1997 STS Ground Wire Missing?

[red97sts]

1997 STS

Please see enclosed photo , behind the bolt that the arrow is pointing to,

there is a small metal piece, looks like a wire of some kind. What is the

proper name of the wire? Need to find a new one. I think it is a ground

wire, it is crimped. Also need to know where it goes to.

[Logan]

Maybe....I think it may be coming off the fuel injector harness. See picture. Some more poking around the service manual is required to figure out the ground # and purpose. My service info really only goes back to 1998.

Yours looks too big to be the same one in the diagram drawing.

[Cadillac Jim]

The 1997 FSM shows the fuel injectors connected to power and the PCM but not ground. It could be for a sensor on the same harness, but the grounds listed in the locator table on page 6-277 are G102 (lower right hand rear of the engine, near the power steering rack), G107 (lower left hand front corner of the engine, below the thermostat housing), G109 (left hand rear corner of the engine, near the park/neutral position switch), G203 (left hand front corner of the passenger compartment, behind the kick panel), and G401 (right hand rear of the passenger compartment, under the rear seat). So, perhaps it isn't a ground, or at least a factory ground.

If the wire is DK BLU, it might be the wire from the knock sensor, which is supposed to go through C131 to the PCM. You would think that grounding the knock sensor would throw a code.

[Logan]

The pic I provided...is from the '97 part of the service manual I have access to. To me...it looks like a anti static strap of some type as it appears to just clip on the fuel rail. The one in the picture looks pretty beefy.

[Cadillac Jim]

The only beefy ground that I know of is the battery ground cable, which is to G105 (right hand front corner of the engine, near the generator).

I found the diagram that Logan uploaded on page 8A-201-15. The pigtail on the left isn't labeled but it looks like it goes to C131, and if so, the wire that red97sts is asking about isn't on that figure. The figure right below it shows the starter motor and starter solenoid, which has two wires with a total of four pigtails. That's interesting because the starter circuit diagram on page 6-203 only shows two wires going to the starter (enable/solenoid actuator from the relay and the battery cable) and no labeled grounds going to the starter. That probably means that the other two wires with pigtails are grounds. If so, the pigtail that red97sts is looking at is probably a solenoid ground.

Someone with a 1996-1999 Eldorado or 1996-1997 Seville handy or that has looked at the wires under the beauty cover and under the manifold can tell us. I don't have a car of that model year to look at anymore.

The figure:

[airmike]

I looked at my 99 sts and the wire is exactly like the one in post #2 by Logan. From the fuel injector harness. Black, likely 16 ga wire with a bare round end.

I can take a pic if needed.

[barczy01]

some of the cars late 96' had a static ground off the fuel rail that attached to the top right cylinder head. 1997-99 they had a ground from the ignition control module rf corner 10mm to the right hand cylinder same place for rf interference and module ground and the fuel rail ground too.

[barczy01]

this image is not correct. Its almost like a confused 1998 seville sls,sts diagram.

[Cadillac Jim]

I think I may have it. Look at Logan's picture again. In the figure, the wire isn't coming off the wiring harness, it's coming off the fuel rail itself, so perhaps It's a ground for the fuel rail. This sort of makes sense because the manifold is plastic for model year 1997, but the fuel rail was also plastic until a recall a few years later to replace it with a metal fuel rail. The schematic of the injectors on page 6-265 shows that the injectors have power on one side and the PCM on the other and thus don't need a ground, so, again, there is no ground on the injector circuit. The MAP sensor has three wires, all that go to the PCM.

This may be a part of the fuel rail recall. That would explain why we don't see it in the FSM but do see it on the cars. That doesn't explain why the ground is such a large wire, unless it's a mechanical stabilization against vibration as well as a ground. But that doesn't explain why it's in Logan's figure, unless that wire is the wire that goes to C131 or is one of the EVAP wires.

Anyone who takes the engine cover off a 1997, please look at that wire and tell us what it hooks up to on the other end.

[airmike]

Jim I am lost on this post. My car is 99 but the wire is exactly what post 2 shows. It looks like a ground on the fuel rail (which is plastic) on my car. It is NOT a large wire. Perhaps we are talking about different wires. In post #1 he asks "behind the bolt that the arrow is pointing to, there is a small metal piece, looks like a wire of some kind".. I figure he is asking about a small wire behind the big wire, which must be going to the starter, (mine is different).

red97sts are you there to clarify?

[Cadillac Jim]

I sold my 1997 ETC a couple of months ago but I have my 1997 FSM handy. That won't help if the wire is part of the fuel rail recall. A photo of the wire or information on what the other end hooks up to would help.

[airmike]

I took pics and it seems someone in my house decided they needed my usb cable more than me. Sorry for now, I can't post.

[Cadillac Jim]

Send the pics to your computer workstation email account.

[airmike]

Cable found

[Cadillac Jim]

airmike - the pics are MIA and your Photobucket account is private.

[airmike]

Trying again. first pic is the center of the plastic fuel rail

[Cadillac Jim]

My goodness, it's a fuel rail ground, on a metal fitting between two plastic fuel rails for the two banks. It looks like it bolts to the front of the timing chain cover.

[rockfangd]

That it is. Does that year have the recall for the fuel rail? I know both my 96 and 97 have replacement steel rails

[airmike]

The wire actually bolts to a threaded boss on the top of the rear head, right behind that wire end. It looks like where the ground wire from the starter bolts on, in the op. My starter wire goes to a fuse block attached to fender (shown in a different post, asking about an unknown vacuum hose) that is not on the earlier version I guess.

As for a recall, I have no idea. Sounds like something to check on, if I ever get this thing to run again.

[Logan]

It all makes sense in the end....Here is the recall bulletin:

General Motors has decided that a defect which relates to motor vehicle safety exists in all 1995-1997 Cadillac DeVille Concours, Seville and Eldorado, 1996-1997 Cadillac DeVille; and 1995-1997 Oldsmobile Aurora model vehicles. These vehicles have a condition in which the original equipment nylon tubing used in the fuel rail construction may degrade and crack. Additionally, the 1995 Oldsmobile Aurora uses a unique underhood fuel return line that may crack at unusually high rates. Cracking of the fuel rail can result in a fuel leak into the engine compartment. The operator may experience fuel odor and possibly engine stalling due to loss of fuel pressure to the engine. If this event were to occur, and if an ignition source were present, an engine compartment fire could occur.

Part of the bulletin. Has the tech unbolt and remove the fuel rail wire terminal /ground.

52) Remove the grounding harness from the front of the right (rear) cylinder head.

53) Remove the fuel rail ground harness.

54) Reinstall the ground harness bolt with the ECM / ignition coil ground harness.

Of course....that's the official version. Any 'good' tech is simply going to cut or wiggle the wire to break it.

There is a plastic fuel rail version that is ok. If the rail is printed GM213M TYPE F (or) M-BOND it is ok.

Picture from the bulletin shows the big wire....and the smaller fuel rail ground wire.

[Cadillac Jim]

The 1997 FSM pages 8A-10-1 show three positive battery cables, one to the "generator," one to the starter solenoid, and one to the RH MaxiFuse block with a dotted connection to the LH MaxiFuse block. Page 8A-14-1 shows two battery ground cables, one to G100 and one to G105. ON page 8A-14-40, it gives the location of G100 as the right hand front corner or the engine compartment, on the radiator support, and the location of G105 as the right hand front corner of the engine, near the generator.

There is no mention of a ground on the rear head. I suppose that the big wire is the ignition module ground and the little wire is the fuel rail ground. The ignition module is grounded through its mounting bolts but without the main ground, the big wire in the picture, you can get a code occasionally, and the FSM cautions you to be sure that this ground is OK when mentioning the ignition module, changing the coils or ignition module, etc.