Quick Confirmation - Fuel Pump Wiring for Good Ground

[Terbro]

See attached pic. My afternoon project is to give my fuel pump (hot wired DW301) a good ground. To orient the viewer, the wires in my hand, from the bottom of the photo, are coming from the top of the fuel tank. That must be the fuel pump. Okay, so I want to ground the black wire; the one on the left in my fingers, yes?

I had Nick Micale build my motor, and he installed the FP and hot wire kit. I'm assuming the little black box at the upper right hand corner of the pic is the hot wire kit. Just want to make sure I'm staying away from those wires.

On my way now to get some 10-gauge wire, and some splicer/connector dealies...forget what those are called...to tap into the ground wire.

 

[Chuck Leeper]

That's stock wiring. I suggest you start at the pump, and replace it all, out to the the end of the hot wire kit.

 

[Boost231]

call nick, he can guide you in the correct way of addressing this issue

 

[dynoman]

That is the stock intermediate harness . You need to get the Racetronix harness . It is made with bigger wire and has a new yellow bulkhead connector on it , which is a known source of poor connections . http://www.racetronix.biz/customkititems.asp?kc=BCWA-G7U
You will have to drop the tank to get it plugged in . Sam

 

[Terbro]

I did do it exactly per Nick's instructions. And that was to take a 10-gauge wire, and splice it into the wiring's ground wire, and run that to the alternator. There's an unused threaded hole there, which he said is a very good ground (an alternative to the battery). Did exactly that, and the weirdest thing happened. Man, I'm f'ing frustrated!!! At first starting it, everything seemed fine. I go head out of the neighborhood (Halloween, kids everywhere) and onto an open, quiet, street w/o houses on it. I set the Scanmaster to BAT and originally didn't notice any change than before...still reading between 13.6 and 14.1 volts...typical. I then get on it, to about 70% throttle, and it feel perfect smooth as boost is building, but then totally cuts out. I happened to notice once that the volts read 15.1. This happened a couple times under heavy throttle, and then I realized I was almost out of gas (1/8th tank. So I figured I was just getting a bit of air in the fuel line under heavy pedal. Put 10 gals of E85 in, and head down another open street. Cruising and medium throttle are still normal, as are the volts. I get on it, and it cuts out, and just then the wiper fluid light goes on, the volts start consistently reading mid to high 14 volts (even at idle), and now...it's sputtering under the lightest of throttle - can barely drive it. It idles fine, but whenever any amount of gas is given, it now sputters like crazy. Again, this all happened as a result of a heavy throttle blast, just after doing the grounding job.

I'm fairly confident I've got all three wires connected and twisted together well at the fuel pump ground wire.

Sigh... Well, I'll call Nick, but I suppose the first thing to do is to see what happens if I undo the ground at the FP ground wire, put it back to the way it was and see if the problem goes away.

Probably didn't need to take a vid...people know what sputtering is, but here it is:

Ran absolutely perfect before.

 

[Terbro]

Disconnected both connection ends (one at a time), i.e., put back to normal - still screwed up. Scanmaster shows two codes now - 23, 34; MAT and MAF. WTF? So, it's now in limp mode, right? Something fried.

 

[Terbro]

No power to the Gen II Translator now. Checked all fuses - all good. Miffed now...waiting for a call back from Nick. He and his associate installed the Gen II. No clue about the wiring. Much of it's tucked under the dash.

 

[Chuck Leeper]

I'm fairly confident I've got all three wires connected and twisted together well at the fuel pump ground wire.

Splicing into that wire is not the correct way to improve the ground circuit, as you still have a ? of integrity at the pump ground. You start at the device, and run the wiring to the new termination point, such as the alt case, or better yet, directly to the batt post.
I hope you soldered those wires when you "twisted them together". Also, you didn't hook that ground to the hot terminal on the alt, did you?
15 v at idle sounds like something is causing the alt to go to a full field condition.
Sam has the answer for the old wiring in post #4.

 

[Terbro]

I'm not going to argue that Chuck. I did exactly what Nick said, which is probably the inexpensive and easy way (instead of pulling tank) to potentially improve the ground. I think Nick reasoned that the stock ground wire is close enough to the fuel pump, that adding the ground at that point will be an improved ground.

No, of course not...I added the ground wire to the open hole on the alternator case. See pic in post #5. Everything is disconnected for the moment, and my sole concern now is getting power back to the Gen II. I'm betting the fact that the car is in limp mode is what's causing the add'l voltage. I'm at a loss at this point...will have determine which of the 6-8 wires in the connector to the Gen II is the power, test for power (which means I need a volt meter), then trace that and figure out what's up. Either that, or there was a surge of voltage, and the Gen II fried.

 

[Boost231]

That is the stock intermediate harness . You need to get the Racetronix harness . It is made with bigger wire and has a new yellow bulkhead connector on it , which is a known source of poor connections . http://www.racetronix.biz/customkititems.asp?kc=BCWA-G7U
You will have to drop the tank to get it plugged in . Sam

racetronix has a nice piece but it still uses the little pin connectors in yellow bulkhead. almost a waste imop. there are better ways to fix the power and ground issues

 

[Chuck Leeper]

I'm not going to argue that Chuck. I did exactly what Nick said, which is probably the inexpensive and easy way (instead of pulling tank) to potentially improve the ground. I think Nick reasoned that the stock ground wire is close enough to the fuel pump, that adding the ground at that point will be an improved ground.

No, of course not...I added the ground wire to the open hole on the alternator case. See pic in post #5. Everything is disconnected for the moment, and my sole concern now is getting power back to the Gen II. I'm betting the fact that the car is in limp mode is what's causing the add'l voltage. I'm at a loss at this point...will have determine which of the 6-8 wires in the connector to the Gen II is the power, test for power (which means I need a volt meter), then trace that and figure out what's up. Either that, or there was a surge of voltage, and the Gen II fried.

I understand you did what Nick said. Being in limp should not put the alt to full field. Once you removed that wire, did you disconnect the ecm power wire to reset it?
Here's some info on the wiring:
http://www.fullthrottletech.com/attachment.php?attachmentid=303&d=1151
Please, DO NOT use house wiring devices on your car! I'd hate to see a post that it burned down, due to an electrical issue.

 

[dynoman]

racetronix has a nice piece but it still uses the little pin connectors in yellow bulkhead. almost a waste imop. there are better ways to fix the power and ground issues

The new bulkhead connector is rated @ 30amps with 10 ga. wiring to it .
HD Harness Features

• 10-gauge wire on main power feeds
• 10-gauge wire on intermediate harness ultrasonically welded to bulkhead leads
• 30-amp Metri-Pack sender interface connectors
• Upgraded 10-gauge redundant grounding system , This is from the Racetronix website

 

[Terbro]

I understand you did what Nick said. Being in limp should not put the alt to full field. Once you removed that wire, did you disconnect the ecm power wire to reset it?
Here's some info on the wiring:
http://www.fullthrottletech.com/attachment.php?attachmentid=303&d=1151
Please, DO NOT use house wiring devices on your car! I'd hate to see a post that it burned down, due to an electrical issue.

The alternator going into full field definitely concerns me. I disconnected the ground wire at both ends. Reset the ECM (twice) yesterday and no improvement. Last night, I started it up and it was over 15 volts. Running the car as little as possible. Next step is get with Bob Bailey later today (will be buying a volt meter shortly) to troubleshoot the GEN II issue). Get to get it out of limp mode first, then let's what's up with the volts.

BTW, where is the MAT sensor? I'm getting code 23 too.

 

[Terbro]

I've got a preliminary theory: For some reason, during the WOT run, the alternator spit out a surge of high voltage and fried the GEN II.

I think the first thing I'll check is to see if there's power to the connector to the GEN II once I get the volt meter. If the GEN II is fried, then maybe new alternator time? I had the thought as I was screwing the bolt (probably 3/4" long) into it, to connect the ground)..."I hope it's not so long that it's contacting the internal moving parts of the alternator".

 

[Boost231]

The new bulkhead connector is rated @ 30amps with 10 ga. wiring to it .
HD Harness Features

• 10-gauge wire on main power feeds
• 10-gauge wire on intermediate harness ultrasonically welded to bulkhead leads
• 30-amp Metri-Pack sender interface connectors
• Upgraded 10-gauge redundant grounding system , This is from the Racetronix website

Your quoting the wrong part. Thats the harness.

This harness features:

- Upgraded 14 gauge automotive-grade TXL wire
- A dedicated ground wire which will replace most factory bonded ground wires found on old senders.

When this harness is used in combination with our upgraded in-tank harnesses the overall resistance is reduced from approximately 0.085 to 0.026 ohms.
When using a HP pump (Walbro, Bosch, Denso) this translates to an improvement of approximately 5.4% in pump performance. *

Some vehicles may have different WeatherPack keying or designations. Alternative connectors and / or pin-outs can be special ordered.

********

The yellow bulkhead connector is OE equipment and has been pressure tested, fitted with an o-ring seal and supplied with a new SS press-on retaining clip.
The bulkhead connector is a perfect match for the keyed hole the factory G75, G77 and many other G.M. senders so you do not have to drill any holes or make any modifications.

 

[dynoman]

I stand corrected , but the harness I posted has been tested with sustained 20a @ 13.5v loads which is more than enough for his needs . His problem is an unregulated voltage output from the alternator . Originally I thought he had a volt booster causing his over voltage problems not a regulator problem .

 

[Chuck Leeper]

I had the thought as I was screwing the bolt (probably 3/4" long) into it, to connect the ground)..."I hope it's not so long that it's contacting the internal moving parts of the alternator".

Could be. That bolt should be 1/2 that length. Take a look in the hole, and see what you may have hit.
It may have done in the regulator, and caused the hi output.
I didn't see one, but do you have a volt booster on it?

 

[87-WE2]

I know nothing of the GEN II, so I'll stay away from that.

For the running rough, it may be that the increased voltage to the pump was causing higher fuel pressure, and therefore a rich condition. Totally agree that you need to concentrate on the gen II issue and map codes first.


Sent from my iPhone using Tapatalk

 

[dynoman]

For the running rough, it may be that the increased voltage to the pump was causing higher fuel pressure, and therefore a rich condition.

Even if the pump was seeing more voltage , thus pumping more fuel , the fuel pressure regulator would keep FP steady & then increase it 1 for 1 when into boost . If it didn't regulate and hold FP steady , your fuel pressure would be all over the place with stop & go driving without even going into boost .

 

[Phoneguy]

If the return line can't keep up with the added fuel , it has nowhere to go and fuel pressure will rise.
Do you have a fuel pressure gauge?

Bryan