You guys have been great with advice. Now if only I could diagnose my problem correctly. Wait, I think I know what MY problem is, but the cars problem is the question.

 

Here are the chain of events leading to the alleged incident. The names have not been changed, screw the innocent.

 

Wednesday - Bought 1990 Legacy 2wd from retired used car salesman whose son is a subaru mechanic (red flag ?)

 

Thursday - showed car off to friends and family

 

Friday - still congratulating self for shrewd purchase

 

Saturday - car would not start, towed home

- swapping parts from other 90 Legacy to try to isolate prob

- coil... not in spec according to Chiltons but works in other car - coil from dead car also works in living car

- same with ignitor module

 

Sunday - swapped fuel pump

- previously dead car roars to life

- congratulate self on shrewd purchase AND awesome mechanical skills

- take parents out to dinner

 

Monday & Tuesday - notice tach modulates between 200 and 1000 rpm at idle

 

Wednesday - car starts well, but dies 10 seconds later

- restart car, head off to work, car dies half way there and will not restart

- walk home, get other car and go to work

- lunchtime - dead car starts, drive it home, go back to work

- evening - previously dead car, which was temporary not dead, dead again

- poked around under the hood, had a beer

- tried fiddling with the fuel pump plug just in case, another beer

- connected black wires under dash for error codes, nothing

- another beer,

- ran out of ideas, notes that Chiltons book is severely lacking in many areas

- searched this forum for ideas

- purchased towing insurance from AAA online (desperation)

 

Thursday - you reading my post, providing valuable insight

 

Thanks in advance,

 

Keith

 

88 DL Wagon:)

90 L 2wd Wagon (garage dweller)

90 L awd Wagon (looks like hell, runs swell):cool:

You need fuel, spark, and air for an engine to work. This of course needs to be coordinated properly, but those are the basics.

 

So you're sure fuel pump works. Have you T'd into the line to check the pressure?

 

If you pull the plugs after cranking the engine for a while, are they wet?

 

If you rest a spark plug up against the block, does it spark when cranking?

 

If you get no spark, you may have a bad ECU.

My parents just went through a similar problem with their Jeep Grand Cherokee. No codes and no / dealer or mechanic could trace the problem. They threw parts at it (Crank position sensor, Throttle position sensor, IAC sensor, fuel pump) and nothing was working. Finally the thing threw a code for EGR valve. Replaced the egr and problem solved. Now I'm not saying your problem is an EGR, just saying to keep checking your codes and hope it pops one. You have the ability to swap parts from your other car to try to trace the problem, try the most likely / easy swaps first. Can you give us more of a description of the starting trouble and how the car dies - then we may have some better guesses at what to try and swap. When it is driving, does it seem 100%. When cranking to start how does it sound? When it dies is it sudden or does it sputter and run rough then die? Does the problem seem temperature related? When it started and then died 10 seconds later, did you try and give it more gas or was there no keeping it running? When it died 1/2 way to work was it at idle or were you driving? Check for spark when it won't start.

 

It is sometimes the little clues that can point you in the right direction. Some quick swaps may be the MAF, EGR valve, throttle position sensor, cam sensor - however if you give us a little more to go off of we may have a better shot of hitting the right one.

i'll second that egr valve. my g/f's dad had a similar experience with a company car, where it quit while running. restarted and it would soon quit again. he parked it and called for them to pick it up. they came out and were able to drive it all the way back to the shop. turned out that the egr valve was bad... worth checking.

 

also check basics like fuel filter ($15) & fuel pressure. it sounds like it is losing fuel when it warms...

1990-1994 legacies did not have EGR valves.

Wow ! Thanks for the questions.

 

Josh - I don't have a pressure gauge for the fuel pressure, but after cranking for a few seconds, I can smell gas. Gotta get a gauge.

 

I tried the spark plug on the block trick on Sunday before switching fuel pumps, and there was spark, but I couldn't tell how strong it was out in the sun. I will try again at night.

 

Can I switch the ECU's from my AWD to my 2wd ? I wasn't sure if they are the same.

 

 

 

Intrigueing - The dying problem is as though a switch is thrown, one second running well (with the exception of the rpm modulation at idle), the next second dead as a stone. When it dies, the starter will turn over all I want, very infrequently it will catch on what seems to be the first cylinder to reach the expansion cycle, the very first revolution of the motor, ~OR~ it seems just as likely to just start right up like nothings happened and run well again. I tried starting fluid and got 3 or 4 ignitions, so I thought it was a fuel problem. It doesn't seem to be related to temp. I was not in the car when it died after 10 seconds, but it started right up again after a few tries. On the way to work, I was moving at about 30 mph and it just quit. No warning, no sputter.

 

Theotherskip - I will get a new fuel filter tonight on the way home.

 

Thanks a bunch guys !!!

I don't think it's the ECU if you do have spark.

 

Do this.....try unplugging the MAF sensor completely and try starting it. It should run, but run like crud, and if it does start, you won't be able to rev above like 4000 rpm.

 

If this is the case, swap MAF sensors.

Josh

 

Dayumm, you're right about the ECU. I switched them and there was no change in either car. Dead one still dead, good running - ugly one still ugly. I do have spark, and a new fuel filter, unplugging the MAF did not work, wouldn't start. I wish I had a fuel pressure gauge. I'm going to keep trying.

 

Thanks again for your help,

 

Keith

hmmm....

 

Well we're going to assume you have fuel here since the plugs were wet. However testing the pressure would be a good idea.

 

Only thing else I can think of is crank/cam sensors, or timing belt is not timed right.

 

 

Last thing I can think of is cat converter is plugged up so bad it's not letting the engine breathe.

Okay Josh

 

I removed the pressure regulator. Not sure how this thing is supposed to work since Chiltons sucks. Should there be free flow through the regulator under atmospheric or vacuum pressure ? I'm getting nothing either blowing or sucking through it, with vacuum applied to the diaphram or not.

 

The timing should be okay since it runs well sometimes, right ? Same with the cat converter ? I could have some lazy sensors, only working when they feel like it. I did a voltage check on the fuel pump harness and I'm getting 10.5 V, so I assume the pump relay is good, wherever that is ?

 

Speaking of Chiltons, they say the 90 Legacy does have an EGR valve, contrary to what you said earlier Josh. They even have a few pictures of the damned thing showing how to remove it, and an open hood shot with an arrow pointing to it (under the pretty plastic cover so you can't really see it). Why would they take a picture of the engine and not remove that cover ? But Josh, you were right again, there is NO EGR valve on this motor where they say it should be. I have to get a real shop manual someday.

 

I think I'll get a pressure reg tomorrow and try that. It doesn't look like it should cost very much.

 

Thanks again,

 

Keith

you said the coil was not in specks but you changed it out and it worked in both car's, but you also said the car's problem are not constance, I think you ought to change the coil pact again and leave it until one of the car's give problem. When you put the coil pact that showed to be bad by specks in the good car did you drive it long enough for it to get warm enough to give trouble?

No, I didn't drive it at all. Just started the engine and shut it off, but it's worth a try. Thanks for the tip.

Did you already check the fuel pump relay? Does it have 2 pumps?

OK - at the risk of displaying my ignorance - I wonder if the 'sock' in the tank could cause intermittent fuel starvation some how?

 

just a wag

 

Carl

1 Lucky Texan

lothar34 -

 

If I knew where the fuel pump relay was located... I think I have only one pump, and I checked the voltage to the harness, seemed to be okay.

 

1 LuckyTexan -

 

Anything is possible. When I switched fuel pumps on this car, I re-used the sock since my local auto parts didn't have a new one on hand. The sock looked clean enough though.

Oh, here's something I forgot to add before. When I press on the accelerator with the key on but car not running, I can hear a faint buzzing sound coming from under the throttle body somewhere, both of my Legacy's do this. Anyone know what this might be ?

My order of guess for solutions:

 

1) Crank sensor

2) Cam sensors

3) IAC Idle air control

4) Throttle position sensor (check voltage)

 

Usually a plugged cat will cause engine to slowly die and is usually like your car is pulling a progressively heavier trailer, until it stops. And usually giving it gas will make it bog down worse.

 

Fuel filter / may be possible I suppose. If both coils are out of speck - maybe try another. Keep us posted!

sounds like intermittant electrical break somewhere, either fuel or timing. 10.5 V at the relay is LOW. Should be 12+. Also, are there relays that power the injectors? (these get the older VWs towed...) Either swap relays, or run a temporary switch to the pump to manually spin it if the car dies. Just be careful not to leave it on by mistake.

 

mike

It's running again !!!!! But it did this to me before when I changed the fuel pump, fired right up like I had fixed the probelm, but then died a few days later. So I not going to trust it yet.

 

I rigged up a fuel pressure tester using my cylinder compression tester, some fittings and some 6 minute epoxy. NO PRESSURE ! So I took the fuel pump back out and found that the insulation on the ground wire was frayed. Of course, everything checked out fine with the meter after the pump was out of the tank, but the pump was not running before I took it out. I replaced the ground wire and also noticed that I forgot to put the hose clamps back on inside the tank when I was testing the pump, could have been part of the problem ? Anyways, it's running at the moment but I'm not going to celebrate just yet.

Oh yeah, and the 10.5 volts was probably due to me cranking the engine over so much, trying this and that. THe last time I checked the voltage at the fuel pump, it started at 10.5 and dropped to 9.5 as the battery was discharging.

I suspect you've look at this, but corrosion on terminals/connectors CAN cause voltage drops/intermittency as oxides/sulphides get 'punched through' then regrow and the cycle repeats. Cleaning battery,starter,alternator terminals and disconnecting/reseating every connector you encounter while working on the car may be helpful. As suggested, 10.5 is low, especially with the engine running. A 'survey' of diffent areas supplied by different portions of the harness may point to a bad/dirty connector. Suppose the ECU is only getting 10.5 volts! Could cause intermittent cutout!

 

thanx for letting us know how its going, might help someone else someday.

 

Carl

1 Lucky Texan

I had this same problem with our 2.2 Outback Sport (may it rest in piece), and it was the crank position sensor, cost about $20 for a new one through Subaru as they had a recall on them for some years.

Did exactly what you describe...I could reach it under the alternator, and unplug it and plug it back in when it'd quit, and it'd start right back up.

That is good to know. If this car dies again, I might have been forced to admit defeat and have it towed in shame to the subaru mechanic. Fortunately, we have a good one here in Augusta, Maine (not the dealer !).

 

My condolences for your loss, I hope no one was hurt.