hugdaturns

The car was bought already swapped with 99 ls1 and tranny, 230/232 cam. 3600 stall. Tuned by pcm4less, harness was claimed to be reworked by speartech but im finding nothing that shows it was done by them(the original fuse box was also retained. Up until a few days ago crank perfectly, ran rough though(needs retune for cam an stall i was thinking). Tried to crank got a stumble and it cut off. Continued to try an crank but no start. Recharged battery, connected scan tool, primed pump(pump came on,had pressure at rail) attempted to crank. Scan tool went out(no power to ecm or pump). Checked relays, three bigger ones had power in and out, smaller relay had power in, not out. Replaced smaller relay (fuel pump came on, yes!) Tried to crank,(went back out no!also forgot to hook up scan tool, retraced wiring to each relay(to my limited knowledge their wired wrong! Hot wire was next to ground, but the relay shows them to be diagnol)Not sure how it ever worked in first place) removed relay, noticed plastic is burnt in the location of ground wire and gray wire( not sure what grey wire is yet) removed wires from fuse block, connected hot wire to 86, ground wire to 85. Got click(relays sounds like its working)meter shows no power out other legs. Tested other relay, samething(guess i fried em, not sure though checked for power at coil connector got 12v tested fuel injectors 12v now im really so know i need to know 1 how was it running if it was wired wrong? 2 is my pcm now fried? 3 what does the grn/wht wire and grey wire go to? 4 where do i begin to fix this issue? Thanks in advanve any would be appreciated. Im learning everday!

Aviator857

In my swap I also kept the 4th gen fuse boxes. But it will be hard to troubleshoot. Download the schematic for the donor car and see if the wire colors match. You can make or buy a bench harness to test the pcm.

Aviator857

Do you only have the one or both under hood fuse boxes? If it is the same relay the two bigger wires, red should be fused power, blue should be going to what ever the relay runs. Orange and green will be the engage positive/negative. Not sure which color is which in your set up.

Is that the underside of the fuel pump relay? Since you said you were able to power on the relay via the pcm scan tool I would assume the orange or green or both wire goes to the engine harness and then to the PCM. There is usually three connectors on the passenger side see if there are matching wires there.

It sounds almost like the power lead to your fuel pump is shorting to ground.

I would disconnect the PCM while you trouble shoot.

The power to the relay could be fused in the box there, they could of used the original fuel pump fuse etc its hard to say.

I made a point to use (and document) the original placement and wire colors from the 2k donor.

hugdaturns

It would've been a lot easier to troubleshoot with documentation of wiring i agree. I found the problem though. I'm not an expert in electricity, i just understand the basics enough to troubleshoot it. Had an open in a connector from a bad tefrminal, and I'm assumming a short to ground also (there was still power on the side of the connector while disconnected). Fixed terminal, rewired relay and pump came on, and fired up. Thing is pump is barely audible, as before i could hear it well. Is that a good thing. And thanks for your help!