Yet another fuel delivery question (95 Jimmy) - amp draw o..

"aarcuda69062" <nonelson RemoveThis @sbcglobal.net> wrote in message
news:nonelson-F81727.08064919022007@newsclstr02.news.prodigy.com...
> In article <C1FEA96E.B165%anixon1@cogeco.ca>,
> AWN <anixon1 RemoveThis @cogeco.ca> wrote:
>
> > I am still hunting for my hard start solution and I noticed that the
fuel
> > pump relay in the glove boax runs very hot. I assume one of two
things...
> > A partial short in the wiring harness or a pump that's running too hard
due
> > to a failing motor or similar... Here's my question...
> >
> > Can I test amp draw for the pump from the relay socket or computer
> > connection or similar??
> > Andrew.
>
> You can test fuel pump amperage anywhere that is convenient.
> Current does not change anywhere in the circuit.
> You do need to compensate for any other powered devices that
> share the circuit though.

The relay gets hot when? You can check the current anywhere between the
relay and the pump, not at the computer connection. If the pump was drawing
too much current the fuse, if it's the correct one, should blow.

Al
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

"Big Al" <sal1 DeleteThis @qwest.net> wrote in message
news:45d9bab0$0$25775$815e3792@news.qwest.net...
>
> "aarcuda69062" <nonelson DeleteThis @sbcglobal.net> wrote in message
> news:nonelson-F81727.08064919022007@newsclstr02.news.prodigy.com...
>> In article <C1FEA96E.B165%anixon1@cogeco.ca>,
>> AWN <anixon1 DeleteThis @cogeco.ca> wrote:
>>
>> > I am still hunting for my hard start solution and I noticed that the
> fuel
>> > pump relay in the glove boax runs very hot. I assume one of two
> things...
>> > A partial short in the wiring harness or a pump that's running too hard
> due
>> > to a failing motor or similar... Here's my question...
>> >
>> > Can I test amp draw for the pump from the relay socket or computer
>> > connection or similar??
>> > Andrew.
>>
>> You can test fuel pump amperage anywhere that is convenient.
>> Current does not change anywhere in the circuit.
>> You do need to compensate for any other powered devices that
>> share the circuit though.
>
> The relay gets hot when? You can check the current anywhere between the
> relay and the pump, not at the computer connection. If the pump was
> drawing
> too much current the fuse, if it's the correct one, should blow.

If it helps any... When the pump in my suburban went it was drawing 18amps.
After the pump was replace the new pump was drawing 2amps peak. I have
heard of times were the wiring to the top of the tank corroded and in cases
actually melted.

good luck,
mark
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Have you ever replaced the fuel pump relay? If the points get bad, the
heat and resistance will increase. A badly worn relay can actually
cause the pump to burn-out due to low voltage to pump motor.

James
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

I just tested the amp draw on my pump from the test connector under the hood
and I saw a fairly steady 8.6A (I checked for glitch capturing within 1A and
nothing turned up). I scoped it while I was as it and it had a very steady
wave with no real drops or rounded edges so either it's in fine shape or
it's worn to a point that it doesn't fluctuate. I read somewhere that these
high output fuel systems will have a draw up to 10A on a good pump. Can
anyone verify this? I still think it's a nasty electrical issue with supply
to the relay but I just wanted to update anyone who's helped out this far.

Thanks,
Andrew.




in article 45d9db88$0$9861$ec3e2dad@news.usenetmonster.com, r_d at
rock_doctor DeleteThis @hotmail.nospam.com wrote on 2/19/07 12:19 PM:

>>> You can test fuel pump amperage anywhere that is convenient.
>>> Current does not change anywhere in the circuit.
>>> You do need to compensate for any other powered devices that
>>> share the circuit though.
>>
>> The relay gets hot when? You can check the current anywhere between the
>> relay and the pump, not at the computer connection. If the pump was
>> drawing
>> too much current the fuse, if it's the correct one, should blow.
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

If anyone knows the flow rate...I could calculate an estimated value based
on the pressure, flow, efficiency and voltage.

Also, you might measure the resistance through the load side of the fuse to
ground and compare that to a new pump.


"AWN" <anixon1.DeleteThis@cogeco.ca> wrote in message
news:C1FFA1D1.B17D%anixon1@cogeco.ca...
>I just tested the amp draw on my pump from the test connector under the
>hood
> and I saw a fairly steady 8.6A (I checked for glitch capturing within 1A
> and
> nothing turned up). I scoped it while I was as it and it had a very
> steady
> wave with no real drops or rounded edges so either it's in fine shape or
> it's worn to a point that it doesn't fluctuate. I read somewhere that
> these
> high output fuel systems will have a draw up to 10A on a good pump. Can
> anyone verify this? I still think it's a nasty electrical issue with
> supply
> to the relay but I just wanted to update anyone who's helped out this far.
>
> Thanks,
> Andrew.
>
>
>
>
> in article 45d9db88$0$9861$ec3e2dad@news.usenetmonster.com, r_d at
> rock_doctor.DeleteThis@hotmail.nospam.com wrote on 2/19/07 12:19 PM:
>
>>>> You can test fuel pump amperage anywhere that is convenient.
>>>> Current does not change anywhere in the circuit.
>>>> You do need to compensate for any other powered devices that
>>>> share the circuit though.
>>>
>>> The relay gets hot when? You can check the current anywhere between the
>>> relay and the pump, not at the computer connection. If the pump was
>>> drawing
>>> too much current the fuse, if it's the correct one, should blow.
>
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

James,

I have replaced the EFI relay 3x to be sure that's not my problem. I don't
think the issue is with the relay unless it's a bad/cold solder joint in the
actual socket itself.
Thanks.
Andrew.







in article 1171930181.757130.123450 RemoveThis @t69g2000cwt.googlegroups.com, James1549
at James1549 RemoveThis @current.net wrote on 2/19/07 7:09 PM:

> Have you ever replaced the fuel pump relay? If the points get bad, the
> heat and resistance will increase. A badly worn relay can actually
> cause the pump to burn-out due to low voltage to pump motor.
>
> James
>
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

I have a Tech2Tech article that suggests 28mmils at 60psi. I have a
flowrate formula:

HPxBFSC
-------
# of cylxMax Duty Cycle

240x0.4 96
-------- = ------- = 20lb/hr??
6x.80 4.8


but I didn't look at it very hard. Do you know exactly whre the fuel pump
is grounded at? I still suspect a ground differential.
Thanks.
Andrew.


in article 5vrCh.59379$QU1.20233@newssvr22.news.prodigy.net, News Skimmer at
NewsSkimmer RemoveThis @sbcglobal.net wrote on 2/19/07 7:36 PM:

> If anyone knows the flow rate...I could calculate an estimated value based
> on the pressure, flow, efficiency and voltage.
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

WTF is all that? Not sure what your formula is for. What unit is your flow
rate in? not sure what mmils are...please spell out. also does that rate
include the recycle...recycle must be included in the horsepower calc.

On the c/k's, the ground peels out of the harness / plug near the pump and
bolts to the frame. If it is a ground problem, I don't think that would
lead to excess amps.

skimmer

"AWN" <anixon1.TakeThisOut@cogeco.ca> wrote in message
news:C1FFE93B.B199%anixon1@cogeco.ca...
>I have a Tech2Tech article that suggests 28mmils at 60psi. I have a
> flowrate formula:
>
> HPxBFSC
> -------
> # of cylxMax Duty Cycle
>
> 240x0.4 96
> -------- = ------- = 20lb/hr??
> 6x.80 4.8
>
>
> but I didn't look at it very hard. Do you know exactly whre the fuel pump
> is grounded at? I still suspect a ground differential.
> Thanks.
> Andrew.
>
>
> in article 5vrCh.59379$QU1.20233@newssvr22.news.prodigy.net, News Skimmer
> at
> NewsSkimmer.TakeThisOut@sbcglobal.net wrote on 2/19/07 7:36 PM:
>
>> If anyone knows the flow rate...I could calculate an estimated value
>> based
>> on the pressure, flow, efficiency and voltage.
>
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Sorry - I was just pluging in some numbers based on a formula I have seen
used. The formula is for flow rate based on Lbs/hr. I believe that it's
used to determine injector sizing with modified motors. BSFC (Brake Specific
Fuel Consumption as a calculation of lbs per horsepower-hour) , Max Duty
Cycle set at .80 b/c most injectors would burn up b/w 90-100 I would think).
Mils (volumetric 1000th of an inch) 'mmils' was a typo.

Anyway, forget the formula - I was just playing with a formula I had seen
used - as for recycle rate - I don't know.

Thanks for the feedback. As for the grounding issue - I'm not so concerned
with high amps now that I know 8-9A is on the normal side for these fuel
systems - the pump will run intermittently at startup meaning that sometimes
turning the key won't engage the pump motor. I thought maybe a bad ground
could be to blame...

Thanks again!
Andrew.



in article DlOCh.47984$Gr2.23311@newssvr21.news.prodigy.net, News Skimmer at
NewsSkimmer.RemoveThis@sbcglobal.net wrote on 2/20/07 9:43 PM:

> WTF is all that? Not sure what your formula is for. What unit is your flow
> rate in? not sure what mmils are...please spell out. also does that rate
> include the recycle...recycle must be included in the horsepower calc.
>
> On the c/k's, the ground peels out of the harness / plug near the pump and
> bolts to the frame. If it is a ground problem, I don't think that would
> lead to excess amps.
>
> skimmer
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Maybe this weekend I'll measure the amp draw on my 99 5.7r

My 93 4.3z TBI with a new bosch pump pulls less than 2.

Based on the 2 at 10-12 psi, 60 psi would raise the amps for the same flow
to 10

skimmer

"AWN" <anixon1 RemoveThis @cogeco.ca> wrote in message
news:C2012F2A.CC66%anixon1@cogeco.ca...
> Sorry - I was just pluging in some numbers based on a formula I have seen
> used. The formula is for flow rate based on Lbs/hr. I believe that it's
> used to determine injector sizing with modified motors. BSFC (Brake
> Specific
> Fuel Consumption as a calculation of lbs per horsepower-hour) , Max Duty
> Cycle set at .80 b/c most injectors would burn up b/w 90-100 I would
> think).
> Mils (volumetric 1000th of an inch) 'mmils' was a typo.
>
> Anyway, forget the formula - I was just playing with a formula I had seen
> used - as for recycle rate - I don't know.
>
> Thanks for the feedback. As for the grounding issue - I'm not so
> concerned
> with high amps now that I know 8-9A is on the normal side for these fuel
> systems - the pump will run intermittently at startup meaning that
> sometimes
> turning the key won't engage the pump motor. I thought maybe a bad ground
> could be to blame...
>
> Thanks again!
> Andrew.
>
>
>
> in article DlOCh.47984$Gr2.23311@newssvr21.news.prodigy.net, News Skimmer
> at
> NewsSkimmer RemoveThis @sbcglobal.net wrote on 2/20/07 9:43 PM:
>
>> WTF is all that? Not sure what your formula is for. What unit is your
>> flow
>> rate in? not sure what mmils are...please spell out. also does that rate
>> include the recycle...recycle must be included in the horsepower calc.
>>
>> On the c/k's, the ground peels out of the harness / plug near the pump
>> and
>> bolts to the frame. If it is a ground problem, I don't think that would
>> lead to excess amps.
>>
>> skimmer
>
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Once again - I appreciate the help. I was able to confirm that 8-10A is
acceptable for a 60psi Vortec fuel system so you needn't worry about
metering your trucks for me. I will post again if I solve the intermittent
no start issue. As a gesture of good faith, I pulled almost every harness
on the truck and packed them with dielectric grease. I sanded and refitted
all the engine grounds also. I didn't put any grease in the computer molex
connectors because I was a little leary about that even though it's likey to
be fine. I have yet to remove and sand down the fuel pump ground but it's
next on my list. Failing all of this, I will replace the entire relay
'convenience center' in the glovebox and then start metering outputs on the
computer.

Thanks!
Andrew.




in article PZQCh.31049$yC5.19679@newssvr27.news.prodigy.net, News Skimmer at
NewsSkimmer.DeleteThis@sbcglobal.net wrote on 2/21/07 12:43 AM:

> Maybe this weekend I'll measure the amp draw on my 99 5.7r
>
> My 93 4.3z TBI with a new bosch pump pulls less than 2.
>
> Based on the 2 at 10-12 psi, 60 psi would raise the amps for the same flow
> to 10
>
> skimmer
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Intermittent no starts (no fire/no fuel) can be caused be a bad ignition
module.

On the fuel pump relay...you might consider removing it and powering the
pump directly with a fused jumper through the load side of the fuse.

On my 93 c1500, you can power the pump through one of the OBD1 connector
pins which then passes through the fuse. You might need to check your wiring
diagrams because that pin might not work if the relay is pulled out or arc'd
close (welded closed in run position). I think my test connection opens when
the relay closes. Make sense? probably not but study your schematics.

skimmer

"AWN" <anixon1.DeleteThis@cogeco.ca> wrote in message
news:C2029A3A.CC95%anixon1@cogeco.ca...
>
>
> Once again - I appreciate the help. I was able to confirm that 8-10A is
> acceptable for a 60psi Vortec fuel system so you needn't worry about
> metering your trucks for me. I will post again if I solve the
> intermittent
> no start issue. As a gesture of good faith, I pulled almost every harness
> on the truck and packed them with dielectric grease. I sanded and
> refitted
> all the engine grounds also. I didn't put any grease in the computer
> molex
> connectors because I was a little leary about that even though it's likey
> to
> be fine. I have yet to remove and sand down the fuel pump ground but it's
> next on my list. Failing all of this, I will replace the entire relay
> 'convenience center' in the glovebox and then start metering outputs on
> the
> computer.
>
> Thanks!
> Andrew.
>
>
>
>
> in article PZQCh.31049$yC5.19679@newssvr27.news.prodigy.net, News Skimmer
> at
> NewsSkimmer.DeleteThis@sbcglobal.net wrote on 2/21/07 12:43 AM:
>
>> Maybe this weekend I'll measure the amp draw on my 99 5.7r
>>
>> My 93 4.3z TBI with a new bosch pump pulls less than 2.
>>
>> Based on the 2 at 10-12 psi, 60 psi would raise the amps for the same
>> flow
>> to 10
>>
>> skimmer
>
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o.. 

Skimmer,

Thanks again. Are you saying that I should run a jumper from the relay
socket to the fuse panel? I assume you mean strictly for testing purposes?
If I were to leave that connected, it ranks up there with dumnping fuel into
the carb with the wiper pump... Your thoughts on the ignition module may be
a good place to look. My only concern about that is if I power the pump via
the test connector under the hood, she fire right away. I've never had such
a battle with an electical gremlin to date - I'm almost ready to take it to
a tech even though that's against my religion (with the exception of
tranny/drivetrain work).

I'm still not sold on the fact that the ignition sewitch might be causing
these issues... At $200 for a replacement I'm not ready to gamble on it yet
though. The reason I suspect maybe the ign switch might be to blame is that
I can turn the key to ACC several times before the pump engages. Once the
pump engages, it starts right up. Some day I will figure this one out. I'm
still secretly hoping that someone with the same issue will reply with a
fix...
Thanks!
Andrew.



in article JLaDh.130$bb1.28@newssvr17.news.prodigy.net, News Skimmer at
NewsSkimmer.TakeThisOut@sbcglobal.net wrote on 2/22/07 1:28 AM:

> Intermittent no starts (no fire/no fuel) can be caused be a bad ignition
> module.
>
> On the fuel pump relay...you might consider removing it and powering the
> pump directly with a fused jumper through the load side of the fuse.
>
> On my 93 c1500, you can power the pump through one of the OBD1 connector
> pins which then passes through the fuse. You might need to check your wiring
> diagrams because that pin might not work if the relay is pulled out or arc'd
> close (welded closed in run position). I think my test connection opens when
> the relay closes. Make sense? probably not but study your schematics.
>
> skimmer
 >> Stay informed about: Yet another fuel delivery question (95 Jimmy) - amp draw o..