[haluska]

A few hours ago, my stock 1990 DX suddenly died going up a hill at about 20 mph. Car cranks. No Check engine light. I have checked spark with an inline spark plug and each gets spark, but I haven't dug into the car cause I got home pretty late. I put in 2 gallons of fresh fuel (even tho I should have had 2 gallons in the tank). Was running fine right before. Swapped main relay with a spare car, no difference. It almost sounds like it'll start and gives like a minor misfire at times. Tried to use starter fluid in the intake, but it was inconclusive. Oil was a bit low.

It sounds like the fuel pump is priming, but all I can think of is fuel system. Anybody else have a likely explanation? I likely will be checking the timing belt tomorrow as well.

 

[shorty_boy]

If the tank was dirty, then maybe fuel filter? Has the fuel filter ever been changed?

Otherwise, remove the cap to the fuel injected carb and see what it looks like. If it is dirty, then you may need to replace the fuel filter. or you are not sealing correctly.

 

[RamaCrx]

I installed a fuel pressure gauge a long time ago. It helped a lot with troubleshooting problems.

 

[haluska]

It was unusually hot today so I only got about an hour on the car.

• Pulled two spark plugs and confirmed a smell of gasoline on both. Visible confirmed it sparks on one of them. Spark Plugs look sooty. Maybe bad fuel injector? I'll take pictures of the plugs tomorrow.
• Checked Coolant Level and added about a cup of coolant.
• Car kind of starts and makes an odd sound occasional, kind of like a back fire. It sounds like it has some sort of mechanical sound to it. I haven't pinned it down yet. Dies almost instantly when I stop cranking.
• Put the battery on the charger while I checked the timing belt.
• Checking the timing took a long time cause the plastic side cover is pretty broken and it rubs into the belts. Previous person must not have put it on correctly, best I can tell is the timing is fine
• I am going to try to swap the main relay back with the other car.

If the tank was dirty, then maybe fuel filter? Has the fuel filter ever been changed?

Fuel filter was replaced in October, about 400 miles ago. About 14 months ago I replaced the IACV.

I installed a fuel pressure gauge a long time ago. It helped a lot with troubleshooting problems.

I am probably going to break down and buy a gauge. I can't really be sure it's the fuel pump or not without one.

Otherwise, remove the cap to the fuel injected carb and see what it looks like. If it is dirty, then you may need to replace the fuel filter. or you are not sealing correctly.

I am probably going to be looking at that tomorrow (weather permitting) and playing with the system.

My current theory is still fuel related. Either cheap fuel filter failed, an injector stopped working, or the fuel pump failed. Due to the sudden onset, I'm leaning towards the fuel pump or maybe the check valve in the fuel pump not allowing it to maintain pressure.

 

[shorty_boy]

Yeah sounds fuel related. Could be weak spark too. Check the cap on the distributor too to see if it has carbon build up or if the contacts are toast.

 

[mossin_90]

I put in 2 gallons of fresh fuel (even tho I should have had 2 gallons in the tank).

This alone is reason enough to test fuel pressure with a reliable fuel pressure test tool.

You are aware that running below 1/4 tank to empty is killing the fuel pump right?

Only 2 gallons of fuel inside the tank is not good under any conditions now add an incline to the equation and guess what? That little fuel is sloshing away from the fuel pump intake.

 

[msc]

Have you checked for ECU codes?

Mike

 

[haluska]

It's been raining a lot and I have to work outside, so it took me a while to get back to it. I got to spend a little more time on the car. I'm not the best at reading plugs, but I get the feeling they're fine.

I did pull the the intake to the fuel filter off and put it into a jar and just primed the car with the key twice. The pump does put out fuel when doing this. I know this isn't a complete fuel test, but more of a partial test for the main relay.

This alone is reason enough to test fuel pressure with a reliable fuel pressure test tool.

I have been thinking about. Do you have a recommendation for a pressure test tool? Is it possible to partially damage the fuel pump?

Have you checked for ECU codes?

There are no codes.

 

[jwharnish]

It's been raining a lot and I have to work outside, so it took me a while to get back to it. I got to spend a little more time on the car. I'm not the best at reading plugs, but I get the feeling they're fine.
View attachment 1873
I did pull the the intake to the fuel filter off and put it into a jar and just primed the car with the key twice. The pump does put out fuel when doing this. I know this isn't a complete fuel test, but more of a partial test for the main relay.



I have been thinking about. Do you have a recommendation for a pressure test tool? Is it possible to partially damage the fuel pump?



There are no codes.

You can rent a fuel pressure tester at Auto zone or similar store. Those tools will test off the fuel filter outlet.

 

[mossin_90]

^2
Spark plugs are showing that the engine is running rich.
But burning fuel that is not atomized correctly will present itself as running rich as well.

Did you by any chance pulled the front passenger side rug back to check the ecu led indicator?
These cars were notorious to keep the CEL off while the ecu was experiencing sensor problems.
pulling the code directly from the ecu is the best way to check codes. The obd circuit on obd0 is not reliable, check the ecu led, there is a sight glass over the ecu.

If there is a problem, your led will be flashing code(s) but the check engine light might be not.

 

[haluska]

Fixed!.......the distributor rotor became unscrewed.

Before I checked the spark with an inline spark checker and then again by seeing the spark plugs actually sparking. So I had spark, it just wasn't sparking at the right time...which isn't something I thought could happen. Today I decided to pull the distributor off to see if I could see anything wrong with the cap / rotor. I was going to check last night but I dropped one of the distributor cap screws and it took me over an hour to find it.

I didn't even notice the rotor loose when I pulled the distributor cap off to check for this problem, only when I went to scrub the edge of the rotor with some rubbing alcohol did I notice it spinning freely. The rotor screw got stuck to a magnet in the distributor. I put the screw back this time with a bit of thread locker. I'm hoping spark plugs were fouled from the fuel not being ignited.

Lesson learned, pull apart the easy stuff first.

 

[shorty_boy]

Thanks for replying back with your fix.

 

[haluska]

Thanks for replying back with your fix.

Of course, I do it so future people can learn from my experience. I wasn't suspecting the distributor cause I had replaced, the ignitor, cap, and rotor, wires only 1400 miles before this incident, otherwise I would have checked it before checking the timing belt / fuel line. I'm guessing the new rotor screw was just a bit undersized cause I know I put it on tightly originally.

So what I've learned from this, if the car dies extremely quickly with no mechanical noises suspect something electrical / distributor. Also "having spark" doesn't necessarily mean the rotor is screwed on correctly. Try to get in the habit of explaining how you diagnosed things so people can have a better idea of the state of the problem.

 

[Baker]

Fixed!.......the distributor rotor became unscrewed.
Lesson learned, pull apart the easy stuff first.

It's the BEST when it is something easy!
ALWAYS troubleshoot from the easiest stuff first!