I have swapped a 1990 350 tpi into my 1986 z28. I have kept it MAF so im using a stock 89 bin with VATS disabled to run it (using an ostrich and tunerpro). Is there anything else i should do to make it run better performance wise? Thanks.

 

the first things i did on my car were the basics=

changed the fan temps to reasonable temps(eg:220f to 195f)
if the car has a perf cam you bump up the idle as needed
you can change the temp that the ecu goes to closed loop , make it gointo closed at a lower temp, eg: might help with gas mileage and perf as youhave no control over the open loop tune ,if the car is modded and you have a good
custom tune it is to your advantage to get the car into closed as fast as possible(o2 sensor temp permitting) anything that you willhelp the car run the way you want it to...........good luck

 

You can also tinker with the torque converter lock-up settings to suit your tastes, and turn on highway mode (lean cruise) for some economy.

Can also make sure the base timing at the distributor (with EST bypass disconnected) matches the chip setting.

Should also disable the ALDL Spark Adder (set it to 0), so that you don't get 10 degrees more timing when connected to a scantool.

Can also check the BLMs to see if your MAF tables need some slight changes.

 

Thanks for the tips.

Ive always had trouble with the torque converter locking up too early even when editing the bin. Dont know why, but it seems to always lock up when i hit 2nd under low accel even though it hasnt reached the set speed in the bin. In the end i gave up and installed a manual switch which i just flick on when wanted.

I have edited the fan temps but i dont think it matters cos my fan runs off its own thermo in the coolant so i just keep that turned down.

I asked base timing to be set at 6deg when the engine was installed which is what the APYU bin is (the one im currently running).

No mods.... yet. I'll will look into the other things mentioned.

Also, i think the minimum air might be set too high - when i start the car it goes to the same idle everytime (about 700rpm) no matter if its hot or cold. So im not sure if the idle is being controlled by the ecm.

 

You should check if the vehicle speed is reporting, and if it's correct. That would affect the lockup. There might also be a problem with the lockup output which enabled it ALL the time, but the transmission disables it for 1st gear (automatically, can't be changed).

Also check the coolant temperature sensor (ECT/CTS). That has the biggest effect on commanded idle speed.

If the IAC wasn't working, your cold idle speed would be 500rpm or not idle at all when cold (but you're in warm Australia, so maybe it's not so bad), so I'd guess the IAC is working, but a bad ECT is reading about 50C (120F) for about 700 rpm. Warm engine idle speed in park should be about 625, in gear would be about 575rpm. 32C (90F) ECT should idle at about 975rpm in park, 925 in gear. I don't think $6E has an absolute idle RPM or max in gear RPM like $8D (but not sure).

I guess, just take a look to see that all is working well and sensors read normal numbers before you try to make more power.

 

The IAC jammed up about 3 weeks ago so i pulled it out and cleaned it (and it really needed cleaning!), the car wouldnt idle without a bit of accel when that happened. Since then it appears to be working fine - the steps move when i have checked it using the ALDL and tunerpro.

Coolant readings seem normal too using tunerpro. I set the following rpm v coolant temp table but it makes no difference.

650.00 - 306
650.00
650.00
650.00
650.00
650.00
650.00 - 176
700.00
700.00
800.00
900.00 - 90
1000.00
1050.00
1050.00
1050.00
1050.00
1050.00 - -40

The minimum air screw (or idle speed screw) is turned all the way through to what looks like the maximum so i think i will try reducing that a bit.

 

I can not for the life of me work out what is going on with this engine

No matter what idle speed i set in the bin, when i put it in D or R, it just drops back down to around 650-700 (sometimes lower and starts to hunt) and feels pretty rough. I set the desired idle all the way up to 900 and made it 0 for the difference between P/N and D/R but it still just drops back down too far. Sometimes in park it just idles at whatever rpm it wants, others it will stick pretty close to the set speed.

What am i doing wrong? Or what couldbe the problem with this engine? One thing i should mention is we used my old 305tpi throttle body as the one that came with the 350 was missing the base plate.

 

TB's are the same for 305 to 350, but they differ from year to year, and plenum to plenum for the IAC outlet, if I recall correctly. I don't know which country my TPI swapper's guide is in, though. I could be dreaming though. I'll take a look around to see if I'm remembering something backas$wards.

Also, if you have a stock torque converter, it may not like to idle higher in gear without really loading the converter/engine.

 

After playing with it some more today i think my IAC is dead. Unless the screw in the TB is screwed all the way through (giving it a higher base throttle) it just wont idle by its self. This is what happened about a month ago when the 305 was still in there - the IAC gave up and it wouldnt idle without keeping my foot on the gas a bit. I pulled it out and it was very black so i cleaned it and it started working again.

I pulled the IAC again today and it was still clean. It seems to be stuck on 160 steps when connect tunerpro. Might have to try a new one and let you know how it goes. Thanks RednGold.

 

What setting is this? Is it accessible in Tunercat or do I have to the hex address?

 

https://www.thirdgen.org/forums/tpi/...lenum+iac+year

https://www.thirdgen.org/forums/tpi/...lenum+iac+year


The hex address for ALDL spark adder is 23.

IACs can be checked for electrical continuity at least. Check the resistance between the pins. There should be 2 pairs that connect to each other, and only to each other. The resistance should be about 60 Ohms (if I recall correctly).

 

I dont get it and the pics in the first thread are gone which would have helped. Maybe i need to talk to someone with more mechanical knowledge than me - im still learning almost everything. Here is what my TB and IAC look like.

 

Redngold, right now my scanner is displaying the timing that I specified in my calibration. Does that mean my cal has already zeroed out address 23?

Does the scanner display this "extra timing", or is it added "behind the scenes" by the ECM?


EDIT: I just checked my bit address 23. It has an 08 in there. So, whenever I have the scanner plugged in, the ECM is adding 8° of extra advance??

 

I got out my dial-back timing light. Checked timing with scanner attached and not attached. Timing was the same between the two.

 

After further reading, im guessing there should be a hole in the plenum directly behind the IAC valve which it doesnt as it is a '90 plenum. This is probably why my IAC sticks on about 160 - its trying to let more air through which it is but the air is not getting through the plenum. Does this sound right?

I think i better start a new thread elsewhere as this is no longer tuning related. Thanks RednGold, your a champ!