I just installed my Ed Wright fastchip (not custom) and scanned a run down the road and need opinions on this data. I have a 350 Tpi engine but until now I've been running the stock 305 chip with it. I was running 35psi fuel pressure because I had LT1 24# injectors with the 305 chip. I wasn't running that rich and getting a good 20mpg. When I installed this new chip I bumped the pressure to 45psi (still with the LT1 24# injectors). The exhaust smells rich but watching the live data (at idle) with Auto Xray it showed Lean and Rich back and forth quite regularly with a little more Rich than Lean which is the way I'd rather have it. Also, I have quite a few knock counts and I noticed audible knock when I floored it. I think I need to back my timing off a little bit. Anyhow, here's the data. All these readings are with the engine in closed loop and running at 166.5 degrees. Thanks in advance for any opinions or advice.

1550 Rpms, 131 int, 712mv O2, 26 knock, 110 BLM, 79 O2 cross counts, 3.3ms Injector pulse, Rich flag

1625 Rmps, 141 INT, 136mv O2, 26 knock, 110 BLM, 85 O2 cross counts, 3.1ms injector pulse, rich flag

1625 Rpms, 141 INT, 136mv O2, 26 knock, 126 BLM, 87 O2 cross counts, 4.0ms injector pulse, rich flag

1725 rpms, 128 INT, 132mv O2, 26 knock, 128 BLM, 89 O2 cross counts, 4.0ms injector pulse, lean flag

(I believe I floored it just prior to this) 2125 rpms, 128 INT, 924mv O2, 26 knock, 126 BLM, 89 O2 cross counts, 5.3ms injector pulse, lean flag

2125 rpms, 128 INT, 924mv O2, 50 knock, 128 BLM, 91 O2 cross counts, 7.8ms injectors pulse, rich flag

3250 rpms, 128 INT, 906mv O2, 107 knock, 120 BLM, 94 cross counts, 7.8ms injectors pulse, rich flag

(I believe the car shifted just prior to this) 2475rpms, 148 INT, 79mv O2, 107 knock, 120 BLM, 94 O2 cross counts, 6.1ms injector pulse, rich flag.

 

Suggestion #1
Get the equipment to burn your own PROMs

Suggestion # 2

Read everything you can on PROM burning on this site and others. Do not forget programming 101

As a stop gap measure in the mean time I would

Take 6 degrees of timing out and retest.

Continue taking timing out until knock is gone.

Redo this after getting different gas (This is to make sure you did not get some that was low octane or knock sensitive)

Play with fuel pressure until performance is best

Play with spark until performance is best with no knock. Shoot for minimum timing.

Remember suggestion #1 as PROM burning is the only way to get fine adjustment for your car.

HTH

John

 

Thanks for the suggestions.

I'm aware that PROM tuning is the best way to go, however I do not have the time or money to do that right now and I was tired of running rich with the stock 305 chip so I opted for the next best thing.

My base timing right now is set to about 7 degrees, I wouldn't think that taking 6 degrees out would be wise considering I'm supposed to be able to run stock base timing with this chip.

I always run 93 octane gas!

I know I should play with the fuel pressure but I'm more worried about running too lean than anything. Last thing I need is a melted rod and having to pull the engine out of my only car that I use to get back and forth to work everyday.

 

My base timing right now is set to about 7 degrees, I wouldn't think that taking 6 degrees out would be wise considering I'm supposed to be able to run stock base timing with this chip.

It is not really about what you or I think but about what the engine is telling you. An audible knock always tells you take timing out. On a car with a knock sensor an audible knock usually means that the computer has retarded the timing to the limits of the program and it is still knocking. Take the timing out and see if it stops. If it does not take another 3-4 out. When it stops you can put back a degree at a time until the scan tool indicates knock. Then back off about 2. Finally test to see what spark around this gives you the best performance.

I always run 93 octane gas!

Just because it is written on the pump does not make it so. I have found that there are great differences in the quality of gas from season to season, from company to company and from day to day.

I know I should play with the fuel pressure but I'm more worried about running too lean than anything. Last thing I need is a melted rod and having to pull the engine out of my only car that I use to get back and forth to work everyday.

You should take a hard look at the plugs. They will tell you if you are rich or not. I would start by testing and then adding fuel. If the car slows down go leaner until it slows down then back to the richest setting for best performance. If the car gets faster keep adding fuel until it slows down then go back to the fastest setting. With your off the shelf PROM you may have to set the FP to one setting for everyday driving and another for the track. If the difference is large you wont be able to get on it with the street setting and should look to Prom tuning soon. Once you have the WOT stuff taken care of the part throttle prom tuning will be easier.

HTH

John

 

IMO, I don't see how track times could determine whether you have the right fuel pressure or not. Times can be faster or slower regardless of fuel pressure based on left or right lane, track temperatures which change constantly, driver error, and other factors. I can understand it's a good starting point and once the track opens here I'll definitely go and give it a try.

As for the gas octane, I don't go around carrying a meter with me to test the octane in the gas. I just stop at the same gas station everytime. I used to shop around but my car seems to run best on the gas from this gas station.

I drove the car today and didn't notice any audible knock even when I floored it. Seems to me like I only notice audible knock when the Auto Xray is hooked up, this is the 2nd time I've noticed this. It's odd. There is still 5-7 counts of inaudible knock at idle and I'll try taking timing out to see if it goes away but I've heard that headers can cause false knock due to resonation so I have a feeling I won't be able to rid myself of the knock completely.