Ehelmsin

About a year ago I helped my friend put a tpi (out of an 87 iroc) into his 77 camaro. It has a 350 crate engine. We got a custom chip, a painless wiring harness, and new sensors. The problem started about a month ago. The car has to crank for 10 seconds (while pumping the gas) before turning over. When it does start, it idles REAL low and slowly comes up to stable (that takes another 10 seconds.) Once it is stable, it runs great. Any ideas????!!!
Thanx!

Rob P

iTrader: (1)

Have you checked sensors? Sounds like something is taking time to either heat up or provide the correct data to the computer. Sounds like it could be either an O2 sensor or the CTS.


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Rob P
89RSconvtZZ4TPI
92Z28convt5spd
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RP1987GTA

1st step ...fuel pess.ck ....2nd ck for spark ...then if these ck out its time to ck the IAC and computer

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87GTA,350,Auto,MAF screens removed,195 thermostat,cold start injector UNPLUGED,K&N,modified air intake,ADSchip,3:73s,3inch cat back Flowmaster single outlet,TPS.54,Bosch Plat plugs,base timing 6BTDC,22 MPG and runs like a bear,Bilstiens in the rear....,don't let yer meat loaf

Blade

If it takes that long to start I think it's the IAC. A good idea would be to take the TB off and clean out all the passages real good. Also unscrew the IAC motor and clean it really good. It was a night and day difference when I did mine...

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92 Z28 L98 350
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Ported and polished heads, ported stock TPI base, ported plenum, Comp Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation 110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster catback with LT1 style tips, MSD coil & wires...

"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)

88FormulaWS6

definitely check the sensors, thats where it should be. tpi should never hesitate like that if anything tpi starts and the idle is hight to start while the computer does all its checks....

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88 Firebird Formula WS6
305 TPI 5 speed
B&m Ripper shifter
MSD Blaster coil
TPIS airfoil
Hypertech fan switch
TPIS 170 degree thermostat
3 inch flowmaster exhaust
alt +crank pulleys
....times to race and see

Ehelmsin

Does the computer use the sensors to start the car? I would think it just has a default "start" setting. Plus once it starts running it runs fine, so I would think the sensors are fine.

GMTech

My guess would be a leaking injector. When you first hit the key, the 2 second fuel pump prime engages. So before the engine is even crank, fuel would be going into the intake. So now the engine is partially flooded and pumping the accelerator cable is allowing more air into the engine helping alleviate the flooding condition. Once the engine is started, it idles low untill all the excess fuel is burned off. It runs great afterward, because the effects of a leaking injector won't be felt, since it is already spraying fuel. Sound like a possible scenario? A quick check with the fuel pressure gauge will help with that. Good luck

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Savannah, GA
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Ehelmsin

That sounds right, because there is also a strong gas smell in the exhaust once the car starts. I can check the pressure, but what should it be, and what will it be if the injector is leaking? Thanks

Yelofvr

Fuel pressure should be around 42-45 psi with the engine off and key on. The fuel pump will run for about 2 seconds and shut off. When it shuts off the system should hold the fuel pressure. If the pressure falls, you are losing fuel through an injector OR somewhere else, fuel lines, filter connection, etc.

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Dave Zelinka

John Millican

iTrader: (1)

The computer does not use the sensors in open loop mode which is where your engine is untill it warmes up then it goes into closed loop mode. Some exceptions are the idle sensors like the IAC and TPS.




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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup.