posted by
someone claiming to be Chris B
on
Tue Sep 28 06:22 CST 2004 [ RELATED]
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My 88 240 died yesterday as I was leaving work for lunch. I had enough momentum to coast into a nearby parking lot. I tried to restart several times during the day and it would start and run for just a second and then die again. I had it towed home and when I tried to start it this morning it ran for around 20 seconds, then died and would not restart. My first thought was fuel pump relay, because I had that problem on a 740 I had. So I thumped it a few times and still nothing. I took it out and the soldering looks to be okay, though I don't know how effective a visual inspection is. My next thought is the fuel pump itself. I've read that the car will still run without the in-tank pump, but if the in-line pump goes bad it will not.
I'm still confused as to why it will start and run for a short period of time after sitting for awhile. If the pump is bad and the car died as a result, shouldn't the fuel system have practically no pressure at this point? If there is no pressure how would the car start?
Since it starts and runs for a second or two, I'm under the impression that it is getting spark. I'm 99% certain that this is a fuel problem.
any ideas?
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On your '88, the pumps should not run at Key On as Tony suggests. That came in with the later LH 2.4 I think.
I don't think the tank pump or hose problems will cause a no-start either.
I woulld try starting with a jumper wire from fuse 6 left side to fuse 4 left side. This bypasses the 25 amp blade fuse and the fuel pump relay, and puts the voltage right where the FI relay does.
Both pumps should run immediately. If it starts this way, the ignition is obviously OK, and the jumper bypassed a fuel problem.
You can test/run the Main pump by itself with this same jumper, but remove fuse 4 first. Then only the Main pump gets voltage.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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Bruce:
Your advice is always very informative - thanks!. I don't think I've ever had much to add. I would like to comment on one of your statements here though:
"I don't think the tank pump or hose problems will cause a no-start either."
I bought a car for parts in the spring, that had a pretty severe starting problem (about 45 seconds of cranking) - cold or hot. Once it started though, it ran well. I was toying with maybe putting it on the road, but I first wanted to get a handle on what the hard start issue was. The tank was almost empty, and I didn't want to put gas into it in case I decided to retire it. I did the current flow test on the pumps, and they were both about right. I did some gas flow tests at the outlet of the FPR, and found almost no flow when I forced the fuel pumps on. I figured if it ran well, the main pump was fine, so I started suspecting the tank pump or hose. I'm aware of the empty tank symptom if the hose is cracked, so I decided I had to try filling it half way. I added a 1/4 tank, and it got a bit better. I filled it to 1/2 a tank, and voila: no problem!.
I then re-did the flow test with a half tank, and now got a decent flow when the pumps were forced on. I pulled the tank pump, and found the hose intact, but the pump was seized. My experience here tells me that a failed tank pump can cause a hard start issue. What puzzled me from the beginning though (and still does) is how this pump problem can cause a severe starting problem, yet it seems to have no symptoms once started.
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I'm afraid I don't have an answer for that siezed pump and the symptoms you describe. Maybe Art B. is watching and will chime in. He's had some interesting experiences with the tank pump—as when he disconnected the Main with the car running (trying to deplete pressure as most manuals suggest) and the '83 kept on running from the tank pump.
My comment was based mainly on a local '81 K-jet that ran summer and winter for several years with an inop tank pump, but also with a rotted hose.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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posted by
someone claiming to be Chris B
on
Tue Sep 28 10:50 CST 2004 [ RELATED]
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So if I jump 4 & 6 and it starts, either the 25 amp fuse is bad (which I've checked and it's not), the relay is bad, or there is a break in the wiring or a bad connection somewhere between those two components? Does that make sense?
I feel pretty certain that it's the fuel pump but I don't want to replace it and still have the same problem. I really want to do all the troubleshooting before I start throwing parts at it. I've been there and it's very frustrating, not to mention expensive.
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posted by
someone claiming to be Chris B
on
Tue Sep 28 12:55 CST 2004 [ RELATED]
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Okay, I tried jumping fuses 4 and 6 and still no start. The main pump is making no noise. Don't know about the in-tank. If I take the in-line out and apply 12 volts directly, that should confirm with 100% certainty whether the pump is working or no?
Thanks for your help.
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If I take the in-line out and apply 12 volts directly, that should confirm with 100% certainty whether the pump is working or no?
Yes, +12V from Fuse 6 Left/hot side (fuses 6 through 10 are always hot) applied to Fuse 4 Left/hot side will go straight to the main pump.
If it still doesn't run, check to make sure the voltage got there (I think there is an intermediate connector under the back seat), and that the ground side of the pump is OK.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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posted by
someone claiming to be Chris B
on
Tue Sep 28 14:00 CST 2004 [ RELATED]
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Okay, tried it. The pump runs if I jump 4 and 6 but still no start. I get 12 volts at the pump with the jumper on. If I take the jumper off and crank the car, I'm only reading about 50 mv at the pump. I'm getting 12 volts at the relay if I remove the relay and jump relay terminals 30 and 87/2. With the relay in, I watched it while I cranked the car and I didn't see either of the contacts move. I'm back to suspecting the relay but if that is the real problem why didn't it start when I bypassed it by jumping fuses 4 and 6?
I would suspect the filter if I were getting 12 volts at the pump when I crank the car.
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Okay, tried it. The pump runs if I jump 4 and 6 but still no start. I get 12 volts at the pump with the jumper on.
Then the pump works. Sounds like either the FI relay is failing OR it's not being energized
If I take the jumper off and crank the car, I'm only reading about 50 mv at the pump.
Ditto above.
I'm getting 12 volts at the relay if I remove the relay and jump relay terminals 30 and 87/2.
Not sure what you mean here. The 4 to 6 jumper takes voltage from ahead of terminal 30, and applies it after terminal 87/2. So the terminal 30 to 87/2 jumper is actually a smaller part of the same "exercise".
With the relay in, I watched it while I cranked the car and I didn't see either of the contacts move.
So you know there are 2 relays in there. One should close with Key ON (and stay closed). You should hear the "click". It powers the AMM and ECU, but NOT the pumps, injectors, etc.
A - If it doesn't click and close with Key ON, that could be the problem, because the 4—6 jumper doesn't bypass that relay, only the Fuel relay (below).
The other one is the Fuel relay, which should close when cranking. But ONLY when and IF the ECU gets an "ignition OK" signal from the Ignition CU. Therefore, it could be:
B - a bad Fuel relay, or
C - an ignition-related failure (preventing Fuel relay operation)
If A or B, you may be able to fix it by reflowing the soldered connections on the relay PC board.
I'm back to suspecting the relay but if that is the real problem why didn't it start when I bypassed it by jumping fuses 4 and 6?
Most likely an ignition problem (C), as indicated by the failure to start with pumps forced on by the 4—6 jumper, AND the failure of the Fuel relay to energize during cranking, as you saw.
I would suspect the filter if I were getting 12 volts at the pump when I crank the car.
IMO, most filters are replaced needlessly. I have never seen or heard of a (240) filter replacement fixing anything. I suppose an extremely rusty tank might clog a filter, as I have seen (once) on a 140 with a much smaller filter at the pump pickup pipe. But I'd check the flow rate before I'd change one.
You might want to start a new (ignition-related) thread, starting with your diagnosis of Fuel relay failing to "pick" while cranking AND the No-Start even with fuel pumps forced to run (the 4—6 jumper also powers injectors, and IAC, just like the Fuel relay would if it could).
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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If the In-tank hose has a crack in it. Your car will suck air when the Tank is about 1/2 full. This is the hose that is between the in-tank pump and the sending tube.
How much gas is in the tank? this is a fairly common problem.
When you turn the key to just the ON position can you hear the Main pump? It cycles on for about 1.5 seconds. That will eliminate the main pump IF you hear it.
Just some thoughts
--
'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
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posted by
someone claiming to be Chris B
on
Tue Sep 28 10:29 CST 2004 [ RELATED]
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Thanks Tony. I just filled up the day before this happened and the gauge is sitting on the F. A friend and I both listened for the pump, but I don't think I heard it. I'll get my wife to help me tonight so I can get closer while she turns the key to ON.
If I jump fuses 4 and 6, will this give me a more clear indication?
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Well that rules out the hose in the tank. I know you can play the Fuse game but when mine was in question I slid under the car with long wires from the battery. I directly hot wired it.
Good luck.
--
'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
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Fuel pumps should be easy to verify they are spinning with cranking engine otherwise hotvired directly. If it's still not running & the pumps are a pumping, try replacing the fuel filter.
garyS - NJ
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