dahammer

Good day everyone .
So a quick story on what has lead up to my issue .
I have a 91 GTA and an 87 iroc , also an 88 iroc for parts .
I decided I liked my 87 better than the GTA . The 87 had valve issues and burnt oil through leaking valve seals. The GTA had a rebuilt engine in it . Both 305 . GTA is auto and 87 is 5 speed . I decided to pull the engine out of the firebird and drop it into the iroc. Got it finished and all running today . Next will be to strip whatever I can get out of the interior of the GTA and stuff into the camaro. GTA has really nice leather seats , door panels , carpet , console ect.
So anyways . The GTA engine ran like a top . I had replaced all injectors,distributor,plugs and wires , computer, coolant temp sensor ect . So I got it in to the Iroc and obviously there are a few differences with wiring from the GTA to the iroc. Alt and stuff is reversed . For the most part I have everything hooked up with the exception of the sensor for the egr valve. For now I have no vacuum going to it or any of the emissions stuff . I have it plugged off on the intake . The car starts up fine , but unless I hold the throttle on for a min or 2 and then slowly let off it will stall . If i hold it for a min or so and then slowly back off it finds itself and idles at around 900 rpm . If I burp the throttle or shut it off , then I need to do the same thing again to get it to idle . I have it timed to 6 degrees with the advance unplugged . I had to turn the throttle stop up a bit to get it to idle at that speed and not stall . Once it is there it is fine , when the fans kick on it stays running . I turn the stop bac a bit to bring the idle down a bit and the fans kicking on will stall the engine . I took it for a quick rip down the road and it doesn't stall when I let the clutch in .
I have all the wires hooked up with the exception as I said of the egr , and there was an extra sensor on the front by the coolant temp sensor on the old engine that isn't present on this one . The only other change is I had to switch the throttle body on for the cable hookups on the throttle cable . I changed the IAC I think it is called from the original throttle body to this one . Only thing is the tps is still the one from the 87 . I left it on .
Hopefully this is enough info to try and figure it out . I have searched the threads but nothing seems to pop out , and this motor ran perfect in the other car . Only thing left I can think of is a wiring problem somewhere , maybe the computer , or that missing sensor on the front . Or possibly the tps . I am just hoping there maybe an idea on something I missed form this before I go switching more parts. I do have a wiring harness in the 88 that should have all the proper hookups needed if I need to switch . I also have the computer from the 88 , but it is an auto , not sure if that matters if I switch the prom . That may be my next step on my next days off to try as it is the easiest to do .

Drew

iTrader: (58)

So you used some of the 91 wiring and efi stuff in the 87? The least difficult way to do it, is to change only the long block and use everything else from the destination car. Or use everything from the donor in the destination. There are all kinds of little differences that can create headaches by mixing and matching.

The throttle stop isn't like the idle speed on a carb. The idle is controlled by the IAC based on the throttle position and a preset amount the throttle is open at closed throttle. Jump on the google and search for something like "setting minimum air site:thirdgen.org". You need to follow the procedure and set the throttle stop so the engine will idle with the IAC bypass valve closed, then when you're finished the ECM can control the idle from that baseline. Otherwise the IAC is going to fight you and adjust itself everytime you move the screw.

dahammer

No the wiring is still the original in the 87 . The engine was dropped in complete from the 91 GTA . I had to extend a few wires for the alt and the AC . The original engine from the iroc had an extra sensor in the front of the block by the coolant sensor and the egr had a sensor plug that the newer motor does not . Other than the that the only diffrence also is the GTA had a map sensor I think it is called and the iroc has the maf in the airtube . So nothing really changed there . I am contemplating taking the wiring harness from the 88 parts car and transfering it to the 87 as it also had the swapped sides with alt and ac . The previous owner had butchered up the wiring in the 87 so just for overall neatness I was looking to maybe do that and clean up the rats nest in there now . It will all depend on whether I have to repin a bunch and if I can figure it out . I will look at setup for the air intake these next days off as a starting point . I wasn't sure if the swap would affect all the values for it or not , but maybe , and more so now that I have moved the throttle stop on it .

I should also add , the reason I didn't pull the wiring harness from the donor , GTA was due to the fact it has a different set up for the speedo VSS and the ecm wiring harness is different to , and I wasn't sure if it would all work for the older model car . With the 88 parts car the setup seems to be identical to mine in the 87 with the exception of the alt and ac being on opposite sides of the block . So my hope is that it ends up working with little to no hiccups if I do go that route .

Drew

iTrader: (58)

Yeah, a 91 Firebird harness isn't exactly ideal for a Camaro. Personally I'd probably try to fix what's in the car if it's at all workable, because you'll have as much work into making a later harness work. GM changed enough things between 87 and 88 to make things interesting, but it's not much of an upgrade. If you had an 89 Camaro harness laying around, that'd be a worthwhile and fairly easy upgrade.

The 91 engine doesn't have the cold start injector, that's your extra sensor in the intake on the 87. The TPS on the 87 is adjustable, on 91 it self zeros at key on and is not adjustable. The internal parts of the 91 engine may be different, there were some minor cam changes and whatnot that may confuse things a little bit. A person would want to go down the list and find all the things that are different on the 91 from 87, and swap all the 87 stuff back onto the engine to limit the number of changes.

dahammer

Yeah I seen the lack of a cold start injector . The other sensor I am missing is on the front of the engine right by the CTS . I havent had time to look at it closely yet and figure it out what it is actually for . I will play with the air control and such and see if I get any progress out of that first . I may dig up and change the egr so I can plug that in to as I am ocd about having something not plugged in lol . I will see if I can find a list of the differences between the 2 years and compare the 2 .
If only I had one more car sitting here in an 89 for parts . I passed up on one because 3 in the yard was already getting crowded . But I am a sucker for a deal on one of these cars so never know one day Lol