Stock injectors, stock fuel pressure, modified bin taken a bunch of fuel out below 2000 rpm from 10 to 50 map. Its running so rich I can see gas dripping out of the tail pipe, no ****.

This didnt happen until I put my 454 tbi on and then ran around with 80 pph injectors which were super duper rich. I only ran them for a night though, about 90 minutes of partial throttle tuning. It was so rich it fouled out the plugs and the car would not run the next morning. So I put the stock injectors on the 454 tbi with new plugs and I have my current gas-out-the-tailpipe problem.

Im gonna hook winaldl up to it tomorrow, are there any sensors I should be aware of that might be out of whack and causing the problem? As far as I can tell its not missing - it'll rev up to 2800 rpm fine but I have a huge cloud of black smoke at that point.

As always, thank you for any help.

*edit*
Changed the O2 sensor, too, when I replaced the plugs.

 

Sure its not just water? If it really is gas then you really shouldnt even start the motor. The gas will wash down the cylinders and ruin the rings. Try using your stock bin and see if the problem still persists.

How long have you had the walbro? It could be a pressure build up upstream of the fuel pressure regulator. It really cant handle alot of fuel flow and the effective fuel pressure will rise if you have a HV fuel pump.

 

The walbro has been in over a year, I'd say it has 5,000 miles on it and it did not give me a problem previous to this. Tomorrow I'll try the stock bin and acutally I stole Shifty's stock chip too to make sure that its not my programmer.

My fuel pressure gague took a dump right when I needed it, so that's no longer any help. I'll probably order a new one from summit this week and see if my pressure is all out of whack.

Can running rich damage the rings and cause bad/incomplete explosion in the cylinder or anything? This is all new to me so if it's a dumb question I apologize to any guru that read that...

Thanks for your help, man.

 

If there is alot of gas going into the cylinders, like alot more then can eb burned, itll settle out and wet the cylinder walls. Since gas and oil mix quite well the gas will wash away the thin film of oil on the cylinder walls. W/o it, there wont be anything to properly lube the rings and theyll wear at an accelerated rate and you dont want that.

Have you checked the return passages in the inj. pod? If there is a restriction that cuts the flow of gas returning to the tank then alot of pressure can build up. It would certainly explain the rich condition. If the chip doesnt fix it and the pressure remains high then its worth checking.

 

Maybe your 454 TB is a 94-95 unit which came with a 30 psi regulator.

 

Brent, awesome call man. I got one of those (94-95 units) and it has a pretty tough spring in it. Chuck, try swapping your stock pod/FPR back on to the 454 unit.

 

Tried that last weekend with no luck Using stock pod right now on top of 454 tbi (stock inj, spring, reg, etc...)

 

there are several sensors that plaly into the fueling.

MAP, Temp, TPS, RPM. The logs will give you the most usefull information, post up what you get.

 

Chuck,

Did you have any luck with my PROM and unit? What about any of those regulator springs I gave you. There should have been 2 or 3 different ones in there.

 

OK, I only took a short log because I didnt want the car to be running

http://homepages.udayton.edu/~kulcha...183043_LOG.txt

It threw a MAP high error, and at idle (-2.2 tps) I wouldnt think it should be high 30s low 40s...

Anyone see anything blatently obvious?

 

The tps is around .44 volts. Could be a tad higher but I dont think its much of a problem. Shouldnt effect the computer any. The MAP looks to be functional, but the high map could have been caused by excess fuel, which will only cause more fuel to be added on top of that. One of the MAJOR shortcomings of SD. It can make problems worse when there is something that causes the MAP to get screwy. Other then that I dont see anything out of the ordinary from the log itself.

 

Chuck,

Did you ever resolve this issue?

 

No he hasn't. He has been to lazy to really dig into it. I think he is done with the car for the season and will be putting it away early this year before he gets the 454 unit really dialed in. We were still suspecting a possble clogged return line but that is not the case. His MAP readings are ok as well. We are stumped and I know he is sick of dealing with it. I am sure he will chime in.

 

get a wide band, I wish i would have known before but if you have a life you really have no business trying to tune an efi engine without a wideband.

Makes things a bajillion times easier, you dont even know. Ill have my car tuned in which is a bit more radical than yours by the end of this weekend (and i just installed huge injectors) because of the wideband. Its so helpful that i can honesly make that a guarantee (short of any X factors that pop up)

 

He has been using a wide band for quite some time now. Things were going great with the wide band tuning wise and then stuff took a dump without any changes made. Tuning is not his issue right now.

 

sounds like the map sensor is disconnected or has a leak on the vacuum hose

 

I got mon, tues off so Im gonna go to the yard and grab a MAP sensor, hoses, stuff. MAP readings are high, in that log you're looking at 30-40 at idle, sick. Im afraid of fouling out my wb o2 as it sits right now, so I dont want to hook it up quite yet.

 

Maybe you fouled out the narrow band O2 sensor?

Plus, if those NB's get way too much fuel in the exhaust it can give a false lean condition (from the cooling off?) and cause the ECM to dump in even more fuel from what a Holley tech told me a couple of years ago when I was messing with a Commander 950 setup on a GMPP 454HO setup I had then....

 

O2 sensor is brand new...

 

30-40 kPa at idle isnt too unreasonable. It looks like the map is still working. It wont hurt to get another one but it may not be your problem.