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Author Topic: Help...Fuel Pump doesn't power up!
iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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We are loading up for the Goblns go, and get ready to drive the car onto the trailer, only to find out it won't catch fire. The car cranks, it turns over, I could tell right away that the fuel pump wasn't running. I checked the fuses under the hood, no power, I checked the relay under the dash, no power, I checked the plug on fuel pump, no power.

The car has power, it is hooked up with a 4 pole kill switch powering a a switch and push button starter.

And no, I didn't wait till the last moment to see if the car cranked, because I moved it on Sunday. Started fine, no problem... and yes, it has fuel.

Any thought's would be great. I was looking forward to some test day action friday.

Thanks!
hoop

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hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
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Have you jumpered the diagnostic box between FP and GND?

--------------------
Keith Novak
(Will work for tires)

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
Status: Offline
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quote:
Originally posted by Keith in WA:
Have you jumpered the diagnostic box between FP and GND?

no? what does that accomplish?

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
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Well not knowing how the circuit works, but knowing with the car off but power on I can run the fuel pump to drain fuel, I'd check to see if it bypasses other stuff and you hear a click and the whir of fuel. If it does, you can leave it jumpered and drive for the weekend, then sort it out later.

--------------------
Keith Novak
(Will work for tires)

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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ahhh... so in theory, it would work like hot wiring the pump? so i could do this, then check to see if i have power at the pump's connector?

so, anything more sophisticated than using a paper clip?

Thanks!
hoop

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
Icon 1 posted  Profile for Keith in WA     Edit/Delete Post  Report this post to a Moderator

Yes, essentially hot wiring it and I have done it with a paper clip. I'd stick a short wire in there though if you drove it all weekend to keep from having an exposed wire.

--------------------
Keith Novak
(Will work for tires)

iambhooper
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Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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Ill give this a try first thing.

Honestly, I can't tell you how pissed I've been. Been working on "cleaning" up the car since last may, runs fine, then this.

I even popped off the cover and gave the fuel pump a couple of whack's! [Big Grin]

hoop

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
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I know the feeling.

[yep]

If that doesn't work, my next thoughts would be:

You wired in a push button ignition. Check the connections to see if somehow that messed up the circuit.

Most of the gremlins with instrument clusters and lights are caused by that ground block under the brake booster. The ignition switch is in the general area so I'd look at that too.

Good luck!

--------------------
Keith Novak
(Will work for tires)

iambhooper
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Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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my co driver just went by the shop. He say's he jumpered the relay on the right side and was able to get fuel pressure, but claim's he didn't see any spark.

I told him of the grnd to fp jumper on the diagnostic, when he tried that the fuel pump didn't run.

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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?... the fuel injection relay in the fuse block under the hood, does that have more than one function? he jumpered one side of it, and was able to get the pump to run, but claim's it had no spark.

seems like i was reading in the helms book that the other side was to the coil. if that's the case, and we have swapped out the relay, then what?

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hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
Icon 1 posted  Profile for Keith in WA     Edit/Delete Post  Report this post to a Moderator

If the relay is good, and you're able to get fuel pressure, but not getting any spark I'm thinking a ground.

Remove, wire brush, and replace the ground on the back of the intake manifold, and the ground that sticks off a metal tab between the intake manifold and the head. YMMV...I have a '95 One of those two caused a friend of mine with a 1.6 a whole heap of trouble even though it seemed tight and I know I forgot to reinstall one and couldn't get the car to start after replacing an engine. Might be a bad connection, particularly the rear one which I think is the coil, and if it was crossthreaded in the intake it would feel tight but not make a good connection.

Beyond that, I can't think of any quick fixes for tomorrow.

--------------------
Keith Novak
(Will work for tires)

iambhooper
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Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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Will do!

Keith, thank's for all the tips!

hoop

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
Status: Offline
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Update... friday morn, got to the shop, checked and cleaned all the ground's I could find. checked relay's, grnd'd the diagnostic, nothing.

at that point I started looking at the racecar wiring that the previous owner's had done... found someting, unpluged it, pluged it back up, hit the starter... vroom! did it again, and then decided I was on to something. the car had a miss, but at least it was running.

cleaned up the wire's, put it all back together, went to plug the original ECU back in and found the switched hot wire was loose!

sumabeyatch! spliced in a wire, fixed that and the car has cranked enough now that I "think" we have it fixed!

at least we are at VIR and ready to play today [Big Grin]

thanks!
hoop

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
Icon 1 posted  Profile for Keith in WA     Edit/Delete Post  Report this post to a Moderator

Cool. Glad you found that. [yep]

Those kinds of problems can be incredibly hard to locate sometimes.

--------------------
Keith Novak
(Will work for tires)

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
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yep... and then the thing reared it's ugly head again today in the ECR!

I finally was getting comfortable in the car today (2nd weekend in a RWD car, and it was twitchy as hell) running the first leg of the enduro. On the first lap, going up hill the motor quit... pulled off in the grass and the car started back up. One lap later, same thing... only in hog pen.

Stuck for ballance of the race, only to have it crank again after the end of the race [Frown]

Now I need to learn how to fix pin outs!

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

Keith in WA Verified Driver Made Donation to Website
Pack Fodder

Region: NWR / Oregon
Car #: 88
Year : 95
Posts: 2000
Status: Offline
Icon 1 posted  Profile for Keith in WA     Edit/Delete Post  Report this post to a Moderator

Take a good hard look at the pins on the wire harness and ECU. This sounds like something that plauged my buddy with a mysterious cutout problem that he chased for a whole year, changing every electrical component including the wire harness.

There's a trick people do sometimes where they twist a pin at a sloppy connection to the ECU to get it to make contact again. Apparently it works for a while, then you have buggered ECU and a buggered wire harness connection and a whole heap of frustration trying to find the cutout problem if you don't know what the prior owner screwed with.

--------------------
Keith Novak
(Will work for tires)

iambhooper
Member

Region: NCR
Car #: NA
SMIM: NA
Posts: 125
Status: Offline
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yea, i'm pretty certain that it's the same wire in the ecu conector that caused me all the greif thursday and friday. when the race was over, and they let me back in my car for the flat tow, i pushed some of the wire's in the harness around and the car cranked right up! go figure!

we aren't going anywere, except to get corner weight's and alignment done, before the st patt's race. so i hope to have time to fix everything that need's fixing.

hoop

--------------------
hoop
'91 Spec Miata
'90 NA Beater/Track Day car
'06 RSX Type S

   

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