Taurus Car Club of America : Ford Taurus Forum banner

21 - 27 of 27 Posts

·
Registered
Joined
·
9,617 Posts
Hi Jeff K (and kekaye56),
Sorry for the late post, but I just got back to this a couple days ago. As you suggested, I pulled off the IAC. It took a couple sprays, some soaking for a couple minutes, and some light brushing with soft solder flux brush (not used btw) to get the carbon/etc off.

Btw, I saw a "auto repair challenged" person on Youtube fill that plunger chamber up with carb cleaner and let is soak "for a while". I bet that solenoid is working much better (not) with carb cleaning inside of it now. Anyway . . .

My plunger is not fully seated, as seen here:
View attachment 215118
If you look closely under the plunger in the top chamber (as seen above), under the seal is a small silver/grey area in the center. That silver spot is actually the plunger shaft we see, because the seal is not yet fully seated.

We have not yet had a shopping day where we make multiple stops, so I don't know if the simple carb cleaner cleaning has fixed the sputtering hard-hot-start issue. Does anyone know if I'm supposed to see shaft under there, or is that plunger supposed to be seated in it's tapered seat?

Thanks again for sharing your experience.

Regards . . .

P.S. Nice that we can insert pics directly now with this new forum software : )
See pic, this car now at 188K looks the same. I inspect every Fall maintenance. If you see oil there, it is caused by the PCV not working right, or it is not OE part. The plunger is always open when not in a running engine. This IAC only passes filtered clean air. However is the PCV is not doing it's job, oil vapor can come back up the fresh air hose to the accordion. The accordion should also be clean and dry.

-chart-
 

Attachments

·
Registered
Joined
·
236 Posts
Discussion Starter #22
Hi chart,

Thanks for the helpful reply and sharing your pic : )

My PVC valve and hose were replaced last year when I did the top engine intake manifold and valve cover gaskets job. That said, maybe I can eliminate the PVC valve with a couple questions:

1. If it starts perfect when cold, but then has a hard start problem when it's parked maybe an hour and is still hot, could the PCV valve cause that hard starting?

2. Is there a way to test that IAC valve? Maybe remove IAC and apply 12v to one of the pins to make sure it closes/opens?

Regards . . .

P.S. I just checked for codes. I hadn't done yet since the battery has was removed last week for a recharge (after a failed hard start had drained it somewhat). No codes yet.
 

·
Super Moderator
Joined
·
7,699 Posts
Hard hot restart after sitting for a half hour or so can be due to leaking injectors or injector. Fuel system stays pressurized after shutdown for quite a while. Leaking injector(s) will drip into cylinder(s) causing a very rich condition and hard start. After a while pressure dissipates due to leaking injector(s) and slight leakage thru the anti backflow valve in the fuel pump and excess fuel in cylinder evaporates so engine starts fine when cool. You wont get any rich codes for this because it takes a minute or so for O2 sensors to heat up and become active. BTDT.
 

·
Registered
Joined
·
6,579 Posts
The IAC valve can’t be tested by simply putting 12 vdc to it. I tested for a failed one by slightly pressing the gas pedal while starting the car. If it starts then it maybe stuck closed. Also I check for fuel issues by opening the throttle plate and giving a five second shot of starting fluid, closing tp , putting snorkel back on and cranking. Also depressing the gas pedal fully will prevent the fuel pump from running to help with flooded engine
 

·
Registered
Joined
·
236 Posts
Discussion Starter #25
Hi Jeff K and Automender1234,

Great info Jeff K. Thanks for that insight into injector operation at wide open throttle (WOT). Ditto Automender1234 too for your help on IAC workings.

Unless I'm off track here, and using the info you both provided, I'm thinking a test for the "...over-rich condition when hot due to leaking injector..." might be to depress the throttle fully when I need to do a hot start, and see what happens. I'm guessing the procedure would be to turn the key to ON, depress throttle pedal fully, turn the key to START to begin cranking starting, and when it starts, immediately let off the pedal. That might confirm the over-rich condition when hot that you described. I'll try this test first as no disassembly required.

Next I could do another test for lean condition using the procedure Automender1234 describes. Some assembly required there.

I'll let you all know how this goes. The Taurus is going on a multi-stop shopping trip today.

Regards . . .
 

·
Registered
Joined
·
2 Posts
I think Jeff K is on to something. Try letting the cold engine run for a minute and shut it off before getting fully up to temp. Let it sit, maybe 10-30 minutes then see if it acts up when starting. If it does, might be injectors sticking. You will likely smell gas for a moment when you start it if this is the case.

Maybe someone can chime in with a more accurate strategy.
 

·
Registered
Joined
·
2 Posts
On second thought, considering you say that throttling it gets it to start, Automender12345 probably nailed it about the IAC sticking. Anxious to hear your results.
 
21 - 27 of 27 Posts
About this Discussion
26 Replies
7 Participants
Naughty Nate
Taurus Car Club of America : Ford Taurus Forum
A forum community dedicated to the Ford Taurus and SHO models, Mercury Sable and Lincoln MKS. Join the discussions on EcoBoost, aftermarket performance, and more!
Full Forum Listing
Top