general question (confused)

[briandu]

i have only been to the track a few times and know this is kind of hard to answer. i am just looking for the common problems or directions to go in. my car is 87 gn the first time i went it had these components hooker exhaust 2"down pipe, no cat.,hyperteck chip,kn air,high flowfuel pump,adj.press. reg.,100 octane fuel, turbo boost at 19 psi. ran a 13.5 smoking the tires i had so much power. now i have all the same but i got the red armstrong 94 octane chip, harder shifting tranny and i slightly higher than stock injector cant remember the specs on that but from what i was told when i ordered from red armstrongs i should be hitting 12.9s approx. but i have a hard time even getting low 14s everything iknow how to check seems fine fuel press. turbo is reading 19psi on aftermarket gauge and still has fairly good power. not sure where to look and dont have anybody around me to ask (gn persons) your help would be appreciated.

[ES1]

1) Do you have a knock guage?
2) Scan tool? Readings?
3) Give your MPH and 60 ft times
Ever car is different but I got lots of knock when I ran a RA chip.

[PaCemkr86]

what tires are you using at the track ?

[briandu]

i do not have a knock gauge but i do have a scan tool and my tires are just cheap tires stock size but dont spin at all or barely (unfortunetly)

[kenmosher]

Some good basic stuff here:

http://www.gnttype.org/resources.html

http://www.gnttype.org/techarea/sunday.html

[ES1]

Sounds like the car might be running real rich.
Post what your O2 readings are @ WOT.

[briandu]

checked knock on the scanner its holding at 0 degrees and the knock sensor area is not moving a friend was thinking maybe i should move the cam sensor any thoughts on that (O2 sensor reading at wot is 950 mvolts and o2 cross counts is at 175 at wot) just wondering how to test the tps sensor does the engine have to be on or just the key on should the voltage jump instantly or should it lag a little behind 0.45 at idle and 4.21 at wot

[kenmosher]

Cam sensor doesn't affect anything ... it just signals that the sequential firing order is starting. If it runs, then it is pretty close.

Timing and injector pulse is timed off the next crank pulse after the cam sensor pulse. I've got O scope traces around somewhere that show it ...

Anyway, do you have a time slip to show us? That'd give a pretty good indication of where/when the car is making or losing power.

[ES1]

What scantool is this?
Must be one that reads different from mine as the O2s on mine at WOT should be 790-810 range, so if yours reads +100 greater than mine, you will still be too rich. Running rich will be a major player in no power.
If I remember, the TPS does react a little slow.

[Keller]

Most scan tools only read every 1.x seconds. Still, 900+ mV O2 is mega-rich. WAY too much fuel. You may have:

- the wrong chip for your injectors
- one injector stuck open
- too much fuel pressure
- a blocked retun line
- bad MAF readings
- bad O2 readings
- a scan tool that just reads differently, so see what it says for O2 when the car is cold and has been off for several hours

or some other problem. Your TPS is not quite right either. See http://www.gnttype.org/techarea/maintenance/TPS.html But don't do this untill you figure out what is making it so fat to begin with.

[briandu]

i cant remember where i put my time slip (probably garbage ) but i ran 14.2 at 98 mph no spinning, last time i did a 13.4 at 101 mph lots of spinning. my scan tool is ez link (auto xray) fuel press. 37lbs no vacum line. i was thinking of throwing the old chip in (what do you think?) injectors are from Kirban green stripe (almost stock inj.) i was also told (when i got this chip) to remove 1 of the screens on the MAF is this normal? as for the blocked return line or one injector stuck open i do have a fuel press. gauge. at what pace should it loose its press. or shouldnt it?

[ES1]

1) I would be a little concerned with the timing in the Hyper chip. I like Thrashers and Turbotweak chips.
2) Some of the chip burners have you remove 1 screen.
3) Most chips have FP set at 42-43 line off. This would seem to make you run richer though. FP has to go up 1# for each psi of boost. You might whant to verify if your FP gauge is reading correct. I had one that read 10psi off.
4) Can you tell us what your MAF and O2 readings are while under boost?

[Keller]

The Auto Xray tool may use a different midpoint for O2. Some use 44x mv for the midpoint, some use 500 mv. That might be part of what is making the numbers read so high. I'd like to hear what his readings are when the car is off before we get all freaked out about the O2 readings.

[kenmosher]

If you take his O2 readings and multiply by 0.88 (to adjust for a 500 center point).... 950*.88 = 836 mv ..

It's a bit rich, but easily corrected by a little more boost (since he has no knock).

[Keller]

...and do the TPS adjustment procedure. Will likely have to modify the mounting slots.

You will need more fuel pressure if you turn up the boost.

I would shoot for an O2 of roughly 890 on your Auto Xray at WOT. (which will read richer than most scan tools) Maybe a hair less, but with no knock. Adjust boost and fuel pressure to suit. You will also need to see 255 on the MAF at WOT. Don't bother with the MAF screens. Really won't do anything.