I've got a 1991 240 sedan, been having problems with the fuel delivery ever since I bought it from a guy for $500 w/ only 101,000 on it. Duh, should have seen that one coming. I can't get this thing to start up consistently for anything. I've put in a new fuel filter,switched out the fuel pump thinking that might be weak ( put a known good one in from my old 740 Turbo), I know it's not the same but it worked, I changed out the fuel pressure regulator. Bottom line- sometimes it starts up and runs fine, good acceleration, idles fine- you'd never know anything was wrong with it. Other times, can't start it-prime the intake w/ gas to see if it fires- it'll run and die. Other times it starts and I can run it down the road for about a mile and it just cuts out- usually restarts after this condition though. Please help- I rarely need to ask advice for my small fleet of older Volvos, but I'm stumped by this one. After a year of off and on driving with this thing, it's getting old.

O.K., over the weekend did some experimentation. Tried to start 91 w/o jumper wire,no go. Took the fuel pump relay off of my junked 87 740 turbo and swapped it out- 91 240 supposedly takes same relay. It fired right up but when I switched off ignition, the pumps kept running,? Took relay out of my 89 240,installed in 91-fired right up and when I turned off everything shut down as it should. Tried 740 relay in 89-worked fine and as it should,? Put the original relay back in 91 -fired up,turned off,tried again-nothing. So, long story short,it's probably the relay, sometimes works,sometimes not.
One question though, I popped cap off all the relays and inspected them carefully-the 740's relay and the one out of the89 240 are identical inside, but the 91's relay is different inside with a couple of the connection prongs extending up to the coils and points area. Is this some variation of this relay that I need to worry about when ordering a new one? I get my stuff from FCP Groton and their parts #'s indicate the same relay for all 3 models.

O.K.,yesterday when i got this thing running,I jumpered it immediately L sides of 4 +6 w/o trying to start it un-jumpered-it was a nice day here in upstate N.Y.,70ish,sunny and dry. Went back today,also sunny,dry and warm ran the jumper wire immediately same way started right up and drove it(still jumpered) for 20+ miles and shut it down. Decided to remove jumper wire (because if I leave it on the pumps operate with the key off, should that happen?) Anyways,wanted to experiment so I tried to start it without jumper wire-CRAP-it started right up, first time I was ever unhappy that it started. Now what is most likely cause? Could it be a failing relay getting temp. sensitive,be it from outside temp. influences or car heating up and relay working better because of that?

I again jumpered the 4 and 6 fuses- with alligator clips this time,and made sure I didn't knock the fuses out of contact (which I may have done the other day) turned on key, listened and both pumps seemed to be operating. Tried to start-still jumpered-and bingo-started right up fine and first time. Does this mean I need a new relay? Thanks again for all your help.

Perhaps someone has already suggested this but have you cleaned the 25 amp fuse and its holder? It is on the red wire leading from the positive battery post and is mounted on the drivers inner fender.

Is the red wire connector at the battery clean? Are you sure there is no corrosion build up under the wire insulation directly behind the connector. Corrosion build up can increase the resistance and reduce the current needed to operate the relay.

Is the ECU a pink labeled 561 (last three numbers on the unit) These are known trouble makers.

Randy

Either the relay (most likely) or a known problem with some ECUs, where they no longer supply the ground to energize the Fuel relay.

If a new relay fixes it, you can try to save the failing one for a spare by removing the white cover for access to the solder connections and reflowing them. This is outlined in the 700/900FAQ.
(See drop-down menu at upper right and scroll down.)
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Well, here's what happened, I jumpered the left side of the 4 and 6 fuses WITH thw fuses still in(hopefully this was correctly done, leaving them in I mean),this is a 91 so I hope I didn't misunderstand Lucid's original directions as far as what fuses to jump and how to do it. I turned the key to the on position (didn't try to crank it at this point). My buddy could hear buzzing coming from the main pump under the car but heard nothing putting up his ear to the open gas tank fill hole. I tried to crank the engine over with it jumpered-but it wouldn't start.
When I disconnected the jumper wire I tried again to start it and it did start right up and ran for about 5 seconds, again I jumpered it and listened to both areas with same outcome,buzzing from main pump, nothing from in tank. Again,I tried to start with jumper disconnected and it started and again only ran 5 seconds.
I also turned the key to on position w/o the jump wire hooked up and could hear no buzzing coming from main pump underneath the car.Again, no sound emitting from the in tank pump,incidently the gas tank is full so I don't know if that would muffle it if it was running.

Do you guys have any more ideas on what I can do. See my previous post,you have more knowledge than I'll ever have.

1) "I turned the key to the on position (didn't try to crank it at this point). My buddy could hear buzzing coming from the main pump under the car but heard nothing putting up his ear to the open gas tank fill hole."
• Then we know the pump runs when it gets voltage. Tank pump is less certain. They can be hard to hear depending on ambient noise level. Try removing fuse 4 and jumpering from 6L to 4R. That should put power only to Tank pump, which is really a moot point right now. IMO.

2) "I tried to crank the engine over with it jumpered-but it wouldn't start."
• How long did you crank? 3 seconds? 5? 10? A wild guess is that you may have stopped cranking just as the fuel rail got filled (which could take longer than normal if Tank pump was inop).

3) "When I disconnected the jumper wire I tried again to start it and it did start right up and ran for about 5 seconds,"
• Still flogging the wild guess—it started on the fuel (and residual pressure) from the failed attempt -- and then ran "dry".

4) "again I jumpered it and listened to both areas with same outcome, buzzing from main pump, nothing from in tank."
• See my question at 2, above. Again, the fuel rail was repressurized but maybe you stopped cranking too soon?

5) "Again,I tried to start with jumper disconnected and it started and again only ran 5 seconds."
• See my comment #3, the wild guess.
To better test the Tank pump, remove fuse 4 and jumper from 6Left to 4Right putting power only to the Tank pump, as I mentioned above. If your jumper has clips, you can go back and listen yourself.
But the fact that it ran for a few seconds (twice) with NO pumps running makes me rule out the Tank pump as being the main problem at this point.

Jumper again (6L=>4L) with fuse 4 in place and try cranking a bit longer, say 5 or 6 seconds. Maybe I'm missing something, but that's all I have right now. Will you be able to take the battery someplace for a charge, if it comes to that?

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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks Bruce, I will try all that exactly as instructed,please be patient w/ me-I'm not very solid on electricals, and yes I can get the battery charged if needed. I appreciate all the advice.

Before you try another start (with a bit longer cranking), run the pump a few seconds first. I'm guessing that with a dead Tank pump, the longer "prime" might help ensure there is pressurized fuel at the injectors.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

O.K. Bruce, Another thing I was thinking about-If I find out the in tank pump is bad, theres no way I can change it out in the parking lot at work,( they'd go ballistic and then I'd have to worry about loss of a job along with loss of the car,and towing it home sounds equally undesirable as I'd have to remove the back part of the driveshaft and tow it w/my 940 w/wife driving(that ain't gonna happen) Is there any reason I could not hook up some kind of temporary gravity fed gas tank,placed on the high part of the trunk,fish a line thru the hole and hook it up to the line to the main pump. All that in tank pump does is supply gas to the main pump at low pressure, right? And if the main pump works it should run, I would just hope I'd have room in the tank for any returning fuel.

Put it on a flatbed. After all, you are still employed.

If you rig what you are talking about, I think your alias may be prophetic. Please don't consider doing that.
--
Art Benstein near Baltimore

The statistics on sanity are that one out of every four Americans is suffering from some form of mental illness. Think of your three best friends. If they are okay, then it's you.

As Bob (rhaire) suggested it may be a bad AMM, disconnect the electrical connector (key off) then try starting the engine. If it idles fine the AMM is bad.
Dan

Well, here's what happened, I jumpered the left side of the 4 and 6 fuses WITH thw fuses still in(hopefully this was correctly done, leaving them in I mean),this is a 91 so I hope I didn't misunderstand Lucid's original directions as far as what fuses to jump and how to do it. I turned the key to the on position (didn't try to crank it at this point). My buddy could hear buzzing coming from the main pump under the car but heard nothing putting up his ear to the open gas tank fill hole. I tried to crank the engine over with it jumpered-but it wouldn't start.
When I disconnected the jumper wire I tried again to start it and it did start right up and ran for about 5 seconds, again I jumpered it and listened to both areas with same outcome,buzzing from main pump, nothing from in tank. Again,I tried to start with jumper disconnected and it started and again only ran 5 seconds.
I also turned the key to on position w/o the jump wire hooked up and could hear no buzzing coming from main pump underneath the car.Again, no sound emitting from the in tank pump,incidently the gas tank is full so I don't know if that would muffle it if it was running.

Well within the broad range of characteristic problems resulting from a bad fuel pump relay. Might also be a beginning AMM problem.

Ignition trumps fuel, so you need to start there, although Fuel system-related problems are more common. The exact sequence of events for starting and running is detailed below. The trick is to determine which step is failing. The 700/900 FAQ has much info on diagnosing and testing the same EZK Ignition and LH 2.4 FI as used with your B230.

Start Sequence

1) During starter cranking, the Crank Position Sensor (aka RPM Sender, etc.) sends timing pulses to the EZK Ignition Control Unit (ICU)

2-a) The ICU uses these timing pulses to trigger the Power Stage (aka Ignition Amplifier), which initiates spark from the coil.

2-b) At the same time, the ICU also propagates these timing pulses to the LH Fuel ECU, to allow FI operation (no ICU pulses means no FI operation).

3-a) The Fuel "System" relay lives in the white case with the Fuel relay. It gets energized at Key On to power the AMM, IAC, ECU, Injectors, and Fuel (pump) relay coil + side.

3-b) When the FI ECU senses the ICU pulses timing pulses, it "energizes" the Fuel relay by grounding the Fuel relay coil to run the fuel pumps.

When all these things work, the engine runs until the Ignition is switched off, which in turn shuts down the FI system.

Determining whether or not there is spark at the plugs (2a) —and whether or not the plugs are getting gas (3)— will allow some analysis of this sequence.

For example, if 2a fails due to a bad Power Stage/Amplifier, there will be a no-start with gas-wet plugs. If 2b fails (practically never) symptoms will be Fuel-related: a no-start with spark at the plugs, but plugs remain dry.

• For testing, jumpering the LEFT side contacts of fuses 4 and 6 will bypass both the 25A blade fuse (or fuse #6 on '91-'93) and the Fuel relay—and should power up both pumps immediately.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks for the response Bruce. As I said the engine seems to run when it feels like it. If i take a turkey baster full of gas or spray starter fluid and squirt it in the intake at the throttle body, the engine will run for 30 seconds or so-until it consumes the small amount of fuel I've artificially injected. That tells me the spark is fine, so theres no problem on that end-right? I'm no electrical wizz kid, so I need advice in basic laymens terms a smuch as possible. I've got the Bently manual but some of the tests in there are a little perplexing for me.

Did you jumper the fuses as Bruce suggested? This will tell if your fuel pump (system) relay is working, if it is not there will be no fuel to the injectors.

For testing, jumpering the LEFT side contacts of fuses 4 and 6 will bypass both the 25A blade fuse (or fuse #6 on '91-'93) and the Fuel relay—and should power up both pumps immediately.
Dan

O.K. I'll try that, I believe thats the way they describe it in the Bently manual.

I had identical symptoms in my '83 245. Drove me nuts for months - I replaced every fuel delivery part to no avail. I could also spray starting fluid into the intake and get it to briefly fire up.

My problem turned out to be a bad distributor hall sender, probably a loose connection in it's wiring. I'm assuming the '91 has the cam driven distributor but I'm guessing it's internals are similar. Good luck - Jim

'89 and up have a Crank positioning sensor to handle the job of your Distributor mounted rotation identifier. I was leaning toward the Crank sensor until I heard he has Spark...I think if it was the Crank positioning sensor, he'd have no spark.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

Thanks for that response also, I hope it doesn't turn out to be that extensive or expensive. I'll start w/ the relay bypass trick and go from there. What gets me is the intermittancy of this problem-I mean starting and running fine sometimes and not others-I don't get it!!!!!Right now, it's stuck in the parking lot @ work and I live 30 miles away from it-so I'd like to get it home at least before I dive in too deep.

"What gets me is the intermittancy of this problem-I mean starting and running fine sometimes and not others-I don't get it!!!!!

Your symptoms are typical of a "marginal" electrical circuit, probably a soldered connection gone bad, and quite possibly in the Fuel relay, where such problems are known to occur with time. A faulty connection like this can also be temperature sensitive, adding to the frustration.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.