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Discussion Starter #1
I need help diagnosing a crank, no start condition.

Ran fine today, I replaced the belts this morning and drove it approx 20 miles on and off throughout the day and parked it in my driveway. I went out later to pull it into the garage and it just cranks, no start. I hooked a timing light to the coil wire and have
no spark.
The same thing happened last week after I replaced the motor mounts and gunked down the engine and chassis and then hosed it off. It started up fine but then started misfiring. I blew it off with compressed air and then ran fine. 1/2 hr later it just cranked with
no spark. I blew out the crank sensor connector, coil, and any other wire I thought might have gotten wet. Then it started and seemed OK until tonight.

Is there any way to test the crank sensor or coil?
I,m wondering if I shorted something out when I hosed off the engine last week.
 

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coil check: primary and secondary windings check (remove wires from coil for this, and set DVM to 20 Ohms register for primary test and to 200 K.Ohms register for secondary test):
on 2 good coils I have, i get 0,50 Ohms across the primary windings (negative #1 & positive #15) and 5,50-6,50 K.Ohms across secondary winding #1 & #4

crank sensor:
undo the plug up near the windshield washer reservoir filler
1. ohms test: Check with Ohmmeter between centre contact and one of the outer contacts (one will give no reading, the other will) of the plug coming up from the sensor (never use ohmmeter on the plug going back to the ECU!). You should be getting 520-600 Ohms.

2. signal test: (This test is normally done with an oscilloscope, but using a DVM set to AC Volt does at least show if the CS puts out a signal whilst cranking): you need a tester that actually can clip onto the 2 male pins of the connector plug (remember, the connector coming up from the sender itself, not the part going to the ECU!), using again the centre pin and one of the outer pins set the meter to Volts AC.......and now crank the engine.......are you getting about 1.4V AC?

3. Volt Test from ECU to CS: Set DVM to Volt DC, between centre and outer pin of the female CS plug leading back to ECU (KO but not cranking); you should be getting a reading of about 4.4V with ign. ON. (note: only turn on the ignition once you have the DVM connected!)

I once had an intermittent problem with no start and found the sensor tip was gunked up with crud.....simple to remove and clean.
If you need a replacement, FAE 79037 works perfect in place of the orig. Bosch 0261210036

but, to be honest, before all that I would check the motronic 'red stripe' diode relay under the rear shelf
voltmeter set to K.OHMS test the relay by putting the negative/black lead of your tester to relay pin #85 and the positive/red lead of the tester to relay pin #86 - you should get a reading of something like 0.60 – 0.77 K.Ohms (ie. 600-770 Ohms)
 

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Discussion Starter #3
Thanks for the info.
I did all the checks tonight when I got home from work.
Coil Ohm checked good.
Crank sensor ohm and Signal tests good.
Red stripe diode relay tests good.

I was kind of disappointed not to find a failed part.
I reconnected everything, plugged the relays in and out a few times to clean contacts
and she started right up!???

Very strange, because I'm not sure I did anything to really fix it.
I,m glad it's running, but I wish I could put my finger on what the problem was.
 

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Very strange, because I'm not sure I did anything to really fix it.
I,m glad it's running, but I wish I could put my finger on what the problem was.
I know that feeling. Once on my 87 Spider the engine stoped on the highway when I pressed the clutch for downshifting. It wasn't a good place to loose the engine. I managed to clear the way but it was a close call. I tried many things, the main fuse for the ECU, I played with few things and it restarted 20 minutes later. It happened again few days later in about the same situation (but at a much safer place). I never found the problem and since then I'm worried when I'm in a situation where it could be critical to loose the engine.
 

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probably pulling the relays a few times cleaned up a dirty contact.....worth giving them a good clean with a toothbrush and some contact cleaner.

if it happens again, pull the crank sensor and inspect (clean) the tip.

glad its working again:)
 

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Very strange, because I'm not sure I did anything to really fix it.
I,m glad it's running, but I wish I could put my finger on what the problem was.
Glad to hear that you got it started again, but I know exactly how you feel about not finding the problem.

I went through this same scenario of not starting on my S4 at the end of last years season. Pulled, this, tested that, then started up.

But, later, failed again and no start.

Ended up being the ignition switch needed replacing.

My advice is if you get the no start again, install a simple push button start connected to the starter. If the car starts up, you have found your problem, the ignition switch.

Good luck,

Vin
 

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Discussion Starter #7
Hey, I'm back with the the same crank and no start condition which disappeared for about 1 month and then returned on Monday, Memorial Day.
Took the 91 Spider out in the morning to run errands with no problem and parked it in the driveway. Went out an hour later with my wife to go visit my daughter in Sussex County and the Alfa just cranked with no spark for 3 tries. Decided to crank it over in 1st gear to get it back in the garage
and halfway in it started. I rolled the dice and decided to drive it 45 minutes to my daughters house and it ran fine, I even pulled over halfway there and let my wife drive it for the first time the rest of the way. Could not have run better.
Later after beers,pool and hot tub we decided to go out to eat in the Village of Lake Mohawk which is beautiful. Cranked the Alfa and no spark for 3 or 4 starter cycles and then it started. Drove to Lake Mohawk and parked directly in front of the outside dining area of a Pub which was packed with people and then went inside for a great meal. By the way, it was my birthday!
After leaving and walking back to the car, my wife asked me if it was going to start, and I told her NO !!
Sure enough, in front of all the outside diners, with some of them appreciating the Alfa for what it was, it cranked and cranked and cranked with no spark!!! How embarrassing!!! It finally did start and we made it home. The next morning it did not start.
Thats my Memorial Day, Birthday story.

What I think is happening is the Motronic relay or Aux relay is not powering up because when I was cranking with no spark, the relay or relays starting making a fluttering sound right before starting almost like a very poor connection.
Is there any specific tests for voltage and grounds to the Motronic relays .
thanks
 

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Relay voltage supply at terminal #30 of both the Motronic red stripe relay as well as the Aux motronic relay (the one with a 15A fuse) should be battery voltage.

Make sure the 12V cable direct from Battery is clean and tight at the big connection terminal near ecu.

I'd remove each relay and clean the relay pins with contact cleaner and an old toothbrush. (disconnect battery!)
Do the same to the relay plugs.
Do the same to the big plug on the ECU and ecu pins.
Reconnect battery...

Voltage at coil: remove wires from coil #1 terminal (negative) and test you have at least 11,5V on coil #1 connection against ground, KO

My other suggestion in post #2 above was to remove the CS and clean the tip.....the sensor tip can get mucky down there. Easily got to from underneath.
 

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Have you tried to install a remote starter, the push button type?

I think you need to eliminate the ignition and see if the ignition is your problem. I had the same symptoms as you did and it was my ignition switch.

The remote starter is $10 and 20 mins to install.

Good luck,

Vin
 

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Happy Birthday!

Is there any specific tests for voltage and grounds to the Motronic relays?
I am not well versed in the Motronic Series 4 Spiders. But my one random thought (based on L-jetronic experience) is to check system voltage during cranking. Don't use a dash gauge (if you have one) - they are usually not wired for this test. Connect a voltmeter to the battery. With everything off a fully charged battery should read 12.6V, 12.3V is half-charged. Next see what it reads during cranking. L-jet requires at least 10.5V to power up the computers. (Our '84 Spider will show 11.8V during cranking.) It can sound like it is cranking over with good vigor but if the battery is marginal or the starter is drawing too much current the available system voltage could be below the threshold for the computer. (I don't know if the Motronic's threshold is the same but I'd suspect it similar.) It could be your car is close to that threshold and after a few attempts at cranking the engine is a little looser or the starter turns a little freer or an iffy connection heats up & gets a little tighter and then it gets just over the threshold for starting.

If you haven't already done so, remove, clean & secure all connections in the battery to starter circuit. They all need to be 100% to pass the electrons needed to start the engine.
 

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Discussion Starter #13
Thanks for all the input.
I am keeping my fingers crossed, but I did get the Alfa to act up with the relays fluttering with no start tonight after I got home from work. I wiggled around the Aux Moronic relay every time it happened and it would start. I swapped out the relay and it seems golden.
Only time will tell.
Hey, when you own an Alfa, it adds a little suspense to your life and it will always be part of my 60th birthday memory!!
You gotta love it!!
The Alfa will have to stay it the garage till next week because I am off to the Jersey Shore and then to the BB&T Pavilion
Sat. night to see the Dead!!!
Surfing, The Grateful Dead and Alfa's !!! Life is Sweet
 

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Have you tried to install a remote starter, the push button type?

I think you need to eliminate the ignition and see if the ignition is your problem. I had the same symptoms as you did and it was my ignition switch.

The remote starter is $10 and 20 mins to install.

Good luck,

Vin
I'm thinking this is my problem with my recently resurrected S3. I will turn the key to run and nothing on the dash lights up some times. If I crank it it does not start. If I jiggle the switch back and forth until the dash lights up it will start.

The worrisome part is that I was driving around the block and the car spontaneously shut off. It was in a safe place and after I pulled over it restarted but I'm afraid to take it anywhere until I fix this.

My question is if there is any option to just replacing the switch. Can it be repaired?
 

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Discussion Starter #15
I would pull down the fuse box and check the back side for loose or not fully seated wire connectors.
If that checks ok, I would hook up a volt meter and confirm the open circuit in the ignition switch before
changing it.
I have found a lot of loose connectors in my Alfa and if your dash does not power up, it will be a very easy
diag.
There's nothing worse when chasing an electrical issue when the symptom disappears.
good luck
 

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Jumping in to the mix here. My 84 has been having a no spark situation on and off for the past 2 years, dies after shut off and restarts when she wants. Will not start in my garage this time so I did check all the connections you have. 3rd battery in 2 years so I have been checking everything in steps. My only consistency is I can put her on a 6 hour 2 amp charge and then have no problem starting/spark. My next replacement is the relay and ECU behind under the carpet. I expect it to die again in about 2 weeks and hopefully it is near my garage. FYI harbor freight has a 4$ spark checker that works well.

Joe
 

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With work this week and a camping trip coming up this weekend it will probably be next week before I get a chance to follow up.
The car is up on jacks getting brakes so I can't drive it right now anyway.
Thanks for the tip.
 
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