Tuning: 3500, 5-speed, 1227730, nAst1, Fiero GT

[robertisaar]

any update? i'm still quite confused as to how you can make changes to IAC stuff and see an immediate effect, but fueling does not?

have you tried changing up the desired idle speed in the coolant temp range you're in just to be completely reassured it's working? that would also immediately show in the datastream.

[LZeppelin513]

No update yet. Currently in Puerto Jimenez, Costa Rica. Tomorrow me and my gf set off for a 3 day hike into Corcovado National Park! Acording to National Geographic, the most biologically intense place on Earth. Be back home working on the car in a few weeks. Thanks for the help.

Blake

[LZeppelin513]

I want to make sure I am not doing something completely stupid so here are a couple pictures of how I have the emulator connected. Is this all correct? Thanks.

[LZeppelin513]

I also would like to check to make sure my crank trigger is set up properly. I believe I have it set at 0 and that is where I want it, correct?

[LZeppelin513]

I received an A1 bin that is supposed to run a 3500 MGB fine but not perfect. I uploaded it to the emulator and it runs about the same. It starts and I can keep it running but it is basically un-driveable. I am beginning to think that something else besides the tune is wrong. I am getting knock and lots of exhaust backfire when I rev it in neutral. I double checked the spark plug wire routing just to make sure. Any other ideas?

[LZeppelin513]

Well it seems like it is actually running a bit better with the A1 bin. A while ago I read that it was possible to datalog the wideband output through A1. Does anyone know how to do this? I think I am going to stick with the A1 for a bit just to get the car on the road.

[pocket-rocket]

Message robertisaar on here, he's got an A1 hack he calls nAst1. If he doesn't have wideband input set up on it yet (I'm not sure if he does, but he will if he doesn't) he's the man to talk to about modified code masks, including customizing one for wideband input, and he is very familiar with A1.

Edit: Duurrrr! I just noticed this thread has nAst1 in the title. That's what I get for clicking the "most recent post" icon without reading a title and posting. So you know who Robert is and you know about nAst1, lol. At least the wideband info was new

[CNCguy]

I use F14 as the wideband input on the 7730 ECM. It was used for the A/C pressure switch. Send me an email and, tomorrow, I will send you the definition file that passes the data through. I have a definition file for an Innovate LC1 which has a linear output and also one for the Zeitronix that isn't linear.

[LZeppelin513]

Ok so I got a couple issues fixed that were making tuning impossible. Now the car is running MUCH much better and I am back to using nast1 code.

For the first time it seems like everything regarding tuning is working correctly.

It is running rich right now. It idles at 13.88 AFR but wants ~15. BUT it seems to be running good. When I lower f28 by about 30 it hovers around the commanded AFR. However, at this new F28 value it has a problem. I rev it a bit, let off and as it drops RPMs it gets much too lean and sometimes dies before coming back to commanded AFR.

Any suggestions?
-Thanks

[LZeppelin513]

I found a scalar called "deceleration enleanment" and tried lowering it way down to 7 and that fixed the leaning out problem.

I have a general tuning question (I am tuning in open loop only):
I adjusted the base pulse constant so that wideband matches the commanded AFR while the engine is warm. Now when I start it cold, it is too lean because the commanded AFR is lower from the cold start.

What do I mess with to fix this?

- Thanks

[LZeppelin513]

So like I said above, I am still not seeing the variable that I need to change for cold starting compensation. If anyone could point me in the right direction I would appreciate it.

[LZeppelin513]

The new narrowband I had bought and installed was faulty so I have been tuning only in open loop. I got a new narrowband yesterday and discovered that my wideband is reading at least a full point or two lean. I checked for exhaust leaks and found a small one around the flange so I adjusted it and fixed it but it did not affect the O2 readings. They are both on the same side but I am not sure what to trust. What is most likely the problem here?

The car was running extremely rich at first due to a wiring problem. Could this foul the wideband sensor and cause it to read way lean?

[LZeppelin513]

Turns out the wideband sensor was fouled. It didn't look too bad but I decided to bite the bullet and buy a new sensor anyway. I replaced the wideband O2 sensor and I think it is now reading correctly.

Roberts 3500 VE table for Nast1 is close so it runs decent.

I have spent a few days now getting my part throttle VE tables closer but I am having a weird idle problem. In open loop it idles nearly perfect. It does not idle correctly after it switches to closed loop AND warms up past around 180* (in closed loop below ~180* it seems to idle fine.)

How it acts when not idling properly: It idles perfect for a bit and then leans WAY out until it either stalls or hunts and recovers... then idles perfect for a bit more until again leaning way out.... repeats this. It sometimes (much more rare) does this when I am coasting as well.

I have tried searching through the parameters but am not sure which one is the culprit.

I will pick up my camera this week to get a vid and a couple pics of the engine bay now that it is starting to look and act like a normal car.

[LZeppelin513]

I fixed the idle problem. It was going into single fire mode each time it would go lean and stall so I slid KAPLL over to zero and now it does not ever enter single fire mode and the idle is perfect.

[LZeppelin513]

Time for an update:

A couple months ago the fuel pump went out on me and have been borrowing my dad's car since. I finally got a chance to do some work on mine. I put in a TRE fuel pump and then discovered that the larger current draw was causing a large voltage drop on the stock wires. So I upgraded the wire system for the fuel pump. Also, the exhaust work done from a shop was pretty bad. It was leaking at the flange and very uneven at the tips. I welded on some 3500 manifold flanges from British Car Conversions and made gaskets from some exhaust gasket material i got off summit. I also ended up redoing the whole system to make it fit and am very happy with how it came out. No more leak, I really like the flanges made by bcc. I kept busting the rubber mounts I had made so while I was at it I also re did the motor mounts. I used 2 poly bushings from here:http://www.ballisticfabrication.com/...ve_p_1453.html. Made a mount on each side of the motor and bought some poly transmission mounts from Rodney Dickman. The engine is not going anywhere anymore, its great. The engine vibration is more noticeable now but it doesn't bother me.

Thanks to Roberts Wideband patch I am tuning with a wideband and no leaky exhaust. So far everything is going very well. I don't have my camera with me so sorry for no pics yet. Will get some and a vid of the exhaust soon.

1) After the car has been ran for a while, warmed up, shut off, and let partially cool back down (like if I go get some groceries), it has a hard time starting again. According to the wideband it is lean at start up (is the wideband even accurate during start?). What table controls start up fuel relative to coolant temp?

2) Also, it runs much leaner than "target AFR" at idle when cold, what table will adjust that?

Thanks