I tried searching about this but no one seems to have posted or I missed it. After turning some poor times at the track after my exhaust mods I used Craig Moates ECM software while punching it down the street. After I did this I noticed the computer pulling some timing out at higher RPMs. Is this normal? I've heard that sometimes downshifting will trigger it but nothing on upshifting. I checked my timing and it was at 6* as per factory spec. Do I need to see about getting an AFPR? Thanks for any help at all. I've attached a graph of some of the data. If you need to see any other info off the "run" let me know and I can post it.

Thanks in advance,
David


PS. In the chart--Advance is listed as "Spark Advance w/r/t TDC degrees" in the program. Total advance is Advance minus retard. ( I heard that retard wasn't factored into the "Spark Advance w/r/t TDC degrees". Feel free to correct me if I'm wrong.)

 

well it's normal for your car to pull timing at WOT, that's what your knock sensor is for. It pulls timing so that you don't get preigniton, at WOT. You can do alittle mod/trick that can help you get alittle better time, you can bump up your timing up to like 10degrees but you need to run a higher oct like 93. That way when you computer pulls timing, you still get alittle more juice than normal. Now about it pulling timing down shifting, I m not to sure about.

 

well actually it's your EST your knock sensor works with it, it listens and EST pulls timing, I think that's how it works if I remember correctly.

 

Thanks for the reply. I wasn't sure if it would pull the timing or not I figured that the spark curve programed into the chip would account for it. I forgot to mention that I run 93 octane all the time. Any other ideas or will this be something that prom tuning is used to take care of?

Thanks,
David

 

also what were your times and from the looks of your sign it looks like you just have free flowing exhaust, anything else done to, Like TPS bumped up, airbox gutted, TB coolet bypass. Any thing like that?

 

Let me list all the stuff. TB bypass. Gutted airbox with Ram Air. K&N filters. Headers, Cat and Catback. I also go Accel wires if that matters (other ones would have cooked on the headers). Other than that I have the typical tune up items that are releltivly new.

For what it's worth my stock time was run in March and my modded times were run last Thursday night. I know the weather would play a factor in the difference but I didn't think it would kill me. Also I couldn't get much traction but then again neither could anyone else.

But, my "modded" times were 15.03@94.82 14.828@93.71 15.389@93.60 15.146@94.15 15.124@93.58.

When I ran stock I ran 14.987@94.32 14.852@94.08 14.745@94.67.

Also on the best runs stock and modded I ran a 2.193 60' time. But generally I ran a 2.3 60' time.

You can kinda see why I'm worried cause times and speed went down. I checked over the car and all the connectors, plugs and other stuff was tight. So I'm not thinking it's a loose wire.

Thanks for the help.
David

 

Yeah your mph is way down in the quarter, there's some up with that. With your 91 motor with the freeflowing exhaust you should be near low 14's high 13's around 96-98mph. You didn't put a stall conv. in there did you? The reason I m asking I had a 3000 in my stock motor, and it killed my time by a sec. 3000 was way to much for the stock motor. You should have seen some gains in someway. Did you let your car cool down, or have alot of tools in your car? If not, just start over from when you start added you mods. It's the only thing you can do.

 

Hey. Nope I have the stock converter in there. Though the Trans was rebuilt when the car was previously owned. I've got the bill from it and it just says Rebuild. So that's not it.

I didn't have any tools or stuff like that. In fact I took the spare tire and jack out to try to reduce weight. I tried to let the car cool down but waiting in line to run would bring the temp back up. But it never got past the 220 mark.

Any one else out there got any ideas? I know I'm not the best driver but.....

Thanks,
David

 

well one last thing have you pulled out your Spark plugs since you put the headers in, Yank them out and check them , I've heard of people having loss of power cause there plugs closed. Just a thought, I could be way off but you might want to see. Thats all that I could think of.

 

Yeah I was thinking about that as well. I just dread getting to the 6 and 8 plugs. But, I'll check it out tomorrow. I appreciate all the help you've given me!!

Thanks,
David

 

No prob, I just hope that you figure it out. Trust me, I've been there done that, it really bites when you do mods and nothing to show for it. I've had two really small big probs you know what I mean. I m talking about too the point where I was about give up, and then it was something simple. I know pulling the plugs is a pain, especially with headers. Keep ticking away at, you get it eventually.

 

Well I checked the plugs and they were ok. I also ohmed the Knock sensor and made sure it was getting 5V. I'm gonna run some injector cleaner through it and see if that helps things.

David