MegaSquirt running rich

[david-b]

Been retuning the car since the latest rebuild and it's going ok, minus that fact that at idle, it's running stupid rich. With the first start, and anytime the ASE is running, afrs @ idle are ~13-15afr, not perfect, but ok for now.

As soon as the warmup enrichment ends, afrs go rich to 10-11 and the rpms raise. Then when driving, the afrs are decent for some of the map (again, still working on it), but between shifts and when rolling up to a light, it goes to 10 and richer. Actually gets so bad, it'll start smoking out the exhaust.

It seems like I have the ve table really low at idle, numbers being in the 20s and even tried lower. When I hit the gas, it generally bogs due to being too rich.

Running 750s, Walbro 255, 1:1 SFMU. Calculated fuel is at 4.4. Had it running fine before, then had to retune and now not working out to well. Lost original map.

Any ideas or is there something I'm missing?

 

[96TurboGS]

It's good to know someone else is running a SFMU 1:1.

Every time you shift, the map will go to a high point (bottom of the map), and if your VE cells are rich it will cause all kinds of weirdness. Try leaning up the bottom of the fuel map and idle. Your ASE sounds about right (AFR wise), but if you lean your idle you will have to re-tune your ASE. Your numbers should be fine as long as you don't go below 0 or over 255. (8 bits) I think the bottom of my map is in the early teens i believe.

 

[DSMnoobsause]

i agree/ lean out your lower portion of the map from 0 to 30-40 kpa and even up to 50-60 kpa at 5k and up. when on decell and no load you can have AFR of 15+ but make sure you dont subtracted fuel from anywhere you would see a load at 35% throttle or more. please if someone that tunes for a living sees this correct me if im wrong. its just worked for me good luck

 

[david-b]

All good info.

I've been working on it a lot lately. Turned on EGO correction and that seems to be helping out some. Today it was super lean across the board at idle and startup but no biggy. It's just being very picky about everything and I'm not likin it one bit.

Part 2 to the question, (or maybe an entirely different problem)... the car starts smoking after it warms up, badly. I thought it had to do with a 10 and below idle afr for a while, but it's still doing it. Can't drive it far without it pretty much going up in smoke. Any ideas off hand?

 

[96TurboGS]

I thought it had to do with a 10 and below idle afr for a while, but it's still doing it. Can't drive it far without it pretty much going up in smoke.

Is it in the 10's when you see the smoke?

Is this the same tune you had going into the rebuild?

What does the smoke smell/look like, are you sure it isn't coolant or possibly oil seeping in through the head gasket/seals or anywhere around the engine from your rebuild? If it smells like straight gas then it could be a timing issue, if cams wasn't added and the tune is the same. I remember someone doing a rebuild and had a rich problem, it turned out to be a timing problem.

 

[david-b]

Is it in the 10’s when you see the smoke?

Is this the same tune you had going into the rebuild?

What does the smoke smell/look like, are you sure it isn’t coolant or possibly oil seeping in through the head gasket/seals or anywhere around the engine from your rebuild? If it smells like straight gas then it could be a timing issue, if cams wasn't added and the tune is the same. I remember someone doing a rebuild and had a rich problem, it turned out to be a timing problem.

Before it was in the 10s when smoking, which is why I assumed it was related. Since the tune is still very poor and running rich more often that not, it still does smoke. Seems like it does it no matter what once it gets up to normal operating temp. Yesterday took for a quick trip to the store, and it had just started smoking pulling into the lot.

The smoke seems like straight exhaust. To me, it doesn't smell like oil at all, but going to have a buddy do a 2nd opinion hopefully today. Oil level doesn't seem to have changed at all.

I'm sure the timing is dead on. Can do it with my eyes close these days. I'm 100% sure. As far as the rebuild, I built the block and once done and running for a while, it wouldn't idle. So I tore it down, and I had the rings in the wrong spots on a couple pistons. Reringed, honed, and put back together. Next, the alt belt came off and ran through the timing belt and skipped, hitting 4 valves at idle. Replaced all intakes, and now back together and these problems.

 

[silvreclips]

Dave you might want to do a compression test just to see what kind of numbers your getting. I remember last rebuild you had it off a tooth or so. Wouldn't hurt to rule that out either.