need help 450sl ignition
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I'm always down to help a fellow nutmegger.
Do you have an extra spark plug lying around? Pull the wire coming from the ignition coil off of the distributor, plug the spark plug into it, crank the engine, and make sure you're getting spark from there first.
From there, it could be a ton of other things. A bad coil, a bad sensor in the distributor (green wire) going to EZL, or the EZL itself. I had an odd problem on my 380 where I hadn't attached the ground strap from the coil to the engine, and while I had spark, the engine wouldn't start. Not sure if my 450SL has that though.
hi thanks for respond. what i did was i painted engine bay and i had disconnected all wires , my concern is wiring (not sure if i reconnected right).I need wiring diagram or better pictures to be sure that wiring is right.for some reason cant find anything for 1978 450 ignition diagram .i rebuild engine, did valve job ,new guides for chain ,clean fuel injection system, intake and more ,put all together turn engine but no spark , i connected 12v directly to coil still no spark , i do not know anything about transistorized ignition system and i ll appreciate if you can help me.thanks
http://www.startekinfo.com/StarTek/outside/11883/?requestedDocId=11883
While it might be a little hard to work with, that is the factory service manual. It's down right now, but once it's up, I'll fish the wiring diagram out of it for you. It should be back up soon. There should also be an ignition troubleshooting guide in there.
The EZL should look like this on your car:
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It's located behind the right headlight. It should have a 4 pin connector and a single pin connector. Make sure they're both connected. The single pin should go to a green wire at the distributor. This wire is a signal wire that tells the EZL when to energize the coil. Start by making sure those are connected and testing for spark at the coil.
Where are you located in CT?
While it might be a little hard to work with, that is the factory service manual. It's down right now, but once it's up, I'll fish the wiring diagram out of it for you. It should be back up soon. There should also be an ignition troubleshooting guide in there.
The EZL should look like this on your car:
It's located behind the right headlight. It should have a 4 pin connector and a single pin connector. Make sure they're both connected. The single pin should go to a green wire at the distributor. This wire is a signal wire that tells the EZL when to energize the coil. Start by making sure those are connected and testing for spark at the coil.
Where are you located in CT?
Ah, that's so far from me.
And yes, I believe between 76 and 79 they were virtually identical. The car is not at my house at the moment, but I can post some pictures as soon as I can get to it.
In the meantime, make sure those two connectors are firmly connected to the EZL that I posted a picture of. Grab a spare spark plug and connect it to the coil wire on the distributor and ground out the plug to the engine. Crank and check for spark.
Pretty similar to diagnosing any old V8. Just need fuel, and spark at the right time. Set your engine to TDC and make sure the distributor rotor is pointing at the TDC mark which can be seen when you pull the dust cap off.
hi Jack
i have good news, i corrected wire connections using diagram you send me and got spark (so happy). then start an engine and its started ,i did not ran it for too long because do not have exhaust system connected only headers , started fine .intake needs some help had to push air flap by hand to let air in manifold ,for some reason air did not work with gas pedal ,any idea? .I want to thank you for all help you are do, and when i registered on this site i thought no one will respond so thanks again
i have good news, i corrected wire connections using diagram you send me and got spark (so happy). then start an engine and its started ,i did not ran it for too long because do not have exhaust system connected only headers , started fine .intake needs some help had to push air flap by hand to let air in manifold ,for some reason air did not work with gas pedal ,any idea? .I want to thank you for all help you are do, and when i registered on this site i thought no one will respond so thanks again
Good news. The airflap you are seeing is not the throttle, the throttle is buried deep inside. The airflap is reactive to the airflow and controls the exact fuel delivery. The airflap movement is depending on a bunch of factors which in your case might need looking into, or maybe your short start just means things have not settled yet (pressures etc)
Now you know the engine runs I suggest you finish the exhaust and make sure you have fresh fuel and correctly working pump and filter. Then you need to be able to drive the car to properly test the fuel system under load and at warmup / warmed up.
I strongly advise NOT TO ADJUST ANYTHING. The adjustment should not change and there is no 'maintenance' adjustment required (unless you know somebody has messed with it) and almost always there is a fault in the system which you need to hunt down and correct, typically vacuum for fuel pressure (blockage) related. A systematic approach is essential and there is a lot of information out there.
Now you know the engine runs I suggest you finish the exhaust and make sure you have fresh fuel and correctly working pump and filter. Then you need to be able to drive the car to properly test the fuel system under load and at warmup / warmed up.
I strongly advise NOT TO ADJUST ANYTHING. The adjustment should not change and there is no 'maintenance' adjustment required (unless you know somebody has messed with it) and almost always there is a fault in the system which you need to hunt down and correct, typically vacuum for fuel pressure (blockage) related. A systematic approach is essential and there is a lot of information out there.
Glad to hear it! Yeah, the air flap is just the air flow meter for the fuel system.
And yes, I totally second JS5D on not adjusting anything. Someone had adjusted the warm up regulator on my 450SL before I got it, and the engine runs like s**t. I have to buy a fuel pressure gauge now to reset it. CIS doesn't like to be messed with, it likes to be maintained. And that just means correcting vacuum leaks and changing the fuel filter for the most part.
Glad I could help.
Sent from my iPhone using Tapatalk
And yes, I totally second JS5D on not adjusting anything. Someone had adjusted the warm up regulator on my 450SL before I got it, and the engine runs like s**t. I have to buy a fuel pressure gauge now to reset it. CIS doesn't like to be messed with, it likes to be maintained. And that just means correcting vacuum leaks and changing the fuel filter for the most part.
Glad I could help.
Sent from my iPhone using Tapatalk
I just got home from work long day ,but i will try to install exhaust tomorrow. when i bought this car it was running weak , think vacuum leaks and maybe wrong adjustment?if anyone can send me pictures of vacuum and ignition i will be thankful . Thanks again
I believe the proper ign timing at idle is 11-15 BTDC. Get yourself a timing light and make sure it's around there. Check out the manual as well. The W126 manual also seems to be a bit easier to navigate, and a lot of the information is similar.
Hi, i just got exhaust up and started engine ,it ran for 5 minutes and stop ,i have water leak from water pump gasket (easy fix) ,so far head gaskets look good no leak, i will try again when engine cools down and i will get timing light and do that .Thanks
Good to hear! So you had the heads off? Good thing you don't have an alloy block... not fun...
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