|
|
|
Hallo, folks.
It's cold out and I really don't want to pull my fuel sender out of my car. I think that there is a pinhole or kink in the in-tank pump on my 1990 740GL *Regina*, which now has 2 fuel pumps in the Bosch style 1 in tank, 1 under the car arrangement.
For the moment, I can turn the key to KP2 and let the fuel pump run for its normal 2 second prime, then repeat that until the fuel pump under the driver's seat makes the noise that tells me the air is purged from the system. It's rinky-dink and I would rather not do that, especially with an aging battery.
I have a bunch of spare EFI relays that need their solder fixed (it's cracked) and want to solder in a simple momentary switch to ground that will let me turn the key to KP2 and then hold the button down to run the pumps for 10 seconds. Can I simply solder a wire onto the EFI relay for 86/2 and then run it to a momentary switch that goes to ground on the other side of the switch?
The diagram would just be
EFI relay pin 86/2 --- ./. --- GND
If I do that, do I run any risk of hurting the ECU by flowing current from the "not grounded" circuit inside the ECU to my ground? Max run time would be about 10 seconds.
The FAQ talks in 2 sections about a bypass for bad pink-label -561 LH2.4 ECUs, but that's on an already-dead ECU. https://www.brickboard.com/FAQ/700-900/EngineFIComputer.htm#ECURelayGroundWorkaround
Happy Bricking!
Will
|
|
-
|
|
|
Hi Will,
Did you rewire the Regina to B230FT (MFI) specs?
If you wired the same as the B230FT MFI
Yes, grounding 86/2 of the Fuel relay would run the pumps.
You would run both pumps and the O2 heater and apply a ground to pin 20 of the fuel ECU. That's uncharted territory, Signal ground is not chassis ground.
Safer would be to apply 12 V direct to the battery side of Fuse 11
and you would run both pumps without grounding ECU pin 20.
To be safe your jumper should have a 15 amp fuse.
You'll need a husky push button switch.
Have you measured current at Fuse 1 and Fuse 11 to gauge the health of the
pumps?
Here's what I get:
Fuse 1 = 10.5A Both pumps,O2 sensor, AMM, PTC, both ECU's, RSR coil, IAC.
Fuse 11 = 3.5A Only the in-tank pump
I can pull fuse 11 and start and run the engine.
Disclaimer: Do these mods at your own risk
Good luck and happy holidays, Bill
|
|
-
|
|
|
Rewire? Hmmm. No, sir. I haven't changed any components over towards Bosch format except for the fuel pump and plumbing.
I only added a pigtail to the fuel pump connection that normally runs to the Bosch under-car pump. I got this car from a friend that died and he had already bodged the pump into place. I gave him a spare pump (since bought a new one) after he told me he installed a low pressure pump into the tank and it wouldn't run anymore.
At this point, both pumps are new, but I believe the sender inside the tank is somewhat misoriented or has a problem with the pump installation. Last week after leaving it overnight to drive a friend home, I started it up and it died on me a few seconds later. After a long-crank attempt, it started and stayed running in place for 10 minutes, so I drove it to a nearby fuel station. It took 10.4 gallons, which is not empty but close enough that a goofy in-tank setup might cause issues. I drove it home and had no issues for about 10 miles.
I was thinking about tapping the relay coil to avoid needing to run any substantial amperage. When I look at that diagram in the FAQ I linked, a second time, I really don't know what exactly that Relay element is and I might be drawing power from somewhere else in that circuit. The last thing I want to do is damage the ECU.
I wonder what would happen if I connected a 12V lantern battery to energize the pump relay coil to both the + and - pins of the fuel pump coil only. That wouldn't be grounded to the system and *shouldn't* have any potential to flow power through anything but the small coil. I wonder if I could even use a 9V battery to do it. I'll bench test one of the relays and see if it will move the coil.
As usual, thanks for your reply, Bill.
-Will
|
|
-
-
|
|
|
Hi Kitty,
He can jump 12v direct to the pumps and forget the main fuel relay and messing with the ECU
>Sort of a similar thing thatg some do to use the rear red fog light position as >an esxtra brake light, yet preserves the fog light function? I forget now. Sorry.
I just replaced a busted tail light in my wagon, and thought who needs fog lights?
Maybe modify the foglight switch to be active with the ignition on (instead of the low beams on) and use the fogs as DRL without all the low beam baggage.
For the rear, Unplug the upper fog wire and run a wire from top to bottom
brake lights and have twin brake lights.
This works with the low current Red LED's. Way more light and way less current.
Yes you use red LED to shine through a red lens. Yellow LED through a yellow lens, etc.
Has anyone been able to salvage sections from Volvo taillights that look like
they are cemented together with PVC cement ? Maybe there's a trick to getting them apart? Heat gun?
Easy does it with that eggnog, especially the high octane variety!
Bill
|
|
-
|
|
|
Hi Bill and Kitty. See a reply I just posted to you, Bill, in the recent 240 thread about LEDs for a note about how I used diodes to share the fogs and brake lights.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
|
|
-
|
|
|
Hi Will,
So you have Custom twin fuel pumps in a Regina.
Where exactly does the new pump get it's 12v?
Do both pumps quit by pulling fuse 11?
How long did the car behave after this modification?
Some ideas:
Check all of the connections of both pumps? Are they Walmart or
Autozone crimp connectors, or worse? Pull on them see if they come apart.
Pull the main fuel (twin) relay and check for loose socket pins.
Use a 1/4 male blade connector crimped onto a piece of solid copper
to make sure they are not loose. The pins can be repaired or replaced.
Check the RSR connector see if the female bullet pins are dislodged, pushed back and making a flaky contact. Bullet connectors are messed up in my car
Get parts from www.davebarton.com.
You can measure fuse 11 with your voltmeter when it doesn't start.
The 12v is supplied by 87/2 of the main fuel relay.
Confirm you have 12V and you can probe the top of the ATC fuse with your meter,
See if you lose 12V to the pumps or not.
It's harder to measure fuel relay 87/1 that powers the ECU's and RSR
you can wire a 12v lamp to 87/1 to diagnose that set of points.
The lamp needs to be on to run the engine.
https://www.ebay.com/itm/223514074403 14V w pigtail leads 50 pieces
https://www.ebay.com/itm/263194224649 12V LED W PIGTAILS 20 pcs $7.55
Both of these could also replace goofy priced Volvo ashtray and shifter lights
You can get 100 pcs bare wire 2.5mm 14V grain of wheat for about $13
https://www.ebay.com/itm/352373542466? The Chinese merchant advertises
these lamps at 14v AND 12v. Take your chances with this guy.
These can be used in Volvo rocker switches, and illumination for transceivers,
radios, etc
You could just as easily wire two lights to the fuel relay to diagnose.
relay coil 1 +12V 87/1
relay coil 2 +12V 87/2
Then you could confirm operation of the main fuel relay's twin coils.
Maybe I should do that here to help understand my evil intermittent failure?
Likely the second pump was installed to solve some unresolved issue
and now you need to fix problem #1 and recheck his work too.
Good luck, Bill
|
|
|
|
|
©Jarrod Stenberg 1997-2022. All material except where indicated.
All participants agree to these terms.
Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.
|
