Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > 700/900 Series General

Notices

700/900 Series General Forum for the Volvo 740, 760, 780, 940, 960 & S/V90 cars

Information
  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and Plus.net users. Forum owners such as us are finding that AOL, Yahoo and Plus.net are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

Radio Suppression Relay mystery

Views : 943

Replies : 26

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Jun 10th, 2019, 23:28   #11
Laird Scooby
Premier Member
 
Laird Scooby's Avatar
 

Last Online: Yesterday 21:57
Join Date: May 2012
Location: Lakenheath
Default

Good point!
__________________
Cheers
Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
Laird Scooby is offline   Reply With Quote
The Following User Says Thank You to Laird Scooby For This Useful Post:
Old Jun 11th, 2019, 03:33   #12
arctan
Member
 

Last Online: Mar 26th, 2024 19:43
Join Date: May 2009
Location: Wembley London
Default Radio suppression relay location

Is this relay involved in switching injectors on and off?
And in doing so, it may generates a lot of interference, so it is located some way away from the radio? If so, where is it? I'd like to have a spare, to go with my other spare relays, as I read it can be the source of troubles...
('97 940 LPT).
arctan is offline   Reply With Quote
The Following 2 Users Say Thank You to arctan For This Useful Post:
Old Jun 11th, 2019, 09:28   #13
Laird Scooby
Premier Member
 
Laird Scooby's Avatar
 

Last Online: Yesterday 21:57
Join Date: May 2012
Location: Lakenheath
Default

Quote:
Originally Posted by arctan View Post
Is this relay involved in switching injectors on and off?
And in doing so, it may generates a lot of interference, so it is located some way away from the radio? If so, where is it? I'd like to have a spare, to go with my other spare relays, as I read it can be the source of troubles...
('97 940 LPT).
Pretty much, apparently Volvo found having the injectors switched by the ignition switch directly caused interference so use a relay to switch them on and off.

There are two possible locations, one is by the coolant expansion tank and the other is N/S inner wing near the suspension turret. It's the same sort of relay as used by the electric cooling fan.

As for the source of trouble, it can be but mainly because the mechanical side of it wears and/or the coil burns out. The contacts rarely suffer as they don't switch a "live" load, they only provide power to the injectors, the actual switching on/off of the injectors is done by the ECU as a relay couldn't cope with the frequency or speed at which the injectors are on/off in use.
__________________
Cheers
Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
Laird Scooby is offline   Reply With Quote
The Following 2 Users Say Thank You to Laird Scooby For This Useful Post:
Old Jun 11th, 2019, 13:04   #14
arctan
Member
 

Last Online: Mar 26th, 2024 19:43
Join Date: May 2009
Location: Wembley London
Default Super!

Thanks Dave. I'll have a look when I'm next mobile. And oddly enough, I have a spare s/h fan relay. I should swap it for the RF relay, just to know it's good...
arctan is offline   Reply With Quote
The Following 2 Users Say Thank You to arctan For This Useful Post:
Old Jun 11th, 2019, 13:28   #15
arctan
Member
 

Last Online: Mar 26th, 2024 19:43
Join Date: May 2009
Location: Wembley London
Default And..

And thanks for the precision of the reply, too. I can see from other posts that you have an electronics background- a handy thing for naughty cars. I had a temp job when I left school selling VW parts. I remember people being almost in tears when they found out the cost of the electronic + mechanical flasher relays. 8 or 9 quid in the late 70's, for a little relay and a pre NE555 astable circuit. I acquired the odd 'broken' one, and gave the contacts a file, then gave these to the needy. I went on to work with 'live' sound, so me and electricity are mates! My next project is to identify and get the fuel pump relay. I see these on fleabay, but need to locate mine, and it's part number. Somewhere in the relay tray, behind the fuses...
arctan is offline   Reply With Quote
The Following 2 Users Say Thank You to arctan For This Useful Post:
Old Jun 11th, 2019, 14:14   #16
Laird Scooby
Premier Member
 
Laird Scooby's Avatar
 

Last Online: Yesterday 21:57
Join Date: May 2012
Location: Lakenheath
Default

Quote:
Originally Posted by arctan View Post
And thanks for the precision of the reply, too. I can see from other posts that you have an electronics background- a handy thing for naughty cars. I had a temp job when I left school selling VW parts. I remember people being almost in tears when they found out the cost of the electronic + mechanical flasher relays. 8 or 9 quid in the late 70's, for a little relay and a pre NE555 astable circuit. I acquired the odd 'broken' one, and gave the contacts a file, then gave these to the needy. I went on to work with 'live' sound, so me and electricity are mates! My next project is to identify and get the fuel pump relay. I see these on fleabay, but need to locate mine, and it's part number. Somewhere in the relay tray, behind the fuses...
Ah, the good ol' 555 timer! I was playing with those in the late 70s/early 80s but not very successfully. Half the trouble was i was using salvaged components from broken old radios, my soldering techniques weren't brilliant and a 35W soldering iron with a huge bit wasn't ideal for soldering tiny electronic components.

That said John, you've given me a nice idea, thanks! Kind of fuel relay related so i'll explain briefly. I seem to have lost the "prime" function from the ECU (which some say never existed on the LH2.x) so need to flick the starter and wait a second while the pumps run before starting, at which point it fires first touch. I bought a time delay relay on ebay that turned out to be incorrectly described (something lost in the Chinese > Chinglish > English translations!) that turned out to be unsuitable for what i needed. I should have thought of the 555 sooner and worked out what i need for it to add a 2 second prime when i either first switch the ignition on or preferably, open the door.

However i have a new in-tank pump to fit first so hoping that improves matters in terms of retaining fuel pressure.

I'd be tempted to not swap the RSR at the moment, disturbing the connections could do more harm than good as i'm sure you can appreciate.
Also the fan relay switches a "live" load in as much as when it operates, the fan pulls current (including inrush) from the moment those contacts make. That means the contacts are more prone to arcing so you could also be introducing a trouble spot into something that currently has no trouble.
__________________
Cheers
Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
Laird Scooby is offline   Reply With Quote
The Following User Says Thank You to Laird Scooby For This Useful Post:
Old Jun 12th, 2019, 08:38   #17
arctan
Member
 

Last Online: Mar 26th, 2024 19:43
Join Date: May 2009
Location: Wembley London
Default

Quote:
Originally Posted by Laird Scooby View Post
Ah, the good ol' 555 timer! I was playing with those in the late 70s/early 80s but not very successfully. Half the trouble was i was using salvaged components from broken old radios, my soldering techniques weren't brilliant and a 35W soldering iron with a huge bit wasn't ideal for soldering tiny electronic components.

That said John, you've given me a nice idea, thanks! Kind of fuel relay related so i'll explain briefly. I seem to have lost the "prime" function from the ECU (which some say never existed on the LH2.x) so need to flick the starter and wait a second while the pumps run before starting, at which point it fires first touch. I bought a time delay relay on ebay that turned out to be incorrectly described (something lost in the Chinese > Chinglish > English translations!) that turned out to be unsuitable for what i needed. I should have thought of the 555 sooner and worked out what i need for it to add a 2 second prime when i either first switch the ignition on or preferably, open the door.

However i have a new in-tank pump to fit first so hoping that improves matters in terms of retaining fuel pressure.

I'd be tempted to not swap the RSR at the moment, disturbing the connections could do more harm than good as i'm sure you can appreciate.
Also the fan relay switches a "live" load in as much as when it operates, the fan pulls current (including inrush) from the moment those contacts make. That means the contacts are more prone to arcing so you could also be introducing a trouble spot into something that currently has no trouble.
Indeed. I remember starting from having very little resources as kid connecting precious things like transistors together, with very little understanding. Then later being in a company, surrounded by Gurus, with an unlimited radiospares account. And now I'm back to having made a 940 code reader box, but having to take it to a mates workshop because I can't find my soldering iron. If I meet one of the Gurus again, I might ask them how to build a code reader with a numeric display- then I'd be king of the code readers, given the nice designs I've seen on this forum!
On the 555 front, I looked up the current capability, what with it being a small chip. 200ma. I don't know if that will suit your 'tickle the carb'
project? I looked around for 'hi power alternatives to ne555' and frequently saw that people stick a power mosfet on the output. And supporting components etc. And then a bit of lateral thinking gave me the name 'Vellerman kits'.
Velleman Interval Timer Minikit MK111
VellemanMK1115410329001117
ex VAT £3.25
http://www.velleman.co.uk/contents/en-uk/p37_mk111.html
Build it yourself or get the iron out. 3 amp relay. Is 3 amps enough though?
And good luck with the in tank pump. One day I might attend to my fuel gauge sender, which is 'non linear' below 50 pc...
And I very much take your points about swapping the RSR. On something else recently, I can't remember what, the phrase ' if it ain't broke' really finally came home to me.
I might just flash the spare relay on the fan circuit, or even just battery it and measure the contacts.
Maybe I should get off my bum, and clean up the contacts on my sunroof switch, with a spare to hand, in case I break it...
Cheers.
arctan is offline   Reply With Quote
The Following User Says Thank You to arctan For This Useful Post:
Old Jun 12th, 2019, 10:00   #18
Laird Scooby
Premier Member
 
Laird Scooby's Avatar
 

Last Online: Yesterday 21:57
Join Date: May 2012
Location: Lakenheath
Default

Quote:
Originally Posted by arctan View Post
Indeed. I remember starting from having very little resources as kid connecting precious things like transistors together, with very little understanding. Then later being in a company, surrounded by Gurus, with an unlimited radiospares account. And now I'm back to having made a 940 code reader box, but having to take it to a mates workshop because I can't find my soldering iron. If I meet one of the Gurus again, I might ask them how to build a code reader with a numeric display- then I'd be king of the code readers, given the nice designs I've seen on this forum!
On the 555 front, I looked up the current capability, what with it being a small chip. 200ma. I don't know if that will suit your 'tickle the carb'
project? I looked around for 'hi power alternatives to ne555' and frequently saw that people stick a power mosfet on the output. And supporting components etc. And then a bit of lateral thinking gave me the name 'Vellerman kits'.
Velleman Interval Timer Minikit MK111
VellemanMK1115410329001117
ex VAT £3.25
http://www.velleman.co.uk/contents/en-uk/p37_mk111.html
Build it yourself or get the iron out. 3 amp relay. Is 3 amps enough though?
And good luck with the in tank pump. One day I might attend to my fuel gauge sender, which is 'non linear' below 50 pc...
And I very much take your points about swapping the RSR. On something else recently, I can't remember what, the phrase ' if it ain't broke' really finally came home to me.
I might just flash the spare relay on the fan circuit, or even just battery it and measure the contacts.
Maybe I should get off my bum, and clean up the contacts on my sunroof switch, with a spare to hand, in case I break it...
Cheers.
Similar beginnings then John!

Interesting thoughts about the Vellemann kit, i wasn't sure if they were still in existence with the demise of Maplins as i believe there was some sort of owneship deal between the two of them. That kit you linked to is an astable set up, i need a monostable set up and so far, the favourite set-up seems to be a blocking diode on pin 2 connected to the drivers door pillar switch for the trigger pulse. If this 760 is like the other 740s i've had, the drivers switch will be a two element animal, one for the courtesy lights in general and the other to trigger the courtesy light timer.

The way it is at the moment, there's a connection from the -ve end of the coil on the fuel pump relay to the ECU, when the ECU takes this low, the fuel pump relay is energised. My idea is to interrupt this cable with a SPCO relay, when the coil of said relay is energised, it will take the fuel pump relay coil to earth while disconnecting the ECU from the relay. This will prime the pumps for 2-3 seconds or whatever the time is set at on the 555 circuit, then hand control back to the ECU by de-energising the relay.

The 555 is capable of operating most relays so that shouldn't be a problem. It would have to be set up so the 555 was sourcing the relay, the big problem with the one i bought on fleabay is that it sinks the relay which would obviously draw more current almost all of the time - whether i'm in the car or not.

Interesting idea about adding a numerical readout to the Volvo code reader. As i understand it, each code is 3 digits and there are no codes that have a zero in - is that correct?

If so, the first digit is fairly easy - link the pulse that currently lights the LED on the code reader to the input of a BCD counter, the output of that to a 7-segment driver and a 7-segment display.
The next digit is a bit more awkward and also gives you choices on how to do the rest of the display. First, you need to detect the pause, a missing pulse detector if you like. When this missing pulse is detected, you either need to rest the single 7-segment display/counter so the next pulse starts the count again or moves the pulse input to the next counter/display driver. Likewise with the next digit.
Then you have another choice - if you've got a 3-digit display for the first code, does it reset after the first code and then display the second or does it move on to a second set of digits and if so, where do you stop? Do you have ten 3-digit displays?

There are several ways and means of doing it, cost would probably become a limiting factor though!
__________________
Cheers
Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
Laird Scooby is offline   Reply With Quote
The Following User Says Thank You to Laird Scooby For This Useful Post:
Old Jun 12th, 2019, 19:40   #19
arctan
Member
 

Last Online: Mar 26th, 2024 19:43
Join Date: May 2009
Location: Wembley London
Default

Quote:
Originally Posted by Laird Scooby View Post
Similar beginnings then John!

Interesting thoughts about the Vellemann kit, i wasn't sure if they were still in existence with the demise of Maplins as i believe there was some sort of owneship deal between the two of them. That kit you linked to is an astable set up, i need a monostable set up and so far, the favourite set-up seems to be a blocking diode on pin 2 connected to the drivers door pillar switch for the trigger pulse. If this 760 is like the other 740s i've had, the drivers switch will be a two element animal, one for the courtesy lights in general and the other to trigger the courtesy light timer.

The way it is at the moment, there's a connection from the -ve end of the coil on the fuel pump relay to the ECU, when the ECU takes this low, the fuel pump relay is energised. My idea is to interrupt this cable with a SPCO relay, when the coil of said relay is energised, it will take the fuel pump relay coil to earth while disconnecting the ECU from the relay. This will prime the pumps for 2-3 seconds or whatever the time is set at on the 555 circuit, then hand control back to the ECU by de-energising the relay.

The 555 is capable of operating most relays so that shouldn't be a problem. It would have to be set up so the 555 was sourcing the relay, the big problem with the one i bought on fleabay is that it sinks the relay which would obviously draw more current almost all of the time - whether i'm in the car or not.

Interesting idea about adding a numerical readout to the Volvo code reader. As i understand it, each code is 3 digits and there are no codes that have a zero in - is that correct?

If so, the first digit is fairly easy - link the pulse that currently lights the LED on the code reader to the input of a BCD counter, the output of that to a 7-segment driver and a 7-segment display.
The next digit is a bit more awkward and also gives you choices on how to do the rest of the display. First, you need to detect the pause, a missing pulse detector if you like. When this missing pulse is detected, you either need to rest the single 7-segment display/counter so the next pulse starts the count again or moves the pulse input to the next counter/display driver. Likewise with the next digit.
Then you have another choice - if you've got a 3-digit display for the first code, does it reset after the first code and then display the second or does it move on to a second set of digits and if so, where do you stop? Do you have ten 3-digit displays?

There are several ways and means of doing it, cost would probably become a limiting factor though!
Hello again Dave.
Ok. I see were you are with the '555' idea, and the surrounding circuit. Pity that the Vellermanns is astable- I knew you needed a monostable, and perhaps a relay- I wasn't reading carefully! Your pursuit of the matter is almost like my curiosity as to why my volvo needs an amount of cranking before it fires, even when hot. Not an awful amount. It's just that other cars seems to fire somewhat quicker. Starter spin speed perhaps?

And the code reader. I think you may be right about no zeros. My electronics background has been mainly about the analogue stuff in between a microphone and a loudspeaker, and their power supplies, back then. I have some oversight of digital audio principles. I made the odd foray into TTL/CMOS devices, and logic, but not much. I can just grasp the BCD and seven segment thinking. And what to do with the pause! I studied Ethernet for a bit. A least a packet on a network has something to say 'this is the start' whereas here we're dealing with silence/a low, for a period of time. (the electronics concept of a 'clock' has just come back to me). I've been (slightly) curious about these things called PICs, Audinos and Raspberry PI's, as people seem to be quick to turn to them these days. As you say, there are probably several approaches, and time and cost exist. I'm hoping I meet up with one of the Gurus, when I go to get my code reader soldering done. Maybe I can PIC their brains...
And.
Missing pulse detector using - a 555! That 555 is such a versatile chip!
https://electronicsarea.com/missing-...uit-555-timer/
PS I don't think I'll make it as king of the code readers.
Regards.
arctan is offline   Reply With Quote
The Following User Says Thank You to arctan For This Useful Post:
Old Jun 12th, 2019, 20:55   #20
Laird Scooby
Premier Member
 
Laird Scooby's Avatar
 

Last Online: Yesterday 21:57
Join Date: May 2012
Location: Lakenheath
Default

Quote:
Originally Posted by arctan View Post
Hello again Dave.
Ok. I see were you are with the '555' idea, and the surrounding circuit. Pity that the Vellermanns is astable- I knew you needed a monostable, and perhaps a relay- I wasn't reading carefully! Your pursuit of the matter is almost like my curiosity as to why my volvo needs an amount of cranking before it fires, even when hot. Not an awful amount. It's just that other cars seems to fire somewhat quicker. Starter spin speed perhaps?

And.
Missing pulse detector using - a 555! That 555 is such a versatile chip!
https://electronicsarea.com/missing-...uit-555-timer/
PS I don't think I'll make it as king of the code readers.
Regards.
You've got exactly the problem i'm trying to solve with my "tickle the carb" circuit John. What i do at the moment is just "flick the starter" - just turn the key to the start position so the starter just begins to turn then release it - flick the key into the start position and let go which makes the ECU run the pumps for a couple of seconds. When they finish running (possibly only one pump on yours), turn the key to the start position again and it fires instantly.

Two possibilities here, either it's not priming or the "check valve" aka non-return valve on the pump outlet has gone weak/failed allowing the pressure in the fuel rail to leak back to tank via the pump. This will also cause fuel vapourisation on hot days/after a long hot run (worse when both happen!) so i'm hoping it's as simple as not priming. Anecdotal evidence from doing the flick the starter thing suggests it's simply not priming but could still be the check valve/NRV at fault.

I did try fitting an aftermarket NRV on the tank output on mine, i have the two pump set-up so the in-tank pump is at most 19psi output but can deliver 60 gallons/hour. The underbody pump runs at up to 60psi and without checking, i can't remember the flow but it needs the in-tank pump as it's not capable of enough suction to overcome the NRV if the in-tank pump has failed. I now have a replacement in-tank pump to fit to mine and if that works, i'll refit the NRV and try it again.

I've just realised we're waffling about fuel supply problems on Ellies RSR thread - sorry Ellie! <insert blushing/sorry emoji here>
__________________
Cheers
Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
Laird Scooby is offline   Reply With Quote
The Following User Says Thank You to Laird Scooby For This Useful Post:
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 08:09.


Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.