So I've been dealing with a somewhat confusing no start issue that i've narrowed down to the fuel/fuel injection system. For a few weeks the car would sometimes take 3-5 turn-overs to get started. I figured it was the fuel filter since it had never been replaced. I replaced it, but the problem didn't go away. Instead, it's gotten worse.

I've been emailing back and forth with Dave Barton (DaveBarton.com) about the issue, because I thought it might be a relay issue. I tried his jumper trick (running a wire from the red to red/yellow wire that connects to the fuel pump relay). The main pump runs (as it's audible) but I am not sure if the in tank pump is running for sure. I hear a hum in the fuel filler pipe and if I put my ear above the tank in the trunk, but can't verify if that isn't just the main pump as well. It doesn's turn over with this trick. However, the other day whilst trouble shooting, I tapped the relay, turned the ignition, the relay made a faint click and the car fired up. I ran it for a minute or two, shut if off, and started it back up fine, two times in a row. That faint click was the same thing I'd hear back when it would fire up after 3-5 turn-overs. Now it's back to no start...

Dave suggest I check the fuel pressure regulator, but didn't give much help except to find a used one and put it on to test it out. Not certain that its even the cause.

I've searched the forums for similar issues but haven't gotten too far. I've checked the fuses and they all seem fine. Not sure where to check next as I'm pretty confused... Any experience with something like this? Suggestions?

Thanks

 

on a 240 that generation, pull fuse 4, and with the ignition off, take a jumper wire and run it from fuse 6 (which is always powered) to either side of the fuse 4 contacts. one side will power the main fuel pump, the other side the in-tank pump. I *think* its the left side for the main and the right side for the tank, but my 240 is now out of state with my college daughter.

the tank pump is quite hard to hear with a half tank or more of gas as its submerged. its easiest to hear with less than a quarter tank, and remove the gas cap and put your ear to the filler pipe while someone jumpers it, you should hear a soft pfpfpfpfpfpfp kind of sound.

 

I jumped the fuses (it's the right side of 4 for in tank pump). didn't hear anything at all... So I am guessing that the pump went out or perhaps there is a short somewhere. What would you wager? Any use looking for use pumps?

 

the tank pump isn't that expensive, just a pain to install.

not sure if I'd trust a used main pump unless I knew the history on the car.

 

So I replaced the in-tank pump--wasn't too difficult, a bit tedious getting the float valve and filter out and into such a small hole. The filter was all torn up where it attached to the pump, everything else looked good.

Alas, still no start.
Any suggestions where to look? I'm going to go back to square one and check to confirm it is getting spark, fuel (pressure), and air.

 

verify that in tank pump is working correctly and pumping the right way. bunches of the aftermarket stuff is misswired, see In the Tank - 240 Volvo Tank Pump and Sender

 

Generally, a failed or non-working in-tank pump won't cause a no-start situation. When my in-tank pump failed, you wouldn't even notice it except my main pump got noisier from working harder.

I would go back to the basics for you no-start. Do you have spark? Does it start if you spray a touch of starter fluid into the throttle body? Work from there.

 

my 740T ran really crappy when the intank pump was dead when it had 1/3rd tank or less. but yeah, it did run.

 

The pump is working--I ordered through IPD. So I'm getting spark, fuel is getting into the fuel rail (haven't checked the plugs to see if theirs fuel on them, yet)...

Where is the best place to spray started fluid into the throuttle body? Not seeing any obvious area that would be easy to spray into...

Looked back at the FPR--the vacuum line is wet with gas and their is corrosion on that end of the FPR (where the vacuum line connects). I'm suspecting that it has completely failed and may be one of the main issues. Does that make sense, failed FPR causing no start?

Also, I've been reading about the 25amp fuse near the battery causing no starts--I see nothing in there. There's the headlammp relay and a small black plastic housing with a splitter inside (not sure of technical name) . No fuse in sight...

 

the 25A fuse powers your whole fuel injection ssystem including the pumps, so if the pumps are running, the fuse is good.

fyi, that black plastic box with all the red wires is the 'positive terminal'. the 25A FI fuse is usually somewhere near the power steering reservoir, its inline on a red wire attached to the battery (+) terminal.

 

Next to the black plastic box, towards the rear of the car, should be a white plastic fuse holder for the 25amp fuse. The red wire coming out of the plastic box should run to this fuse. Previous owner may have relocated the fuse with a different, more weather tight, fuse holder as the original setup was exposed to water and a cause of many no-start conditions.

Regarding the Fuel Pressure Regulator, if you have gas coming out of the vacum hose, then you need to replace it. I haven't had one fail on me so I can't say that it will cause a no-start condition but from what I have read, it can cause poor running and hard warm starts. Your car won't run right unless it is fixed so I would address it immediately

 

on our 87 240, the EFI fuse is directly off the battery terminal, not off the positive terminal.

 

I've yet to find the fuse, even after tracking down the wiring. It does look like a lot of the wiring has been fiddle with...

Replaced the faulty regulator, but that's not what's causing the no start. I spoke to someone at IPD an they told me to check the air mass meter—unplug and see if it starts. So I unplugged it an tried starting. Before trying to unplug I would not hear the fuel pumps or the fuel pump relay power/actuate. After unplugging the AMM I could hear the pumps go on and the relay actuate—but still no start. When I put the key into the second position, the pumps run, but don't stop after a few seconds as I know they are supposed to, correct? Plug the AMM back in, no relay/pump action again.

If someone has a second, could they give me an explanation of why unplugging the AMM would do that? Does that mean the AMM is faulty and a big part of no start?

Also just read on this thread a fix (cleaning all electrical connections in positive terminal) in and I think I need to head that way in the mean time. Seems electrical, somewhere...

 

mmm, if the pumps stay on, sounds like someone jimmied with the fuel pump relay wiring.

 

That is possible, but doesn't seem to get to the core reason as to why a no-start condition arise (wouldn't it have happened sooner?—if the wiring was jimmied, it was before I got the car 4 years ago—I've never had a no start). That's why I was surprised that unplugging the AMM caused that to happen. Does that indicate that the AMM is faulty and inhibiting fuel injection? I don't understand the starting sequence in the car enough to know for sure...

 

unplugging the AMM/MAF shouldn't have had any effect on the fuel pumps running, but they are powered off the same circuit as the rest of the EFI stuff, so if the wiring has been 'enhanced' (insert sarcasm smiley here), all bets are off.

 

Hm. Still unsure as to why 'enhanced' wiring would just now cause this issue. Wouldn't it have happened earlier? Not sure what to do now. I just don't know enough about the electrical.

It's getting fuel (but not certain the fuel injectors are spraying...), air, spark...