Alfa Romeo Forums banner

1 - 20 of 29 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter #1
Purchased a 88 Spider that’s been sitting for two years with a full tank of gas without being started. I changed the fuel filter and started it up with starting fluid , at 1st on 3 cylinders and then eventually all four firing. Changed the spark plugs and cables and car ran great for one day, still on that full tank of old gas. A week later won’t start, main high pressure fuel pump seized, replaced it with a new Bosch pump and drained the old gas out and replace it premium and now cranks for a few seconds and turns off. With this being said, car has spark and about 30ps of fuel pressure at the return line. If I clap the return line hose it stay on a few extra seconds. I replaced the fuel pressure regulator, new low pressure fuel pump in the tank, changed the rubber fuel line from fuel regulator to the metal piping. Switched out the ECU with good spare and still have the same, cranks for a second and dies. With both ECU i have pulse with the injectors using a noid light. If i use starting fluid while cranking it, will stay on. I am thinking its’s either injector issues or maybe a defected air flow sensor? Help!!
 

·
Administrator
Joined
·
16,652 Posts
Did you also change the fuel filter? It is located near the main fuel pump.

My thought is the injectors are possibly clogged. They might be spraying a little but not adequately for the engine to run. There is nothing I am aware of that you can add to the gas in the tank that'll clear them out. Place like Cruizin Performance will test them, clean them in an ultrasonic bath and cycle appropriate solvents through them and re-test them. They usually come back as good as new.

One test you can try is to peek in via the spark plug hole and see if the injectors are squirting. Look for the cylinder with an open intake valve (you can see the edge of the open valve through the spark plug hole). Cycle the key on-off-on-off-on-off to pressurize the fuel rail. Now briefly apply 12V + & - to the injector's electrical terminals (polarity does not matter). You should see the injector spray some gas against the back of the open intake valve. No smoking of course... This won't tell you how well the injectors are spraying - just whether they can.

Make sure the wire harness is securely connected to the AFM. And peek inside the connector - sometimes the metal connector inside the plastic housing gets displaced. It thus looks like the connection is good but if the metal part is not in position the electrical connection is not made.

Click below to see my 'full signature'. There is a link there to a page of info about diagnosing the L-jetronic system in our cars.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #3
Did you also change the fuel filter? It is located near the main fuel pump.

My thought is the injectors are possibly clogged. They might be spraying a little but not adequately for the engine to run. There is nothing I am aware of that you can add to the gas in the tank that'll clear them out. Place like Cruizin Performance will test them, clean them in an ultrasonic bath and cycle appropriate solvents through them and re-test them. They usually come back as good as new.

One test you can try is to peek in via the spark plug hole and see if the injectors are squirting. Look for the cylinder with an open intake valve (you can see the edge of the open valve through the spark plug hole). Cycle the key on-off-on-off-on-off to pressurize the fuel rail. Now briefly apply 12V + & - to the injector's electrical terminals (polarity does not matter). You should see the injector spray some gas against the back of the open intake valve. No smoking of course... This won't tell you how well the injectors are spraying - just whether they can.

Make sure the wire harness is securely connected to the AFM. And peek inside the connector - sometimes the metal connector inside the plastic housing gets displaced. It thus looks like the connection is good but if the metal part is not in position the electrical connection is not made.

Click below to see my 'full signature'. There is a link there to a page of info about diagnosing the L-jetronic system in our cars.
Thanks for the reply! I changed the filter before i even started it the 1st time when purchased it. I my question is can a damaged air flow meter tell the computer to not send fuel to the injectors? I find it hard to believe that all 4 injectors are clogged. It start from the cold start solenoid and then dies. If I clap the return the cold start solenoid gets more fuel do the higher fuel pressure. Can the injector only get pulse if the ECU is getting proper voltage? Can all 4 injectors go bad at one time?
Help!!
 

·
Administrator
Joined
·
16,652 Posts
When I have sent injectors out for cleaning the 'before' reports often showed a wide variation in flow rates. And these were out of engines that were otherwise running OK. I doubt they all clogged simultaneously - more likely one or two were partially clogged and the others somewhere between fair and poor. After you got it running on the old gas they all became worse.

Try the peek in the spark plug hole test to see if they are even capable of spraying. You might be able to discern the difference between a decent squirt and an erratic squirt. Cycle the ignition between each cylinder so the fuel rail starts at full pressure each time.

A faulty AFM does affect the signal the SCU gets as far as how much fuel to inject. But they tend to be pretty reliable so it is not the first place I'd look for a fault. Make sure the flap moves smoothly against its spring tension. The flap needs to 'float' on the incoming air.

Is there any evidence the black plastic cover on the AFM has been removed? From the factory the glue line was very neat & small. If it has been removed the glue line is usually large & a bit messy. "Back in the day" some would remove the cover to adjust the spring tension thinking they could fool the computer into injection more fuel for more power. It didn't really work and was more likely to mess up the AFM calibration.

Do check the wire harness connector closely. Displaced connectors inside is more common than you'd think. The metal parts are supposed to held in place by a tiny bent tab on the connector. That tiny tab is easily un-bent then the electrical connector will move (but still inside the plastic housing) and fail to make an electrical connection. See: Bosch (sensor) connector
 

·
Administrator
Joined
·
16,652 Posts
One other thought. Multiple failed attempts to start can lead to fouled spark plugs - which then gets worse as the fouled spark plugs prevent further starting attempts. Clean or replace the spark plugs. Even if they were clean or new before your trouble starting began.
 

·
Registered
Joined
·
124 Posts
You didn't mention draining the old fuel. I bought my 87 in about the same condition. It required me dropping the fuel tank. Cleaning it and recoating it. Replacing the fuel lines (rusting from inside out). Both fuel pumps and sending the injectors out for cleaning.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #7
One other thought. Multiple failed attempts to start can lead to fouled spark plugs - which then gets worse as the fouled spark plugs prevent further starting attempts. Clean or replace the spark plugs. Even if they were clean or new before your trouble starting began.
It will always start for one second and then die with fuel starvation, if i spay carb cleaner or quick start, i can keep it running as long as I keep spraying. Thanks for your replay
 

·
Registered
Joined
·
24 Posts
Discussion Starter #8
You didn't mention draining the old fuel. I bought my 87 in about the same condition. It required me dropping the fuel tank. Cleaning it and recoating it. Replacing the fuel lines (rusting from inside out). Both fuel pumps and sending the injectors out for cleaning.
I did one more step that i forgot to mention. I used a plastic 5 gallon boat external gas tank with fresh premium gas and by passed the gas tank thinking i had water in the fuel. same exact results. The car starts and dies, I did get this car to run 100% perfect with that old fuel combination and new when it ran great for a day
 

·
Registered
Joined
·
24 Posts
Discussion Starter #9
When I have sent injectors out for cleaning the 'before' reports often showed a wide variation in flow rates. And these were out of engines that were otherwise running OK. I doubt they all clogged simultaneously - more likely one or two were partially clogged and the others somewhere between fair and poor. After you got it running on the old gas they all became worse.

Try the peek in the spark plug hole test to see if they are even capable of spraying. You might be able to discern the difference between a decent squirt and an erratic squirt. Cycle the ignition between each cylinder so the fuel rail starts at full pressure each time.

A faulty AFM does affect the signal the SCU gets as far as how much fuel to inject. But they tend to be pretty reliable so it is not the first place I'd look for a fault. Make sure the flap moves smoothly against its spring tension. The flap needs to 'float' on the incoming air.

Is there any evidence the black plastic cover on the AFM has been removed? From the factory the glue line was very neat & small. If it has been removed the glue line is usually large & a bit messy. "Back in the day" some would remove the cover to adjust the spring tension thinking they could fool the computer into injection more fuel for more power. It didn't really work and was more likely to mess up the AFM calibration.

Do check the wire harness connector closely. Displaced connectors inside is more common than you'd think. The metal parts are supposed to held in place by a tiny bent tab on the connector. That tiny tab is easily un-bent then the electrical connector will move (but still inside the plastic housing) and fail to make an electrical connection. See: Bosch (sensor) connector
Thanks your for you input. I replyed to everyones comments but i have one last step that i didn't mention. In the early stage of trouble shooting i accidentally connected the battery with the ignition ON, (a big NO NO.) The car already had the NO start issue. Thats why i did the ECU swap thinking i could have damaged the ECU but it behaved exactly the same with either ECU so put the original one back. I have spark, fuel pressure, and injector pulse with the noid light with both ECU. Could that power surge have damaged my AFM? I don't have a replacement or even know how to test it with a volt meter. Thats why I still have my doubts with the AFM. Or should i continue to trouble shoot it a s possible injector issue? Thanks for your reply any suggestion will be greatly appreciated...
 

·
Registered
Joined
·
1,193 Posts
I would run Eric's visual test for the fuel injectors first. If the injectors are not squirting, then I would make doubly certain the fuel pumps are running when the engine is running. One approach is to connect a voltmeter to a fuel pump and see what the voltage does as the engine starts and then dies. Alternatively, you could connect a fuel pressure gauge with a T fitting at the line feeding the cold start injector, and see if fuel pressure is maintained as the engine starts and then dies. If pressure looks good, then it might be time to get the injectors tested and cleaned. You could have a flakey AFM but as Eric mentioned, they are pretty reliable. At least until they fail...
 

·
Registered
Joined
·
24 Posts
Discussion Starter #11
I would run Eric's visual test for the fuel injectors first. If the injectors are not squirting, then I would make doubly certain the fuel pumps are running when the engine is running. One approach is to connect a voltmeter to a fuel pump and see what the voltage does as the engine starts and then dies. Alternatively, you could connect a fuel pressure gauge with a T fitting at the line feeding the cold start injector, and see if fuel pressure is maintained as the engine starts and then dies. If pressure looks good, then it might be time to get the injectors tested and cleaned. You could have a flakey AFM but as Eric mentioned, they are pretty reliable. At least until they fail...
I am planning on ruling out the airflow meter 1st, by testing or finding one to do a quick swap, then take those injectors out and send them to get them to get clean out. I am avoiding removing the injectors because when i drove the car on the one day after plugs and wire change. it ran good, as if it was new and then the main fuel seizes the next time I go to drive it and thats when the problem started.
 

·
Premium Member
Joined
·
1,514 Posts
If you think the AFM is faulty or sending the wrong information to the ECU, try unplugging the AFM and then starting the car. It may start and run, but idle poorly.
 

·
Registered
Joined
·
7,668 Posts
car has spark and about 30ps of fuel pressure at the return line. If I clap the return line hose it stay on a few extra seconds. I replaced the fuel pressure regulator
you checked pressure at the return line, not the inlet line?

fuel pressure test.JPG fuel pressure test 2.jpg

you replaced the FPR, but did you check the vacuum hose... is there perhaps a slight split not allowing full vacuum, or is the nipple on the plenum slightly blocked?
 

·
Registered
Joined
·
24 Posts
Discussion Starter #15
you checked pressure at the return line, not the inlet line?

View attachment 1613202 View attachment 1613203

you replaced the FPR, but did you check the vacuum hose... is there perhaps a slight split not allowing full vacuum, or is the nipple on the plenum slightly blocked?
I tested it at the return off the fuel regulator fitting that goes back to the tank. I even changed the 3 ft, rubber hose from the regulator to the metal fuel lines under the car. I had about 29-30psi. is that correct?
 

·
Registered
Joined
·
7 Posts
I tested it at the return off the fuel regulator fitting that goes back to the tank. I even changed the 3 ft, rubber hose from the regulator to the metal fuel lines under the car. I had about 29-30psi. is that correct?
Hello Luca, fuel pressure should be @35 psi.If the fuel pump is running while you are cranking the car over and the pressure is correct then your air flow meter is doing its thing. I have seen stale fuel hang open exhaust valves as the car is running,and get bent from it staying open.I have also had fuel injectors stick closed from stale fuel.One trick i have used in the past is to take a screw driver and a pair of pliers and tap the injectors on there sides next to the bosch connectors,do not go crazy with this beating but I have had good success with un sticking stuck injectors . If you get a couple of the injectors to work and the car starts you can also tap them as the car is running this will help also.If the fuel was that bad the tank should come out and be cleaned by a pro,stale fuel can continue to cause drive ability, problems in the future ,
 

·
Premium Member
Joined
·
114 Posts
I did one more step that i forgot to mention. I used a plastic 5 gallon boat external gas tank with fresh premium gas and by passed the gas tank thinking i had water in the fuel. same exact results. The car starts and dies, I did get this car to run 100% perfect with that old fuel combination and new when it ran great for a day
To me, this sounds like clogged injectors. I understand your concern with the ECU and AFM and Im not saying that this isn't a problem.
BUT If it will run on starting fluid but not under its own injection, my assumption is that the ECU is sending spark.

Over on the Jaguar V12 forum, many users have had great luck cleaning their injectors with carb cleaner. They pull all injectors off and use a 9v battery (or 12v battery), and have a tube connected to the inlet so that the injectors suck in the cleaner. They attach the ground wire and tap the positive wire on and off for just a second, so that the injector pulls in the carb cleaner.
It is NOT the same as having the injectors cleaned or better yet replaced, but it will show you if the injectors will fire at all. And it will show you if the car will run after the injectors have been cleaned out. My suspicion is that once the old fuel had time to sit in the injectors after running the car, it gelled or maybe it carried rust chunks from the fuel tank into it.
 

·
Registered
Joined
·
7,668 Posts
when you say the car starts and dies.....do you mean you can do this time after time, iow as soon as it dies you can start it again and it will run again for a few seconds...etc etc?
Or do you mean when it dies, you have to wait some between tries?

Iyou say above, when you clamp the return line from the FPR, it runs a little longer. If it runs a little longer the fuel injectors must be firing.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #19
when you say the car starts and dies.....do you mean you can do this time after time, iow as soon as it dies you can start it again and it will run again for a few seconds...etc etc?
Or do you mean when it dies, you have to wait some between tries?

Iyou say above, when you clamp the return line from the FPR, it runs a little longer. If it runs a little longer the fuel injectors must be firing.
not every time will start, but if i let it sit for a day it will crack a few times for a second. If I clap the the return line it likes that,it stays on slightly longer like three seconds. If i disconnect a vacuum line and spray carb cleaner it will stay on as long as I spray a squirt every few seconds until the can runs out. I am planning on mounting back my 5 gallon boat fuel tank with fresh fuel and give it another try this weekend. Thanks you
 

·
Registered
Joined
·
24 Posts
Discussion Starter #20 (Edited)
To me, this sounds like clogged injectors. I understand your concern with the ECU and AFM and Im not saying that this isn't a problem.
BUT If it will run on starting fluid but not under its own injection, my assumption is that the ECU is sending spark.

Over on the Jaguar V12 forum, many users have had great luck cleaning their injectors with carb cleaner. They pull all injectors off and use a 9v battery (or 12v battery), and have a tube connected to the inlet so that the injectors suck in the cleaner. They attach the ground wire and tap the positive wire on and off for just a second, so that the injector pulls in the carb cleaner.
It is NOT the same as having the injectors cleaned or better yet replaced, but it will show you if the injectors will fire at all. And it will show you if the car will run after the injectors have been cleaned out. My suspicion is that once the old fuel had time to sit in the injectors after running the car, it gelled or maybe it carried rust chunks from the fuel tank into it.
I think your theory may be right especially after finding out that the car can start with the AFM connection unplugged. Thanks
 
1 - 20 of 29 Posts
Top