME.

A trip to the dyno will help. However, make sure that there is nothing else wrong. The hickup you are experiencing may or may not be related the the MAF/Chip you are using.
Things to check, and if uncertain of condition replace first: Distributor cap, rotor, plug wires, plugs, vacuum hoses & fittings, wiring connections, BOV... These are minor maintenance items that can cause hiccup problems.

If that doesn't help. Swap the chip you have woth another one. Diagnose by elimination..

Make sure you do all you can to eliminate the problem before going to the dyno. Dyno time is expensive and it should be used for tuning not replacing parts...

Good luck.

Danno

Mike, just get a revised chip that removes those hiccups from your chips. The only thing with the Lindsey digital-MAF is that it only provides voltage-in --> voltage-out massaging with no regards to load or RPM. This is similar to how the Apexi S-AFC or the HKS AFR works. It's fine for tuning full-throttle/WOT linear fuel-maps, but you also need to take into account the partial-throttle operations. You get a lot more fine-control with RPM- and load-based 3D mapping like EFI systems. This provides much more precise tuning and can make opposing adjustments to the same voltage.

Good example is a car we tuned with big ported & polished heads, aftermarket cam and big turbo. This had some extra reversion and lag in the 3-4k range compared to stock. The air-flow in this zone was less than stock and ended up being too rich with stumbling. The voltage here was around 2.0v and it was at 25-30% throttle. Massaging that back by 15% around that area reduced the richness and eliminated the lag and stumbling.

On the same car, there was a lean spot from 2-3k under full-throttle. This also caused some extra turbo-lag as well. The voltage here was also 2.0v but at 100% throttle. So with the 3D mapping, we were able to increase the voltage about 10% to richen up the mixture and clean up the air-fuel curve. So being able to massage the same voltage in opposite directions based upon load really makes for more precise tuning. You can check out the same 3D map under the "Digital-MAF Upgrade" section on our website to see what I mean by opposing adjustments.

crazyracer

Which chips are you running? Stock? I have a set of HR chips and they should work very well together with the LR MAF.

pikey7

Hi Danno, I'm actually running the digital MAF from Lindsey. I thought I was relatively close to the optimal tune (I've been down to a dyno here, but with a guy who didn't really know what he was looking at on my car!), but it seems that I do have some holes somewhere. On my other thread, I think I point out a bad O2 sensor, but I'm not convinced that it is bad, or just a symptom of something else not right!. I'm off to the UK in a couple of weeks, where I'm going to a dyno with a guy who has a few years (try 40) of tuning high output cars, so hopefully I'll get a lot better, but I was trying to understand what part the chips play in all of this if the MAF is telling it lies anyway!??

Anyhow, I'm gonna disconnect the O2 sensor at lunchtime, and see how she runs (It should have a higher idle right??), to get rid of that problem, and then also try to see if I'm getting any DME error codes. We'll see.......

Danno

"I'm actually running the digital MAF from Lindsey. "

Hmmm, I've actually dyno-tuned two of those systems this past week. One had a set of AutoThority chips and one some custom HR chips. Not sure which one you have. I like the way AutoThority does it on their MAF kits, just a sensor and a matching set of calibrated chips. No interceptors necessary. They've done the laborious task of dyno-tuning to map each and every single fuel-cell on those chips. Next comes ignition testing for each and every map cell...

"but I was trying to understand what part the chips play in all of this if the MAF is telling it lies anyway!??"

Because there's only so much you can do with signal-massaging. One big factor is knowing exactly where and how much to skew the signal:
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As you can see with these chip-maps, increasing the voltage tends to move the air-flow path into a richer range of the maps (red line skewed to purple path). However, in the middle chip-map, you'll see that it will increase fuel in the idle and top-end, but will actually decrease fuel in the mid-range. A lot of corrections are typically needed and sometimes, you need to make up AND down adjustments several times on that air-flow path through the chips (often times within just a couple hundred-RPMs of each other). With only three tiny ***** to adjust, you just don't have the resolution (4th **** on Lindsey digi-MAF is beyond range of sensor anyway).

One thing you can do is identify the specific operating conditions when you get the stumbling so you'll what specific zones you need to modify. For example, 2575rpm and 25% throttle or 3750rpm and 20% throttle. Easy way to do this is hook up a digital voltmeter to the air-flow signal wire (#7 DME). Then note the voltage at which this occurs and the RPM. This data will then pinpoint the exact fuel-cell on the chips maps. With O2-sensor feedback from the dyno, you can them modify your chip maps to be more optimal.

The ideal scenario is to map out your entire 3D fuel-map such that you have the MAF-Tuner set to zero adjustments (no massaging at all). This can be done through datalogging and recording stripes based upon boost-pressure. Using an electronic boost-controller, set it for say... 0psi. Then run from 1000-&gt;redline with that boost-setting. Record resulting air-fuel ratios. Then do it again at 3psi, 6ps, 9psi, etc. Then you can match your data-runs with the specific rows on your chip-maps and figure out which one to modify.

EDIT: Fixed picture links.

pikey7

Holy 3d-maps batman! What sort of kettle of fish have i've opened up here! Looks like i'm gonna need to have a nice long read up on this today (I'm a bit bored at work anyway, so....! )

I'm actually running the Kokeln chips (Don't know if you've had much experience with these?), but I couldn't get the guy here to understand I needed the A/F maps also to see where things were going (He basically shut me out to play himself!). I'll try that little trick on the DME#7 pin, and see what that brings me (Maybe I'll see a lot of trends, and be able to get my head around this a little easier.

According to the LR manual, and advice I've recieved from Dave, The MAF box has a set of led's under the respective dials, and if there is a 'problem' with the respective performance, then it indicates the **** to play with. Is this stumbling a general sign of too little, or too much voltage?

Danno, you've proved to be a star man yet again. Thanks for all of this!

Looks like i'll be taking a friend out in the car this weekend to help take readings down! Do you know if there is some basic datalogging software available that I can make a small harness up to plug into the DME to take some of these voltages/info down with? Building a little serial harness shouldn't be too much hassle, it's just reading it all!!??

I suppose it also loks like I'll be talking to the WBO2 boys today to find one of their nice version2 setups.......

fast951

Why are you guys complicating things so much?

Assuming all you ignition/fuel systems are operating correctly.

Identify the RPM at which you experience the problem. Also note the light on your controller.

Now determine if it's rich or lean mixture that is the cause (assuming the mixture is the cause).
To make the determination, adjust the appropriate **** on you controller to run richer or leaner.
If your problem is gone, you figured it. However you just moved it up/down the RPM.
Each **** on the controller handles a voltage range. This will indicate the load range, and you have your RPM. Now you can tell the general area of the MAP.

And I must add this LOL. If you want to Data Log your AF/ratio, Load or MAF signal, plus many other parameters, and be able to adjust based on Load/RPM look at the Vitesse PiggyBack. LOL

pikey7

Hi again Fast.

I have this pretty bad habit of attempting to understand everything I do! As such it would be nice to understand what Danno's on about! (Plus, like I say, I'm bored at work today!)

Like you say though, At the end of the day, it doesnt matter what your 3D mapping blah blah blah looks like, as long as during the operation of the car over it's rev range, the A/F ratio is where it should be!

fast951

Mike,

It's great that you want to understand the details, this what makes it a hobby.

I was not very serious in my post (LOL)..

pikey7

I've known less stressful, cheaper hobbies..... Whateven happened to stamp collecting anyway??

crazyracer

With the lindsey digital MAF you cannot only adjust the voltage with the 4 ***** but also with your PC. You have to do it offline but then it gives you 20 or so adjusting points. Dave Lindsey has posted I think 4 or 5 different MAF batches in his libriary (pick one of those and start tuning from there) on their web page and also a detailed procedure on their web page as well. It is possible to get an almost prefect A/F ration at WOT doing this procedure. But as Danno and John pointed out, half throttle is a problem as with all other MAF kits but their's. Of course as wih all tuning procedures you need the correct measuring advise for the A/F ratio otherwise you don't know if you have to adjust up or down. What are you using for that?

pikey7

Hi Crazy,

I'm just judging it for now on the standard crappy AFM (I know!), but I have 'apparently' had it set OK at the dyno before. If i'm getting a stumbling, then it usually means something is out a bit though, and since I replaced the head over the weekend thanks to oil getting in from a worn valve guide, I suspect that the mixtures are now slightly out again. The point of the original question I suppose was to find out the purpose of the chip, and with all this talk of 'custom' chips, and me being 10 days return post away from the nearest re-programmer, I was considering a 'chip-bypass' so to say.

Now I know it's relatively clear to sort the MAF settings - IN THEORY - then I'll get as close to optimimum as possible first, and if I still have a hole somewhere, then consider either a bypass, or a custom chip.

I am aware of Dave's library, and I have used it to get to a good basic tune, but as you know, all cars are different, and need a bit of tuning anyway. I'm quite close to mine, and so that can be adjusted from the box in the car, and then downloaded/saved etc....

Anyways, I'm back to the UK in two weeks, and I'll be checking out a friend of my Fathers who's been tuning cars since before I was a glint in the old man's eye! . Hopefully that'll be that then, but depending on that mid-throttle hole.......