I have an 88 Iroc with a 305 tpi and it has trouble starting. It usually takes a minute or two of total cranking(no I dont hold the starter that long it is the combined time).
I think it might be the cold start valve or something, except that GM discontinued the cold start valve so I cant find one anywhere.

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88 IROC-Z 305 TPI LB9

 

u arent flooding it are you?

 

No its not flooding

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88 IROC-Z 305 TPI LB9

 

I've heard that if your fuel pump relay is going bad, it will act like that.

 

i was told the same thing too - fuel pump relay. also told that could be the erg going out, especially if it is idling erractically.

 

What's an "erg"? My friend has same problem with his Buick.

 

i got same problem with my mods aswell as new fuel pump/filter/relay, new magnetic pickupcoil and ignition control moduel, base timing @ 8BTDC new plugs/wires, new IAC and clean passeges, new EGR

for some reason though it is easyer if i hold the throttle open (donto see why it
makes a difrence on a EFI engine.

-Stell

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1988 IROC 305TPI MINT!!
Mods= Accell SuperCoil, MSD 6A, Ported Plenum, No MAF Screans , K & N, 160 Thermostat+ Temp Switch, Relocated MAT, Cold Air

 

When you hold the throttle wide open the ECM goes into what is called "clear flood" mode. I believe it then cuts back on the fuel pulse width or "lean out" the mixture.



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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, Dual IROC Fans.

http://www.sethirdgen.org/octride.htm

 

When you turn the key to "on" (but not to "start") do you hear a humming from the rear of the car? This will let you know if the fuel pump is priming properly. It's always good to let it prime first before you turn the key to start for faster cranks.



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 160,000 miles, K&N filter

 

Yeah I hear a humming comming from the gas tank. I also have tried holding the gas pedal down it doesnt seem to really make a difference.

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88 IROC-Z 305 TPI LB9, crane cam, K&N, JET chip, 700R4 with B&M shift kit <<Henry Ford was a ****>>

 

Gun,

A fuel pressure gauge would be a real help to you. You need to verify adequate fuel pressure when you turn on the ignition. This will help determine if the fuel pump relay, pump, filter, and regulator are all doing their jobs. Monitoring fuel pressure after the ignition is turned off will help diagnose the condition of the regulator and injectors. If the regulator leaks down, it takes a bit longer to get the rails up to pressure for starting. If an injector(s) leaks down, you may have flooding problems, requiring extended cranking to clear the cylinders. If fuel pressures are proper, I'd start looking at the ignition.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

I have to agree with Vader. I've been struggling with a hard starting '91 Bonneville (non-third gen, but MPFI). I replaced the fuel pressure regulator today (after replacing the fuel pump in July). It started right up the 1st try, and hasn't run better in the two years we've had it.

I don't have a fuel pressure guage, but I did know that there was no pressure at the Schrader valve right after trying to start it (and hearing the pump running like it should). For me, the regulator was cheaper than the guage, but I'm sure the guage will be in the tool box sooner or later.

 

If the pressure leaks down very fast after the pump shuts off, remember that it could also be the check valve in the pump. It's not all that common, but I have replaced a few because of it. Typically, it is an injector, but don't for get to check everything! You can check it out by pinching the supply fuel line as the pump is shutting off. If it then holds pressure, it is the pump, if it still drops like a rock, then look into it being an injector.

I also agree with checking out the ingition system, and maybe even giving it a full tune-up. Even if it has been tuned-up recently, at least check everything out, you never know what could be going bad before it's supposed to!

Good luck!

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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

My euphoria lasted about 12 hours. My Bonneville is back to its old habit, although it is at least starting every time. I had it running tonight, depressed the Schrader valve enough to get a spurt. Turned off the engine, tried immediately, nothing. I seriously doubt an injector would bleed down that quickly, and the thing runs like a champ once you get it started.

Sounds like I get to exercise my warrenty on the fuel pump. Since my right arm is in a sling until about Christmas time, we just might have to live with this for a while.

Also might be getting that fuel pressure guage sooner than I planned.

 

Are you getting any trouble codes? I just scanned the post and didn't see any mention of it so forgive me if you already answered it.

I had a very similar problem recently with a bad Coolant Temperature Sensor. Since it was malfunctioning, it did not tell the computer to add fuel via the ninth injector and therefor it took forever to start. I fixed the CTS and have no more problems. Obviously this was only a problem when the motor was cold.

 

For my Bonneville, the SES light is only on when the engine is not running. I checked for codes, nothing.

gunnman mentioned his cold start valve, but the Bonneville doesn't have one. If the CTS was causing a problem, it should also cause running problems (or set a code, like you said). But, like I said, it runs great once it starts, and no codes.