'85 Turbo: Won't start - Suggestions Needed
05-26-2011, 05:20 PM
#1
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Join Date: May 2011
Location: Austin
Posts: 7
'85 Turbo: Won't start - Suggestions Needed
Greetings Z-Owners. A Dying but proud breed. Great site here, just found and searched through tech section and couldn't find what I needed. Here's the problem.
1985 Turbo Z, 5-Speed, always parked in garage. 160,000 miles. Drive several times a week. It has always started easily until last week or two. One anomoly: For years now, when the engine is warm, every fifth or sixth start, it coughs for thirty seconds or so, but once that's done, no problem. A few days ago, all that changed. I'd start it, it would run for a few seconds and then die.
Error codes were 14, 24, 31, 41. (14)Speed sensor - My speedometer only works intermittently. (24) Neutral Park Switch - big deal it's a man. trans. (31) Load Signal Circuit - various switches that havent' worked, I think (power steering fluid is low).
The culprit appears to be 41 Fuel Temp Sensor Circuit. (Two years ago, I had a similar problem and the mechanic replaced the "fuel sensor" but the temp sensor screwed into it is obviously old old old. The engine has spark.) Before I take it back to the mechanic, here are my Questions: Can this sensor actually cause the computer to shut down the engine? Could this be a sign of of a problem with fuel pressure? Should I disconnect the fuel line and make sure that that is okay? (It has a new fuel filter). Thanks in advance for the help.
1985 Turbo Z, 5-Speed, always parked in garage. 160,000 miles. Drive several times a week. It has always started easily until last week or two. One anomoly: For years now, when the engine is warm, every fifth or sixth start, it coughs for thirty seconds or so, but once that's done, no problem. A few days ago, all that changed. I'd start it, it would run for a few seconds and then die.
Error codes were 14, 24, 31, 41. (14)Speed sensor - My speedometer only works intermittently. (24) Neutral Park Switch - big deal it's a man. trans. (31) Load Signal Circuit - various switches that havent' worked, I think (power steering fluid is low).
The culprit appears to be 41 Fuel Temp Sensor Circuit. (Two years ago, I had a similar problem and the mechanic replaced the "fuel sensor" but the temp sensor screwed into it is obviously old old old. The engine has spark.) Before I take it back to the mechanic, here are my Questions: Can this sensor actually cause the computer to shut down the engine? Could this be a sign of of a problem with fuel pressure? Should I disconnect the fuel line and make sure that that is okay? (It has a new fuel filter). Thanks in advance for the help.
05-26-2011, 06:11 PM
#3
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Join Date: Jan 2006
Posts: 203
I don't think the fuel temp sensor would cause it to die. If it were just unplugged it will still run.
I had a similar problem with a 280zx and it took forever to find. Completely different car..
I have unplugged the CHTS, O2 and FTS on my 87 and the car still ran fine. maybe the mixture would be off but the car still ran.
Do you here the fuel pump run of a few seconds when you turn the key on before you try to start it?
Put a screw driver against your ear and on one of the injectors while someone cranks the engine. can you here the click of it firing? Pull the coil wire of so it doesn't fire if you need to. You can practice on a running car first so you can get used to what you are looking for.
Put a timing light on it and make sure the spark isn't cutting out on you.
I had a similar problem with a 280zx and it took forever to find. Completely different car..
I have unplugged the CHTS, O2 and FTS on my 87 and the car still ran fine. maybe the mixture would be off but the car still ran.
Do you here the fuel pump run of a few seconds when you turn the key on before you try to start it?
Put a screw driver against your ear and on one of the injectors while someone cranks the engine. can you here the click of it firing? Pull the coil wire of so it doesn't fire if you need to. You can practice on a running car first so you can get used to what you are looking for.
Put a timing light on it and make sure the spark isn't cutting out on you.
05-26-2011, 06:21 PM
#4
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Join Date: Jan 2006
Posts: 203
Some more ideas.
I think the only sensors the car really needs to start are the Air flow meter (AFM) and the Crank Angle sensor (CAS). All the others are used to adjust the mixture while the engine is running.
Some will tell you the CHTS will do stuff like this but I'm here to tell you I have started and driven my car without it even plugged in at all. Although not sure what the ECU would do if it were shorted???
If you have the FSM or a Haynes man you can run many of the test on the sensors yourself. I'd do all of them before you pay anyone to work on it. These cars are very easy to work on.
get your manual here
http://www.xenonz31.com/reference.html
I think the only sensors the car really needs to start are the Air flow meter (AFM) and the Crank Angle sensor (CAS). All the others are used to adjust the mixture while the engine is running.
Some will tell you the CHTS will do stuff like this but I'm here to tell you I have started and driven my car without it even plugged in at all. Although not sure what the ECU would do if it were shorted???
If you have the FSM or a Haynes man you can run many of the test on the sensors yourself. I'd do all of them before you pay anyone to work on it. These cars are very easy to work on.
get your manual here
http://www.xenonz31.com/reference.html
05-26-2011, 07:43 PM
#5
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Thread Starter
Join Date: May 2011
Location: Austin
Posts: 7
"Can I hear the fuel pump?" When I turn the ignition to on, I can definitely hear something whiring behind me and it isn't the antenna. I was wondering what that was. Must be the fuel pump. I guess that is good news. Thanks for the suggestions.
Even though the fuel filter is only two years old, I might check it out. This all started a day after I filled up at Sams. It can't be bad gas, I drove a good twenty miles after the fill.
Even though the fuel filter is only two years old, I might check it out. This all started a day after I filled up at Sams. It can't be bad gas, I drove a good twenty miles after the fill.
05-26-2011, 08:04 PM
#6
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Join Date: Jan 2006
Posts: 203
Be sure to pull the fuse for the fuel pump and crank the engine over for 10-15 seconds to bleed off the fuel pressure in the lines before you take the fuel lines off. Unless you want a bath in gas.or maybe you do?? if you do take the lines off while under pressure and gas goes everywhere guess that tells you that it's not a fuel supply problem. I have done that before but held a rag over the end of the hose to limit how much gas sprayed everywhere.
The odds of your filter being plugged up will be very low.
The odds of your filter being plugged up will be very low.
05-27-2011, 02:39 PM
#8
Grumpy & Helpful
Join Date: Sep 2006
Location: Mill Creek WA
Posts: 1,415
fuel temp sensor makes no noticeable difference in how the car runs. run a check on your fuel pressure that will really make a difference. fuel filter is cheap and they do plug up. fuel pressure regulator can cause problem will be shown by fuel pressure test as will a bad fuel pump. My faith in the codes is like zero I have never had any help from them in diagnosing problems. If you can get it running run a vacuum check. air intake leaks are the bane of an FI engine. 160K. have you replaced your timing belt?
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