luke4907

iTrader: (5)

OK I'm just posting this, not because I know you veteran DIYers all are going to cringe when you read this, but because I want to hear if there's anything I've done that puts my motor at greater risk for damage. If not, then hopefully it'll give someone else in my situation an idea to work with. so here it goes:

My 89 tpi350 had been running terribly. 220k mi, ~13mpg, rich as hell, surging, stalling, etc etc. It's got exhaust, TB foil and coolant bypass, K&N, hacked up airbox and gutted MAF, no smog pump, you get the idea. I had done some logs, and found that my ECM thought the car was running lean (150+ BLMs), but it smelled rich as hell. I know my O2 sensor is crap because every morning I get blue smoke at startup. Yes, I know oil is not good for O2 sensors / spark plugs heh. So I figured I'd take a stock vette bin (ARAP) and just set BLM min/max to 128/128. My reasoning behind this was to stop the ECM from compensating for the low O2 sensor voltage from it being fouled with oil.

The car now seems to have a noticable power increase, as well as giving me 17-19mpg. This isn't a difference between city/hwy either, I drive lots of highway miles. I don't get overwhelming odors of gasoline anymore. The car also seems to behave alot better at idle (minimal, if any, surging) and I have not been able to get it to stall as I used to be able to. I put in my code key while driving the car and noticed the ECM was just cycling between PE, open loop, and closed loop mode. I know it's an ugly BIN, I just don't have the means of getting my motor into a "clean" running condition. Now to the questions:

1) Am I going to blow up my motor running this vette BIN without the aluminum heads (and vettes had a different cam too, right?)? What I mean is, will the changes in timing cause pre-ignition or detonation?

2) If my car is still a tad rich, would adjusting BLMs to 120/120 or 115/115 have an effect on taking out a little injector pulse width or whatever it's called?

3) Instead of the above, should I maybe bump up my injector constant by a pound or 2?

I welcome all comments / insults / warnings, as long as you provide me with some constructive suggestions (don't tell me to get rid of my 3rd gen hehe). Thanks in advance

PS I'd really like to see a Super ARAP, although I doubt anyone would want to work with me on it haha

RBob

iTrader: (1)

Personally, I think I'd start by replacing the valve stem seals, cleaning the MAF, putting the screens back in and changing back to a paper air filter element. Then seeing how it runs. May need to replace the O2 sensor, but this would depend upon whether it is an A/C Delco unit and how old it is.

RBob.

luke4907

iTrader: (5)

well, I've only put the pulleys and exhaust on it, everything else was there when I got it (not to say I wouldn't have done it if they hadn't been there). Right now I don't have the time or means of replacing the valve stem seals. It's definately a must once I get the chance though. O2 is a Bosch unit I replaced a little while ago. I have another ready to go in, but I don't want to throw it in there just for it to get fouled up like the other. Waste of $20 ya know

BTW How would I go about cleaning the MAF? Are you suggesting my K&N has deposited oil onto it and I'm not getting a good reading from it (hence the switch to paper filter)?

RBob

iTrader: (1)

I would use a spray cleaner, just don't break the wires, use a light spray.

On reason for MAF work, is that the Firebird have a 90° bend in the intake duct right before the MAF. Without screens this upsets the air flow through the MAF, with the result being an incorrect reading.

The immediate goal would be to get the engine running well. Then go on to making it run with modifications. Set the fuel pressure to the proper value, double check timing, and what injectors are in the engine (never know what a previous owner did). Set the minimum air and TPS values. All the little things that are required before diving into the calibration.

RBob.

luke4907

iTrader: (5)

I'll try some TB cleaner that I have (not carb cleaner) I imagine that would do the trick for the MAF. Too bad I have a spare off my friend's that I parted and that one has the screens gutted too. At least I have a spare in case I screw mine up. I think the ease of that "mod" caused just about everyone to do it to their cars, so probably most of the MAFs with screens are new replacements.

Before I jump into the deep end of things I will definitely have my engine in good mechanical working order. Timing is <1*off (closer to 5*). The PSI might be a little high, I haven't checked it since I put the adjustable unit on. Need to get a gauge. I heard some injectors work better at higher PSI (better fuel atomization), so that's why I got the AFPR. Is there a conversion formula for how many pph 22pph @ 40psi injectors would run at 50psi? I'd like to change the injector constant to whatever my injectors would run based on the increased fuel pressure. If all these ideas of mine are ludicrous, just let me know. Thanks for your feedback RBob

Captain C

Just a few minor suggestions.....

1. Leave the fuel pressure alone until you fix what you know is bad.

2. Convert to a heated O2 sensor, it will resist fouling better and doesn't cost much more than a single wire unit. You will have two wires of one color and a single wire of another. The single wire connects to your existing O2 wire. The other two: One needs to go to a keyed 12V and the other is a ground. Doesn't matter which one you use for which. (Be sure to get an AC Delco. The Bosch unit is probably already bad if you have more than 20 seconds of run time on it)

3. DO NOT USE CARB CLEANER ON THE MAF. Use electrical contact cleaner. The K&N's work fine, you just have to watch how much oil you put on them. If your car starts running badly a couple of days after you re-oil them, clean the sensor again. Paper filters are so restrictive they usually negate all the gains from the airbox work....

4. Until you can replace the oil seals, try running STP or some kind of stop leak. That will help with the smoking.

5. Do as RBob suggested and put the MAF screens back in. Any changes you make that affect airflow require changes to the fuel curves in your chip.

6. Adjust your IAC and TPS

7. Run a plug one stage hotter than stock. This will also reduce oil fouling and help the engine to run better. One trick to do is get plugs with the recessed tip vs. the extended tip, it may cost you one mpg, but they won't foul as easy and that will gain you more mpg in the long run.

7. I would run your stock chip after you do the other items. It was calibrated for your engine and should run better than the other stuff until you burn your own based on a clean running engine and lots of data logging.

luke4907

iTrader: (5)

Thx for the suggestions, Cap.

1) sounds good
2) plan on it in the future, read lots of suggestions on how to wire it up, just didn't want to waste money on one that will get fouled up. if they really do resist fouling better then maybe I will put one in.
3) I wouldn't use carb cleaner, but throttle body cleaner. I was told TB cleaner doesn't have any oils or anything that coats the parts to resist carbon buildup, but electrical contact cleaner sounds like a much better idea.
4) I use an engine flush before most oil changes. This seems to help alot. I'll try some stop leak next oil change (soon, a little overdue).
5) Don't have any MAF screens to put in =\
6) IAC and TPS should be fine, checked recently. I see TPS voltage with every log I take too.
7) Any recommendations on a plug? Part#? I know some people use platinum plugs, but when I went to get some, the guy there (who claimed to have a camaro and firebird 3rdgen) specifically recommended regular old cheap plugs.
2nd 7) I agree that the stock chip is a better setup for what I am running. I think I'll use an AUJM and set BLM min/max to 128 and see how well that runs in the meantime. Once the engine is in good mechanical condition I'll start modifying the AUJM further. Thanks for your input

Captain C

Whatever you do, don't use Bosch anything!!!! Especially not the platinum plugs or O2 sensors!!!! I have melted the electrodes on the Bosch platinum plugs.

In an Autolite plug. #24 is stock for TPI, #25 is stock for L69 HO motors, and #26 was stock for the Low performance 305's (TPI was the cold one in an Autolite).

In an AC plug, I was running a 43 you might want to try a 44 or 45.

I haven't used Champion in years although they always gave good performance. J-12 would be stock for a TPI IIRC, you can use a cross reference at the store to check.

I think you get a better spark from the AC but they have the shortest life. The Autolite's give the longest life but I don't think the spark is as good. Champions are in the middle......

IMHO ofcourse