I have an 83 cfi z28 I've been restoring. Cars been in my family since 85. Injector 2 (forward injector) is not firing. Replaced both injectors, no joy. Cleaned out the throttle body, no joy. Swapped injector harnesses between the two and the other injector didn't fire so I figured wiring. I read for continuity from the injector plug to the ecm, .2 ohms. Then read to the fuse box. .1ohm. No wires shorted across or to ground. I check voltage at the injector and got 0v. Check wires from the fuse box to ecm and those are good as well. Took the ecm out and opened it up and didn't notice any chips loose, capacitors blown, or any of the traces open either. Am I looking at an ecm change? Would it just be a plug and play or will it have to get flashed/tuned and timed etc.
any help is appreciated as this is the only thing I have left that reminds me of both my mom and my dad from my childhood.

 

you should remove and reinstall each fuse one by one(even those unrelated to the fuel injection)to re-establish good connections.The two "INJ" fuses supply power to the injectors and the ECM grounds the other side to "fire" the injectors.Is there signs of activity from the ECM-IAC valves working,correct CEL operation ? ECM can be swapped with another correct model ECM and see what happens.Removable "chip in original ECM is installed in the replacement-there are no "new"ECMs-just used ones and "rebuilt"(checked out)ones.The 1984 Corvette uses the same ECM as the LU5 F-bodies.An '82 ECM,again shared with Corvette) is larger,but will work as long as suitable '82 f-body chip is installed . Did the fuel pump come on and supply fuel to the TBI?-it is common for the foam-rubber coupler hose in the fuel tank to turn to goo and blow out on a long-disused car.

 

I have done all fuses, fuel pump is brand new, as well as the tank and filter, and blew out the fuel lines. No engine light, Replaced the IAC on both throttle bodies, got a fuel pressure gauge that's reading 12 lbs between both throttle bodies. I started it the other day and they both worked, wen too put it in drive and my shift linkage came off. Had to leave for 4 days for work, came back, reconnected the linkage, now the injector isn't spraying again. I cut open the wire harness and replaced the wire from the ecm to the injector just because the old one looked like trash (I'm an electrician on jets by trade so my ocd got the best of me lmao) started it up, and for a second on crank it sprayed but when the engine came online it stopped.
the only used ecm for my 83 cross fire I could find, the guy wanted almost 500 bucks for so I'm trying to exhaust all other options first.

 

Need to get that ECM apart again and with a bright light and strong magnifier,look over all the solder joints for breaks-usually seen as a circular crack in the solder where a component lead or connection pin goes through PC board and soldered.If any found fix with small tip soldering iron I will look at my CFI spares stash for a spare 83/84 ECM (this could take a while,i have CFI parts stashes in several areas)

 

sounds like a plan. Some reason earlier today, i got the injector firing for a solid half hour probably. Got to take her on the road for the first time in 20+ years. Got the wife in her and took a small trip down the street and around the block. Discovered some other minor things but the injectors both fired the whole time. No telling how tomorrow will go with them lol Got to put her back on jackstands and dig into some suspension issues so whenever that comes around ill do exactly as you suggested.
thank you so much for digging through for another possible ecm. Ill gladly buy that off your hands. It's awesome to talk to someone with cfi knowledge.

 

Could also look over the plugs that plug on top of the injectors if you have not already.Very cool car BTW .

 

Well I came out today to mess with a temp gauge issue, the injector isn't firing again...
I checked the injector plugs and all is well there. Reverified the wiring, again, and all is still good. She threw a code 33 again this time. I replaced the map sensor a while back the one time it threw that code prior. Didn't fix it though. Back to square one thinking it's the ecm 😭
thank you btw. Ive wanted this car since I was really little when my dad would take me out in it on Sunday drives.

 

New update. I bought a noid light, it'll come on one start up. Be off the next. Come on/off intermittently. Plugged up the injector plug, tbi sprayed fuel for probably 15 minutes then just randomly stopped. I'd hit the gas, it would spray, then stop randomly a few min later, then wouldn't come back. I took an endoscopy to look for broke grounds behind the engine on the firewall, didn't notice anything. Looked at the other grounds along the engine and firewall, nothing stood out. Such a pain gripe 🤣😭

 

local hot spell is starting to let up,so may be able to get into some of my sheds to look for a #6026 ECM.Back in the '90s, #7747 ECM was sometimes used on CFI because it is a little more modern design and and easier to custom program.#7747 was common in 1987-91 TBI light trucks and is not plug and play-adapter plugs must be made or plugs that fit 7747 spliced in.I do not know any details on using a 7747 with CFI-just that it was done.

 

Idk if this is the right place or not... i have an 89 firebird formula 305 tbi. I put a 91 350 in it from a yukon. Just dropped it in and it runs. It is very sluggish though. It also has a rough idle. If i tune the idle with the dist it idles nice but stalls when you put it into gear. Im at a loss with it... being that i used a complete 350 motor/intake/injectors do i need to use the yukon ecm? I do have it. Thanks!

 

I hear that!!!! This heats been killin me painfully 🤣 i appreciate all the help from you!!!