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I've got an 1989 245 wagon who has been good to me (420,000 miles on it), but has had some trouble lately. For several months, it had a rough idle when started, for about a minute, before smoothing out. The engine light would come on and indicate a fuel system problem, but wouldn't give the code for what it was (meanwhile ignition system tested clean). During this time, the car ran well on long road trips across the country, starting and running smoothly...
But now it won't start at all. Turns but won't start. I've checked a fair number of things.
-Changed plugs, fuel filter, wires, cap and rotor, tried another AMM (ran similarly), new fuel pump relay, new oxygen sensor, changed/cleaned 25amp fuse near battery. Car has good compression.
When ignition is turned on I hear the fuel pump relay click but when I turn to start it the relay buzzes a bit: due to incorrect voltage reaching it?
This car does have a leak through the passenger side under the dash, but the ECU appears high and dry (took it out and checked it out---it is the infamous pink label ECU, however).
Anyone have any ideas? It seems like it could be a short to me, could anyone suggest some grounds/their locations to check? I'd hate to lose this wagon...
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posted by
someone claiming to be Felix_the_caT
on
Mon Aug 30 17:00 CST 2010 [ RELATED]
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The first thing sounds like a bad check valve, did you change that when you did the fuel filter? I also noticed that you didn't mention the crank sensor, a frequent culprit in codeless no starts. Just my $0.02 worth of suggestions in case the other electrical stuff isn't the problem.
good luck
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I am in agreement with Art on checking the wire from the battery through the 25 amp fuse to the relay.
I had a similiar problem and it turned out the connection at the battery was at fault. The connector was corroded, but cleaning it was not the solution. The corrosion had worked its way up the wire (under the insulation) and had increased the resistance enough that the amperage needed to close the relay was not available.
Randy
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Only replying as #3 in agreement.
This is not always the solution. I have seen it where the computer has simply crapped out and the car runs either:
1) like garbage
2) not at all
The computer could be shot. After all of these years on the original computer, I would be carrying a replacement for it (based merely on experience).
----------------
Chris Herbst
Phoenix, AZ
2005 S80 40k
1992 940 152?k
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When ignition is turned on I hear the fuel pump relay click but when I turn to start it the relay buzzes a bit: due to incorrect voltage reaching it?
Based on this symptom, I recommend you go over the red wire and blade fuse holder under the hood one more time.
--
Art Benstein near Baltimore
I don't feel old. I don't feel anything until noon. Then it's time for my nap. - Bob Hope
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This was the issue on my daughter's '90 a few weeks back. It had been running a bit erratically, had died on her a few times, it all seemed good whenever I looked at it though.
Eventually it dies and wouldn't restart, I told her to leave it there and not mess with it any more.
Went and (thankfully) it wouldn't start. tried to verify the fuel pump was working by jumping the two fuse box terminals, and got something like 1.5 volts at the wire under the back seat. Which isn't right. Took out the kick panel, took a look at the main relay. Noticed it was buzzing. Bad relay? I checked where the 12V+ was supposed to be (thick red wire) and it was 1.5V there as well.
Went under the hood and the white fuse holder seemed fine, followed the red wire from it to the battery terminal - and found the bolt on the battery terminal it was bolted under was loose. Tightened it, car started right up.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)
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The blade fuse and wiring seem like they are in good condition, though that would certainly be an easy fix!
Someone suggested the crank sensor and the fuel pump check valve. Would either of these cause the relay to buzz? Or could a bad computer cause that?
I'm still thinking it could be a bad ground, but am unsure where to check.
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When a relay turns into a buzzer, it is caught in a functional loop, much like a dog chasing its tail. The loop is this:
1. The control for the relay causes a small current to flow through its electromagnet.
2. The electromagnet attracts an iron clapper that causes two contacts to touch.
3. The two contacts create a path for larger current to flow to a large load, in this case your fuel pumps.
4. Some other resistance in the path to the relay now becomes too large to support the high current load, so the voltage available to energize the electromagnet falls below what is needed to hold the clapper down.
5. The clapper releases the contacts connecting the high current load, so the small current once again is available to the electromagnet. Go to #1.
The high resistance causing this tail chasing is usually in the red wire circuit for LH fuel relays, not a ground, and not the ECU, but this "usually" is not without exception. I looked at one buzzing LH relay to find it full of water.
The easy way I would check this, is by using a test light at the relay's terminal 30 - the light should stay (reasonably) bright during cranking. I take it one step further in ease - by checking that voltage (with a test light) at the orange AMM wire under the hood. Peel back the boot and probe where the orange wire goes in the AMM. This works for all LH 240's, LH1.0 (1982)through LH3.1.
--
Art Benstein near Baltimore
Ever consider what our dogs must think of us? I mean, here we come back from a grocery store with the most amazing haul -- chicken, pork, half a cow. They must think we're the greatest hunters on earth! -Anne Tyler
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I went ahead and checked the voltage at the relay (test light stayed bright while cranking) and at the AMM. So it is getting power. Have any idea where to go from here? Thanks for your help.
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Hello,
Just because the lamp glew (glowed), doesn't mean it is getting a good ground. The grounds are near the throttle body. Clean them.
Goatman
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Thanks for your help folks...still puzzling over this problem!
Goatman--I cleaned the two grounds on top of the manifold, were there any others I should be sure to check?
I also went ahead and cleaned out the throttle body (plenty of gunk in there) and checked the fuel pump by jumping the #4 and 6# fuses. The main pump sounded like it was running fine.
Now I'm at a bit of a loss again...any suggestions? The car had a leak through the right windshield wiper and down through under the passenger side dash, due to accumulated leaves in the hood intake, so I'm wondering more and more if this is an ECU problem due to that moisture--though the ECU always seemed dry. Or some other wiring in that area.
Sheesh...
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Is your fuel injection relay still buzzing? Have you looked inside it for water damage? Would the car run with fuse 4 jumpered to fuse 6? Sorry, it has been a while...
--
Art Benstein near Baltimore
Marriage is a wonderful institution, once you are ready to be institutionalized. - R. Cooke
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My fuel pump relay is still buzzing. I tried switching it out with a new relay, and that buzzed as well, so I don't think there's water damage to the relay.
The car would still not start up when I jumpered the fuses...but I could hear the pump running.
Thanks!
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Have you checked the AMM contact per Art's post?
And I quote from the Cleanflametrap Master,
"The easy way I would check this, is by using a test light at the relay's terminal 30 - the light should stay (reasonably) bright during cranking. I take it one step further in ease - by checking that voltage (with a test light) at the orange AMM wire under the hood. Peel back the boot and probe where the orange wire goes in the AMM. This works for all LH 240's, LH1.0 (1982)through LH3.1."
No power to the AMM = No Start, pump running or not on some cars, have the T Shirt for that on my 86.
Most worthy advice IMOH,
Regards,
Paul
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If there's buzzing going on in the fuel relay, the test light might still show "power" at the AMM wire, although if the system relay is the one doing the buzzing, the light might be less than full brightness.
My approach would be to open the buzzing relay and see which of the two inside is buzzing. Then my instincts would have me holding the clapper down on it. If it is the fuel relay, the 4-6 jumper should have bypassed it, but if the system relay, the ECU may have water damage. I've seen it before, but only in the junkyard. If so, I'd open up the ECU to check for the white stuff made by solder, water, and electricity.
--
Art Benstein near Baltimore
Remember what Cardinal Cooke once said:
"A man would do nothing if he waited until such time as no one would find fault with what he has done". - originally John Henry Cardinal Newman
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