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gEtYOpApiOn
01-13-2006, 11:59 PM
FIRST WHATS IN IT :

87 GRAND NATIONAL
CHAMPION HEADS
CHAMPION INTAKE PORT MATCHED TO HEADS AND PLENUM
ROLLER ROLLER T n D ROCKERS
RP309H 214IN 210EX 109 WITH A .548/.504 LIFT
STOCK TURBO
009 INJECTORS
CHIP BURNED BY FULL THROTTLE PERFORMANCE


OK CAR USED TO RUN REAL GOOD AS STOCK
....AFTER THIS GUY INSTALLED MY STUFF (HE RAN TOO :biggun: ) THE CAR NOW MISSFIRES HAS A ROUGH IDLE IT FOULS UP THE PLUGS RUNS RICH IT BASICLY PERFORMS LIKE A CRAP

I CHANGED COILS IDLE AIR CONTROL TPS INJECTORS DIFFERENT CHIPS
AND STILL THE SAME RESULT ....ANY TIPS WOULD BE APRECIATED ...

PaCemkr86
01-14-2006, 01:49 AM
is the firing order correct?

Keller
01-14-2006, 02:42 PM
May be a bad ignition module.

Does it miss at all RPMs and all the time, or only when cold, only when warm, etc.

Have any scan tool numbers? Would be good to check MAF numbers to see if there are leaks, too.

Fast_t_type
01-15-2006, 02:53 AM
Does run like a big block with a big cam at idle or does it blow black smoke at idle. These are some of the things that mine did. I check everthing. It turn out to be the MAF. I went through everthing three time over. It you have a scan tool like direct scan or some thing like that. Its the best way to check things. I hope this helps
Paul

JSAautomotive
01-15-2006, 05:56 AM
If it's the MAF, the idle should be better by disconnecting it. Black smoke is a sure rich running condition since the Buicks are MAF systems and not Speed Density. The backfiring is most likely caused after the plugs have fouled. Disconnect your coolant sensor also and see if it straightens out. When you have a large rich running condition, you need to look to the things that will address a large rich running condition as in the heavy hitting sensors in that dept (i.e. MAF, Coolant temp, Air temp, ECM itself, Injectors, leaking fuel pressure regulator into the vacuum line, etc). A sensor can fail a couple of ways. If the sensor fails by skewing it's parameters (say the coolant sensor is off by one volt, or say the MAF is outputting an intermittant 75 gps at idle vs it's normal 5-10 gps at idle) then the computer will believe the sensors output and use it's signal............... thus creating the poor running condition. OBDI computer systems are stupid in that regard. Sometimes it's better when a sensor shorts or opens, because then the ECM will kick the check engine light on and not believe the sensors output anymore and use a backup value from an internal backup table.

An easy way to check the coolant sensor is when the engine is dead cold. You intake temp sensor and coolant sensors are both negative co-efficient thermistors, so they will be at pretty much the same reading when at ambient temp. Another way to test the coolant temp sensor is to use a thermometer in the radiator and compare the coolant temp to the scanner reading of the coolant temp. Considering the coolant temp sensor is on the motor, and your thermometer is in the radiator, there will be a little bit of differential (maybe 10 degrees or so), but they should be very close to each other. Suspect the ones that are 30 and 40 degrees apart in readings.

gEtYOpApiOn
01-17-2006, 02:13 AM
So We Changed The Sensors Except The Coolant Sensor Ill Try That Tomorrow Thanks