Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: V8Cowboy on 31 January 2016, 12:59:10
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Helly guys,
I'm desperate right now. I came home on friday, put the car in the harage, everything fine. Yesterday evening it just wouldn't start.
It is turning, you smell the gas, but it just won't come to life. No fault code stored, no flashing of the MIL.
After checking some fuses in the engine bay by removing them one at a time I somehow seem to have confused the system, suddenly the immobilizer put fault codes, flashing MIL, recognizing different keys though.
I called the automobile Club and at least the guy could solve the immobilizer issue... simply by cutting off battery for a few minutes. The main problem persisted. No spark on all 6 plugs. Tried another coil - the same. Coils have ignition line and ground, but don't seem to be feeded by the ECU. You can Access it and read fault codes, measure data and so on.
I'm not sure if I can suspect the crank sensor, the guy from the club said he sees an rpm signal. Some years ago I already replaced it, but the symptoms then were stalling when warm, no problem at all starting cold.
I had to leave the car at home for this week and don't really know where to look. Should I buy a new crank sensor just for fun and try it? Had anyone of you a similar problem and perhaps a solution?
I really really appreciate any input and help, my weekend so far is a catastrophy anyway, besides this trouble.
Thank you!
All the best, Kristof
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I'd still go with crank sensor,if nothing else you'll at least then have a spare.I've never had a 3.2 so I don't know if they suffer any issues specific to that engine.Others will be along with better advice soon I'm sure.
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Sounds like crank sensor to me too
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Thank you for your replies.
I was just wondering, if a failing crank sensor shouldn't block the fuel pump too?
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Thank you for your replies.
I was just wondering, if a failing crank sensor shouldn't block the fuel pump too?
Fuel pump runs to prime on ignition switch on, then cuts pump until engine fires...
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So fuel pump runs anyway when turning the ignition on, no matter if crank sensor works or not, did I understand it right?
The engine should get just enough gas to cough IF sparks where working.
Hmmm... I ordered a new crank sensor (and cam sensor as well as it was only a few Euros more, who knows...good to have one on spare) and I hope it arrives in time on friday at the latest. Changing it is not that hard and at least another factor to be ticked off.
I'm still curious, as the guy said he gets a rpm signal, anyway strange. From one day to another...
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If there are no gas, may be injection relay??
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No no, gas is there, enough to fill the whole garage after a few starts, it's definitely the sparks that are missing.
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Ok, so is possible the crank sensor
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Hello guys,
just to give you a little feedback. It indeed was the crank sensor. :) I was sceptical, but you proved me wrong. After measuring infinite ohms on the plug it was clear even to me. Runs again :) And again I could learn something! ;D
Thank you all for your advice and please forgive the typing Errors I made :-[ Didn't find any button to edit it later.
Have a nice evening!
Kristof
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Glad you're sorted :y
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Was the previous one a genuine GM crank sensor or a pattern one? And what about the replacement, GM or pattern?
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Hi,
sorry sjc, I somehow didn't get a notification or failed to recognize it.
Both sensors, the one I replaced back in 2008 and now, are Bosch sensors. I was taught not to use any cheap aftermarket brands on the Omega, as this would most likely result in buying it twice ;)
Anyway, being happy the car started again I drove it a few days ago the first time. After maybe half a km I got the MIL lighting up, together with losing power. I stopped and blinked out P0325 knock sensor 1. Ok, it was late, I had to drive, car drove somehow, let's try it. After another 8 km or so the MIL suddenly disappeared. Car ran fine again. Since then, I get the MIL every day, but only for a few seconds. Car runs fine with full power though.
As I understand the fault code, P0300 -306 are for actual misfire the knock sensors register, while P0325 is a knock sensor malfunction itself? I was not able to check wiring right now, hope to do this tomorrow evening. I was just wondering, as this came once again very suddenly, if this can be somehow related to the crank sensor issue, or maybe because the mechanic unplugged coil pack 1 for testing? And did not snap it in correctly?
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I think that unless you use a genuine GM OE crank sensor, you can never be 100% certain of its reliability, and even then they fail. Many of us carry a spare GM crank sensor in the boot. :y
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Thank you for your replies.
I was just wondering, if a failing crank sensor shouldn't block the fuel pump too?
Fuel pump runs to prime on ignition switch on, then cuts pump until engine fires...
I'm sure you're right Al, but somewhere I got the impression that fuel pump operates, ignition on, when either the starter is cranking or the engine is turning at 400rpm or more, as advised by the crank sensor. This tallies with the OP stating that he had plenty of gas, after a few cranks the garage stank of it. Please explain to me how pump knows when engine is primed.
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Pump operates at a fixed pressure.So running it for x amount of time will force y amount of fuel into the pressure regulated fuel rail...
As soon as the crank/cam sensors tell the ecu that both ends of the engine are moving at the same speed, it fires up the fuel pump permanently :y
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I must be misunderstanding this... Surely if both ends of the engine are NOT moving at the same speed then you have far more serious issues than the fuel pump? :-\
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Begging your pardon, Al, I have just done a quick test. I removed the fuel hose from the manifold and had a friend turn on the ignition; no fuel emerged. He then cranked the starter and fuel gushed out.
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Begging your pardon, Al, I have just done a quick test. I removed the fuel hose from the manifold and had a friend turn on the ignition; no fuel emerged. He then cranked the starter and fuel gushed out.
Now try doing the same thing with a faulty Crank Sensor. ;)
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Begging your pardon, Al, I have just done a quick test. I removed the fuel hose from the manifold and had a friend turn on the ignition; no fuel emerged. He then cranked the starter and fuel gushed out.
Now try doing the same thing with a faulty Crank Sensor. ;)
I don't have a faulty crank sensor to hand, though reading reply 7 I would expect the same result.
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I don't have a faulty crank sensor to hand, though reading reply 7 I would expect the same result.
It does depend on the engine, though. Some Omegas prime the fuel pump for a few seconds when the ignition is turned on, whereas others won't activate it until the crank sensor indicates the crank is rotating.
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Begging your pardon, Al, I have just done a quick test. I removed the fuel hose from the manifold and had a friend turn on the ignition; no fuel emerged. He then cranked the starter and fuel gushed out.
Now try doing the same thing with a faulty Crank Sensor. ;)
I don't have a faulty crank sensor to hand, though reading reply 7 I would expect the same result.
2.6 and 3.2 probably wont spark or pump fuel when being cranked with a faulty Crank Sensor, which is what the OP has, if that was the question.
On the earlier 3.0 Ive had some that do and some that don't with a faulty CS.
A faulty CS can throw some funnies, and don't allows through a Code, I've replaced CS before and they can fire up straight away, then Ive had others that will need the CS Code clearing before wanting to fire up.
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I assumed that the fuel pump not running unless the engine was turning at 400rpm was a safety measure. However, I have bump started a 2.0, it fired easily after a very brief tow. Maybe a much lower rpm is required.
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The usual sequence when firing up a fuel injected engine is that the fuel pump runs for a couple of seconds to "prime" the fuel system when the ignition is turned on, then it switches off until crank rotation is detected. Once running, it will switch off again if the crank stops rotating for any reason.
Once the engine has stopped, it will retain fuel pressure for a long period if not indefinitely, since the only way the fuel pressure can escape is via the now closed injectors or FPR (which closes once flow from the pump stops) and return path back to the tank.
So, bump starting a dead car is possible either because there is likely to be enough energy in even a discharged battery to kick the fuel pump over for a couple of seconds or, failing that, because the fuel rail remains pressurised anyway.
Some Omegas (non-dbw V6s and some of the 4 pots, IIRC) don't use a priming procedure, so the fuel pump doesn't run until cranking is detected. I know for a fact that a 3.2 runs the fuel pump for a few seconds when the ignition is switched on.
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The usual sequence when firing up a fuel injected engine is that the fuel pump runs for a couple of seconds to "prime" the fuel system when the ignition is turned on, then it switches off until crank rotation is detected. Once running, it will switch off again if the crank stops rotating for any reason.
Once the engine has stopped, it will retain fuel pressure for a long period if not indefinitely, since the only way the fuel pressure can escape is via the now closed injectors or FPR (which closes once flow from the pump stops) and return path back to the tank.
So, bump starting a dead car is possible either because there is likely to be enough energy in even a discharged battery to kick the fuel pump over for a couple of seconds or, failing that, because the fuel rail remains pressurised anyway.
Some Omegas (non-dbw V6s and some of the 4 pots, IIRC) don't use a priming procedure, so the fuel pump doesn't run until cranking is detected. I know for a fact that a 3.2 runs the fuel pump for a few seconds when the ignition is switched on.
Thank you. Now all is clear. I did my test on a 2.5, non-dbw. I suspect I got my belief from the Senator Haynes manual. The dead 2.0 I bump started had a failed starter, it would not jump start. I suppose OP filled his garage with petrol
from the priming dose.