nick rayer

I haven't had any luck finding out why my 85 iroc takes a good 15 seconds of cranking before starting. Runs fantastic once running, but does puff black smoke, like its flooded. All 8 injectors ohm check at 17 ohms hot, and no fuel in the vacuum line for the fpr. If i only let is sit a couple minutes it will fire right up. Other than that 5 minutes, or 8 hours make no difference. It will crank for 15 seconds then fire up at a smooth 1800 rpm then drop to idle. To me it seems as though the injectors are spraying fuel like they should, but something is preventing the fire. Ignition module?

Nick

305sbc

iTrader: (3)

Did you do the fuel pressure leak-down test?

John 89 Formula

My 89 used to do that, i found if i let it crank for 2 seconds or so, stop, and crank it again it would start right up.

nick rayer

So today as I'm cruising down the highway at 70 thinking maybe I can live with the hard start, because it runs so smooth on the road, my SES light come on. Pull the codes. 34 and 42. Can this all be related and where to begin?

Nick

nick rayer

Clear the codes and drve it again, 10 minutes on the highwayand the SES light is on. Codes 32, 34, and 42!!! WTF is going on.

nick rayer

Update, got all the codes cleared, car is running fantastic. Still tough to get started when warmed up though. Same symptoms, 15 seconds of cranking, then fires up, but lots of black smoke. Most surely flooding itself. Runs smooth at all times. Injectors test at 17 ohms hot. No fuel in FPR vacuum line and it holds fuel pressure after shut down. Will start immediately when cold.

rgarcia63

Have you checked the CTS it may be telling the engine that it's really cold while still within the operating range so it doesn't throw a code.

IROCThe5.7L

Sounds like your injectors are leaking when you turn the car off. I had the same problem. Next time you try and start it when its warm, put the gas pedal to the floor and crank it. If it starts faster, you engine is flooding when your turning the car off.

nick rayer

Well I replace the CTS since it was onlt 12 bucks. No difference. Looks like I may need to dig into the injectors a little closer.

nick rayer

Well, with the rain the iroc hasn't been driven much, but there is no improvement. After the last drive I let it sit an hour and pulled a couple plugs. Both were tan and dry. Reinstalled them. Car took its usual 15 seconds of cranking to start. RPM's shot to 1800 then slowly drop to idle. When cold it will fire instantly. Still seems to me as if the injectors are spraying, but the ignition isn't firing. I can drive it to work and let it sit 8 hours and it will start hard. Drive home, pull it in the garage overnight and it will start like a new one in the morning.

Nick

y84pauloflondon

1) Do you any of you guys think he(nick rayer) should check his Cold Start Injector/Valve??? Could the Cold Start Injector be flooding the engine? Or NOT priming the engine!

2) Are codes 32, 34, and 42 still coming up, or are they gone for good? And how did you get rid of them(codes)?

rgarcia63

Holding it WOT before starting should keep it from flooding, if it is flooding removing the crank fuse will disable the Cold Start injector, or just disconnect the injector itself.

That injector is easy to remove and check for function/leakage.

nick rayer

All codes are gone. After reseting the iac and tps 34 and 42 are no more. I cleared 32 by disconnecting the battery. It hasn't came back since the cooler weather has arrived, allowing the car to run cooler. I was only getting it on the highway when hot out.
The cold start valve is a possibility I'll check out. I noticed tonight after a 10 minute drive in 40 degree weather it still happens. So the car isn't even fully warmed up.

Nick

nick rayer

Ok, took a little drive . Engine temp was just starting to warm up. Shut off and waited ten minutes. Pulled the crank fuse to disable the cold start injector. As usual 15 seconds of cranking and it starts. Put the fuse back in drive a little more shut down, wait ten minutes again. Same thing happens. If the cold start injector was malfunctioning I would think cold starts would be my issue, not warm.

Nick

MTXaudioSYSTM

i had similar issue. fuel regulator had a bad diaphragm.

y84pauloflondon

***I'M NOT 100% SURE*** But I think that the Cold Start Valve is basically a primer for start up....regardless of engine temp! Waiting those 10 mins, might be telling the ECM too prime the engine via Cold start valve, and that injector is not doing its job.

1)How does it start up for the first time of the day?
2)If you were to drive it around for a bit, get it warm, shut it off, then can you start it right away?

I don't know buddy, I'm just looking for more info to help you out!

y84pauloflondon

Can you get your hands on a Fuel Pressure Gauge.....Hook it up to your fuel rail after you have driven the car and see how much fuel pressure is lost over time.

EX. Your gauge should read about 43ish PSI at first(During Cranking). Walk away and then read gauge, lets say, 2 hours later... 38 PSI, walk away, come back 4 hours later....now at 32-35 PSI........

Well you get the idea... try the gauge!.....And post results.

rgarcia63

The Cold start circuit doesn't feed back to the ECM. It turns on once per start cycle. The injector's on time depends on the coolant temperature if the engine is at or above operating temprature it won't turn on at all. It shouldn't be a problem unless it's turning on when it shouldn't. Which is what you said "injector is not doing its job"

88formula305tpi

Like 305sbc said, i would perform fuel pressure leak down test. I had the same problem thought it was valve seals. but while I was changing my plugs I pulled out number eight and heard spraying and plug smelled of fuel. I beleive it was a TSB back in the day. Anyway I went online to www.fiveomotorsport.com and bought a set for around 250. The car was like that when I bought it 5 years ago and I must have put 30k on it starting it like that. Ran great since but now its tired. Today im tearing the engine down for a rebuild and found some problems with that cylinder scoring compared to the rest. Also found valve seals were indeed bad however never had any more smoke on startup after swapping injectors. I have all the original receipts and this was a complaint on my car since 91 with 36k miles, long crank and smoke on startup. Valve guides replaced by dealer at 36k and made no difference. Of course i found out during rebuild heads are cracked around valve guides from being sleeved.

TTOP350

iTrader: (8)

you neep a psi gauge.. you could have more than one problem also.. your fuelpump check valve could be bad, your fuel psi regulator could be bad or your inj could be leaky..
then there is the oil psi switch,ign module,coil, pickup coil and wiring. lots of things to check..
buy a factory servic manual from Helm. If they still have them. worth every penny.

norcalz28

iTrader: (13)

where is the "fuel pump check valve?"

rgarcia63

it's an integral part of the fuel pump, in the outlet port of the pump.

nick rayer

I have a factory service manual for it. Starts right up first thing in the morning. I can drive to work, let it set 9 hours and it will take a good 15 seconds of cranking. Another tip, is that after sitting for 5-15 minutes it will crank a long time and when it does fire the rpms instantly jump to 2000 and slowly drop.
I am starting to think injectors, but it runs so damn good, I hate to dig into it. Been living with it for a year. I did a fuel pressure test last year, but can't remember them. I'll get a guage and check it again.

Nick

305sbc

iTrader: (3)

Try unhooking the coldstart injector or plug off the port that feeds vacuum to the FPR to troubleshoot those.

Also follow up on those trouble codes:
https://www.thirdgen.org/service-eng...ht-error-codes

rgarcia63

I for one would like to know the results of all the suggestions that have been posted.
Can't learn from this without some answers.

88gta_hiflyer

iTrader: (1)

For what it's worth I had the exact problem. My car would fire up within a second first thing in the morning with the engine cold. Once hot, if it set for any length of time it would take a LONG time to start, unless I held the throttle open. I diagnosed the problem as leaking injectors (I could actually hear one hissing after turning off the engine). Installed a set of Bosch IIIs from southbay last week and the problem is totally fixed. I should point out that the car ran great once I got it started even with leaking injectors and I drove it that way for a year so it's not necesarily an emergency situation if your injectors leak but replacing them will take care of the problem. It's an easy job and a good opportunity to clean up your plenum and runners and throw on a new set of fel-pros.

cameo

i had the same problem and it turned out to be leaking injectors.

rusty vango

you might think about the MAF relays. I get mine from oreilleys. mine would start running stooped rich but no codes .turns out the relays were going away.

nick rayer

Well. i think I am going to set aside some time and replace the injectors. I have a couple questions though.
1. Southbay has 2 different 19lb injectors listed for my car. Is one preferred over the other>
2. Should i mess with the cold start valve while I have it apart?