Possible Bad Ground - EFI

[jesus888]

I'm not sure if we have a bad ground on the truck or not. HOW can I figure it out?

This came about after a couple of things started happening...

First off, in order to check the EFI codes that the truck was throwing, we plugged in the tester and it just wasnt' reading properly... when we called the mfg of the tester, they suggested that the ECU may not be grounded as well as it needs to be... is there a way to test this, and are there any tell-tail signs?

Secondly, we're having an issue with our fuel gauge... not getting proper readings. We are certain that it's the correct gauge (ohm range) however when we called Autometer, one of their questions was whether the gauge had its own ground or if it was a a shared ground... it's a shared ground so he suggested that we give it its own ground because "just because you complete the circuit (with the test light) that doesn't mean it's a good ground, which could be causing your problem"

Thanks!

 

[DirtDonk]

Not sure about specific issues, but I'd start with the main grounds first. Make sure that the battery negative is going not only to the engine block, but also has at least some decent size jumpers running to the body and the frame. Your fuel sender gets it's ground from it's own little pigtail on the frame rail just above the sender, so the frame is just as important as the other items.
The engine itself should also have jumpers to the body. And even to the frame if you want to get serious. A good spot, and where the factories all seem to put them, is to run a wire from the intake manifold bolt to the firewall. Autoparts stores sell lengths of pre-terminated braided cable just for grounds. I picked up several and hooked them up all over the place. Including between the body and the frame, since it sits on rubber insulators.
With this method, if you've got your ECM bolted to the body anywhere, you're more likely to have a good ground too.

Good luck. And, as we like to say here on CB, you just can't have too many grounds!

Paul

 

[ransil]

Bad ground??? First rule in customer service give the customer home work to get him off the phone. 90% of the time they never come back weather its good advice or bad.

Did you properly connect pin 30 (NSS) of your computer, how it is connected depends on weather the computer is for a manual or an automatic, it does not matter what tranny you have.

Do you have good grounds??
"sheet metals screws make for a crappy ground"
good ground will be a welded stud on the body and frame, connected Batt-Engine-Frame-Body

All the EFI wires should ground in the same place.

put 2 gallons of fuel in the tank and check pressure, ignore the fuel level gauge for now.

Did it ever run??

 

[jesus888]

Bad ground??? First rule in customer service give the customer home work to get him off the phone. 90% of the time they never come back weather its good advice or bad.

Did you properly connect pin 30 (NSS) of your computer, how it is connected depends on weather the computer is for a manual or an automatic, it does not matter what tranny you have.

Do you have good grounds??
"sheet metals screws make for a crappy ground"
good ground will be a welded stud on the body and frame, connected Batt-Engine-Frame-Body

All the EFI wires should ground in the same place.

put 2 gallons of fuel in the tank and check pressure, ignore the fuel level gauge for now.

Did it ever run??

assume you mean vss on 30 pin; it is not connected;
got computer with motor do not know if donor car was manual or auto-is there a way to find out----

have dual batteries--main battery has ground from Kolibar harness,winch, and ground strap going to body,also goes to a/c compressor on motor

efi harness has another ground going to alternator mount;

second battery has body strap going to frame, and ground going to alternator mount--

alternator (3g) has ground going to alternator bracket--

ground coming from ecu ties to body----

 

[RV77]

Re-read what he said about the trans and the Nss (Nuetral safety switch) He said it does NOT matter what trans you have.

 

[jesus888]

Re-read what he said about the trans and the Nss (Nuetral safety switch) He said it does NOT matter what trans you have.

O.k I saw on fordfuelinjection about the 30 pin; I have no idea what it is hooked to Kolibar did my harness; once I find 30 pin should it just be grounded; or tell me what I should do;

 

[Viperwolf1]

Does the computer have a catch code on it, like A9L or A9P? Once you find that you can go to FFI.com and see what kind of trans it's programed for. After that we can figure out how pin 30 is supposed to be connected.