[Kemer]

My car will only start with starter fluid.I read many post and now more confused then ever.I did the ground cleaning thing,new battery,checked the fuses.I can hear both pumps click on I cleaned the computer harness,I turned the key on while holding the relay and can feel it click.I looked for air leaks.I had the car running for awhile when I first got it and this happened so I cleaned some grounds and it started so I thought I had it fixed.Then I took it for a little ride and it died on me.So I think its a fuel thing.Can someone suggest what they would check or a list starting with the most common problem.Thanks for any help.I'm worried if I start ripping and tearing I'll just cause more issues

 

[miami592]

Is this the "barn find" S3 you wrote of in earlier posts?

If so, how fresh is the gas? Have you changed fuel filter yet?

Just for starters-M5

 

[Kemer]

yes It is the barn find and no I didn't get to the filter yet but I will

 

[Alfar7]

Fuel

Often the short hose in the tank connecting the pump deterirates. so it isnt supplying fuen to the main pump. Fill the tank and use an air hose to pressurize the tank to force fuel out to the main pump. If the main pump is working it should run, but the intank pump must be fixed.

 

[Stan Murray]

When you say starts .. does it keep running? If so then maybe the cold start injector is not working .. sometimes caused by the plenum not being grounded.

 

[Kemer]

The car only starts until the fluid is used up.I'm sure its a fuel issue but is it mechanical or electric.I don't know if I should start from the engine and work backwards or from the tank and forward.Are there any "check this first" things anybody would recomend like pulling the fuel line off the rack or somewhere else first?I can't help but think I'm over looking something obvious.
Thanks Harry

 

[ghnl]

Power to the fuel pumps (there are two - the main pump under the car & an in-tank pump in, umm, the tank) is controlled by the drive relay. The drive relay gets a signal from the tach (aka a tachymetric signal) to know the engine is running and power on the fuel pumps. To ensure the engine gets fuel during cranking (i.e. before it starts & sends the tachymetric signal to the drive relay) there is a bypass circuit to power on the pumps when the key is turned to 'start'.

If the engine starts but then dies after a few seconds I'd suspect that the bypass circuit is working but not the drive relay.

If the engine only starts with starting fluid I'd want to know how & where you are injecting the starting fluid? Are you putting all the air ducts/hoses back in place before starting the engine? If not, then the Air Flow Meter (AFM) is not getting the info it needs to tell the computer the engine is drawing in air. The signal from the AFM lets the computer know how much (if any) fuel to squirt.

As RJ suggests in reply #4 the fuel pumps may be pumping fine but not not getting fuel to the engine if there is a fault in the fuel supply. Between the in-tank pump and the outlet pipe (inside the tank) there is a special stepped hose connecting the two. When that hose deteriorates, fuel does not move from tank to engine - the main pump sucks air - especially when the fuel level is below 1/2 full.

 

[Kemer]

Thanks Guys.I only took the afm of to squirt fuel in to see if it fires then I put it back on after inspecting for air leaks.Is there a idea place in the engine compartment to see if fuel is flowing?When I turn the key switch and hold the drive relay I can feel it clicking.I had the intank pump out once and checked the connections once but I'll pull it again and recheck the stepped hose.What baffles me is it ran great going up the road and then just shut off as I was turning around in a drive.

 

[ghnl]

Go through the checks in the L-jet Spider Diagnosis page (link below). A flywheel sensor could be faulty. There are two sensors - one for timing, one for speed (rpm). If one is faulty it could explain the problem. (sensor testing info is in the L-jet page)

 

[Bjorn S]

Often the short hose in the tank connecting the pump deterirates. QUOTE]

That could be the issue , a few years ago I had that problem on a TR6 I had....hose collapsed due to ethanol......would only start run , quit...new hose fixed it