Car runs 30 secs then stubles and dies like the fuel is cut off or pinched off.

My question is, what happens in the ignition system after a cold start after 30+- secs that could cause the car to look at a sensor, that could be feeding bad info that it is not identifying at the initial cold start.

I've been through my Volvo official manual, looked athe computer, no codes
Changed out with known good part (off running 91 w/ same ignition), ECU (main computer), both fuel pumps, Idle air control valve, radio supression relay, fuel pump relay, I get a spark pulse to the dying revolution.

Does the ECU take into account a signal from the AMM or O2 sensor after a certain time???

The car will not restart after a stall, I can turn the ignition switch several times, then it will restart. I thought fuel, and swapped out the main fuel pump, filled the tank to the tip top, the intank pump was already replaced as I swapped out the sending unit (rusted out).

Tonight I will put a fuel gague on, it is a deal as there is no test port, and the rail connection is stuck, as in the rail will twist up prior to letting go. I'm going to move fuel pressure regulator off, splice in a guage with rubber hose and a tee. I had replaced the fuel pressure regulator with my old on removed for preventative maintenance a year ago with no change.

UUUGGGGHHHHHHH.

Any thoughts appreciated

I wil likely swap AMM and supply hoses with my running car on Sat also as a shot in the dark.

A couple of clues in your posts: "rusted out" in-tank pump or sending unit, and sparks still firing as the engine dies. So...Fuel starvation? Fuel filter badly clogged with rust particles?
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Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD; hobbycar 77 MGB, and a few old motorcycles)

I forgot to mention I did the fuel filter (replaced it).

I'm going to put a fuel guage on it hopefully, it sparked last night down to the last 1/4 revolution (timing light) as it died.

Then I will do the power stage as I am out of options here.

It was 1 degree this morning (deg F for you Canadians) so I'm going to let it warm up.

Thanks for the input

My money is on the power stage-- I've had these symptoms before with a faulty one. They are plentiful in the pick-n-pulls (same part # in similar vintage SAABs, but with a different heat sink base). I have boneyard spares in the glove boxes on both of my cars...

Good luck!
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Herb Goltz, Aurora, Ontario, Canada '92 245 w/124K mi, '92 945T w/200K mi

As for breaking the gas-line to fuel rail connector, trying taking two hammers-one to back up the "banjo" type nut and the other to mildly stike the nut itself. These things get "frozen" on and need to be freed up sometimes by jarring them.

THAT PRETTY WELL DESCRIBES THE BAD 016 AMM SYMPTOMS FOR AN LH 2.4. Accidental caps, sorry.

I did the amm swap, no change. It still has spark even as it dies out, this is maddening.

The ECU does not account for the O2 sensor signal until that signal exceeds the 0.5v reference signal, which happens only after the sensor has heated up enough to operate. That's the only thing that comes to mind in the fuel system. The ignition on the other hand could be the source of problems if the power stage (ignition amplifier) is failing. Try swapping that from the running car. It's located on the inner fender, driver's side, just back from the headlight.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina

I do not have a meter that meets the impedance requirements to measure the signal straight. I have the correct ohms on the heater, I have volts to the heater and a good ground. Sensor was new last year and is Bosh ($$). I disconnected the sensor to account for that and saw no change in the symptoms.

Any other ideas to diagnois are appreciated.

Eric

Then swap the AMM, and swap the ignition power stage, one at a time, from the known working car. It's bound to be one or the other.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina

I swapped them both, it still is dying after 30 sec.

I have fuel pressure after a stall, how much is the question. My fuel pressure rig failed when the schrader valve on the guage line wasent depressed so the whole contraption charged up but the guage line. I'll have to modify it this week. Makes you appreciate the test ports on new cars.


If this keeps up much longer shes headed for parts car heaven

If this was a 240 I'd easily jumper fuses to hot-wire the FI system, guessing Ignition is maybe OK, and the 30 second run is from the short pump cycle with Key On before cranking.

Jumping 700/900 fuses is harder, but can be done like this:

• Remove Intank pump Fuse 11 and improvise a jumper wire to apply voltage to the Fuse 11 terminal that is farthest away from you, i.e., toward the engine.

• You can get battery voltage from the Fuse 1 terminal closest to you, after the fuse is removed. Use a jumper wire with a flat male terminal on each end, to take voltage from F1 to F11.

The pumps will run immediately — try starting to see if it runs longer now.
If so, the jumper is bypassing a fuel problem.
If not, it's more likely ignition.


NOTE: This is from a '93 Green Book wiring diagram, which is all I have. It should work for you if Fuse 11 is for your Intank pump.

If I'm reading my '89 green book correctly, Bruce, for a B230F LH2.4 system, you can do as you say, but you also need to restore fuse 1 functionality with a jumper wire and ideally you'd want fuse 11 jumpered as well. Battery power looks like it's on the back terminal of fuse 1 (not the front as you indicated) while the front terminal provides power for the injection system (the ECU and indirectly the AMM and IAC valve). For fuse 11, the back terminal can be used to directly power the main fuel pump as you indicated. The front terminal of fuse 11 feeds the in-tank pump and O2 sensor heater. I'd also try jumpering only to the back or front terminal of fuse 11 to see how attempting to run on only one pump changes the symptoms.

An alternative is to slide out the relay tray, remove the injection system relay (fuel pump relay, middle row, leftmost) and in the relay socket jumper together pin 3 (terminal 30), pin 5 (87/2) and pin 1 (87/1). Note that pin 3 is always hot (battery voltage). I'd probably use paper clips to jumper at the relay socket as there is a fair power draw. Do visually check the f/p relay socket for signs of overheating -if the plastic melts, the terminal connector may push out which makes for poor or no contact. Unfortunately you can't use jumpers at the relay socket to operate just the main or in-tank pump -that's best done at the fuse panel.

I sure agree that's a good test to try. Too bad proper fuel pressure testing can't be done to totally rule out fuel delivery problems. Operation of the main fuel pump is certainly suspect. You can't ignore the fact that '89 ECU's are certainly famous for providing poor f/p relay ground and 30 seconds may be just enough to overheat a faulty transistor.

Another thought, if the main fuel pump was out, the in-tank pump alone should start and run the engine, but if it was in the process of failing it might run for less than 30 seconds before seizing. That in-tank pump behaviour I've seen when playing with a "dead" one. I certainly agree with others that a bad AMM can cause a stall after starting, but in my experience it's more like a stall immediately after catching, not 30 seconds of running.

Given all that's been swapped/replaced on this car, my next prime suspect would be the rpm sensor. I don't think they usually fail with such consistent symptoms, but the original '89 sensors were certainly known weak spots for stalls and no-starts.
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Dave -own 940's, prev 740/240/140/120's & quasi-expert only on a good day

David, thanks for your comments. My idea was based on '93 diagrams, which I've found in many cases to apply to late '80s LH 2.4 models. And I believe that when I first posted this, I got a favorable response—saying it worked—a memory (perhaps faulty) which encouraged me to offer it this time. I'll try searching for that response. EDIT: see** below...

I based my fuse orientations not on the actual FI diagram page, but on the fuse schematic pictorial at the front of the WD book. This looks like an overhead view of the fuse panel, which I took to be a realistic view—although the directional current path does differ from how Fuses 1 and 11 are shown on the FI diagram page.

On the "Electrical distribution, fuses" pictorial, the Battery input to Fuse 1 comes in from the bottom (output at the top). But you're right about needing "functionality" (other than jumpering to fuse 11). I overlooked the fact that Fuse 1 has multiple outputs, the others leading thru C2 to EZK pin 5, and C3 to LH ECU pin 4.

As I said, I thought I'd recieved positive feedback when I first posted this (as theoretical but untried, I hope). But fuse orientation aside, my overlooking the need for the other fuse 1 functions says it won't do what I thought.

As for fuse 11, I blew it there too, relying on my 240 mindset where jumpering +12v to the tank fuse "input" is electrically the same as FI relay 87/2 and powers both pumps, but only when the fuse is in place. Of course, the 700/900 blade fuses don't allow that kind of jumpering.

Alternative possibilities(?) below:

1) Get battery +12v from another (removed) fuse input, such as #5 which powers only miscellaneous lights, radio, etc. (on '93 diagram), leaving #1 for the important stuff.

2) Make up a pluggable Blade Fuse holder extension, with a pigtail to recieve the jumpered voltage, and substitute it for fuse 11 (and maybe other applicatinons?). As with the 240, it could force either pump, or both—depending whether the extended fuse was in place or and, and how the pigtail input was oriented.

I know that this jumpering only substitutes for FI relay 87/2, but my 240 experience (with 2 exceptions-both in family LH 2.2 '87s) is that the "System" relay half (87/1) seldom fails. Our fix for those exceptions was a 3-way jumper like you describe—from 30 to both output harness sockets. The tip-off was not hearing the LH 2.2 relay "click" at Key On. Not hearing the LH 2.4 pumps at Key On could be due to either half of the FI relay, I believe.

Another time I'll brag about my 940 FI relay's home in the glove box.

** I found my "favorable" response here, but now see it was just for a pump test, not a no-start. I see I bragged about my FI relay in that thread too.


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

Egg on face? -no, just an incomplete thought. You're right, like your '93 green manual, the '89 manual has inconsistent fuse orientation on the FI page compared to the fuse panel diagram at the front. By the time they got to the '95 manual it was consistent. Moral of that story, if there's any doubt then use a meter or check under the fuse panel to see which wires go to which side of the fuses. As you lament, life was simpler with 240's, the fuse panel wires were exposed.

Now as to bragging about putting your 940 FI relay remotely in the glove box so you can hear it clicking, I'm starting to worry about you. That's precious real estate in there, especially after they did such a poor job of re-designing the glove box to accomodate the air bag and condenser. Perhaps you haven't completely adjusted to owning such a refined car. With 240's that might be considered rational, but with 940's I'm afraid that's an indicator of "relay phobia", which you mis-diagnosed as anal behaviour in your previous post. With time I hope you can be cured, but it may take professional therapy. At least you didn't go overboard by attaching a stethoscope or rigging up a baby monitor -that might have required an intervention. ;)
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Dave -own 940's, prev 740/240/140/120's & quasi-expert only on a good day