775carguy

I purchased an 86 Iroc 305 with TPI. The guy i got it from had just rebuilt the motor but gave the rest of it to me in boxes.The electrical has ALL been unplugged from under the dash to the engine compartment.He also spray painted the engine compartment Black, Wires and all. I have NO idea how to put it back together. The main intake is in and i just got the Plenum gaskets. The injectors look a little rough though. IM not sure i want to spend a ton of money to fix it. Not to mention my wife will kill me. Maybe a carb is a better option. Either way im open to feedback. I am very mechanical and am willing to do the work. I know i bit off alot here but i am not one to let a car go to scrap. I have wanted one of these since high school and yes it was new then.

lethaldomestics

Not a nightmare hell half the work is done. you are gona spend more time reading wire diagrams. if you convert that thing to carb itl cost more i think at this point.

lethaldomestics

If your gona keep the stock application this is what i would do (not in paticiular order)

confirm weather you have a speed density set up of maf. Should be MAF but you will never know till you confirm. who knows what could have been put in there

i would pull all aftermarket ignition parts and use stock one to get base tune and build up from there.

pull the engine harness (it looks a lil tor up) and go over the whole thing for repairs Get it out of the way skip this step and you'll be back haha.

find out what the overbore on the engine is because you may have to tune

if your not gona run the smog pump your gona need to tune it . some people will argue this....consider it. As far as i know the ecu compensates for the air pumper into the exhaust system so you may run a lil rich if u dont tune. just somthing to keep in mind

when i think of more i will let you know got go eat me some turkey

http://www.hotrodhandbooks.com.au/eB...Line-06-1.html

MoJoe

iTrader: (5)

Scotchbrite + cleaner, such as 409 to clean the wires to see the colors.

Service manual / wiring diagrams are key to working on the wiring. The wires are set to the necessary length to reach where they need to go. If you have too much or too little wire, the plug probably goes somewhere else.

Tuning... Removing exhaust air injection requires no programming. Overbore is close enough you will not need programming. Since this should all be the original parts, the engine is 305, injectors are 19#, 9th / cold start injector (drivers side, lower middle of runner), and there should be a MAF.

Read the manual, look at pictures, figure out which parts go where and bolt it all together. Post questions and pictures and you should get plenty of help from the TGO family.

775carguy

Thanks for the input. I think im going to have to dive in. Like i said before , i think the injectors are junk but i wont know for sure unless i put them in and try it. I did get some pretty good parts with it though. Comp Cams Cam shaft part 12-256-4, flowmaster exhaust, Mallory digital 6a box, Taylor wires, new cap rotor and coil, new carpet kit, Edelbrock headers, The engine bore im unsure of. He did say he had it honed but didnt mention bore. It also has a mini starter, all Royal purple fluids and filter and Dual K&N air cleaners. Someone did remove the A/C but im sure i can figure something out later for it. I need to find a gas pedal since mine is missing. I just dont want to spend a bunch of money to find out it has major elecrical, computer or EFI issues. Wish me luck.. Im gonna need it.

Jersey89GTA

iTrader: (1)

Throw a OHM test on the injectors, save yourself a lot of work. Should be +.015 and higher, anything lower is going bad.

I paid $120 for a new set of Bosch 3's 19# ... well worth the money.

TTOP350

iTrader: (8)

I really hate a flatblack engine compartment, looks better with clean factory paint scratched up a bit. That's the 1st thing I'd get rid of!

Most of the hard work is done. Use google and a factory service manual, they are life savers.

lethaldomestics

Although removing air system does not require a tune, the ecu compensates 100mv for the added o2 in the system. if you are not running your air pump you will run slightly lean. therefor making it harder to achieve 128 blm or stoich. if you want a solid base tune tune with pump on.

Im no expert all i know is what i have read on tgo.

OP>>>I have heard of improved power without air system. I do agree. as well i also noticed better mpg. but i was also runing lean at idle sometimes but my idle was not as smooth as it was with the pump hooked up. closed and open loop. also got a random spike in BLMs. Hooked the pump back up and idle issue went away

Also if you have a cat the air system as far as i know heats the cat up to burn emissions in open loop (when warming up) to make up for it running rich as required by ecu. i know a cold cat while running rich is not a good idea.

put it to you this way if you can get a base tune with all stock components ( i think you can get away with those smog headers) you will have greater understanding of what you are doing while tuning. and if there are any issues with the stock components.... and then fix them you can easily rule them out if you have any future issues with/while installing aftermarket parts.

This is my experience talking,some turkey, and rum haha

MoJoe

iTrader: (5)

This is incorrect. Since you say you are not an expert, please stop repeating this incorrect information from other non-experts.

Air is injected into the manifold when the engine/cat are cold and the engine is running in "Open Loop"... which means the computer is not adjusting via the O2 sensor. The extra O2 in the exhaust causes any unburned fuel to continue/complete burning in the exhaust, which helps heat the catalytic converter to operating temperature. Once sufficient temperature has been achieved, the computer goes into "Closed Loop" operation... which means air is no longer injected into the exhaust, and the O2 sensor provides feedback on the air/fuel mixtures.

Put simply: O2 sensor feedback and air injection into the manifolds never happens at the same time... Either or. Pick one.

Further proof: Injecting an un-metered amount of O2 into the exhaust means the O2 sensor will NEVER have the correct reading, and you can NEVER say "it's just 100mv too high" and adjust. Therefore, GM could never have programmed Closed Loop to work properly.

darbysan

Here is a good link that shows pictures of all the connectors. I'm sure this will help.
https://www.thirdgen.org/forums/ltx-...erchanges.html

775carguy

That is a thing of Beauty, Thank you. Also I put a VOM to the injectors and all read about 16.0 except 3 which read about 22.0 give or take a .3 or so. The other issue i have is some of the injector caps are missing that go onto the intake side. I may just try to find some after Christmas. With 4 kids and 5 Grandchildren Christmas is already expensive. Where should i look at them for the best part and best price?

nomind

I went with SouthBay (they are a sponsor here as well, so there is a discount), and went with the Bosch type 3 injectors. I want to say it was about ~140 for the set. Much more reasonable than just replacing one or two.

Jersey89GTA

iTrader: (1)

Put in a new set of injectors and a fuel reg while at it ... check egr valve - do it all while plenum is off. New gaskets for the tpi stuff/upper/lower.


I have some old multechs that ohmed out at .15, but I'd recommend a new set that is balanced and tested, that way you flow is even.

775carguy

I will be looking up Southbay this evening.. Thanks for the info guys.

Fred SS

iTrader: (3)

TpiParts.net is a good source for connectors, parts, etc for tpi. I agree with other members, get a shop manual and learn the wiring.