Starts, but doesn't run long....

VARam1500 · 10-08-2002, 03:45 PM

Thanks to everyone who has helped me to this point with trying to get a dead car running!

Now I'm at the point where I've got fuel and spark at the same place at the same time. It started for the first time two nights ago and ran for about 5 seconds, then wouldn't start again. After work yesterday, it started right up and ran for about 9 seconds and then stalled, not to start again. Same thing tonight--started right up, ran 9 seconds and died.

Does that ring any bells? Where should I go from here?

--Case...

JP Noonan · 10-08-2002, 06:24 PM

on a friends similally equipted Japanese car it was a hard to spot vac leak, but the car would restart everytime.

On my 1.7L similar problem was fouled plugs. If you have been worjing on the car with lots of cranking but no running try new plugs.

on my 2.0L it was rusted ignition points.

What is your fuel pressure? Also check the cylinder head temp sensor.

btw I'm not a big L-jet guy so FWIW

SummerSledSix · 10-08-2002, 07:30 PM

I'll second the fuel pressure question. Could look OK when you're just starting it, but then almost immediately starved for pressure due to bad fuel pump, tired fuel pump relay, clogged fuel lines, or clogged fuel screen in the tank. Check your pressure with a fuel gauge. If you don't have a gauge, try disconnecting the fuel line supply side at the engine (disconnect the coil primary for safety too), put the end of the fuel hose in a gas can, and have someone crank the ignition for you. See what kind of output you're getting. As you mentioned in your post, it boils down to fuel, spark, and timing.

VARam1500 · 10-09-2002, 04:14 AM

I've put in new plugs, but the points may be iffy. I've got a spare set that came with it from the PO so I'll drop them it. Is there a method for 'checking' the head temp sensor? Is it a 'measure-the-resistance' type of check?

Fuel (turned to lacquer) has been the gremlin up to this point in the project. I'll go ahead and order a new fuel filter, and as for that screen in the bottom of the tank, how is it attached? Can a hand get in there to pull it out?

Thanks a lot, guys!

--Case...

SummerSledSix · 10-09-2002, 07:28 AM

You'll have to reach up from under the car, there is an access hole under the cross-arm stone guard. The challenge will be loosening the 22mm aluminum nut(s) that hold the fuel lines on the tank. The fuel strainer screen is clamped in place by the nut and hose nipple. If it's clean, it'll drop right out, if it's crud-challenged, it might not survive the operation. Good idea to have a replacement on hand, PP has 'em. Hope you don't have much gas in the tank.

If you can't get the nut loose from below (I had to grind a slot in a cheap box wrench to get a wrench skinny enough to get in there), you can get at it by pulling the tank. If crud is the issue, best to pull the tank and do a proper cleaning (see tech article).

VARam1500 · 10-09-2002, 09:52 AM

What kinda noises does the fuel pump make when it's starved?

John2kx · John2kx's Garage

I think SummerSled6 is on the right track here. Even if it's not the problem and your car has been sitting for a extended time, a flush of fuel tank should be performed.

You should be able to see the metal screen using a flashlight while looking into fuel tank fill opening. Not sure if you can really do a proper inspection of screen from this view but lower a piece of welding rod, coat hanger, etc. and see if you can stir up any crud or determine if a layer of muck has developed in bottom of tank.

I just did this operation a few months back and found about a 1/2" layer of crud in bottom of my tank. It was removed easily with water hose but the killer here was that crud was actually sealing rusted holes in bottom of tank. After flushing my perfectly working fuel tank to get ready for fresh paint, the interior water flush turned out to be a leaking mess.

My car was running perfectly prior to this "upgrade" and all I wanted was to paint my fuel tank to match the front trunk restoration. A POR 15 fuel tank sealer kit was ordered and took care of problem.

Pulling rear fuel line to check for fuel flow is a good idea as well.

John

SummerSledSix · 10-09-2002, 11:59 AM

The fuel pump makes a slight high pitched whine when it's working, sometimes tough to hear if your muffler is loud. A dry fuel pump will be slightly louder and raspier. Not a good idea to run a fuel pump dry for any length of time. If your fuel pump transitions from wet to starved (but not dry), the whine MAY increase in frequency kinda like when you put your hand over the inlet of your shop vac.

VARam1500 · 10-10-2002, 09:27 AM

I asked about the sound of the pump because I had replaced the lines under the tank. The pump sounded funny so I probably had a kinked line under there.

After that I put the fuel return line (post pressure regulator) in a can and moved the vane to see how it flowed. I got about a half gallon in about 25 seconds. That was just to make sure the fuel was moving. Does that amount sound about right?

The problem is still there, though, so I'll try to get a fuel pressure gauge this weekend.

Thanks.

--Case...

SummerSledSix · 10-10-2002, 09:45 AM

1/2 gallon in 25 sec is about 2 gpm, and for sure a 4-banger doesn't suck gas that fast

. That's a good sign, though not a "bulletproof" indicator. The efi brain depends on a specific pressure to measure the fuel properly. I'm not sure what you meant by "vane", but if the pressure regulator doesn't hold rail pressure up, your car will either run very poorly or not at all. When your car poops out, does the engine die "cleanly" like you turned the ignition off, or does it sputter itself to death?

VARam1500 · 10-10-2002, 12:01 PM

Mine is l-jet so I was moving the air flow sensor vane with the key on to force the fuel pump to run.

When it dies, it doesn't diesel. It's more like you've jammed a potato in the exhaust and it dies because the engine power is overwhelmed by backpressure. Just slows down then stops.

How hard is it to unbolt the exhaust manifold? I guess that would rule out an exhaust blockage. I know I'm getting some exhaust out of each side, but that only verifies that one clyinder per side is pumping. Maybe I'll try that and see if it runs for a longer spurt.

derek_sf · 10-10-2002, 12:04 PM

same thing happened to my car after sitting for a while. the cold start valve (or whatever it's called) was giving enough gas to start the car, but the pump was actually not working. tapped the pump with a hammer lightly and it worked for years after that.

SummerSledSix · 10-10-2002, 06:35 PM

If your exhaust system has been on there awhile, a root canal will be more fun than pulling those manifolds. Think rusted, perhaps snapped, exhaust studs. If you're trying to determine if your exhaust system is blocked, pull a spark plug, rotate the crank till the exhaust valve is open, and try to pressurize the cylinder with compressed air. You shouldn't be able to.