Rough start after build - Performance Forum

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Rough start after build
Sunday, September 09, 2007 9:35 PM
ok this is what i have done
Weisco 10.5:1 Pistons
Weisco Piston Rings
Block Bored .020 over
Clevite 77 Main Bearings
Clevite 77 Rod Bearings
Polished Crank
Block Resurfaced
Ported and Polished Head
Valve Job
New Valve seals
Secret Cam Swap
Head Resurfaced
56 mm Throttle Body
Knife edge butterfly valve
Bomz air intake
2.3L H.O Intake Manifold (Ported and polished to match flange)
Chris Fontana adapter flange
OBX Header
New Timing chain
New Oil Pump
New Water Pump
All new Gaskets
B&M Shift kit
Computer Tuned By “shifted”
Blocked EGR Code
Removed Top Speed Limiter
Full Cat-Back Exhaust
2.25” pipes
Magnaflow Street series muffler
Magnaflow Hi flow Cat
Thrush 31” resonator

So my car struggles to start and if i touch the gas it will die or stall until the car warms up. it seems to start easy in the morning but after that if i let the car sit for a couple of hours it will struggle again. My computer was sent out to shifted to be tuned and according to him my a/f ratio is right. paul suggested bigger injectors, does anyone else know why it might be doing this? it never did this B4 i built the motor.


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Re: Rough start after build
Monday, September 10, 2007 5:54 AM
The A/F ratio's he's telling me are:

WOT: 10.5-11:1
Cruising 14.2-15.8:1, cycling

Its a bit on the rich side because its a mail order tune, and I'd rather it be rich than lean and detonate. Nothing was done to the low RPM VE table or the idling RPM table.





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Re: Rough start after build
Monday, September 10, 2007 7:39 AM
Well with stock injectors i was stil running really lean. With brown tops i was getting 14.2-15.8:1



Re: Rough start after build
Monday, September 10, 2007 6:17 PM
no one has anymore ideas ???? still think its just the stock injectors like i said before my stockers were leaning out pretty good.



Re: Rough start after build
Monday, September 10, 2007 6:27 PM
His AF ratio's are fine.

He throws cam and crank codes every so often, I'd fix those problems first.





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Re: Rough start after build
Monday, September 10, 2007 7:00 PM
no i just throw a crank code now and its only when i hit high rpm's..... i tried changing it again and it still does it, how would i go about checking my wires to see if there is a short or something?


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Re: Rough start after build
Monday, September 10, 2007 8:54 PM
we'll if he has the same comp as me then why would his stock injectors flow enough fuel and mine don't ??? Not saying your wrong Ron just wondering how his are big enough and my stockers arnt?



Re: Rough start after build
Monday, September 10, 2007 10:51 PM
Paul Tjepkes (N/A MADNESS) wrote:we'll if he has the same comp as me then why would his stock injectors flow enough fuel and mine don't ??? Not saying your wrong Ron just wondering how his are big enough and my stockers arnt?


Your stock injectors are not too small paul. On the factory tune they aren't supplying your car with enough fuel. If you were tuned they would be sufficient. You are just running the brown tops right now to suffice until you get it tuned to sexyness.



Re: Rough start after build
Tuesday, September 11, 2007 5:02 AM
Paul Tjepkes (N/A MADNESS) wrote:we'll if he has the same comp as me then why would his stock injectors flow enough fuel and mine don't ??? Not saying your wrong Ron just wondering how his are big enough and my stockers arnt?


I really can't say, but the AF numbers he told me don't lie, they are on the money. I'm not saying there isn't a lean spot that he's missing somewhere in the power band (would most likely be at torque peak), but from the information I have, his injectors are holding up against his build. PM me what it was about yours that you decided the injectors were too small... was it through datalogging?

Robert-

The crank sensor is vital to spark timing. When the crank code gets thrown, the ICM can't figure out where your engine is, so the ECU puts it into limp mode and it will run barely enough advance to keep the car running to prevent damage. The limp mode change and sputtering typically happens before the light ever comes on, since the ECU will take care of saving the engine before it takes time out to inform you about it. It will also hold limp mode into the next engine start so if you throw the crank code and then shut the car off and try to start it again with an active code, it will be hard to start. I'll see if I can dig up the crank sensor wiring diagrams to tell you what pins do what, and then you can start tracing the wiring back from there.







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Re: Rough start after build
Tuesday, September 11, 2007 12:46 PM
Ok i just thought of something. when i first got the car it ran, but would spit lots of gas out of the tail pipe. i didnt know much about fuel injected cars beck then so i started with the electronic control module. it tested bad so i replaced it and it still continued to do it so i thought maybe the ground was bad on it. i cut the ground wire coming from my ECM and grounded it myself and left the original ground coming from the wiring harness unhooked up. That didnt fix it and it ended up being a stuck open fuel injector, but could that ground wire from the harness be causing this?


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Re: Rough start after build
Tuesday, September 11, 2007 1:21 PM
If its at a ground reference different from the other ground wires then yes. There are quite a few ground wires, and you may have one grounded to a noisy spot.





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Re: Rough start after build
Tuesday, September 11, 2007 1:34 PM
i'll try fixing that tonight to see if it does anything, but as for the rough start do we know anything about that?


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Re: Rough start after build
Monday, September 17, 2007 11:23 AM
ok so my car seams to start alittle better with the Air intake temp sensor not in the air intake... i dont know if this will help or not


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