Thread: Cutting out

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I'M NOT SURE WHAT YOUR AIR INTAKE SYSYEM LOOKS LIKE, BUT I HAD A SIMILAR PROB. ON MY 97 SUBARU. I WOULD START IT UP AND WHEN IN CAME DOWN TO IDLE IT WOULD JUST DIE. IT TURNED OUT TO BE A HOSE (1" ID) THAT CAME DETATCHED ON THE UNDERSIDE OF AIR INTAKE TUBE. MAYBE LOOK FOR SOMETHING LIKE THAT. IT PROVIDED SOME KIND OF VACCUUM TO THE MANIFOLD, AND TOOK ME WAY TOO LONG TO FIND, YOU KNOW ONE OF THOSE SIMPLE, OVERLOOKED THINGS.

Next I would try the MAP sensor....but...

Does it run smooth or does it sometimes run rough...?

When it cuts out can you describe it more....? Is it consistant...? Does it sometimes cut out but then doesn't all the way die....Like a shutter....

I have a 89 Astro that does this and it is caused by the torque convertor....I does it mostly when cold and is intermttent....The convertor tries to "lock-up" at idle and when it does it cuts out...

Dear Doc Browtie,
It's an intermittent fault, never cuts out when the engine is cold and the coke is on. When hot it will cut out while stationary whether in neutral, drive, a/c on or not, the engine revs drop very slightly just before it cuts out. Without touching the throttle, I turn the key and it fires up immediately. Apart from this problem, it runs smooth, leaves most European/Japanesse cars at the lights.

Do you think kicking it more or threatening it with a pick axe handle might do the trick?

I am not familiar with the tbi setup on the suburban, but it sounds like if the IAC is new then it is running out of fuel at idle. Are the fuel injectors partially blocked ie cause a slight reduction in fuel flow when fired, not enough to be a problem when above idle, but not enough fuel to keep running at idle.

The other thing would be the oxygen sensor, if there is some fault with it, it may cause lean running conditions at idle when running in closed circuit, (oxygen content of exhaust gases used to control air fuel mixture), it would also explain that when cold it runs fine as it uses the air fuel data tables in open circuit (ie no exhaust oxygen content feed back to control air fuel ratio) until engine temp is sufficient to go into closed loop. It may not be the actual sensor itself, it could be the wiring from the loom not maintaining a steady resistance and causing a variation in the voltage reading from the sensor. This may be because insulation has worn through, wire is too close to exhaust etc and is overheating???

I don't know the answer, just trying to help with some suggestions.

Justin

could also be an Ignition problem

I'd like to take this opportunity to say how impressed I am, not only with the information in regard to my engine problem, but also with the wiliness and helpfulness of all those that have replied to my 'cry for help'.

I'm still having the 'cut out' problem, despite searching for vacuum leaks, using that tried and tested technique of spraying brake drum cleaner on all the hose connections, I only had a small rise in revs, and I think that was some of the vapor/fumes going into the top of the carb'.

I shall persist, even if it kills me . This machine will never beat me, I am better than any small block Chevy. I've threatened to replace it with a F**d but it just laughs at me! Then cuts out giving me the finger.

Originally posted by Horse
I'd like to take this opportunity to say how impressed I am, not only with the information in regard to my engine problem, but also with the wiliness and helpfulness of all those that have replied to my 'cry for help'.

I'm still having the 'cut out' problem, despite searching for vacuum leaks, using that tried and tested technique of spraying brake drum cleaner on all the hose connections, I only had a small rise in revs, and I think that was some of the vapor/fumes going into the top of the carb'.

I shall persist, even if it kills me . This machine will never beat me, I am better than any small block Chevy. I've threatened to replace it with a F**d but it just laughs at me! Then cuts out giving me the finger.

you wont never find it using "brake drum cleaner" because it wont burn. you should be using carb. cleaner.

Dear All,
Still struggling with this pissing cutting out problem, I've noticed that if I turn the idle down (using my home made throttle stop) to a point where want cut out while drive and stationary, if I turn the steering to full lock the engine dies. I have replaced the power steering pump a month ago. Any ideas?

you still need to know if you have good vac. get a vac. gauge and check the vac. idling at around 800 rps's you should have steady 15" or higher. do you?

lt1s10 & DennyW.
I'll look for wires round the steering rack, and get a vacuum gauge to check out the vacuum. Cheers
Keep Rockin'
Gus UK
PS. Gas gone up another 6cents a gallon

Hi,
No wires from the steering rack or power pump. The vacuum checks out, just a touch over 15"
Keep Rockin'
Gus UK

Originally posted by Horse
Dear All,
Still struggling with this pissing cutting out problem, I've noticed that if I turn the idle down (using my home made throttle stop) to a point where want cut out while drive and stationary, if I turn the steering to full lock the engine dies. I have replaced the power steering pump a month ago. Any ideas?

sounds like we're back to the idle air control motor. you put a new one on right? did you turn the idle back down to where its suppose to be? if you didnt you could have your TPS out of range now.

Hi Mike,
Yep, done all that. I'm now wondering about replacing the MAP, just in the process of elimination. However, I don't know what the MAP is supposed to do Any ideas?
Keep Rockin'
Horse

Cheers for that Denny,
From what you say, it could well be the MAP, I'll check it out. Cheers.
BTW, It's 7.30 in the morning here Saturday, what's where you are?
Keep Rockin'
Horse

About bed time then 4 u. We put are clocks back tonight so I can get another hour in bed tomorrow
Keep Rockin'