warm engine = hard starting? Just started today...WTF??? - TCCoA Forums
 
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post #1 of 21 (permalink) Old 12-25-2003, 12:08 AM Thread Starter
 
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warm engine = hard starting? Just started today...WTF???

Ok, so my 95' 4.6 normally takes 4-6 seconds to tstart in the morning (Temps around 18), anyway, once she has been running for about 5 mins, I can turn her off and she will start no problem...well, today, it took at least 2 tries...First one she was turnin' over for 10 seconds, I waited 5, and then she started after about 8 seconds of turning over the second time. <--this not normal, wheather hasn't changed much). we let her warm up and drove to the store to get a few items, and after being off for only 10 mins, again, it took 10 seconds of turning over before she stated. Heather told me that this JUST started happening today...It runs fine once it is actually running, can't really prove acceleration (Due to the solid sheet of Icw we are driving on), but we can drive her fine and she idles fine, etc...Any ideas??? I was thinking plugs...could that be the prob? I put platinums in the about 15K miles ago. Other then that, it has a new are filter, MAF just cleaned, and fuel system just cleaned too. I don't want the bat to go dead during the winter, so ANY help would be great! AaronT, ever happen to you? The '94 is out in the same weather, and she takes about 4 secs to start!

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post #2 of 21 (permalink) Old 12-25-2003, 06:18 PM
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Man that sux.
Never had any issues with starting, even without pluggin it in (the 95'). Before I bought the 95' it had sat for about 3 months I think, and it started right up.
With it idling and running fine that's weird. As for the plugs I would change them anyways cuz platinum plugs are only good for longevity anyways, and "bad" for performance. Just get some Motorcraft coppers.


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post #3 of 21 (permalink) Old 12-25-2003, 11:58 PM Thread Starter
 
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I used some of that chevron w/ techron sh*t...I tried it this morning, but in stead of just putting the key in and starting it, I put the key in, and turned it on for like 2-3 seconds (You know the point right before starting), and then turned it and it took not even 2 seconds to start up...WTF? Maybe it is that time of the month for her or something, but it still doesn't seem normal to me :-?
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post #4 of 21 (permalink) Old 12-26-2003, 12:44 AM
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the two things most related to startup problems we see around here are IAC and Crank Position Sensor... to me this sounds a lot like a funky Crank sensor, but these things are hard to tell.
My IAC has been acting up recently (frozen? lol), time to clean it up again soon...

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post #5 of 21 (permalink) Old 12-26-2003, 12:47 PM Thread Starter
 
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IAC huh? And that would just cause diffuculty starting and not rough idle? Hmm, I'll check it out. Yesterday she started fine, as well as this morning...Hmmm, I'll keep an eye on her and see if it fixed itself, whatever it is, it is intermittent...

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post #6 of 21 (permalink) Old 12-27-2003, 01:38 AM
 
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Maybe the coil is going bad? They act weird when hot when they start to go.
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post #7 of 21 (permalink) Old 12-27-2003, 05:04 PM
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Test your static and running fuel pressures too. I had hard starting problems which caused by and eventually boiled down to a fuel pump failure.
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post #8 of 21 (permalink) Old 12-27-2003, 09:24 PM Thread Starter
 
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wouldn't that lead to poor topend though and loss of performance? the fuel pump that is?
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post #9 of 21 (permalink) Old 12-27-2003, 10:11 PM
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Well when my fuel pump was weak it started with hard starting then intermittent dying near idle and eventually stuttering of the engine.

I checked the fuel pressure and got fluctuating 20-30psi at idle and had to keep revving to keep the engine running. It probably was running lean intermittently.
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post #10 of 21 (permalink) Old 06-09-2008, 09:29 PM
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What is the IAC?

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Originally Posted by Silver95Bird View Post
the two things most related to startup problems we see around here are IAC and Crank Position Sensor... to me this sounds a lot like a funky Crank sensor, but these things are hard to tell.
My IAC has been acting up recently (frozen? lol), time to clean it up again soon...
What is the IAC? Is this like the EGR or ? Where is it on the 4.6? It's about the only thing I haven't changed for my hot hard starting issues I've had for 5+ years now. Starts fine cold and fuel pump pressures are fine. Just passed smog, no check engine light and no performance issues. Just won's start hot worth a darn. I have changed the fuel pump, filter, plugs, engine temp sender, position crank sensor and still nothing. Maybe the IAC is the culpret, whatever that is???

Thanks, Phil

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post #11 of 21 (permalink) Old 06-09-2008, 09:34 PM
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holy thread resurrection!

the IAC on the 97 is on the front of the elbow/plenum with a plastic box going to it from the intake tube.

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post #12 of 21 (permalink) Old 06-09-2008, 10:01 PM
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Iac

What does IAC stand for and what does it do?

Thanks, Phil

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post #13 of 21 (permalink) Old 06-09-2008, 10:09 PM
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Idle Air Control, in its simplest form it lets air into the motor during idle so it doesnt stall.

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post #14 of 21 (permalink) Old 06-10-2008, 08:45 AM
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If this idle air control (IAC) was acting up, wouldn't the idle be messed up and the check engine light come on. It just passed smog perfectly but won't start hot, only cold. Also idles perfectly.

Phil

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post #15 of 21 (permalink) Old 06-10-2008, 02:00 PM
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the iac will cause pulsing.. CEL may not come on

cold starts ok but warm starts are a no no?


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post #16 of 21 (permalink) Old 06-10-2008, 03:44 PM
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By pulsing, do you mean surging while at idle? Like I said, it runs perfectly, passes smog by flying colors but won't start hot worth a damn. Even the smog guy had a hell of a time getting it to restart but all ran perfectly when it started. That includes under load test. Whatever it is, it only affects starting and not running. Go figure.

Phil

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post #17 of 21 (permalink) Old 06-10-2008, 03:48 PM
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Have you checked fuel pressure at the rail when you try to do a hot restart? The fuel pressure regulator could be the culprit.

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post #18 of 21 (permalink) Old 06-10-2008, 03:58 PM
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Quote:
Originally Posted by 97Bluebird View Post
By pulsing, do you mean surging while at idle? Like I said, it runs perfectly, passes smog by flying colors but won't start hot worth a damn. Even the smog guy had a hell of a time getting it to restart but all ran perfectly when it started. That includes under load test. Whatever it is, it only affects starting and not running. Go figure.

Phil
by it's very nature.. idle air control valve... more air = more RPM... less air = less rpm

if the valve is not working right and lets in too much air then the rpm's will rise and vice versa... if you unplug the iac, the car dies.. i don't know about starting w/o it. haven't tried


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post #19 of 21 (permalink) Old 06-10-2008, 06:11 PM
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Quote:
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Have you checked fuel pressure at the rail when you try to do a hot restart? The fuel pressure regulator could be the culprit.

You're right, I need to do the fuel rail test when hot. I have checked it cold and with it running and it is within spec. I have also replaced the fuel pump but have never checked it as you said. I need to catch it when it is acting up, hot.

Yes, I have used the search engine too, in fact I have started many previous threads on the subject and have done most all of the suggestions but still won't start hot. Maybe I need to carry starter fluid and spray the intake. The smog guy told me it might even be the security system in the car. I also suspect the computer.

Phil

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post #20 of 21 (permalink) Old 06-10-2008, 07:09 PM
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Two things to try. Before trying to start the hot engine, turn the key to "ON", allow the fuel pump to prime, turn the key "OFF", then turn the key "ON", allow the fuel pump to prime again, and finally attempt to start the engine. In other words, cycle the fuel pump twice before trying to start the engine. If it starts right up without issue, I'd look at changing the fuel pressure regulator.

If cycling the pump twice doesn't bring about any change, try just barely cracking the throttle open when starting the engine (don't put the throttle to the floor). If that allows the engine to start right up, then I would recommend cleaning the IAC.

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post #21 of 21 (permalink) Old 06-10-2008, 09:17 PM
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Quote:
Originally Posted by racecougar View Post
Two things to try. Before trying to start the hot engine, turn the key to "ON", allow the fuel pump to prime, turn the key "OFF", then turn the key "ON", allow the fuel pump to prime again, and finally attempt to start the engine. In other words, cycle the fuel pump twice before trying to start the engine. If it starts right up without issue, I'd look at changing the fuel pressure regulator.

If cycling the pump twice doesn't bring about any change, try just barely cracking the throttle open when starting the engine (don't put the throttle to the floor). If that allows the engine to start right up, then I would recommend cleaning the IAC.

-Rod
Thanks for the tips, I will try these things and get back later. Good ideas that I haven't tried yet.

Phil

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