No power and engine pinging at acceleration

THOMAS H

MEMBER
1995 MERCURY MYSTIQUE
110,000 MILES

I have a 1995 Mercury Mystique GS, 2.0l engine I got the car with a blown head gasket after replacing the head because it was damaged and the gasket, the car starts and idles good, as soon as you put it into gear it runs rough, when pressing the accelerator it has no power, and the engine pings, the car acts like it is starving for fuel, and drives like you are starting off in 5th gear. Once the car gets moving down a hill it shifts through its gears and reaches adequate speed, as soon as you reach an incline it looses all power and pings as it climbs the hill at 10 to 30 mph depending on the incline. I have replaced or tested the following parts.
Torque converter replaced, cat convertor not clogged, ignition coil replaced, plugs replaced, map sensor replaced, fuel pressure tested and stays at 37psi to 40 psi, fuel filter replaced, ECU replaced, MAF sensor cleaned, EGR valve seems to open and close. I am at a loss and can not figure out why it is acting like this and am tired of guessing, oh and I have redone the timing more then once and also replaced the injector wiring harness due to wires cracked from previous owner over heating it so bad, compression tested good in all 4 cylinders does not smoke, does not loose water or oil, plugs look good after running the car, the car still over heats or the temp sensor is bad, have not checked the water temp but it shows on the gage that is is right at the red. Any suggestions would be great Thanks

5 Replies

CJ MEDEVAC

MECHANIC
11,004 POSTS

I SAW YOU HAD BEEN WAITING FOR 4 HOURS

IMMA JEEP CJ KINDA GUY.I AM PRETTY GOOD MECHANICALLY, NEW STUFF, LEARNING AS I GO!

I MAY NOT BE YOUR "MAN", BUT MAYBE IF WE GET THINGS ROLLING. THE OTHER "COOL", "WILLING TO HELP TO THE FULLEST EXTENT", WILL JUMP IN BEHIND ME, AS THEY DO, WHEN I START GETTING IN OVER MY HEAD. SO BE ON THE LOOKOUT FOR SOMEONE DIFFERENT ADVISING YOU!

LETS DO THE #1 BASIC QUESTION. WHEN YOUR "START", DOES THE CHECK ENGINE LIGHT "VERIFY" THAT IT WORKS?

IS IT ON NOW?

IF YOU CANNOT CODE IT, MANY POPULAR AUTO PARTS STORES, WILL DO IT FOR FREE. INSURE YOU WRITE THE NUMBERS DOWN, SEND 'EM TO US TOO. (EVEN IF THE AUTO STORE GIVES YOU A DIAGNOSIS, A 2ND OPINION, FROM OUR GUYS, MAY BE DIFFERENT)

HAVE YOU REMOVED AND CLEANED THE IAC. IT'S SORTA LIKE THE IDLE CIRCUIT ON A MODERN CAR (I'M MORE INTO, STUFF WITH CARBS)

KEEP INFO FLOWING. WE'LL GET 'ER DONE, EVEN IF I HAVE TO GO KNOCK ON A FEW DOORS HERE!

THE MEDIC

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Sunday, August 21st, 2011 AT 2:02 PM

THOMAS H

MEMBER
3 POSTS

Yes the check engine light works and if I unplug the oxygen sensor or the mass air flow sensor I can get codes but with nothing unplugged it shows no codes or does not come on, so the car is not throwing codes. And the idle air control valve was replaced sorry that was the one I couldn't remember.

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Sunday, August 21st, 2011 AT 5:21 PM

JDL

MECHANIC
16,098 POSTS

Did you do a compression test? Pinging is preignition. Can you check if the system is running rich or lean?

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Monday, August 22nd, 2011 AT 3:30 PM

THOMAS H

MEMBER
3 POSTS

The ignition timing is set perfect have done it at least 3 times to make sure, compression test was either 150 or 180 psi in all cylinders, car seems to be running lean, I am not sure if it is but it seems to be starving for fuel. Would lack of fuel cause a ping?

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Monday, August 22nd, 2011 AT 4:37 PM

JDL

MECHANIC
16,098 POSTS

With dis ignition, you can't set spark timing. Yes, being lean can cause it to ping. Have you tried a higher octane gasoline? The info I looked at showed an octane adjust plug, I can't say that removing that plug will help? I don't know enough about a mercury.