This has been happening since I installed new Bosch III injectors in Sept 2011. Before I installed the injectors, the car would fire up as soon as you hit the key, in hot weather or cold.

Since the Bosch III's, about 90% of the time the car takes very long to start. I have changed nothing besides the injectors on the car. I dont believe it has anything to do with the fuel pressure regulator, fuel pressure or anything like that. The day I put the injectors in, it has acted like this. Hot or cold, so that rules out the CSI, and the pump primes with key on, so that rules out the relay.

If I shut the car off and start it again right away, or within 2-3 minutes it fires right up. Anything after 3-5 minutes, it cranks like this.

Heres a video of what it does. Click on the pic below.

 

maybe you got a vacuum leak somewhere, double check all the hoses and connectors you had to disconnect to do the injector swap.

 

Im positive I reconnected all of the vacuum hoses. The car runs great otherwise. About one time out of ten it will fire right up. Its getting embarrassing. Im ready to put my old injectors back in.

 

Sounds like a leaky new injector bleeding off pressure. Got a fuel pressure gauge?

 

Ya I could check the pressure. Could a leaky injector explain why I can fire it up no problem if the engine is off for only a few minutes?

These are Bosch III's, thought they were supposed to be a really good injector.

If worst comes to worst, I could put my original injectors back in, since I later found out that they were not the cause of my misfire issue from last year, and I never had to crank and crank with those injectors...

 

where did you get your injectors? if you didnt buy them from southbay you had to use extra O rings to make it work.

 

I got them from southbay. I noticed the issue as soon as I installed them. Long crank time like the video anytime car sits longer than 5 minutes, including next day. Car runs fine otherwise.

 

Hey Motown, sorry to hear that you are having a problem. If you think that it is injector related, send them to us. We will put them on the bench to see if there is a problem with them....no charge to you of course.
If they are good, then unfortunately you will have to search for another problem

Let us know

 

Do you have a link for the injectors you bought?

Have you verified the 9th injector is working?

Have you played with the 9th injector in any way?

 

Frank, I don't think anything is wrong with the injectors themselves, I think it's a tune issue. Some c4 vette guys were having the same long crank issue with their TPI+b3's. Since I saved my original injectors which are still good, I will put them in to see if there is a difference and send Frank at southbay my b3's for giggles.

I've never altered my cold start injector in any way.

 

Agreed completely. For giggles, which injectors did you buy from Southbay, do you have a link.

 

These are what I bought.

http://www.southbayfuelinjectors.com...o_305_TPi.html

 

Please make sure you update us...As you know I'm having the same issue.

By the way, were yours yellow like the picture or were they gray?

My misfire was injector related so I won' be going back to the old.

 

Mine are the pale yellow just like that picture. I'll be sure to update.

 

Not sure if anyone else has issues with these injectors but if they spray differently, the startup fuel tables and crank tables may need adjusted to make it work better. I know when I went from my stock 22lbs to accel 24's, my car's tune changed abit and I had to adjust a few things

If you have adjustable fuel pressure, try changing it around to see if it helps

 

Two things come to mind. If the injector connectors have rubber boots on them, pull them back and inspect the wiring. It may be deteriorated and by R&R'ing the injectors made worse.

The second item is more interesting, it may be that there is a lot of carbon built up on the back of the intake valves. The old injectors likely spray a pencil stream and the fuel bounces all over.

While the Bosch III's spray a fine mist which is quickly absorbed by the carbon. Creating the long crank times as need enough fuel to saturate the carbon before the engine gets any.

RBob.

 

sea foam !

 

carbon buildup on the back side of the valves is a possibility.
i've repaired many cold start problems caused by it using a can of BG 44K in the tank.

i noticed in your vid that the volt meter drops pretty low while cranking.
low voltage to the ECM can cause long crank times and no starts if the voltage is too low.

 

Thats funny you say this part because that is why I changed the injectors to begin with. I had multiple misses last year and changed the injectors. Turns out 5 connectors were broken internally.

Carbon on the back of the valves sounds like a really good possibility.

Voltage gets low because of all the cranking.

Thanks for the tips everyone. I may try BG44K and see what happens first.

 

I too have long start times with my B3's. However, they weren't purchased from SB. The car had all bad injectors from varnish due to sitting for a period of time. After the car has started, it will fire right up, same as OP. SB, I will be sending you a message seeing how much it'd be to get mines tested.

 

Does an engine running lean create more carbon?(probably a dumb question)
Is it possible to get that much carbon buildup after about 3000 miles on a fresh rebuild?

 

For anyone wanting an update:

I took out the Bosch III's and re-installed my OEM stock injectors. I barely engage the starter and it fires up instantly.

Keep in mind the 85's had some sort of Rochester or Bosch injector. Not the faulty Multecs like the 88+ cars had. Also my car had a 9th injector, unlike the 88+ cars with faulty Multecs. Those cars also had different computers. I think something with the newer cars with no 9th injector had different fuel tables and those cars dont have any issues with the B3's. Again, this is just a wild uneducated guess of mine.

Im chalking this one up to a tune issue with the 85 computer.

Hope this helps.

 

It's not the difference in the tune... I am running the 89 computer with the same issue. In my 85.

 

Its a tune issue regarding those specific injectors. They must not flow well at low pulse width. I had to do a lot of tuning to get mine to start quickly. Motown, glade you figured it out.