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Car starts hard on cold starts only


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#1 SySTeMaT1c

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Posted 13 July 2012 - 04:38 AM

Hey guys I have an issue,

My car starts hard (as in cranking over for a while and bogs down at start, and it's not cold outside, it's summer, lol) on the first start of the day when the engine is cold. It does not do it when warm, although i can smell gas sometimes when starting it warm. After it starts hard though, it clears up and it seems like there are no issues what so ever with the car when driving. I have no idea where to start on an issue like this. 134,XXX miles, maybe the fuel pump is going?

I put my scanner on it and I have no codes at all.

EDIT: Forgot to add, I have no SES light

Thanks guys!
Shea

Edited by SySTeMaT1c, 13 July 2012 - 04:40 AM.

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1996 Pontiac Firebird Y87: 3.42 Posi W/ Auborn LSD, 14.4:1 steering, Rear Disc, 275/40r17 Tires, WS6 T/A Wheels, AVS Tailshades



#2 98firebird

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Posted 13 July 2012 - 06:05 AM

Hey Shea, check this thread out, it should give you some good leads on diagnosis. http://www.firebirdn...184#entry808184
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#3 Injuneer

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Posted 13 July 2012 - 08:42 AM

Use your scanner to see what the coolant temp sensor says the temp is when you try to start it cold.

Engine off - check the fuel pressure after the pump primes, then shuts off. Watch how fast the pressure drops after shutoff.

Does the engine start any faster cold if you put the accel pedal on the floor before you turn the key to start, and hold the pedal on the floor until the engine starts?

Does the engine start any faster cold if you cycle the key on/off a few times before trying to start it?
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#4 djfirebird93

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Posted 13 July 2012 - 09:35 AM

Sounds like you may have a fuel pressure issue. As Fred said, check the pressure first. That will give you the best indication if there is a fuel related problem.
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#5 brarei200

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Posted 14 July 2012 - 01:45 PM

Is this a good tester?

http://www.ebay.com/...15ebac6&vxp=mtr

http://www.ebay.com/...9e1d89b&vxp=mtr
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#6 Injuneer

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Posted 14 July 2012 - 04:27 PM

The first one (Actron)is the only one to consider. Appears to have the correct fitting to connect to the Schrader valve, and has a button to relieve the fuel pressure. No idea of the quality of the pressure gauge itself, but most Actron stuff is decent.
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381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor 0.78:1 O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor

#7 GaryDoug

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Posted 14 July 2012 - 06:32 PM

The first one says it for TBI vehicles that do not have the fitting on the fuel rail. The one I bought that works on my 98 (cheapo one, can't recommend it really) says it will not work on TBI GM cars. Must be a different fitting? Or maybe an adapter is included?
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#8 Injuneer

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Posted 14 July 2012 - 07:38 PM

The "adapter" for TBI converts a non-Schrader valve fitting to the -4AN configuration of the Schrader valve, so the fitting that is in the end of the hose will screw onto it.

•Large easy to read 0-60 psi scale
•36" flexible connection hose
•Adapter fitting for GM TBI systems
•Solid brass fittings
•Pressure relief valve for safe, clean testing
•Instructions in English and Spanish
•One Year Factory Warranty


An alternative would be the Actron CP7818, without the adapter.
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#9 SySTeMaT1c

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Posted 17 July 2012 - 04:22 PM

Use your scanner to see what the coolant temp sensor says the temp is when you try to start it cold.

Engine off - check the fuel pressure after the pump primes, then shuts off. Watch how fast the pressure drops after shutoff.

Does the engine start any faster cold if you put the accel pedal on the floor before you turn the key to start, and hold the pedal on the floor until the engine starts?

Does the engine start any faster cold if you cycle the key on/off a few times before trying to start it?


I can't find coolant temp on my scanner's live feed. (It's not an expensive scanner)


I don't have the proper tools to check fuel pressure, maybe I could get it in sometime or order the tester and do it myself, but I have no idea what to order.

Yes, it does start faster if I put my foot on the accel pedal.

Yes, it does start faster if I cycle the key on/off.



Thanks for the reply's guys!
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#10 brarei200

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Posted 17 July 2012 - 04:25 PM

I think if you cycle the key its priming the fuel pump multiple times?
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#11 SySTeMaT1c

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Posted 17 July 2012 - 04:36 PM

I think if you cycle the key its priming the fuel pump multiple times?


Idk man, but it works. Maybe I have a loss of pressure in the fuel system before startup and that helps build pressure? Definitely not a guru here though, just taking a guess.
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#12 brarei200

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Posted 17 July 2012 - 05:49 PM

Idk man, but it works. Maybe I have a loss of pressure in the fuel system before startup and that helps build pressure? Definitely not a guru here though, just taking a guess.


Mine does the same thing lol
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#13 GaryDoug

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Posted 17 July 2012 - 06:24 PM

I can't find coolant temp on my scanner's live feed. (It's not an expensive scanner)


It may be abbreviated "ECT".
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#14 SySTeMaT1c

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Posted 17 July 2012 - 07:23 PM

Mine does the same thing lol


Your car starts hard cold also Brandon?

It may be abbreviated "ECT".


Thanks Gary, I'll look into that tomorrow as soon as I'm off of work
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#15 SySTeMaT1c

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Posted 23 July 2012 - 05:00 PM

Okay, so my scanner read 86 degrees F engine coolant temp on a cold start yesterday, and that was in fact the temperature outside. Then after that it just slowly started to climb after the engine was warming up.

Thanks!

Edited by SySTeMaT1c, 23 July 2012 - 05:14 PM.

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#16 brarei200

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Posted 23 July 2012 - 05:21 PM

Your car starts hard cold also Brandon?



Yeah, only if I don't prime the fuel pump 2 or 4 times lol
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#17 brarei200

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Posted 13 August 2012 - 01:29 PM

Did you ever figure this out?

I replaced my fuel filter and it starts a lot better now!! Black fuel was coming out of the fuel filter, no wonder it started hard, try and replace yours!
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