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VACUMN PROBLEMS


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1dodge1mopar
User

May 22, 2010, 8:48 PM

Post #1 of 8 (1624 views)
VACUMN PROBLEMS Sign In

I HAVE A '93 CHEVY BLAZER S-10, 4.3L V-6 TRANSPLANT (ENG CODE=?), 4-W DRIVE, AUTO W/OD.,

I NEED A CAR BRAIN THAT CAN ANALYZE THE ASPECTS OF MY PROBLEM.

THE PROBLEM IS 2-FOLD:
1) INSUFFICIENT VACUMN SUPPLY TO BRAKE BOOSTER (WHEN IN GEAR) TO PROVIDE CORRECT BRAKE OPERATION. BRAKES APPEAR TO WORK SUFFICIENTLY-BRAKES APPEAR TO "GRAB" AS WITH NORMAL BRAKE BOOST-WHEN "OUT OF GEAR-NEUTRAL".

2) BLAZER WILL ACDCELERATE TO 55MPH WITHOUT MAJOR PROBLEMS-ENGINE DOES SEEM TO LABOR AND TRANS DOES NOT SEEM TO SHIFT NORMALLY. WHEN SPEEDOMETER REACHES 60MPH, THE TRANS WILL "KCK DOWN" INTO D-2, AS LONG AS
ACCELERATOR IS HELD AT SAME LOCATION, AND QUIT WHEN ACC'R LET UP (ON CRUISE @ 55MPH, COME TO LONG HILL, TRANS WILL "KICK DOWN"-AS NORMAL-INTO D, INCREASE SPEED BACK TO OD). WHAT IS VERY UNUSUAL HERE IS THAT WHEN THIS HAPPENS-"KICK DOWN", THE SPEDOMETER REACHES 60MPH, TRANS "KICKS DOWN" TO D-2--SPEEDOMETER WILL GO BACKWARD TO, MANY TIMES, 45MPH-WHILE AT THE "KICK DOWN" SPEED (SPEED SENSOR PROBLEM HERE??).

ONE OTHER SIDE OF THIS PROBLEM IS THAT THE ENGINE IDLE GOES TO A STALL MODE. I HAD TO DISCONNECT THE IDLE
SENSOR TO KEEP THE ENGINE IDLE UP. I HAVE RETARDED THE DISTRIBUTOR, JUST A BIT, TO KEEP IT FROM BACKFIRING LOUDLY AT START-UP AND SHUT-DOWN SOMETIMES. THIS HAS WORKED FOR THE PAST 3 WEEKS.

I HAVE TRIED A NEW EGR CONTROL VALVE-WHICH DIDN'T CONTROL IDLE OR BRAKE BOOST OR THE "KICK DOWN" AT 60MPH. THE ASST. MGR @ OREILLY'S SAID THIS WAS MY PROBLEM-IT WASN'T.

I HAVE CHECKED THE BRKE BOOST HOSE TO MANIFOLD-SEEMS OK. I HAVE CHECKED NEARLY ALL THE VACUMN HOSES -THAT I CAN SEE/GET TO-ON TOP OF THE ENGINE, AND THEY SEEM TO BE CONNECTED/OK.

IN DOING RESEARCH IN MY CHILTON MANUAL, THE DESCRIPTION ABOUT THE SPEED SENSOR MAKES SOME RELAVENT SENSE TO THE SPEED PROBLEMS BUT NOT TO THE VACUMN PROBLEMS.

I SUSPECT THE VACUMN PROBLEM LEADS TO SENSORS READING ENGINE RPM, SPEED, TIMING AND MAN APP PRESSURE WHICH , IN TURN, CAUSES THE SPEED, ROUGH IDLE AND LACK OF ACCELERATION OVER 55MPH.

DOES ANYONE OUT THERE HAVE ANY SUGGESTIONS THAT A LAY MECHANIC (WOKING ON OWN CARS/ENGINES FOR ALMOST 50 YEARS) CAN USE TO CORRECT THESE RELATED PROBLEMS WITHOUT HANDING OUT A BUNCH OF $$$$-HAVE BEEN UNEMPLOYED FOR 8 MONTHS.

THANX FOR LISTENING.

ED BASS
BOONE, IOWA


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 23, 2010, 6:25 AM

Post #2 of 8 (1614 views)
Re: VACUMN PROBLEMS Sign In

Even as old as 1993 you need to know this engine is a match and all sensors for original are in place if from another year but still bolted in.

What do you know about this engine? Miles?

Speedo I can't explain but the erratic boost for brakes is the same as it ever was. A check valve should hold the best vacuum it got till using the brakes depletes it and again replenished. Take a manifold actual vacuum reading at idle in N or P and again in D. Rev to 2,000 or so in P or N and should read about the same or exhaust restriction could be playing games.

Check for excessive timing chain lash via timing marks and crank bolt. More than 5-6 degrees of lash is about enough to cause problems or chain can jump on and off correct tooth,

T



1dodge1mopar
User

May 26, 2010, 9:51 PM

Post #3 of 8 (1596 views)
Re: VACUMN PROBLEMS Sign In

tom,

after some further inspection-for vacumn leaks- i found a wire with a broken coupler w/rubber grommet loose on right side of engne (driver side).
the wire was an open-end wire (solder-type end). upon inspection, i conclude it is the wire that goes to the "knock" sensor.

according to my chilton, "loss of the esc signal...could cause the ecm to constantly retard the est...cause a code 43 to set..." the explanation of causing the vehicle to have "sluggish performance"-which exists here-among other poor performance traits. i have a code 35 (iac is disconnected), code 43 and code 45 (os2 rich sigal).

the connector is broken to such an extent, it will not re-connect. i plan to go to a local salvage yard and find a "good" connector and wire in to existing line and purchase a new k-s.

if this cures the problem, i will get back to you.

thanx for your adviece. thanx for listening.

ed bass
boone, iowa


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 27, 2010, 1:56 AM

Post #4 of 8 (1592 views)
Re: VACUMN PROBLEMS Sign In

Great - I think you found your problem. A broken part sensing vacuum to control things would be the start of a bunch of codes and operational problems. Good luck finding a good one to replace it,

T



1dodge1mopar
User

Jul 4, 2010, 1:46 PM

Post #5 of 8 (1535 views)
Re: VACUMN PROBLEMS Sign In

TOM,

WANTED TO GET BACK TO YOU ON MY "VACUMN PROBLEMS" POST OF 05.27.2010. YOU OFFERED SEVERAL SUGGESTIONS AND I HAD MENTIONED THE EGR SOLENOID VALVE AND THE VSS. I DID ELIMINATE THE EGR VALLVE AS THE PROBLEM. I DID RETURN THE EGR VALVE AND GOT MY $235 CREDITED TO MY BANK ACCOUNT. THE CAR AS BEEN GETTING PROGRESSIVELY WORSE.

THE OTHER DAY I HAD TO DRIVE TO WEBSTER CITY (WHERE MY DAUGHTER LIVES) TO GET MY GRANDSONZ. ALL THE WAY UP THERE THE SPEEDO SHOWED 45-47mph AND I KNOW I WAS CRUISING ABOUT 55-57mph-CARS WOULOD PASS BUT, NOT GET TOO FAR AHEAD (SPEED LIMIT 55mph . AT ONE POINT, I PASSED AN 18 WHL'R AND IT KICKED DOWN TO 2nd GEAR AND WOULD NOT KICK OUT WHEN I LET UP-AS IT USUALLY WOULD. I STOPPED, TURNED OFF THE ENGINE, STARTED AND CONTINUED. I GOT MY SPEED UP TO SAME AND SPEEDO READING SAME.

I DROVE ALL THE WAY BACK TO AMES, IOWA FOR MY WIFE TO SHOP @ JCP'S. THE TRUCK ACTED THE SAME. WHEN I LEFT AMES ANDE GOT OUT ON JIWAY 30 (SPEED LIMIT 65). I BEGAN TO SPEED UP TO 55 AND KEEP SPEEDING. IT GOT UP TO 60-AND DIDN'T "KICK DOWN". I KEPT ACCLT'G ALL THE WAY UP TO, WHAT I THOUGHT, WAS ABOUT 80mphy AND BACKED IT DOWN AND SPED UP AGAIN PASSING CARS THAT I KNOW WERE DOING 70. I DROVE ALL THE WAY BACK TO HOME (BOONE, IOWA-15 M ILES). AFTER THAT IT WOULDN'T REPEAT THIS ACTION.

LAST NIGHT I TOLD MYSELF "ENOUGH IS ENOUGH". I WENT DOWN TO OREILLY'S, BOUGHT A NEW VSSL. EVEN THOUGH IT WAS RAINING TODAY, I JACKED UP THE DAMN TRUCK AND CHANGED THE VSS.

I TOOK IT OUT ON 30 FRO A "TEST". I GOT IT UP TO ABOUT 90mph WITH NO "HICUPS",, SLOWED DOWN TO 55mph AND "STOMPED " ON THE BRAKE-TO CHECK BRAKE ACTION. THE BRAKES LOCKED UP, CAUSING THE TRUCK TO SLIDE ON THE WET PAVEMENT. I DO NOTICE A STRONGER/FASTER RESPONSE FROM THE BRAKES WHEN I SHIFT INTO "N" AND TRY THE BRAKES.

AT ANY RATE, FOR ABOUT $69 USD, I CURED THE "OL' BEAST" OF IT'S TEMPORARY PROBLEMS. NOW, IF I KCAN CURE THE "POOR MPG" PROBLEM, I'LL BE TOTALLY ELATED.

I THANK YOU AGAIN FOR THE ASSISTANCE YOU OFFERED IN THE PAST. I WRITE THIS TO YOU FOR YOUR FUTURE "TROUBLESHOOTING" SOMEONE ELSE'S SIMILAR PROBLEM IN THE FUTURE.

IF I HAD FOLLOWED MY "GUT" 2 MONTHS AGO-REPLACED THE VSS-I WOULD HAVE "PATTED MYSELF ON THE BACK" AND TOLD ME: "GOOD JOB, ED".

THANX FOR LISTENING.

ED BASS
BOONE, IOWA


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 4, 2010, 2:58 PM

Post #6 of 8 (1530 views)
Re: VACUMN PROBLEMS Sign In

Just a comment on brake boost:

The booster behind master cylinder will hold and save the best vacuum it got and keep in in check. Decelerating created higher vacuum and it would have that. In P or N there's no load on engine so vacuum is higher then just in D idling. You shouldn't notice varied amounts of power assist.

The check valve in typically right on the booster in a rubber grommet. Easy to break old stuff to see if you can only blow thru it one way so another way it to check that brakes have power assist when left overnight. It should. If not it's leaking out the reserve of vacuum. You would know by holding medium pressure on brake pedal with engine off and feel it assist when engine is started if still the first try.

Loss of manifold vacuum anywhere plays games with an assortment of adjustments automatically done by other devices,

T



1dodge1mopar
User

Jul 4, 2010, 3:25 PM

Post #7 of 8 (1525 views)
Re: VACUMN PROBLEMS Sign In

TOM,

I PULLED THE CHK VALVE, TRIED BLOWING THRU BOTH ENDS. IT WOULLD NOT PASS AIR. I GOT IN, PUT MY FOOT HARD ON THE BRAKE HARD AND STARTED-THE PEDAL DROPPED TOWARD THE FLOOR. THIS MEANS THE VALVE IS FULLY FUNCTIONAL-RIGHT?

THANX

ED


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 4, 2010, 3:42 PM

Post #8 of 8 (1522 views)
Re: VACUMN PROBLEMS Sign In

The first touch/push on the brake with engine off should still be power assisted. It will be better once engine is running. If it can't hold something's not right. Perhaps the booster itself is the problem. TMK and I don't have one handy to check the plastic check valve only passes air one way. It must work in part or you wouldn't have power assist at all if it was behaving as just a plug. May require more than you can produce just blowing thru it - not sure.

I'd be inclined to get another just because and as I recall they weren't expensive at all. Heck - test one at the counter before you buy it. I get strange looks for stuff like that so go ahead and join the clubCrazy

T







 
 
 






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