347 Tech Advice - Rich - Low Power - Surge

[AnthonyR23]

Hey guys, so my project is on hold until I have enough to get a few more parts, new 75mm tb, n/a power pipe with velocity pmas meter.

So I have my other parts listed on ebay and am just waiting till I can get some replacement parts, what I was experiencing was a surge, which I think could be related to my camshaft. I read that some people experienced problems at a certain rpm range with surging with a aftermarket cam. Have any of you experienced a problem with surging with too low of an idle, eg. between 800 and 1000. I have a powermax 2030 cam in my 347, with tfs street heads and intake. I think that running rich could be because I was running too small of a tb, cold air intake with small mass air meter, and with my moates was trying to scale back the mass air flow to lean it out because it was running to rich, but I don't think it liked that and I just seemed to loose power big time. The car seemed to almost buck, with sudden huge losses off power including stalling. I set everything back to stock settings with the quarterhorse, but at times was running close to 13.5 to 1. But before giving up and pulling off the tb, cold air, and mass air meter, was running from 8 to 1 up to 10 to 1, with black footprints behind each muffler.

Any one experience similar problems after serious mods, like 347, trick flow upper kit, with aftermarket cam. Timing was dead on 10 degrees, and fuel pressure was right on 39 without vacuum. Only way I was able to get it to 13.5 to 1 was to adjust the maf curve. But I think I was just forcing it to lean out. I think this engine just needs some air and is choking.

Seriously any input would be great! Thanks guys!

 

[86turbo]

you using moates?? good stuff man. What codes is the computer throwing? I'd personally take the moates off there until you get the car running somewhat normal. I don't know how experience you are at using quarterhorse but I have read how you can really f things up if you don't know what you're doing....

Have you read over the infamous surging idle checklist???

Lets see those codes!

Drew

 

[AnthonyR23]

I can't check codes at the moment just because I have the TB and stuff off waiting for the replacement parts. But I did have a few error codes but was pretty sure I cleared them up. I think the issues I was having were due to having to tune the mass to hit my desired a/f ratio, I have a innovate kit too.. so I think the problem was with the maf, tb, and intake pipe. All I tried to do to get it running right the last time was change basic things and while saving tunes in between changes so I could always go back to what worked. It did seem pretty good a few times, but started seeming like it was chocking or something and smelt really rich. After I get these parts what I will do is just set it back to the basic A9L tune. Then get it running as smooth as possible before making changes. But just wondering if anyone else has had similar issues after a new rebuild, h/c/i swap, on a 347. It's kinda frustrating cause it is pretty pricey but I'm getting there!

 

[AnthonyR23]

Oh, I do have a datalog of a few of my last runs. Where it coughed and died, would restart and run like **** to get it back done the street to my house, that's when I gave up and pulled the tb, cold air kit, and maf meter. Not starting it till I get the replacement parts on there.