5.7 GSI running issue

[cnotecherry]

Sorry my last post was more about how to go about diagnosing the problem then getting my wire colors right I think his ecm is not getting power I was not talking about the fuel pump and the key does feed power to the engine switch to turn on ecm then ecm turns on fuel pump the oil pressure switch goes through ecm but I thought when it trips the ECM kills the fuel pump not trying to give false info just trying to help

 

[rtoomey641]

Thanks So purple is power to relay correct

 

[cnotecherry]

Yes purple turns on the ignition relay when key is on

 

[rtoomey641]

So got a used harness from a GI looks the same has a couple extra plugs but has all of mine except I have to move ecm to front mount mine was on riser.My ecm plugs in from front the one the harness came out of plugs in side plugs are same should I get that ecm or is mine ok also on feed to breaker by relays I have 3 wires new one has 2 is this an issue? Thanks

 

[alldodge]

Unable to answer your questions with certainty with differences between a GSI and GI. The wiring diagram shows to be the same but there are differences otherwise there would just be one model, at least the way I see it

 

[cnotecherry]

Why do you need a new engine harness?

 

[rtoomey641]

Because I cut plug apart and don’t know which wire is bad on my alternator the jumper wire is connected to orange not like pic new harness looks like pic how should I hook it up

 

[cnotecherry]

Alldodge already explained that that diagram was not for your exact engine sounds like your new harness is for an mefi2 and you have an mefi3 I would think there would be slight differences in the harnesses but I'm not sure I personally would not use that harness

 

[rtoomey641]

Yes harness was incompatible so I’m going to take it to my boat guy he’s an hour away but he knows his stuff and is only $60 an hour do you have a diagram for my engine it is a 5.7 GSI PWTR 3868947 is serial number harness number is 3858281 Thanks

 

[cnotecherry]

No I do not I thought all you were doing was splicing your 10pin connector if it was running fine before you spliced it and you spliced in proper than you should be fine if you have some wires crossed than like I said in one of my first post you will have to trace all your wires the 10 pin only connects your helm yo your engine so everything is easily traced by colour matching instruments/ignition to sensors/ignition on engine a wiring diagram is only good if everything is bone stock and engine is stock to instruments/ignitoin and noone has ever tampered with the electrical system/wires witch your boat being an 87 is not likely however they have been using the same colour coding for a long time

 

[rtoomey641]

He’s going to splice for me