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427 FORD DYNO RUN!!!!!!!

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Big Block LS. Why not? 1 Reply

Started by John Derek Mitchell. Last reply by Chris Aug 13, 2013.

Throttle Body Injection swap to Tune Port Injection

Started by John Munrow May 23, 2013.

sbc 383 starter to fly wheel 4 Replies

Started by jay pimentel. Last reply by jay pimentel Dec 13, 2012.

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Comment by Kevin Lee on July 14, 2009 at 8:07pm
I hope I was helpful, and glad you fixed the problem!
Comment by THOMAS E EVERAGE JR. on July 14, 2009 at 10:12am
HEY I FOUND THE PROBLEM,I HAVE REPLACED THE EGR SENSOR ON THE TBI,AND PUT A NEW EGR VALVE,THE SENSORR WAS CRUDED UP WITH CARBON,KLEENED IT OUT BEST I COULD RUNS GREAT NOW!THANKS FOR ALL THE HELP,WELL MAYBE MY LUCK IS CHANGEING WITH CHEVYS,NEVER HAD MUCH LUCK WITH THEM ,I HAVE HAD MANY CAR AND TRUCKS ,BUT THE GMC AND CHEVY LINE HAS ALWAYS GIVEN ME SOME BAD HEADACHS,THANKS AGAIN FOR YOUR HELP
Comment by Kevin Lee on July 13, 2009 at 8:11pm
Not necessarily. There are default values built into the PCM in case of failure. Granted, it wont run as good as it should if it was hooked up, but it should run none the less. What does concern me that the shop couldnt establish communication with it. This could be the heart of all of your problems. Just start with the basics, and make sure you dont have any blown or missing fuses. After that you need to amke sure all computer grounds are good on the engine. One question, when you turn the key on, but dont start it, does the check engine light come on? It should as this is called a "bulb check"
Comment by THOMAS E EVERAGE JR. on July 13, 2009 at 12:10pm
WELL I TOOK IT TO A SHOP THIS MORNING TO SEE IF THEY COULD HOOK A COMPUTER UP TO IT,WELL THE COMPUTER COULD NOT COMINECATE TO TRUCK,AND ALSO UNPLUGED THE TPS AND IT STAYED RUNNING LIKE I NEVER UN PLUGGED IT?THOUGHT IT SHOULD DIE BUT DID NOT?
Comment by Kevin Lee on July 12, 2009 at 9:40pm
No problem, I didnt take it as anger. Some people like to use all caps anyway. The TPS is possible. I didnt mention it before because you said you had a misfire. A TPS would cause more of a hesitation. Just curious, before you had disconnected the MAP sensor, did you retrieve any codes from the PCM? I am sure there is a code in it for that now
Comment by THOMAS E EVERAGE JR. on July 12, 2009 at 9:24pm
Thanks,i just tryed the egr and it did not change anything,i am pulling my hair out trying to figer it out ,someone said it might be the tp sensor i guess i will just keep changing parts till it stopps,thanks for all of ur help and sorry about the capps earler i fogot it was on i wasnt upset
Comment by Kevin Lee on July 12, 2009 at 9:07pm
Fair enough, and you dont have to have smoke out of the exhaust. But like I said, unplugging the MAP is only covering up the problem, not a fix. OK, now you said you are getting a surge when going down the road? You did say you changed the fuel filter, you might have a fuel pump going out. And Thomas, I didnt say you definitely had a bad cylinder, just giving you some tips on how to test and find the misfire, and why
Comment by THOMAS E EVERAGE JR. on July 12, 2009 at 7:45pm
THANKS ,I WILL TRY THOSE,BUT I HAVE NO SMOKE OUT OF THE EXHUAST?
IT JUST HAPPENS WHEN U GIVE JUST ALITTLE GAS OF WHEN COME TO A STOP,SOMETIMES IT DIES,BUT WHEN I UNPLUGGED THE MAPP SENSOR IT RUNS LIKE A BRAND NEW SURBURBAN EXCEPT EVERY ONCE IN A WHILE IT WILL JUST DIE,BUT IT U PUT U FOOT INTO IT ,IT WILL RUN LIKE A BAT OUT OG HELL,WHEN U GET UP TO SPEED ,U CAN FEEL IT LOSE AND GAIN POWER ,I JUST DONT THINK IT A BAD CINLINDER
Comment by Kevin Lee on July 12, 2009 at 7:44pm
Forgive me, I forgot one other thing. You said the misfire happens just off idle, part throttle. Try unplugging the EGR valve, plugging the vacuum hose to it. If it goes away, the valve is opening too soon. The cause for that will be either a weak valve, or partially clogged exhaust, causing too much backpressure
Comment by Kevin Lee on July 12, 2009 at 7:38pm
OK, Thomas, that means it is a throttle body engine. Going by what you have already done, I will say there are a couple possibilities left. One, you have a vacuum leak, like a bad hose, or even around the intake manifold. I use either a can of brake cleaner or carb cleaner to spray around and see if you make a change. If not, the problem most likely is engine internal. To pnpoint the cylinder, have a friend put it in gear and LIGHTLY brake torque the engin until the misfire happens. while holding it there, you take well insulated pliers (they do make spark plug wire pullers for this) and take one plug wire off at a time. The cylinder that doesnt change when taking off the wire is the problem cylinder. The next step would be to check static compression on that cylinder. With the tester, it should be around 120 to 150 PSI. Under 100 PSI, you have a weak cylinder for sure. You can also "read" the plug from the misfiring cylinder. If it is very white, no deposits at all, it is either lean on that cylinder, (the vacuum leak) or even possibly getting coolant into the cylinder, effectively "steaming" the plug clean. If it is black, the cylinder is weak, and cant effectively burn the fuel. If it is oily, have a lot of flaky deposits, you have engine problems for sure, like faulty valve guides, or even bad psiton rings. Hopefully these suggestions get you on the right track
 

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