|
|
|
1990 745 Regina
Hello, long time lurker, first question.
I was trying to trace why i had no power at the IAC valve connector.
things i did: removed IAC, unplugged connection block near driver side strut tower, unplugged a single connector next to connection block, turned key to ON position for several minutes while i probed the ECM pins for information on the engine temp. sensor (readings ok).
I put everything back together - went to start the car but all it would do is crank. sprayed starter fluid and it hit for a few seconds. I can hear the relay click when key is moved to ON position, BUT i no longer hear the humm for a second or two like it did before. Fuse #1 and #11 are good.
Finally the question (s)
Is there another fuse or relay to look at?
Would the fuel pump itself get fried just because i had the key in ON position for less than 10 minutes?
Is there a way to test/power up the pump without pulling it out?
It is a new pump with less than 2k on it and its a bit of a bear to r&r that thing.
Thanks for any suggestions
|
|
-
|
|
Hi Rona,
You have folks way smarter and well practiced with Bendix Rex ignition / Regina injection to support your root cause fault finding so you can effect repair.
This site contains Mitchell wiring diagrams in PDF files that may help you as well as other information.
http://www.v8volvo.se/mekartips/volvo/
Download Volvo 740 1991 Mitchell.pdf
PDF page 23 of 28.
Wire color is your primary guide as relay pin #'s are not highlighted.
The RSR is in the 12 VDC power path provided to the injector. The ECU closes connection to ground for the injector pulse duration.
An issue with 700-900 series is the fuse panel and relay board hidden behind the ashtray at the bottom center console. After 30+ years and less, corrosion forms at high current connections such as fuse sockets (the spade terminals locked into the plastic of the board) and relay sockets. Sometimes you can see heat malformation of the plastic and, worse, black charring around these sockets on the board. The fuel pump relay socket can show in time heat malformed plastic.
In the 700-900 FAQ, a user identifies the fuse/ relay board as a serviceable items. Maybe early in life one could use a DeoxIT-D spray or grease, remove fuse and relays, spray, and reconnect.
I'll guess the Regina fuel pump relay through age and use may form cracked solder welds internally as with the Bosch fuel pump relays.
Though your discovery of a disconnected Radio Suppression Relay wire harness connector socket may indicate prior owner modding to get your 740 running by hacking it.
How many miles? Any fuel pump will fail in time and miles (hours?) of use. Don't go after market!
The 700-900 FAQ does not support Bendix Rex / Regina the best. I sort of like the Bendix system as it is like Bosch D-Jetronic with the manifold vacuum (or pressure) sensor.
Sorry to go so long.
Hope that helps.
I'm sure you'll figure the thing out. Also, search the RWD forum for others prior posts with Bendix Rex / Regina issues.
Questions?
Earl Grey Tea Boyeeee Gettin' a Tech Writer Job.
--
Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity
|
|
-
|
|
|
New AIC......They change idle speed when failing.
|
|
-
|
|
|
740 regina.
I too am having a start issue. I have not done any extensive investigation as yet as I am busy with other projects. The fuel pump is intermittent. ( sometimes sounds and sometimes not). Last time I tried starting I could hear the pump priming for its duration, the engine would start momentarily but once in the "run mode" it does not continue running. Thanks for all responses to Rona's issue. I have learnt a lot and will try some of the fixes suggested. Within the next coming weeks I will take a closer look and report back. Be safe out there in these trying times.
Cheers
paul
|
|
-
|
|
|
Just jumping the pump in the relay area only activates the pump and not the ECU......For the low cost, just buy and new pump/ECU relay and a new radio relay. It just might be the fix.
Typical failure that I carry an extra set.
|
|
-
|
|
|
Hello,
The radio suppression relay (RSR) supplies power to your IAC, fuel injectors and fuel pump relay (magnetic coil part). Could be your RSR has issues. Its location - somewhere nearby behind your right (passenger side) headlight area in engine bay.
Amarin.
|
|
-
|
|
|
Thanks for the heads up on the RSR. I will try changing out that relay tomorrow. The fuel pump problem is still a problem though.
|
|
-
|
|
|
Hello Rona,
As per your first posting you don't have power to the IAC. So I checked the circuit diagram for Regina and found the RSR is the key in providing power to those items I've listed. And like rstarkie mentioned the RSR could be rejuvenated back to life (if its the culprit). The RSR is a simple robust relay only that its solder joints on the inside could get cracked and needs reflow. With a small jeweller screwdriver you could pry open the RSR at its base.
Besides the solder issue, the RSR's rubber insulation at its electrical plug could have been disintegrated over the years allowing moisture to cause some contact corrosions. These you can clean. Do have a look at these issues.
The fuel pump as you said is quite new. I'd put that aside for time being and ensure power comes to the IAC and other items first.
Amarin.
|
|
-
|
|
|
Amarin,
That was a very good idea to check the RSR. Turns out the ground wire was off the pin and the power wire came off the the pin when i took the RSR off of the bracket. I was SO stoked, problem solved!
I cleaned up the connectors and pins, checked that there was constant power at the red wire (there is) and pushed the connectors back on. Tried to start the engine but it was exactly the same - crank but no start. I then jumped the red wire to the IAC/injector wire - still crank but no start. Double checked that i could hear clicking from the fuel pump relay when key is turned on and off (i could).
Had my sister turn the key to ON while i listened down the fuel filler pipe with a hose to my ear -no sound from tank. Before when i applied power to the fuel pump wire i had heard a faint whiring sound, although back when everything was working i could hear the whiring sound from the drivers seat when i turned the key to on position.
Does this sound like a reasonable test?
Apply power directly to fuel pump, if i again hear it spinning, try to start car.
Thanks to eveyone for their help.
Ron
|
|
-
|
|
|
Get a couple spare ECU's off Ebay. I carry one in my car along with several relays. Test any ECU you get.
|
|
-
|
|
|
"Apply power directly to fuel pump, if i again hear it spinning, try to start car"
-> Yes. That should start the car, unless the fuel pump is defective or there's still some other unaddressed issue. Even with a working fuel pump, Regina cars uses manifold vacuum sensor ie. manifold air pressure sensor (MAP) to decide how much fuel to inject into engine. If the fuel pump is working then thats good. Next to inspect is the MAP - any vacuum leak at its rubber hose and its electrical connection.
Amarin.
|
|
-
|
|
|
Amarin,
Its been a few days since i posted about the problem. I decided to throw another $25 at the problem and ordered a brand new RSR. It finally arrived yesterday and i changed out the old one today. Everything is still the same - no power at IAC connector, fuel pump relay clicks but no noise from fuel pump, faint fuel pump motor noise when red wire from pump gets 11.4v (battery is getting low).
I might have to pull the fuel pump assembly again to see if something broke randomly at the very same time i was looking at the IAC. Seems really really unlikely, but who knows.
Does your book say why the IAC connector would not have power? Its my understanding that there should be constant 12v at the connector and then the computer interrupts the power to control the air flow thru the valve. I think you are right about fixing the original problem first and then go after the new fuel problem.
|
|
-
-
|
|
|
Everyone, very sorry for delayed update. Restarted the apartments painting project and forgot to post back.
As i said in earlier post, i thought a new rsr would solve problem (did not).
After mulling/sleeping on it for a week or so i thought it might be a bad ECU because all the individual components -rsr, fuses, relays, fuel pump and even the IAC would work when power was applied directly to them. So i bought an ECU from ebay, swapped out the original one. Car started! But still had the original problem of a 1800 rpm idle. i checked the IAC connector and i now have 12v there.
When i take the IAC out of the car and apply 12v it will click open and close, so no idea why it won't work. i am just so happy to get my car back i plugged the air hose from air filter to IAC to bring the idle down to 600 rpm. i might revisit that problem later, but a 600-700 rpm idle is working ok for me now.
I guess what happened is that over many years the wires on the RSR had finally shook loose from the pins and one or more touched. Maybe when the wrong ones touched the ECU was fried somehow. i can't know for sure, but since a new (very old) ECU fixed the no start problem i believe that for now.
note: lesson learned yet again to put things back the way you found them.
The wires that go to the RSR were originally in a gray connector. During the no hot start nightmare of 2004- the material holding/sealing the female connectors in the gray plug connector just disintegrated and fell out. so i discarded the gray plug connector and pushed the female connectors onto the pins in the RSR. Meaning to get back to it later. Have not had a hot no start problem in all the years since. Never went back to fix it right ... so this happened.
I crimped the female connectors tight to the pins, shrink tube over the top to protect them, and rubber stuffed into the void where the gray connector should go. Hopefully will last a few more years before i stop driving.
Thanks everyone for all the help.
|
|
-
|
|
|
IAC do fail. The symptom are sometime low / high idle. Their not too expensive now.
|
|
-
|
|
|
Rona,
Does your book say why the IAC connector would not have power?
-> There should be full 12v power to the IAC, fuel injectors when ignition at KPII and KPIII (cranking). This power comes from RSR. If the fuel relay is clicking then the RSR is doing its job (supply power to magnetic coil of relay) and ECU is grounding the relay (means ECU OK too).
The power from RSR goes further to IAC and fuel injectors thru a 8-pin connector located behind the strut tower at passenger side within the engine bay. Look for 8-pin connector connecting only 5 wires (not all 8 slots are used). Among those 5 wires is a yellow wire (can't miss it). Unplug and clean all connections there. This area is prone to corrosion from water coming down from the wiper scutter above.
You already mentioned fuse 11 is good so substitute the fuel relay with a known good one. Yes the relay is clicking but what about its internal contacts condition? Check fuel pump connector too in the boot.
Last but not least check the OBD for any codes. Recharge the battery also - a few past anecdotes about Regina can't start with weak battery. It would crank but won't start.
Hope these helps,
Amarin.
|
|
-
|
|
|
I would think that if a faulty IAC were at play that it would throw a fault code. Maybe, maybe not. But even if the IAC wasn't functioning, you should be able to start the car and keep it running by feathering the throttle. Have you read out the stored OBD codes?
It sounds to me like you have a fuel delivery problem. Do you have access to a fuel gauge? It needs to be able to read up to about 40psi as I think Reginas run at about 36psi + or - depending on the vacuum influence on the pressure regulator.
|
|
-
|
|
|
I will second Amarin's suggestion of checking the radio suppression relay. A fuel pump can be just fine but if the injectors are not pulsing there will be no fuel injected.
The relay is in a black case measuring about 3/4" x 1" x 1 1/2". The case is sealed to the base with silicone. I believe the relay on a 1990 Rex Regina car is mounted very near the coolant reservoir. Actually there will be two identical relays mounted there. One is the radiator cooling fan relay and the other is the radio suppression relay. I can't tell you which one is which but if you use a jumper wire as described in the next paragraph and the fan engages then the radio suppression relay is the other one.
Remove the relay and insert a jumper wire between the two heavier wires on the plug. Try starting the car with the jumper in place. If it starts you have found the problem. Remove the cover on the relay and reflow the solder on the board joints.
Randy
--
Any twenty minute job is just a broken bolt away from a three day ordeal
|
|
-
|
|
|
https://www.brickboard.com/FAQ/700-900/EngineFuelinjection.htm#FuelPumpandFIRelayDiagnosticTests
--
Post Back. That's whats makes this forum work.
|
|
-
|
|
|
"...Is there a way to test/power up the pump without pulling it out?..."
The pink wire running into the top of the fuel pick up assembly is the pump power wire. If you follow that pink wire away from the pump you should find a disconnect somewhere around the LH rear wheel tub. That's a convenient place to connect your meter and test for momentary 12v when you first turn the ignition on.
Conversely......
You can run a temporary jumper wire from the battery + post and connect it to the pink wire at the pump side of the disconnect to see if the pump will then run.
|
|
-
|
|
|
Chris, thanks for the clear diagnostic procedure.
I put power on the pink wire and could here a faint whirring from the pump.
I then jumped pins 30 and 87/2 at the fuse box and could here a faint whirring.
tried to start car with the jumpered fuse box and it refused to start.
Put a tiny splash of fuel and a spritz of starter fluid in the hose at the filter box - she fired up for maybe 3-4 seconds and stopped.
This is a mystery to me. How can the pump be running, but no fuel gets to the intake? Before i started messing with the IAC the car started and ran, it would run at very very high rpm, but it did run.
Oh well, probably will part out the car. called a couple of wreaking yards and they were not interested in a volvo this old. it was a pretty good run, 30 years is a long time for a car.
Thanks again,
Ron
|
|
-
|
|
|
On my first attempt to replace one of those pumps I didn't get it locked into the pick up assembly properly, so when the pump ran it blew itself loose from the hose connection above the pump. Consequently I could hear the pump run but there was no pressure to the fuel rail. Had to do the whole job over again.
|
|
-
|
|
|
i know what you mean. i replaced the pump myself. put everything back together and the the car ran fine. went for the smog check a couple months later - failed the fuel vapor test part of the inspection. replaced gas cap - still failed. in the end had to take it to volvo mechanic. i had failed to seat the rubber gasket properly so the giant lockdown nut was not seating and vapor was escaping. Ouch -$100 for not being carefull with the details. car was running (poorly because of the IAC i think) when i drove it into my sisters carport a few days ago. now not at all. :(
|
|
|
|
|
