1988 w126 300SEL starting possible fuel issue
 

Hi,

Can't get my 300 SEL started, here's what I have done so far.
The fuel pump wasn't working so I replaced the fuel pump with an old one laying around.
The car still wasn't starting, so I jumped the relay. Ok, so now the fuel pump works and the car still would not start.
I then removed the main line to the fuel distributor and fuel comes spraying out when the relay is jumped.
I then removed the first fuel injector line closest to the radiator and no fuel reaching the injector with pump running.
Any thoughts on what would be between the fuel distributor line and the injectors that would impede the fuel from reaching the injector.
Am I troubleshooting this wrong, any ideas?
Issues first started today when I went out, turned the car off then and I went to start the car and no go. There were no issues driving to the store. The car then sat for about 15 minutes as I waited for a tow truck and it then started and ran fine and I was able to get home. I turned the car off, waited a few moments and here we are. Car cranks fine, just no start.
There were no issues before the car not starting today.
Thanks, Dwayne

1) Remove an injector line as before. With the pump running, push down on the air flow meter plate. Does fuel appear at the injector?
2) Between the FD inlet line and the injectors is, in fact, the FD! If there is no air flow the fuel flow path through the FD is closed. Pushing down on the air flow meter plate simulates an engine-running condition, and hence, air flow.

Frank, I'll check it out and get back - thanks.

Frank, prior to following your suggestion, I jumped the relay and the car started right up and ran fine.
I then shut the car down and then followed your suggestion, lowered the air flow plate and fuel came out of the first injector with the relay jumped.
Put the injector line back on and attempted to start the car again and no start.
Thanks, Dwayne

Odds are that there is an ignition system fault. When you next have a no-start event, check for spark. The flywheel trigger/pickup is often the culprit in a temperature related situation, though it is by no means the only possible culprit.

K, thanks

Removed the first spark plug and grounded it against the exhaust manifold and no spark. I hope I did it right, but with that being said the engine is cold.

In checking the ignition system it may be helpful to work backward from the spark plugs.
The distributor cap, rotor, and the shaft seal behind the rotor have gained notoriety over the years. Deterioration in that area is easy to see.
If the distributor seems OK, putting the coil secondary lead close to ground to check for spark would be next.

An easy way to safely see if you are getting spark is to connect a timing light.

I know it is not a Mercedes and Members of this forum are repulsed at using Stating Fluid. But it is effective to determine if you are not getting fuel or ignition.
If it won't attempt to Start with starting fluid you usually have an ignition issue. If it starts right up with starting fluid you usually have an issue of not getting fuel.

"You could hear the Fuel Pump running but I had my Wife crank the Engine while I sprayed in a bit of Starting Fluid. If it attempts to start like that you know your are not getting fuel in the normal manner. If is does nothing like that you know you are not getting Ignition."

Note that a running Fuel Pump does not mean your Fuel Pressure Regulator is working as it should.

https://www.peachparts.com/shopforum/off-topic-discussion/412403-trouble-shooting-no-spark-1986-chevy-cavalier-4-cyl.html

To all,
I double checked, and I am convinced I've eliminated the fuel problem, so it seems to be ignition - no spark.
I double checked with a timing light, as I cranked the engine and there is no spark.
I also replaced the ignition coil with a coil I know to be good and the same issue. No hot start. It started fine when cold.

"The distributor cap, rotor, and the shaft seal behind the rotor have gained notoriety over the years. Deterioration in that area is easy to see.
If the distributor seems OK, putting the coil secondary lead close to ground to check for spark would be next." All checked out good.

Frank, what and where is the "flywheel trigger/pickup." I did a few searches and I can't find it - thanks

Any other thoughts would be appreciated - thanks in advance, Dwayne

Is the flywheel trigger pickup commonly known as the Crank Sensor - thanks

Yes.

It should not be hard to verify if the Coil is getting voltage from the Ignition Switch when it is on. On mine I verified that and I also swapped a coil and still no spark. (I also verified that the distributor was actually rotating.)

All that was left electrically was what ever triggers the spark and the Ignition Module.

There is a sign at the local AutoZone that claims the test Ignition Modules. I don't know if that is on the Car, you need to pull the whole distributor and bring that in or they are speaking of the bare ignition module.

Update...
Replaced the camshaft sensor (front - realized later, it's just diagnostic) and the crankshaft sensor (in the rear, by the flywheel).
Replaced the rotor and distributor cap.
Replaced the coil.
Same exact issue...starts when it's cold - when the above was replaced.
When I shut it down and try to start it back up, for a "millisecond" it feels like it wants to start and then after a few moments it just the starter cranking.
Thanks in advance for any additional thoughts.

Dwayne

Do a residual fuel pressure test. The system should hold pressure for 30 minutes. If not the fuel in the lines can vapor lock. I don't know what the exact pressure should be ~ 2.5 to 3 bar for thirty minutes. You will need a fuel pressure gauge kit for this test- no guessing.

Working back from the injectors, the culprits could be-
Leaking fuel injector(s)
Leaking cold start valve
leaking o ring that seals the Fuel distributor piston- on the bottom side of the FD
Fuel accumulator
check valves by fuel pump

Hey Dave,

Based on stuff I've done in the past, I'm getting no spark.
Seems to be a hot start issue.

Thanks,

Dwayne

OK

I would check battery voltage when cranking at hot start. If it gets down to ~9 volts you will have a hard time starting. Also, if you haven't all ready, check and clean all grounds around the battery and coil.

Thanks Dave,

Question...when the starter engages, it cranks as strong as a mule. Wouldn't that indicate the "battery voltage when cranking," is fine?

The starter engaging is strong during a cold or hot start - the only difference is the car is not starting hot.

Thanks again, Dwayne

Just checking the boxes Dwayne. Its very hard to diagnose remotely.

Is your coil getting voltage?

Dave, I appreciate that...I did a few searches and I couldn't find the answer.
How do I determine if voltage is getting to the coil?
Thanks to all.

Never mind, I think I found it, I'll test when I get home - thanks

Ok, started right up this am.
I checked the ignition coil with a circuit tester light prior to the start up and it lit up.
I let the car run for twenty minutes - shut it down, tested with the coil again with the light and it again lit up.
But I was not surprised, the car would not start.
So...thoughts.
I guess the issue would have to be "upstream."
"Upstream" meaning; plugs, wires, rotor and cap?
Wires look fine.
Rotor and cap were just changed. Plugs? I can't see a no start condition for plugs - misfire, yes.
Thanks in advance for your thoughts.

OK

You have power to the coil. Next check the coil to plug wire. Do you have spark out of the coil wire?

FYI- The wires have resistors in them. Under heat they can short out. So, you can take an OHM and continuity reading on your wires.

What plugs are you running ?

I don't know your model, I have 190e's. Can you put a spark plug in the coil wire to test for spark?

Your new coil could be bad or the wrong one too. Just talking out loud.

There may be an easier way, so maybe someone else will chime in.

There are two situations under which to test for power at the coil (or the diagnostic connector):
1) Key ON, engine not cranking.
2) Key ON and engine cranking.
There should be power at the coil under both conditions. If there is no power at coil when engine warm and cranking (situation 2), look to the key switch as the likely suspect. If, however, there is power when warm & cranking, look to the ignition controller (EZL).

Ok, the car is now starting hot, cold and whenever.
Please chime in to let me know what you think.

I thought it was a spark issue, I was convinced it was, due to my troubleshooting.

Now I'm not sure, but, I'll be the first one to shrug my shoulders and admit I screwed up somewhere.

To recap, I could have sworn there was no spark due to my past trouble shooting...mainly using my timing light and also by holding the spark plug by the exhaust manifold.

Fast forward to this morning...As, stated there was power to the ignition coil this AM with the key "on."

As I'm in the engine bay checking things out and asking my Son to turn the ignition on and off, I hear the Idle Control Valve (ICV) "clicking."

I remove the electrical connection, reconnect it, start the car and it starts right up.

Let the car run for a while...turn the car off, it starts it up immediately. I repeat this numerous times and the car starts again no issues. I'm still thinking - something is wrong here because the ICV leads me to think it's fuel related, not spark/ignition.

So here we are. I'm happy it's starting as it should. I'm assuming it was the ICV. Am I missing something? I was skeptical, but, it's starting and running as it should.

If someone wants to "school" me...please do so.

I wanted to make sure I post the results to help someone else.

Kinda drives me crazy when someone reports an issue, they get alot of help and they don't post the results.

Thanks so much to everyone (Dave, Frank and Diesel) who posted! Dwayne

So you think you had a bad electrical connection of the ICV?

You know Dave, I have no idea.

As I posted earlier, everything led me to a spark problem.
But it can't be a coincidence that after removing the ICV and cleaning it up, the car starts right up.

I guess the valve in the ICV could have been stuck in such a position that the car was having an issue with the amount of air that was getting in there during a hot start, but there should have been spark; but what do I know.

I even double checked for spark with a timing light.

But what I do know is that ICV was making a funky "clicking" sound, as I had my head in the engine bay.

Electrical connection? Not being an electrical guy, there had to be something going on, because it was making a clicking noise. So could the valve have been stuck? I think so, because it was making noise. I did leave out, from my earlier post, that I cleaned the heck out of the ICV with carb cleaner. It was pretty dirty in there.

So in the end, I guess it was the ICV, electrical or a stuck valve - I don't know.