This may be normal but, I seem to remember my old 91 rs 305 tbi starting better. When I cold start my current 91 rs 350 tbi it will crank over several times before starting (3-5 seconds). The 305 tbi that was in the car prior to the swap also did the same. The motor(s) run fine after starting with absolutely no problems at all. The cap, rotor, plugs, wires are new. Is this normal or is there a possible fuel filter or pump issue? This really isn't that big of a deal it just irritates me. Thanks for any suggestions.
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Timing is also dead on 0 deg. TDC

 

i need to say i'm having the same "problem" with a 70kmls L03 here. i just got used to it, but it's true. it definately needs some time cranking it up from a cold start. i know it needs some new ignition parts, but seems like that's not the main issue when this is the case for you as well.. i also just changed oil+filter so it's most likely not the oil pressure switch that's keeping it from starting after the first turn.

 

I dunno, maybe its taking a few seconds for the fuel to get up there. Try turning the key on and waiting a few seconds and then trying to crank it over.

 

thats usually how it is with mine, but i do the samething like i did with my silverado which was tbi, i turned the key to the on position for a sec of 2 literally and then it seems to turn over faster. thats what i do, and it cranks right up. undercover is right though.

 

Bump for the same problem.

I turn the key to run untill the fuel pump is finished priming and everything else has finished, and then start it. Turns over slowly at first, especially when cold, and then starts after several seconds.

 

To make sure the fuel feed line is 'full' turn the ignition key from OFF to RUN and wait for the two second fuel pump activity to finish. Then turn the ignition key to the OFF position and wait about 10 seconds. Then do the same couple more times. That should make SURE that the fuel feed line is completely full and up to pressure. If it then starts in less time than you currently experience then the long cranking time is most likely directly related to the priming of that fuel line.

On my 1989 Camaro 305 FI Vin E (TBI) I find that it starts within about 3 seconds every time. I would say 2 complete seconds is most accurate. Anything longer and I am sure it would draw my attention. I pay particular attention to it now since I recently replaced the 1.75 inch submersed hose that connects the fuel pump motor to the hard line that exits the fuel tank. So I am really paying attention to see if everything seems to sound right.

 

I have the same issue and I believe I know what causes it. When turning the ignition on, no matter how many times, the fuel pump only runs for about 2 seconds, which means the fuel line is only pressurized for 2 seconds. I can verify this by the fuel pressure gauge I have installed. So, unless you crank it over immediately there won't be any pressure at the injectors after 2 seconds. But even knowing this, mine doesn't always fire up right away - I don't think 2 seconds is long enough. It would be nice if the fuel pump ran for more like 5-10 seconds during the start sequence.

Does anyone know if this controlled by a parameter in the ECM that can be changed when burning a chip? I also wondered if simply putting a check valve in between the pump and the throttle body to hold the pressure would help.

So why does it eventually start after cranking it longer? For one, there's an oil pressure switch that powers the fuel pump again once it detects oil pressure. Also, according to the wiring schematic the ECM is suppose to run the pump after a period of time in case the oil pressure switch doesn't. But, I don't know how long that delay is and haven't verified that it actually works that way.

 

There is supposed to be a check valve inside the fuel pump. When the fuel line is full and pressurized that volume should remain in place for some time, lets say at least 10 minutes. But tiny 'weep holes' built in the system will eventually allow that pressure to decrease as it sends fuel back to the fuel tank. If the pressure and volume in fuel feed line drops immediately I would suggest the one way valve in the fuel pump motor needs replaced. But I do not think you can replace it.

Also, to verify when the fuel pump relay is actually turned ON, I started my 1989 Camaro and let it run for a minute. I then took a voltage reading of the DARK GREEN/WHITE wire that is used to energize the relay. The voltage I found indicated that the relay was still being activated. However I did not wait say 5 minutes and check it again. One of these days I will do that. But my conclusion, based on this 'one minute wait then voltage check', leads me to believe that the fuel pump relay is energized the entire time the engine is running. And the oil pressure switch is in parallel with the relay. At this time I do not understand WHY that oil pressure switch is in parallel with the fuel pump relay. The ECM looks at the voltage on the wire that is supplied by BOTH of these. It appears to me that if one stops sending voltage and the other continues to send voltage the ECM cannot tell there was any change.

 

That makes perfect sense and explains why our cars take some cranking to get them started. That check valve in the pump is probably stuck open or its spring has failed.

 

my 89 rs tbi do the same

when I go the garage after 1 week it starts up right away , after i go for a ride and its now hot it took a bit to start and as soon it starts it puffs black smoke from the exhaust

but i noticed if i press the gas pedal to a half position and try to start up the motor its starts more quick than if i dont press the gas pedal!!

any help?

 

After I got my reman starter this issue stopped for me. Fires right up everytime. But it sounds like its a valve issue for you guys.

 

Sometimes I would turn to ON, waiting for the FP relay to kick off, bump the starter, wait for FPR again, then start. IIRC, it would start always immediately after that. It was as if I just added a bit of fuel into the manifold on the first bump, giving it a little prime.

As far as going from 305 to 350, there are setting in the ECU for SA while cranking. I have mine at 20 I believe.

It could be that there is oil seeping past the valve seals.