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Won't start & occasionally stalls at idle
Topic Started: Aug 26 2011, 06:12 PM (1,462 Views)
ggielen
New Member
[ *  * ]
Car: 1998 3-cylinder stick. 160,000mi (of which 12,000 in my ownership, exactly one year)

Couple weeks ago the engine all of a sudden started having trouble starting, would need a few tries, and stalled at idle, no warning, no time to react, bam: stalled. Instant. One time had to push-start, took 2 tries and away she goes. I had the impression that on a few occassions of trying the starter wouldn't kick in, but this was minimal.

A few days later started driving her again, no problems for a week or two. Yesterday, again wouldn't start, so I figure we push start. Tried a few times, nothing. Waited for a friend for a bit, tried twice again and off we go: success. Stop at Home Depot and after getting back to the car: nothing. So we try push-starting again. About 15 times this time, going downhill too so I'm certain we had enough momentum going, but no start. In the end had to get her towed home (yay AAA).

Here's the diagnostics so far:
- I can hear the fuel pump prime, that's good
- starter cranks the engine just fine
- problem occurred intermittently, now more permanently
- never had the issue while driving, only when idling
- after repeated starting didn't specifically smell fuel in the engine bay

Based on the behavior thusfar, I suspect either a fuel supply problem or no spark. To check for fuel, I can check if the spark plugs are wet after a few tries. To check for spark, can I just undo a sparkplug and hold it against the block (ground) and see if it sparks when cranking? This is how we used to do it as kids on the motorcycle engine. Just to get the troubleshooting downselected to one of the two main avenues...I don't think it is a bad sparkplug, if it is a spark problem then it affects all three (little more upstream), otherwise I should still get some cylinders to fire.

I have limited opportunity to do testing, I just bought a house yesterday which needs immediate attention (the day Rolling Thunder died), this morning my alternate vehicle (1987 toyota pickup) starts bellowing enough smoke to hide a tank battalion, so that's grounded based on the assumption of a Major Situation. Earthquake couple days ago, hurricane tomorrow, both vehicles die within 24hrs of each other, this is turning out to be a great week :)

Here's a couple other things I read on the forum so far that I can check:
1. Ground on throttle body
2. Oil pump failure
3. Injector
4. Clogged cat (I'm almost excluding that already as some 'bypass holes' have developed anyway)
5. some or other bad connection to a sensor (the intermittent nature leads me to bad connection in some electrical circuit)
6. Some sensor died (engine speed sensor,..)
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Woodie
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I vote injector or bad ground. Get a flashlight and look down the throttle body while cranking it. You should see a nice little cone of fuel spraying.
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Bad Bent
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Facetious Educated Donkey

If you have a Digital Volt/Ohm Meter (DVOM) you can check the Cam/Crank position sensors: http://geometroforum.com/topic/2703156/1/

Also the wire on the starter:
Posted Image

And My favorite in my '91 is the floor mat riding up and under the clutch pedal so the switch does not make contact unless you push really hard.

What were the last 3 things done to the engine and electronics?
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ggielen
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Thanks, I will go through these troubleshooting steps. In the meantime, I have cleaned the grounds that I could find (1 near the ECM from pile of ECM wires to chasis, one right next to the battery from battery to chasis, one on throttle body and the big guy right from the battery to the transmission case. I also looked in the throttle body and I can see fuel pearling on the butterfly valve, can't really see the conical spray from the injector, I think it is just obstructed from view. But there's fuel nonetheless

Car started up fine before all this a few days ago, and after cleaning grounds it started fine as well. Went for a ride and she died again, this time while driving (that was a first, although I may have been coasting in which case it is similar to the few stalls I had at idle). So I opened up the hood right away as this was a primo chance to do troubleshooting (which is hard with an intermittent problem, hard to find the issue when everything is working). I pretty much immediately saw the butterfly valve was bone-dry, no fuel being injected. Could be injector or fuel delivery issue (pump, filter). I can hear the pump prime, that's good. I pulled the fuel line right where it enters the engine bay, no fuel. So at this point I'm thinking fuel filter (the sock at the fuel pump, it's a '98). This is purely a theory, but she seems to start ok after sitting for a while, my theory is that fuel slowly seeps through the now clogged filter, so I have just that little bit of fuel to work with.
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Shinrin
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Do you see fuel dripping from it after you shut the car off?
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ggielen
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No, no fuel dripping from injector upon shutoff. I did check the injector spray pattern, while idling it is pretty hard to tell, I guess because fuel flow is so minimal that you basically don't see much. When I throttle up, I do see a nice conical pattern, so that looks OK.

The fuel line in the engine bay that I disconnected earlier to check for fuel flow when the injector wasn't spraying was apparently not the fuel line, but a line that goes to a little white box right on the gas tank. Inside the engine bay it goes to a big black tank, and goes through some other hoses and little magic black parts that I have no idea of what their function is. Something to do with evap?

I will try disconnecting the hoses that go to the injector, one must be supply, the other return as the fuel pump just delivers constant flow and the injector sends whatever it doesn't take back right? That third hose going to the big black box will still puzzle me. By disconnecting supply hose I can check for fuel flow, and maybe drain a bit out of the tank should I need to drop it. If I get a chance I will go to harbor freight and pick up a fuel pressure tester.

I will also measure resistance across injector, I saw mwebb post the values I should read somewhere.
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Shinrin
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Here are two topics about injectors
http://geometroforum.com/topic/2184553/1/
http://geometroforum.com/topic/3880200/1/?x=40

Look for MWebb
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ggielen
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All I have changed so far is oil & oil filter (seafoamed as well at that time), transmission oil (synchromesh), and the crankshaft seal. I constantly have one fuse pulled, the radio-dome light-ECM memory circuit, as a problem in there depletes the battery. All these are several 1000 miles ago, so I highly doubt they influenced the problem.

What I should have changed already and have not yet are distributor cap, spark plugs and associated wires and air filter (though the air filter looks OK).

I disconnected the supply fuel line at the injector and hooked up a bottle (the line right on the TB closer to the front of the car, I assume the one right behind it to be the return line from whatever the injector decides it doesn't need to spray in). Key on engine off no cranking I got a nice amount in the bottle, couple shotglasses worth, from priming. So at this point I don't expect fuel flow to be the issue, but rather fuel injection or the command chain to open the injector (crank position sensor, throttle position sensor, wiring,..

I don't suspect spark is the problem, but rather fuel delivery, as the one time I got a chance to troubleshoot right after stalling the butterfly valve was completely dry. When the car runs, it runs excellent, no notable problems. And cutoff is instant, so it's across all three cylinders all at once, so I don't expect individual spark plug or something like that.
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ggielen
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I've been working on my house a lot and little time for the car, winter is coming and I'm still showering outside with the garden hose, but two days ago I just tried starting her again and she gave me the little golden nugget I had been waiting for: no start. So on to troubleshooting! The injector connector looked a little dirty with oil, so I decided to clean it and spray some contact spray on it. Plugged back in and hey presto, start! Now it could be just dumb chance, but has been running fine for the last two days. I don't dare take her far or on the highway yet, better do some cycle endurance first, but it would correspond to the symptoms I've experienced. I almost always blame intermittent problems on bad electrical contacts and 90% of time that's what is has been in my experience..
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Memphis metro


If you suspect fuel problems look at post 46 and 64 here,

http://geometroforum.com/topic/4464045/4/

I hope this helps you find your problem.

First test fuel pump. If good test injector, if specs are good on injector, clean injector.
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starscream5000
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Got 70 MPG?

It sounds like you're off to a pretty good start with diagnosing the issues just by talking yourself through it :thumb
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