Crank sensors

Started by four90s, September 14, 2014, 01:58:32 PM

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four90s

Hi All,

Can anyone tell me if the crank angle sensor off the 75 TS engine is the same as the one on the 164 V6.

The 164 I just bought doesn't fire. I can't get any spark at all, so I'm going to start with the cas, but I don't have one for a 164, only one for a TS.

Thanks
Steve
Adelaide
Four90s
Too many others to list
(33 Alfas and some other things since 1979)

MD

If the mounting is the same, the clearance between the 60-2 wheel and the sensor face is the same and finally if the connections are the same, then there is every chance it will work. One millimeter clearance will do as long as it doesn't touch the pulley.

Mount it up and check these parameters.
Also use an ohmeter with a high impedence range and measure for continuity across your old sensor. If it shows continuity, this is not likely to be a problem initially but they get intermittent from rise and fall of temperatures causing a make & break circuit of the very fine wire windings. So the engine may fire and run but as it warms up it may cause intermittent ignition issues.
Transaxle Alfas Haul More Arse.

Current Fleet
Alfetta GTV6 3.0
Alfetta GTV Twin Spark supercharged racer
75 1.8L supercharged racer

Past Fleet
Alfa GT 3.2V6
Alfetta GTV 2.0
Giulia Super 2.0
Berlina 2.0

four90s

Four90s
Too many others to list
(33 Alfas and some other things since 1979)

four90s

Hi Again,

Well, I ended up using a known working 164 cas, but that didn't work. Also swapped out the ecu and that again didn't work. I've now tried replacing the cas, ecu, coil and have checked the front plugs, which are old but good.

I still don't have any spark. Can anyone suggest anything to try to get me on the road.

It's actually quite a late 164, being built in 1992 and the overall condition is good. I would like to get it out of the po's front yard. The po said to me that the power steering doesn't work, but when I took the cover off to get to the cas, I saw the p/s belt was off the pump, so I think maybe that's the problem.

Cheers and TIA
Steve
Adelaide.
Four90s
Too many others to list
(33 Alfas and some other things since 1979)

Mick A

Gday,

Check your coolant temp sensor plug on the front of the thermostat. It is blue. The ecu won't work without a signal from it.

Cheers.
Mick.

MD

1 I presume you have checked that there is fuel pressure.

2 Replace the igniter. If this has failed it doesn't matter that you have done, it cannot fire.

3 Replace the high tension lead from the coil to the distributor just in case it is open circuit. The coil may be working but not delivering high tension for distribution if this is  circuit open.

4 If you can establish a spark and you have fuel but it doesn't fire, you have an ignition timing problem.

Don't give up. You will achieve a great sense of satisfaction if you sort it out.
Transaxle Alfas Haul More Arse.

Current Fleet
Alfetta GTV6 3.0
Alfetta GTV Twin Spark supercharged racer
75 1.8L supercharged racer

Past Fleet
Alfa GT 3.2V6
Alfetta GTV 2.0
Giulia Super 2.0
Berlina 2.0

MD

Good call Mick. Learned something myself ! Cheers.
Transaxle Alfas Haul More Arse.

Current Fleet
Alfetta GTV6 3.0
Alfetta GTV Twin Spark supercharged racer
75 1.8L supercharged racer

Past Fleet
Alfa GT 3.2V6
Alfetta GTV 2.0
Giulia Super 2.0
Berlina 2.0

festy

I'm pretty sure the ECU will attempt to run without a coolant sensor.
It will either use the IAT sensor value or substitute a static 'limp home' temperature, depending on a number of variables.

Does your fuel pump start running while the engine is turning over? If so, the ECU is seeing a valid signal from the CAS.
You can also wire up a 'check engine' lamp, and flash out any error codes to help with diagnosis.

Mick A

Quote from: festy on September 17, 2014, 07:28:16 AM
I'm pretty sure the ECU will attempt to run without a coolant sensor.
It will either use the IAT sensor value or substitute a static 'limp home' temperature, depending on a number of variables.

Does your fuel pump start running while the engine is turning over? If so, the ECU is seeing a valid signal from the CAS.
You can also wire up a 'check engine' lamp, and flash out any error codes to help with diagnosis.

Attempt is the correct word mate!

It'll start and run like a bag of shit then cut out with a bad connection on a cold engine. 

Mick.

festy

The point I was trying to make is that a faulty CTS will not stop the ECU from triggering the ignition.


Cool Jesus

Is this a dizzy/rotor set up or individual coil packs?

You've managed to rule out some major components at least for the no spark issue, but you need to work backwards from the spark plugs to the ecu. A multimeter would come in handy. Coolant temp sensor? I tend to agree that the engine would still fire up with a faulty coolant sensor.
Present:
* '76 Alfetta GTAm 2.0 (project)
* '03 147 2.0 TS
*'12 159 Ti 1750 TBi
===================
Past:
* '10 159 2.2 JTS
* '89 164 3.0
* '98 Spider 2.0 TS

Cool Jesus

Just noticed that you mentioned coil.
Well I'd start checking continuity on HT lead, there resistance, coil pack resistance, check rotor and dizzy cap continuity and tracking, is the rotor spinning? Then you can move onto the wiring and fuses, is power and ground where it's meant to be.
Noticed some mention an error code check with the check engine lamp. Not sure if how that's done, but if you don't have diagnostics, see what errors are logged with the ecu. Anyhow, soldier on mate, it will be something stupid and simple in the end.
Do you know when it last ran?
Present:
* '76 Alfetta GTAm 2.0 (project)
* '03 147 2.0 TS
*'12 159 Ti 1750 TBi
===================
Past:
* '10 159 2.2 JTS
* '89 164 3.0
* '98 Spider 2.0 TS

Cool Jesus

Damn it, back again. Just an after thought. Is it an auto? Check the trans cutout switch is ok, switch may be stuck/faulty and registering that it's not in park or neutral.
Present:
* '76 Alfetta GTAm 2.0 (project)
* '03 147 2.0 TS
*'12 159 Ti 1750 TBi
===================
Past:
* '10 159 2.2 JTS
* '89 164 3.0
* '98 Spider 2.0 TS

four90s

Hi All,

Thanks for all the suggestions. I feel that I'm groping around in the dark a bit with the Motronic, as I've only ever worked on L-Jet up to now. (Apart from wrecking a few.)
Jesus, yes it is an auto, but it will crank, and I am assuming the trans lockout switch works the same as any other and if it's cranking, it should be good to go.

MD, haven't checked fuel pressure yet although after a bit of cranking, I can smell fuel from the exhaust, so once again I'm assuming.

As it seems to not be anything obvious, I've decided to add to the $210 purchase price and have it brought to my place on a flatbed for $125. Once it's there I can have another go, preferably in daylight on the weekend.

I think I've still got a spare set of leads and cap from a 164, so that will be the next step.

Once again, thanks for all the suggestions. I'll keep you informed and there may be more questions.

Cheers
Steve
Adelaide.
Four90s
Too many others to list
(33 Alfas and some other things since 1979)

four90s

Hi All,

Got it in the driveway now, but the mystery continues. I do have spark. Don't know if I had it before, but I was using the old screwdriver in the end of the lead and didn't get a spark. Andrew suggested I use a plug and I do have spark.

I also have fuel pressure. I sorted my pressure gauge and I get 50psi at crank and it takes about five minutes to go away at rest.

I've swapped the ecu and afm for known working ones all with no change.

Where to next, oh knowledgeable ones?

Cheers
Confused
Adelaide.
Four90s
Too many others to list
(33 Alfas and some other things since 1979)