DSM Link v3 lean issue.

[4cefed4g63]

The car is a 95 GSX. We put the cat on CBRD's dyno to brush up the tune. The problem we are having is at about 2800 and 4200 rpm the afr dives off the charts lean. It does this in every possible condition. (free rev., 5% throttle, 100% throttle, any gear, ect.) We replaced every ignition based component. On the dyno we add an extreme amount of fuel in these cells with no results. Parts replaced are transistor box, coil packs, plugs, wires, and cas. Tom at ecm does not feel it's the ecu or link. I'm out of ideas. Any thoughts? Thanks.

 

[96accordsir]

exhaust leak?

 

[4cefed4g63]

No exhaust leak. Just an update. We replaced the ECM, and injector driver. No change. I know it's something small but I'm out of ideas.

 

[ram rt]

Dont know if the cars on speed density, if not check the maf. Otherwise I'd check fuel pressure make sure it's where it should be. Sounds tricky...do you have any spare injectors or friends that would let you try theirs to see if that's what's causing issues? Goodluck

Matt

 

[Boost Demon]

What fuel, fuel pump, and injectors are being used? Was the fuel pressure set to 43 psi w/ the vacuum line off the regulator?

 

[4cefed4g63]

Fuel pump is a 255. Injectors are FIC 1150's. Fuel pressure is confirmed and rises with manifold pressure. The car is speed density with an AEM 3.5 bar map and GM AIT sensor.

 

[ram rt]

Well subscribed for the answer cause I'm pretty baffled. Anyway to test injectors? All sensors are reading normal?

 

[4cefed4g63]

Looking at the logs everything looked in line. I guess I'm going to put the stock injectors, eprom, and mass air back in the car. If nothing else it will eliminate the dsm link from the mix. If it still does it it has to be the car. As far as the injectors, they were recently tested and flowed. I can't see that they are the problem.

 

[snowborder714]

Shannon, I spoke with Craig (calan) the other day and he said it sounds similar to an issue he experienced a while back. He went through 3 sets of injectors to finally find a set that worked properly (ended up being my set of 1150's). I'm hoping it's not the injectors as they were serviced by FIC before they were installed, but hopefully by installing the 450's back in, we can eliminate that as well.

Craig's thread - http://www.dsmtuners.com/forums/tuning-engine-management/409538-ve-dip.html

 

[clipto]

And the famous thread too. http://www.dsmtuners.com/forums/ecmlink-tuning-log-file-advice/443297-please-read-before-you-ask-ecmlink-dsmlink-log-advice.html

 

[4cefed4g63]

So this is where we are. Swapped out the 1150's with 510's, put the stock eprom back in the ecm (used the same ecm just replaced the chip), and wired the stock mass air back in. The car ran perfect! That means injectors or dsm link. Any thoughts? I'm leaning towards injectors due to the post, but not sure how to confirm.

 

[snowborder714]

I'd lean towards injectors (not just because I tuned the car . We can put everything back but temporarily swap in my 1150's and see how they react. This will at least test the injectors using the tune that's already there. If it still runs weird, it's the tune. We can then set it back to factory in every aspect and slowly add changes back in one at a time to figure out where the issue is located.

If that doesn't work and it's still weird, we can swap in my link chip and retune it. I highly doubt this would be the issue though.

If it's the injectors, I'd suggest sending them back to FIC for inspection, testing, cleaning, etc. to figure out what's going on with them. It'd be odd considering they've already looked at them, but not unheard of.