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Technical => Engine Tech => Topic started by: massCougarxr7 on April 28, 2009, 01:19:36 PM

Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 28, 2009, 01:19:36 PM
Okay guys, My girls 88 has benn running on the hot side for a couple months, and i cant figure it out,....
Heres what ive done so far,....
New water pump
New spark plugs
New thermostat<<compression test
test results
Istarted from the front driver side,(soryy i dint look up the actual #)
 (After three turnovers)
120lbs    135lbs  <<150lbs    130lbs
150lbs    150lbs
Im thinking since the car has 158k ont the clock, that first cyilinder gasket's about to go,......i dont need to add coolant that often, but im thinking that first cylinder is leaking into the coolant causing the car to run hot,
 Another thing, if i take it real easy on the car, it stays by the "R" in normal, but highway or passing someone, will get to the edge of Hot zone,.....(when this gets clsoe i stop the car and turn it off for a bit)
Let me know what you think it could be,..... all aspects and op.'s appreciated....


P.S., fan clutch is good......
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: blackcougar71 on April 28, 2009, 02:47:40 PM
sounds like you have air the the system or your head gaskets are bad.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 28, 2009, 02:54:46 PM
yeah, i checked the rad, over and over, let it run from bone cold to normal, but i didnt get any bubbles from the rad????????? just when it got up to temp, more fluid came out,.......let it cool looked in rad had low fluid ,so i filled it again..... noticed afterward, small amount of coolant leaking from overflow jug,......????????? IDK
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: wnt2gofst on April 28, 2009, 03:20:42 PM
bad headgasket for sure....mine did the same thing:punchballs:
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 28, 2009, 03:22:07 PM
:punchballs::punchballs::punchballs::punchballs::punchballs::punchballs::punchballs:
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: thunderjet302 on April 28, 2009, 03:43:06 PM
Head gasket is screwed....
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: jpc647 on April 28, 2009, 04:58:53 PM
didn't you have the same problem on your 5.0 as well?
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: CatCarMan2012 on April 28, 2009, 06:41:38 PM
Is it running lean?
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 28, 2009, 08:52:55 PM
The 5.0 had burnt valves, my old 93 had blown both before, so if i can change that one in a day, i can do this one faster,..... and yes, i  think it is running lean, my next steps are fuel filter and then pump, it squeals sometimes.........And has a hard time shifting when theres less than half a tank,...(almost stalls between shifts)
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: Ductape91 on April 28, 2009, 09:01:34 PM
you didnt happen to check to see if your cooling system was clogging up? original rad. cap? milky  on the oil cap?
the last time i saw red (not that headgasket fix junk) on a thermostat was from the cooling system on my dads truck being full or rust.
was the sparkplug for the weak cyl. wet when you pulled it?
you sure the fan clutch is good, did you take the spring off and rotate it counterclockwise and then drive the car to see if theres a difference or did you just get it up to temp and spin the fan by hand?
i dont know about the FI ones but the CFI ones i had ran hot and lean when the EFE valve acted up, from a million different reasons at that:punchballs:
 i wouldnt just assume the headgaskets blown from what ive read here
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 28, 2009, 10:09:36 PM
original everything!!! lol but slight milkyness in the coolant but no reddish color anywhere else,.... ill flush it tomarrow... by the way ive always liked to use water inn the summer, but other people tell me to 50/50 it... is there a difference?????
But what should i make of the comp. test results????? that one cylinder is pretty low compared to the rest.....
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: CatCarMan2012 on April 28, 2009, 11:18:36 PM
I think you should always run some coolant.  I think it has pump lube in it as well as rust inhibitors.  I think you can buy an additive and run straight water.  A few people run water + Water Wetter.  Just don't forget you have water in there come winter.

Also, using distilled water is a good idea.  Tap can calcify the radiator (depending on hardness).

As for the compression test.  You can do a couple things.  The easiest is probably a leakdown test.  This is basically where you turn the engine till both valves are closed.  Then apply compressed air through the spark plug.  Then you listen for leaking.  Hearing air in the intake = Intake valve, hearing air in the exhaust = exhaust valve, air through the oil cap = rings. 

I have seen this done once, and it didn't work so well.  I think the cyl has to be in pretty bad shape for this to be apparent.

The other thing you can try is re-torque the head and see if it improves.

Lean running can cause excessive heating.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: jcassity on April 29, 2009, 04:53:13 AM
Quote from: massCougarxr7;269582
by the way ive always liked to use water inn the summer, but other people tell me to 50/50 it... is there a difference?????
QUOTE]

you shouldnt be driving ,,:rollin:

compare the boiling point of water to the boiling point of anti-freeze / "coolant"

compression says your rings are wearing,, not to shabby though.
or
headgaskets "could" need changed.


Buy a fan clutch and you will see the fix instantly.

as for the water thing,, stop doing that.  You could remove the tstat as a temporary means to not blow a hose.  You live in a pretty cooler temp area so it wont hurt anything for now.


discoloration in the coolant would tell me to be prepared to swap headgaskets soon as preventative maint.

If there is a slight but alway steamy look to your exhaust, you are probabably burning coolant.

looking at your plugs will tell the tale on the low cyl comp numbers.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 29, 2009, 11:15:50 AM
Well all the plugs probes in the middle were melted down on one side and one plug was two pieces, the inner moved around separate from the outer, the car has been runn ing okay since i chaged the plugs,.... they also had a little bit of white residue on them but not heavily,..... im going to flush it tomarrow, forgot i had to work today,.... and thanks for clearing that up,..... i wont be using water,.,. cause the tap over hereis pretty hard water,........last summer i left the coolant in it.....
And like i said,,,,, the car had about 160k on the clock,.,.,. and with a 19 yo girl driving it,,.... id bet the head gaskests are going.......  i need to get going on my h.o................ im short on time,... trying to get this welding job,.,., while i alredy gave my boss my two weeks......... ggrrrrrrr
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: thunderjet302 on April 29, 2009, 09:00:58 PM
Have you looked at the oil yet? If it looks like a milkshake it's the head gaskets.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: DVP on April 29, 2009, 11:23:55 PM
Quote from: thunderjet302;269771
Have you looked at the oil yet? If it looks like a milkshake it's the head gaskets.


That was my first thought, or thermostat
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 30, 2009, 08:54:39 AM
no milkshakes here guys,... sorry........ thats the first thing i looked into when i suspected the gaskets....i did the comp test, spark plugs, and t/s all at once two days ago,......flushing the coolant today, sooo ill get back at ya!!!!
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: Grumbles on April 30, 2009, 10:30:58 AM
The good news is, if it does end up being the head gaskets, the oil will look delicious when you drain it.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on April 30, 2009, 01:15:08 PM
No, the good news is,  replacing them will only take a day, but getting the time to have the car sit and be worked on, even for just that one day is imposssible......its providing 3 people with transport to work,...... and my xr7 hasnt even come apart yet.....
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on June 20, 2009, 12:15:43 PM
UPDATE::::: the car has been fine for a while,.....
Now the car stalls everytime it tries to shift from 1st to second, if i let off the gas pedal when it starts stalling, and very lghtly/slowly pump it, itll catch and stay running,...the car also stalls coming out of turns,......im going to replace the steering rack sensor, and then the IAC,......
Reamember its a 3.8l ls cougar 160k
Anyone think of other reasons this could happen????
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: CatCarMan2012 on June 20, 2009, 02:40:15 PM
Steering rack sensor?  I call that the driver.  What your describing sounds like a fuel supply issue.
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on June 20, 2009, 10:27:43 PM
I just changed the pump, and filter,......sometimes the car will stall just by sittting in park at idle by turning the wheel left then right,...... i also noticed that a motor mount is broke....... shes gonna be pi$$ed!!!! Its just odd, its like when the car idels down to shift, it wants to completely cut out,........
Can anyone tell me how to clean out the iac,...... maybe to see if the problem will be better????? Gonna go searchin now back in ten......
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: massCougarxr7 on June 20, 2009, 10:44:41 PM
yeah nothing so far on cleaning the IAC.....
Title: 3.8l stalling when shifts!!!! 88 merc,....
Post by: CatCarMan2012 on June 21, 2009, 02:46:18 AM
Its real easy.  Remove it from the side of the intake. And load it up with carb cleaner.  Wack it on the work bench a few times to free up any crud.

I take a little screw driver and make sure the little valve inside moves up and down freely.  It should move in one direction only and whack down shut by itself.  If you blow in one side it should let almost no air through (wait till the carb cleaner is gone).  I have tested a few this way and it seems that some air is ok.  I think the computer just learns how much to open the valve.  The one from my mustang engine wont let any air through, while the one from the cougar lets a decent whistle.  Both operate fine.

I have had success removing the screws that holds the two halfs together.  The bottom is just a solenoid and the top is just a valve.  The last time I did it, I put a little light oil in the solenoid and soaked the upper half in carb cleaner.  Be sure you put it back together clocked the right direction.

Seems to me, the only way they really "fail" is if the solenoid winding blows.  They are expensive as bawls too.