Thread: JWT ECU makes my car run rich.....

About a hundred a hour, i say it shouldnt take more then a hour and a half.

Stratton.

That's not to bad really...

I would stop toying around with band aids and go with a Calumn RT or Nistune. Both will cost you about the same much as JWT + Safc sell for.

No replacement for proper engine management!

I have to agree with you here.

Hacking the MAF signal for tuning affects a lot more than just your fueling.

It inadvertently skews everything else that has a look up from the maf voltage.

I tuned my previous setup with stock ECU + neo afc and I must say it did great, buth when I switched to Calum RT, a whole new world opens up, there is just no comparision...

$100 for a safc II tunning sounds about right, and it shouldnt take more than an hour, its fairly simple

It's like taking headache medicine when you have a brain tumor.

I highly disagree with systems that get you results by skewing the initial readings. You will always have the ECU fighting the numbers, which could render to be limp mode.

I went with OBD1 for this reason, even though I had an OBD2 RT ecu, I still have to fight the ECU constantly correcting my AFR's to it's own likings. But even an OBDII RT ecu is worlds better then SAFC

Do you have a wideband? I had the same jwt ecu with same program and mine didn't run rich. I had a PLX wideband so at idle my engine was 13.8-14.2, but that is because my AIV isn't working so the ecu isn't seeing the extra air at idle it needs. Also during cruising it would be at 14.6-14.9 toggling back and forth just like the fsm says it is supposed to. Consider this if ur car is a B13 try regrounding the maf, or use a MAF cleaner to clean the element. My car ran lean at 1st because the maf was dirty and read less air than the engine was taking in.

After I cleaned it my AF alpha dropped to 106% vs 112% it was B4. Also if your o2 sensor is old then of course it will run rich because the ecu has to relearn the engine. Where as your stock ecu had adjusted to the engine over a much longer time period. You may also see some good results from a FPr that u can adjust.

i don't know what a wideband even is or what it does.. ugh..

you're talking sooo far over my head.. your engine was 13.8-14.2 ?? what does that mean?? lol

i will have it dyno tuned..

folks who are recommending something beyond an SAFC2 piggy back to my JWT ECU, you realize I just have S3 cams, header/exhaust right? i'm N/A....

planning to stay that way..

With proper dyno tuning on the SAFC2, do I really need anything else? I will probably get all buck wild when I have my spare RR block bored to 92mm and drop in C2 cams ... but that's a year or two off.. I just want to get rid of the rich smell my car is putting off, it's not good on dates.. the fact that I drive a 1991 Sentra is already a big enough problem.. lol

No, I have the same setup and it works perfectly. JWT ECU with SAFC II piggyback. The JWT program that I have is not too bad, but I am not using a wideband and I have had two different sensors put into the muffler of my exhaust to read back my air fuels. A true wideband needs to be placed right after the collector and before the cat (if running one). RUnning through a cat and collecting air fuels via that method can cause leaned numbers.

A wideband is an oxygen sensor that can read all variations of what the air fuel ratio is of the exhaust coming out of your engine. The oxygen sensors that are on our cars are narrowband. They only read 14.7:1 (the natural and default stoichiometric burn ratio) and reads LEAN or RICH from the target 14.7:1.

Widebands read the whole range and can give u back live feedback of what your air fuels are on the fly. No dyno needed or anything. They are very useful and can eliminate the need for dyno tuning (unless you just really want a dyno sheet and whp numbers).

The number 13.8:1-14.2:1 is his air fuel ratio.

The lower the first number, the more rich an air fuel ratio is. 10.6:1 is rich.

The high the first number, the more lean an air fuel ratio is. 17.1:1 is lean.

It seems the wide agreement that in a naturally aspirated engine, you lean it out as much as possible without raising the air fuel ratio into a range that will run too hot aka too lean and damage some things inside the engine from heat.

Someone can chime in about turbos. I have zero personal experience with that. I hear richer is the trend for air fuels on turbo cars.

A wideband is an exhuast sensor that can measure the air/fuel mixture from 10.0 to 20.0, stock sensor is a narrowband and is only accurate from 14.5-14.9. If u r going to tune ur car a wideband is manditory. Don't take this the wrong way but it seems that u might want to do some reading on Sr20 tuning. IMHO 1st thing u need is to get a wideband o2 to see what AFR your ecu is running in open and closed loop.

I know the jwt will run the correct afr but that is only if ur sensors give correct feedback. Also u need to know what kind of feedback the ecu is getting from it's sensors too. U need to know ur AF alpha and AFR to fine tune fuel trim. Clean your maf sensor, get an adjustable FPR, and a wideband.