Chevy86 IROC-Z

iTrader: (17)

My IROC would turn on fine and immediately until a week ago. It slowly progressed. The problem is that the Camaro has a hard time turning on. I can crank it for about 5 - 10 seconds and it starts to sputter but doesn't start. Now as I crank it again, it'll sputter and turn on. Has anyone had this issue? I have a 2 year old stock coil, 21 lbs Bosch III's injectors, Durolast plug wires, AutoLite Spark Plugs, Duralast IAC valve. The IAC was loose but I re tightened it but to no avail. I turned on the IROC at night to see if there was a stray spark but nothing. All seems fine other than the hard start. Oh, the FPR is about 2 years old. There are also no trouble codes. Can it be a bad 9th Injector? Thanks in advance guys.

Timothayyy

iTrader: (2)

Check cranking fuel pressure, pump could be going bad.

SinCityLocal

I am having the exact same problem, but mine is L98 without a cold start injector.
Sometimes I have to crank, wait, crank, wait, crank, wait, crank... Oh, it started!
I have a new ignition module, idle air control valve, 24 lb. Bosch III injectors, fuel pump and pressure regulator.
My fuel pressure at startup is 40 psi.
My problem only happens at first startup, or after sitting for an extended period.
Starts and runs fine when warm.

Chevy86 IROC-Z

iTrader: (17)

That is the same damn thing that is happening to my Camaro. My FPR is 2 years old, the FP is 2 years old too. The guts of the HEI Dizzy is 1-1/2 years old. I got 21 lbs Bosch III injectors. Im gonna try a Fuel Pressure test to see if I have the proper fuel pressure. My Fuel filter is got to be atleat 10 years old but Ill see what happens when I change it. Its too hot to work outside where i live. Right now its 104*.

Chevy86 IROC-Z

iTrader: (17)

The pump is around 2 years old. I will check the Fuel Pressure levels tomorrow when I rent a FP gauge.

Stevolwevol

iTrader: (1)

Almost sounds like a relay going bad.

Chevy86 IROC-Z

iTrader: (17)

Relay?
MAF relay
MAF Burn-Off relay
Fuel pump relay
Hatch release relay
Fog light relay
A/C blower relay
Power Antenna relay

Nope. I don't think its either one of those relays. My MAF, MAF Burn-off, and Fuel pump relays are also 2 years old.

Stevolwevol

iTrader: (1)

Yeah, probably your hatch relay.

Chevy86 IROC-Z

iTrader: (17)

No time to play games. I really take things serious. So please, if your gonna post anything, please post anything that'll help with the issue at hand. Thanks.

jchaussee

Fuel pump relay could be bad. I had same problem with truck. Have to take it out and tap it to reset it. Worked. Have to do it anytime it get to hot or if it sits for to long.

Stevolwevol

iTrader: (1)

Chevy86 IROC-Z

iTrader: (17)

Im not sure if my fuel pump relay has the resistor inside. I had a similar problem with my A/C blower motor relay. It wouldnt stop when I turned off the IROC awile back. So I had to tap on it to release the mechanizm within. Some relays contain a small resistor to prevent the relay from welding itself in a close circuit. This resisstor prevents the "arching" when the relay enters close circuit. But right now its a guessing game. So tomorrow im gonna rent a FP gauge to verify that I have the proper pressure.

cliff1970

my car acted up like this for over a year. replaced everything but the motor itself. ended up being a clogged up conveter

Chevy86 IROC-Z

iTrader: (17)

The torque converter?

Chevy86 IROC-Z

iTrader: (17)

Just got done performing a fuel pressure test. For the prime, the pressure went to 49 lb. While cranking, the pressure was agian at 49 lb. While idling, the pressure was bouncing up and down at 39-40 lb. Im gonna look around to see what pressures I should have.

IROC212

iTrader: (1)

Does it hold the pressure or does it bleed off right away?
Could be a bad cold start injector...
Maybe a bad or shorted coolant temp sensor.

Chevy86 IROC-Z

iTrader: (17)

I just read my Haynes repair manual and it says that normal pressure range is 34-47 psi. While idling the pressure should drop atleat 3 - 10 lbs below the piming pressure. So with that said, I am 2 lbs over the maximum range and Im right on the money while idling. So my fuel pressure is fine. Im gonna check the resistance of the injectors later when it cools off.

Chevy86 IROC-Z

iTrader: (17)

It drops about 1 lb a second. Should I take video?

Chevy86 IROC-Z

iTrader: (17)

Funny that u mentioned the cold start injector. I was thinking the samething too. What should the resistance be on the CS Injector? I know the Coolant Temp Sensor is ok because I dont have any Troublecodes.

IROC212

iTrader: (1)

I'm not sure of the resistance, I'll have to see if I can find my shop manual when I get home.

I had a coolant temp sensor say it was at -20F when it was 80 degrees outside, but it didn't set a check engine light. Made the car hard to start, but it ran rough too.

Chevy86 IROC-Z

iTrader: (17)

I was reading another thread that starting issue can be related to a "Cold Start Injector Switch". Im gonna have to pull the CS injector and crank the engine. If there is no fuel coming out of the injector, then either the CS injector is bad, or the CS Injector Switch is bad. This sux man. The whole time I thought it was my IAC valve. But that works fine.

Tuned Performance

iTrader: (92)

The cold start switch is kinda spendy gm 14084318 acdelco 213-312. Unplug the stupid ninth injector and get a memcal from a 89 f-body

Chevy86 IROC-Z

iTrader: (17)

Well the ninth injector is around $120. Let alone that a memcal runs about $100. Also with shipping. Hell, it all comes down to about the same. Would there be a difference between a 87 memcal and the 89 memcal other than the 9th injector? I do know that the 89 spits more fuel through the injectors at start up. But what else is different?

SinCityLocal

I'm starting to think my problem is IAC, as I don't have a cold start injector.

Chevy86 IROC-Z

iTrader: (17)

My IAC was loose. So after tightening it up, I was like HELL YEAH!!! But as I fired up my IROC, it was still the same ol troubled start-up.

stealthroc89

Hmmm, plug gap, timing, is it getting a good spark? Make sure the TPS is set right and working correctly.

Chevy86 IROC-Z

iTrader: (17)

yeah im gonna do the timing, idle stop screw, and TPS voltage reset. Hopefully itll work.

Bullydawg

iTrader: (7)

My buddies Trans Am has the same issue. We replaced the Distributor, Plugs, Both Relays, Fuel Pump, IAC, Injectors, Fuel Pressure Regulator, MAF... and I am prob missing a few things... It just cranks for like 10 seconds then starts. If it is really cold though, it won't start at all. We are lost what to do. Sounds like the same issue we are having.

topless roc

I recently had a 92 RS TBI that would do similar things, long crank then rough run when finally started. In cold weather it was worse than warmer weather and it ended up being a fuel pump relay. It wouldn't start until it finally got oil pressure then it would fire the injector and start. Eventually it wouldn't start at all unless you primed it and at that point the oil sending unit had went out also, no oil pressure reading, no start!!!

Chevy86 IROC-Z

iTrader: (17)

Wait a minute!!! I could be the oil pressure unit. If there is no oil pressure, it'll will not close the circuit to feed voltage to the fuel pump. Damn. I forgot what is on that little splitter tube behind my dizzy. There is the oil pressure sending unit and something else. I just can't remember what it is. Perhaps that's the problem. There is one other way to get the engine started fairly quick, starting fluid. Works every time!

stealthroc89

Nah, I have my oil pressure sensor unplugged. Had to unplug it due to it wanting to run my fuel pump all the time. It could be different for cold start systems though.

Chevy86 IROC-Z

iTrader: (17)

. I was refering to mine. But hey, how is your pump running while on? is it hooked up to an "ignition on" hot source?

stealthroc89

LOL, funny you say that! I had just taken my harness out to replace all of the plastic conduit and fix some bad spots when the sensor went out. Theres a lot of conflicting info about the oil pressure sensor. On one hand, it's supposed to cut fuel when there is no pressure, on the other you can unplug it and the car will still run. So to answer your question, there is no splicing in my harness, thank god!

Chevy86 IROC-Z

iTrader: (17)

interesting.

Chevy86 IROC-Z

iTrader: (17)

Okay guys. I got some injector resistance results. My injectors are the Bosch III 21 lbs. So here we go....
Injector/Cylinder #

1. 15.8 ohm
2. 15.8 ohm
3. 15.9 ohm
4. 15.8 ohm
5. 15.8 ohm
6. 15.6 ohm
7. 15.7 ohm
8. 15.7 ohm
9. (Cold Start Injector) 4.4 ohm

Now that I got the resistance of the injectors, according to my TPI Fuel Injection Swappers Guide, I should have a resistance of 16 - 22 lbs. As you can see, Im just below. So should I be okay with my Bosch III injectors. Also is my Cold Start Injector at its correct resistance rating?

Chevy86 IROC-Z

iTrader: (17)

Here is a video of my start up. I recorded the fuel pressure on prime and during start up as well. Notice that it is a bit hard to start up. But Ill get another video of it starting up while "cold". Other than that, is this pressure common?

http://www.youtube.com/watch?v=E_BbCaJ43w0

SinCityLocal

Mine started just like that when cold. Once it fired up the first time, it started fine afterward... until the next cold start.

By chance, I found the solution to my problem.
I ultimately developed a misfire, and narrowed it down to an injector.
When I pulled the fuel rail up found some jellied substance in my #8 injector.
While I had my upper plenum out, I decided to install my adjustable fuel pressure regulator.
When I pulled the diaphragm out, to purge the jelly out of the fuel rail, I saw that half of the area under it was full of what appeared to be crystallized honey.(I wasn't sabotaged)
This stuff was as hard as carbon buildup on an exhaust valve.
After I re-opened the port from the right side fuel rail, and cleaned it all out, I reassembled it and she fired right up!
Been starting fine ever since!

F-body-fan

fuel pressure looks good, Is this only on cold starts?, or all the time?
I have a simular problem with my 87 that I am still working on. I unplugged
my cold start injector for testing purposes & mine sounded just lke yours when I tried to start it.

Chevy86 IROC-Z

iTrader: (17)

In order for the CS injector to inject fuel at start-up, the coolant HAS to be at 90* F. If above, the CS injector does not inject while cranking. But lately its been 100* = days and 100* nights. I did connect an extra Coolant Temp Sensor that I have in a cup of ice. It did start up right away, but I dont know if my IROC started because of the CS initiating its function. Sometimes the IROC turns on quick, and sometimes I have trouble like in the video that I provided. Other than that, a quick shot of starting fluid gets her up quick. I guess this winter Ill know for sure when the temps drop.
I noticed that you mentioned that you have an 87. Would I interest you in a copy of the 1987 GM Camaro Shop Manual? If so, just click on the 1987 below in my signature block for further details.

Tinoco17

hi did you fix the problem the same thing is going on with me

F-body-fan

Mine, I am going to have to live with as I have for the past decade
Ruled out just about everything, But I am fairly certain its fuel related. If I spray
just a smidge of starting fluid in the airbox right after I fire it cold, it will run perfect.
Cold start injector checked out fine. But for what ever reason my car doesn't get enough fuel for the first 8 seconds after startup. This only happens when its at room temperature & been sitting afor 8+ hours.

At some point I will see If I can find someone that I can swap ECM's with, just to rule that out.

camaro1185

Thats exactly the way my car acted when the fuel pump started going. The pressure would bleed off like that once I turned the car off. It ended up being a bad check ball in the pump. Replaced the pump and it has been PERFECT ever since. Although I do have a slight hard start problem, but its because my distributor is on its way out.

F-body-fan

Should the fuel pressure be higher at cold starts? I have 45psi at all times. It does bleed off pressure after the inital prime,(10+ seconds) but jump right back up to 45 the second it starts no matter if its a rough cold start or a smooth warm restart.

camaro1185

Nope, It should not be higher. It should bleed off, but not after 10 seconds. That means something is off, although I know people whos cars do that and they dont have any problems.

FWIW, my car with a new injectors, regulator, o rings, pump etc will prime to about 43ish psi and stay there after the key is turned off for a while. its down to about 25 after 1hr and damn around 5-10psi after that 2nd hr. This is on a completely stock 77K motor with just the free mods.

Prior to doing my pump, it never blead down faster than I described before, but when it started giving me running problems, thats when I notice it bleeding down about as fast as you and the OP describe.

There is a way to check if your pump is bad or on its way out, Ill have to search for it, but its something like clamp off the return line, prime your system and if your fuel pressure shoots up into the 60+ (maybe more, i forgot) range then your pump is good if not, it can be bad. I did this trick AFTER replacing my pump and got something crazy like 95PSI, then once the pump shut off it blead down to 43psi and stayed there.

stealthroc89

Coolant temp sensor will give cold start problems as stated above. Fuel pressure shouldn't bleed off too fast, depends on the pump, but it should take a while for the presure to fully bleed off. Could be a sign of leaking injectors. I solved my hard start problem by swapping distributors, got bored and figured it was worth a shot lol. Check your spark plugs and their gap, you might want to prime the fuel pump and let the pressure bleed off, so when you're checking the plugs you can see if they are wet from fuel.

Chevy86 IROC-Z

iTrader: (17)

Good point. But if the intake valve is closed, the fuel wont leak into the cylinder.

stealthroc89

HAH, I've read that a few times and never realized that, DUH!! Boy, I feel dumb for handing out advice I've never tried myself or thought through. Vacuum leaks will also cause longer start up's, my car just started doing it out of nowhere one week, as I was about to pull the CTS out I notice e line that plugs into the bottom of my throttle body had came off, plugged it in (with a drop of glue) and started right up! Nope, still feel dumb.....ugh.....

Chevy86 IROC-Z

iTrader: (17)

its not a big deal man.

stealthroc89

Oh I know, I'm still lughing at myself for it though. It's not like I suggested removing the transmission to change the fluid.

Chevy86 IROC-Z

iTrader: (17)

True that. It would of been worst if u would of said " change the spark plugs on that diesel truck".