Hay Monsonmotors


Just keep it clean please....

Golden Jubilee
Golden Jubilee

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Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Dec 30, 2017 6:19 pm

Hay Monsonmotors

Got a 1999 SOHC Ford Explorer, Run real bad, hard to keep running in the cold (below 0) when 1st started, runs fine after a mile or so. Don't have a scanner or manual, but some are suggesting intake gaskets, Came on relatively fast. Also I think it needs a thermostat. Do intake gaskets sound like the problem? I have neither the time nor the place to do the work in sub-zero temps, so am hoping for some guidance on what to expect. Engine has less than 100,000 miles.
At 1st no CEL but is on now, which should help a bit.

Golden Jubilee
Golden Jubilee

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Joined: Fri Apr 08, 2016 4:52 pm

Post Sat Dec 30, 2017 7:57 pm

Re: Hay Monsonmotors

Hi, CB!
Gotta get that code out, somehow. Cheapie code reader, whatever.
PO171 and PO174 "lean exhaust, banks one and two" are VERY common Ford codes, for example.
Look at freeze frame in the OBDII Generic side of things. Lean at IDLE (when the computer set the code) very likely points to a vacuum leak SOMEWHERE. I usually can HEAR it. I suspect you could, too.
:)
Lean codes set at RPM above idle points to something OTHER than vacuum leak.
If the thing straightens up and flies right after only a mile hard to condemn ignition, injectors, compression, etc.
I really think that code is the key. What is it?
We see so many weird things...poor running at first start in our much warmer climate often points to a swallow of coolant past a leaking headgasket.
I've seen my share of sticking valves. Hooking up a vacuum gauge for a quick check is easy, even in those temps?
Give me more info and I'll tell you what I think.
Good luck!

Golden Jubilee
Golden Jubilee

Posts: 5170

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Dec 30, 2017 8:34 pm

Re: Hay Monsonmotors

Odd thing is a runs pretty good once warm and in "closed loop". Just my gut feeling, all symptoms fit un-metered air getting in. It was my parents car until they stopped driving last spring, always sat in a semi-heated garage in a retirement home. This is the 1st winter it sits outside. With being gone all week, I am going to have my wife drop it off somewhere and hope they are good. Just wondered if you ran across something like it, so I would know if the shop is paying attention to detail or not. I know O' Rilley's (or as some call it "Oh really?") will read a code for free. I just don't have the time or the place and the cold weather is making a "sissy" out of me.
Thanks for getting back to me.

Golden Jubilee
Golden Jubilee

Posts: 2028

Joined: Fri Apr 08, 2016 4:52 pm

Post Sat Dec 30, 2017 8:57 pm

Re: Hay Monsonmotors

I've seen things cause "open loop" problems only to straighten up in closed loop. One of those things is a wacked out fuel pressure regulator. Usually line pressure is about double the specification when this happens, something like 80psi vs 40psi.
Another thing might be the evap system adding fuel when it shouldn't. Open loop can't handle that, closed loop can. Hence the better running after a minute or so.
Pinching off the evap line will check that.

Golden Jubilee
Golden Jubilee

Posts: 2028

Joined: Fri Apr 08, 2016 4:52 pm

Post Sat Dec 30, 2017 9:09 pm

Re: Hay Monsonmotors

Forgot to mention that Ford (unfortunately) uses a FRP (Fuel Rail Pressure) sensor on some models. I don't know if yours has this. You can tell if there's an electrical sensor attached to the fuel rail.
This is the stupidest and most cantankerous system I can think of at the moment. The computer uses a fuel pump driver module to vary fuel rail pressure to the ECM desired. Another feedback circuit. POS.
Causes SO many problems.

Golden Jubilee
Golden Jubilee

Posts: 5170

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Dec 30, 2017 9:16 pm

Re: Hay Monsonmotors

WHen the problem shows, it seams much more like a lean problem than excess fuel, I may hear a vacuum leak but haven't been around it much, if it runs I don't pay it much attention. I'll let you know how it turns out, thanks again.

Golden Jubilee
Golden Jubilee

Posts: 2028

Joined: Fri Apr 08, 2016 4:52 pm

Post Sat Dec 30, 2017 9:18 pm

Re: Hay Monsonmotors

Yes, it's hard to believe that extra fuel is the culprit at 0F. I agree. However...
:)

Golden Jubilee
Golden Jubilee

Posts: 5170

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Jan 27, 2018 4:54 pm

Re: Hay Monsonmotors

Just an update: Runs a lot better now with not nearly as much stalling cold. Finely got a code reader on it and no surprise it kicked a P0174 (lean bank 2) code, Cleared the codes and has not returned as of yet.
Only other code was a B1869 (SRS indicator) , but it works on "prove out" when the engine is started, So don't know if that is an old code or not.

Golden Jubilee
Golden Jubilee

Posts: 2028

Joined: Fri Apr 08, 2016 4:52 pm

Post Sun Jan 28, 2018 7:46 pm

Re: Hay Monsonmotors

Next time before you clear codes go to "freeze frame" and write down all the info. Once you clear codes all that info is erased.
Reason is...PO174 set at, say 2000 RPM is probably not a vacuum leak.
Most "lean things" that affect the entire engine shouldn't set a lean code for one half of the engine. There should be a P0171, too. Perhaps it just is a bit behind bank two. That's when you need to take a look at LTFT long term fuel trims for bank one and see if it's on the brink of setting a P0171. Like plus 10 or more added fuel.
Ford is notoriously slow about setting misfire codes. "Mode 6" in the OBDII generic side of things can help find a misfiring cylinder that hasn't set a code. "Hexadecimal $48" or $52 is where you look. You can tell you are in the right section when there are the same number of entries as there are cylinders.
:)
Good luck.

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