Been kind of through the ringer with this car and it's acting up again. Problem just started about 1 to 2 weeks ago. Since some fairly extensive repairs around 8 months ago including a ECU from the used parts emporium along with various other things..it's been running pretty good. It does have a problem with highish idle after driving over 30mph or so. If I turn it off then right back on again the idle returns to normal until I exceed that certain speed again. Haven't been able to pinpoint this problem as of yet.

Now there's another new problem. Sometimes it starts and sometimes it doesn't. Starter and battery are operating fine. Just won't fire up. Very random. When it doesn't start, if I keep trying with short cranks, eventually it'll start. If I hold the key All the way to #2 position it just keeps cranking and I get nothing. Almost seems like fuel starvation, but when it does fire..it's like nothing was ever wrong. Sometimes it'll fire up and die right away like an electrical (loose wire) problem. Haven't been able to find any. Then take 15 or 20 short cranks to get it started again. But when it runs it runs. No stutter..no nothing. Runs perfect. Pull over and shut it off, then try and start it again and it almost always fires right back up. Let it sit for 15 minutes and it won't start again. Does it both when hot and cold and weather seems to have no effect either. Anyone got an ideas of where to start looking?

The only code I'm pulling is 232, and occasionally a 231 but have no check engine light on.

232 which is either Lamda adjustment or Adaptive heated O2 sensor control (94-up). First start up in the morning it can run rich for a while but usually mellows out. Gas mileage is fair to good.

Could the O2 be causing this? Could it be a different sensor or switch going bad. Which ones can I check myself? Thanks in advance. Jim

 

Gremlins are hard to isolate. Have you tuned it up, doing the usual? New spark plugs, distributor cap, rotor, spark plug wires, air filter? (I hesitate on fuel filter, as that can be a bitch to replace.) Go to www.stepbystepvolvo.com and take the "Real-Life Volvo Quiz." That might help you.

 

With everything connected and running, peel back the rubber boot on the big green o2 sensor output wire and measure the voltage, it should swing quickly between .2 and .8 VDC.

Clean the LH blade fuse on the fender near the battery, and clean fuse 4. Measure the voltage on the right side of fuse 4 during the no-start condition (to ensure correct pump voltages and the fuel relay).

A common cause of random no-starts is the crank position sensor, especially if it's original.

 

Crank sensor was replaced recently. I think I've narrowed it down to one of the fuel pumps..most likely the one in the tank. This morning I couldn't get it to fire up after many tries with the usual short cranks. Pulled the tube going to the throttle body from the AMM and sprayed a little starting fluid in it. Viola..cranked right up. Definately fuel starvation..but only on start up. Once running it seems fine.

 

But I'll do those voltage checks and report back..

 

Baffled. It's been sitting out front of work since 1:30 this afternoon. Just gave it a try and it fired right up first try.

 

The right side of fuse 4 is the wire that runs the in tank fuel pump.

 

I know it's obvious but I've had similar issues and it was three little things, all intermittent. When I finally got around to changing out the main fuel filter I couldn't even blow air thru it and the sock was missing on the in tank pump.

 

Seems like the pusher pump in the tank. Gonna check the filter(s) too. Starting it now by popping a vacuum line that runs straight into the TB and spraying a shot of starting fluid in there. Fires right up...

 

My 240 will run (not very well) with just the main pump, and not the in-tank pump. Could be the pump relay. You can also run a jumper wire from the left side of fuse 4 to the left side of fuse 6 - both pumps should run (constantly) at that point, allowing you to listen for them. Is this a sedan or wagon? I would also inspect the in tank pump ground connection.

As a safety feature, neither pump will run if no spark is present (without the jumper).

 

OK here's where I'm at. I've replaced the fuel filter on the frame rail. I've replaced both the in tank pump and the one next to the fuel filter. Still have the starting problem. Can still get it going with a shot of starting fluid (I'm on my third can lol). Still have the high idle problem once it's gotten up to speed. If I turn it off and start it right back up it almost always fires and the idle returns to normal. If it sits a while it won't start again. Also of note..if I start it up in the morning (almost always fires up first thing but not always) then drive a short distance and turn it off..then try and restart 5 minutes later it won't start. Once it's reached operating temp I can shut it off and if I try and start it again within say 5 minutes it'll start. If it sits a bit it won't.

Checked voltage on the O2 (green wire by shock tower on passenger side) it reads 1/2 volt to 1.5 volts consistently..fluctuating fairly quickly back and forth. This is at idle. If I rev it up the range seems to increase slightly but not much. I'm assuming this is my idle problem.


Checked voltage on right side of fuse number 4 with key in number one position and get nothing. Once started It has a very steady 12+ volts. Fuse is good and cleaned. Waiting for it to "not" start so I can check fuse number 4 again. But without it running I'm getting no voltage so a bit confused how I would see any under the "no start" condition. Should I be actually cranking it over during this no start period and checking voltage simultaneously?


There are no apparent vacuum leaks. Any help is greatly appreciated as I've been just soaked by this thing already and cannot afford to take it in and deal with who knows what kind of bill again....


*edit* just tried and it wouldn't start. Checked voltage on right side of fuse 4 with key in number one position and it's dead. While cranking it over..dead. Sprayed some starting fluid in the TB and it fired up. Checked fuse 4 while running and have a strong 13.8 volts. Starting to sound like the fuel pump relay maybe? Where do I find this relay? Thanks Jim

 

While cranking you should have battery voltage on fuse 4. If you don't that means the pumps aren't getting power. That could be the fuel relay or less likely the fuel ECU since that controls the relay. Its white and clipped to the firewall above the passenger's feet, behind the carpet.

If you run a jumper wire between the left side of fuses 4 and 6 both pumps will run all the time (constantly). So if it won't start, you install the jumper and it starts - that suggests the relay, which correlates to no voltage while cranking. But this is also a known failure of the "pink label" 1990 ECU's.

See:
http://www.brickboard.com/FAQ/700-90...nsor_Diagnosis
1.5VDC is too high, and 2-3-2 points to being too rich. Isn't this a new sensor? Make sure you don't have gas in the vaccum line that goes between the fuel pressure regulator and the intake.

 

Thanks bubba. So I made a jumper and hooked it up from the left side of fuse 4 and 6 and viola it cranked up. Also pulled the cap off of the relay. Here's the weird part. It's a double relay with 2 contacts. When I turn the key to #1 position only one side of the relay trips. If I hook up the jumper it'll start but as soon as I remove the jumper it dies..unless I manual trip the other side of the relay. Then I can remove the jumper and it stays running. The weird part being that a shot of starting fluid usually gets it going. What's going on with this relay or is it even the relay? Jumper on the fuses gets it going but both sides of the relay must be tripped in order for it to stay running without the jumper..and doesn't seem like the jumper causes the one side of the relay to always trip. Asking because it's a dealer item (of course)...

 

*edit* PROBLEM SOLVED after noticing some of the solder points and the back side of the relay looking suspect..I resoldered the bad ones and viola..starts every time now. Both sides of the relay are clicking each time. First one clicks when key goes to number one postition and the other clicks when the engine starts cranking over. Thanks for your help Bubba..looking in the direction of the relay. Probably would not have figured it otherwise. Owe ya a cold one! We'll make it a sixer if you can help me figure out this idle problem.

 

For others maybe having this same problem:

The package contains two relays - a system relay that powers the air mass meter at key position 1, and a fuel relay that powers the pumps once the ECU sees the spark pulses and grounds the blue-green wire.

So if you ground the blue-green wire and the problem persists, you can be 98% sure its the relay - not the ECU.

You can find them cheap on ebay, the junkyard, or www.fcpgroton.com