Carabajal87108

84 Crossfire for around a year and have done the following: New plugs Wires, Coil, Cap, Rotor, coolant sytem flush, new oil and trany gaskets, trany filter, Coolant Temp. Switch infront of intake, Fan Switch on Dside moter between plugs, Fan Relay, Fuel Relay, New Ground from frame to intake, and New ECM.

Car ran pretty good before new fuel relay and ground and ECM were installed. Replaced Ecm, due to no codes were availiable when scanned, but check engine light was always on. Fan/Fuel relays were changed due to prev. owner had opened and siliconed them back together. Before fan relay wap, fan would come on when hot the first time then would not come on again afterwards causing it to overheat on a 30 min run. So I replaced relay and fan switch with new pigtail, prev. owner had eliminated fan switch and rewired connector to battery. Can't tell if the issue is fixed, because after I replaced Ecm and relay right after.

Now I am not getting any power to fuel pump or relay unless I jump it from the battery. I tried the "G" terminal jump the outcome was barely a trickle or small spay. Injectors pulse when pump is not jumped, but when jumped no pulse straight spray, causing flooding in a 2 min start up. Fuse at fuse block is good, and when jumped at relay to battery pump works but no pulse from injectors, constant spay. same thing happens when jumped from fuse block constant spray. The ECM is less the 2 weeks old. Since I replaced it check ingine light is gone but car is not running. PLEASE HELP, she is my daily driver. I do have scan tool and OBD2 adapter, checking green white wire for constant 12v tomorrow. Need car running soon, only car.

Anything would help.

speedreed8

try the C4 forum, those guys can probably help you out better. fyi...

hugie82

CFI after key on prime, needs to see oil pressure from the oil pressure sending unit. It has 3 wires going to it that tells the ECM to turn the fuel pump on.
Your electric fan should stay on with the AC turned on. Try that and see if it's the fan or may be a short.
CFI is a very simple system once you get the basics and no one before you screwed with it. Good luck

74 LS4-454

He has a CFI, and already has posted in the C4 Forum, but it doesn't matter if it is an 82 or an 84 IMO. I suggested to the OP to post in this section when I read his other threads located elsewhere. So I don't understand your response It doesn't matter what year it is, a CFI is a CFI and maybe with the combo of both sections, his problems will get solved..................Tom


To the OP, I remember there was a thread where there was a similar problem like yours, as I stated in another one of your threads. I still can't located that thread, but I do remember that jdp6000 (Jim) had alot of input in that particular situation. If I remember correctly, when all said and done, it turned out to be a short of some type, that eventually got resolved. So don't give up, with all of the exposure here from other CFI owners, and if Jim, happens to see this thread, he might remember exactly what was done to correct the problem. In the meantime, go through the "sticky" again, http://forums.corvetteforum.com/c3-t...solutions.html (if already done), as you may pick up something else that can help you out. I will still try to locate that thread and post the link.................................... ......Tom

texaswilkins

I had a rat eat one of those three wires to the oil pressure sender and that caused all kinds of things to not work right.

Bill

speedreed8

""So I don't understand your response It doesn't matter what year it is, a CFI is a CFI and maybe with the combo of both sections, his problems will get solved..................Tom""

didnt know that he already looked elsewhere, hope he gets it fixed anyway with everyones help......

Carabajal87108

ok, thank you Tom,. There is only 1 wire to oil sender, brown or tan wire. The tree wire set up you speak of is on 85 TPI set up, totally different then CFI set up. the power set up for CFI on 84 goes off of fuel relay for 2 secs on start up then oil sender causes ecm to pulse injectors. Relay has five wire set up green constant 12v, two reds fuel pump, and black ground, orange wire not sure what or where it goes, same thing on red single wire. that makes 5 pins. Just bought volt tester and ground tester tonight, will test tomorrow. Could not locate exact forum that you speak of and others I read are not helpful, either mention relay which is new and old one was working ecm which is also new. Can't give up, already heavily invested to turn back now. I'll rewire the whole motor before that, no joke. there is a ground that is on intake that is in same wiring for injector wires. is it suppose to be grounded to intake?

Carabajal87108

exact location of grounds and fus able links foe fuel relay and pump, are what I am most after, description is better then diagram, diagram in Chilton's is not helpful and I don't have resources to by original manual. Do have Aldata, Corvette CD, repair and other information. All in all nothing in any part of my research is to exact, very broad and chopped with other issues. A lot is informative, but need more, Thank you guys it means a lot.

74 LS4-454

Misunderstood your thought...


It seems that the wires that "hugie82" was referring to are different on the 84.
As far as the forum, we are referring you to our "sticky" in the Tech Section, with the link above in previous post #4.

There may be a difference bewteen the 82 & 84 model years for the locations of the grounds and fusible links that you mention. You really need the Shop Manual for your year, and maybe one of the 84 owners who have one can copy the pages that you need from the C4 Section.

When you changed out the cap & rotor, did you check the ignition module? Did you make sure it had lube between the bottom of the module and the plate it attaches to?
IMO, I think there is a short somewhere and you need to go through your electrical system and make sure you have good solid connections.
I would also go through all of the connections that you made when you were replacing parts and double check everything.......Tom

It just seems kind of odd that after you replaced ther ECM and relay that it doesn't run. It is possible that you have a dective part (replacement) in that it is not working like it is supposed to, it has happen before, so don't rule it out.

Carabajal87108

I just finished checking connections with volt meter, I was incorrect on oil sending unit, there is a 3 wire plug on one end and a threaded end on other. 2 red wires and 1 orange for sender plug. I have been using Aldata and the wire diagrams have been useful and when I jumped the 2 red wires from oil unit it got voltage from relay, that is the reason I bought a new one. As for grounds I disconnected the ones located on the back of drivers side head, there were 5 wires on 3 connecting rings that were dirty. When I used ground finder tool I have a good ground on intake. the 2 visible fusible links coming off of fire wall connector are good 12v's on both sides of links. If that does not fix issue I am leaning to bad replacement ECM, that is after I check ECM connectors. On plus side ecm fuse is receiving 12v's and getting power from oil unit is promising. I think 82 and 84 CFI are the same wiring set up but not totally sure.

Carabajal87108

On distributor question getting fire from distributor, car runs when I use gas or staring fluid. When I replaced cap and rotor everything was in good shape. When I mentioned ground on intake I should have explained it more. Before it had an amp pos wire in place of broken ground strap, under amp wire was a smaller black wire that is connected to injector harness. That was reason I replaced that wire.

Arkyvette

Are you using stock prom chip from old computer? Are you sure you got it in right and didn't jam any pins together? Just a random thought.

Carabajal87108

yeah, new one did not come with prom chip, pins should be straight. none were bent when I removed it from old one.