for as long as ive ovned my iroc it has had an extended crank before starting. if it sits for a long time (weeks, months) it most of the time starts right up but if i let it sit over night its the biggest pain in the *** to start, and sometimes if it sits for a couple hours it starts right up, it dosent seem to be too picky. anyone else had this problem? its kind of annoying and embarassing not to mention the valve seals leak so it smokes like crazy too when it starts. i was thinking that there could be a build up of carbon on the back of the valve because of the leaking valve seals and it restrict the flow but it runs great once it starts. any ideas thanks!
*eric*

 

I have a similar problem. I got a fuel pressure gage and my fuel pressure drops too quickly after turnoff. I belive I have some leaky injectors or a bad regulator.


When its cranking and cranking, if you push the throttle half way to the floor, will it start up then? If so, I read this means your engine is likely flooded with fuel, and pushing the throttle cuts off the injectors while cranking. If I do this with mine when its cranking and cranking, it starts right up.



Mine will start awsesome if it has been sitting a day or two. But If I start it anywhere from 30 minutes to 8 hours after running it, it starts like crap.


Heres a pic of my fuel drop off.....

http://users.adelphia.net/~coolj88888/pressure.jpg

 

yeah i have noticed if you hit the throttle real quick while cranking it does seem to start easier... and when i had a fp gauge on it it does drop kinda fast... are the injectors cleanable?

 

I am sending my injectos to rich@crusinperformance for him to clean and flowmatch them. He told me if a few of my injectors are leaking because they are dirty, he can fix them. But if they leak because they are broken, Id have to buy replacements.

 

hmmm ill have to look into that... so that is probally the problem then, it cant be leaking too bad though because im getting 24mpg city and 30mpg hwy...

 

You could run your car, turn it off, and pull your plugs to see if they smell of raw fuel too.

 

they make this cleaner in a pressurized bottle....and you hook it up to your fuel rails...and then you run the engine for like 15 minutes off the bottle, and it is a really concentrated cleaner, and it does a great job of cleaning up the injectors...I forgot the name of the stuff, but its abotu 15 bucks, but you need this pressure regulater thingy to use it...We tested it out in autoshop at school the other day and it worked like a charm. i think you just need some deep cleansing, it doesn't sound like they are broken just yet..

 

i think i know what you are talking about, was it a company called bg products... ill try that because i know a dealer of their products

 

my car did the exact opposite. in the winter when i let it si for a few days. when i went to start it it would start then cough and gag for a couple of seconds before stalling. if you pressed the gas it stalled quicker. second time it would fire up fine. now since it warmed up a bit all it does is drop a few rpm but dosent stall. i think it has something to do with my 9th injector. as for your cleaning needs i have an easier solution, i didnt think it would work myself but pour a cup of methanol in your motor. its the same stuff in the injector cleaners but concentrated and much stronger. i poured in 2 cups and literally heard my miss go away cleans the fuel system out greatly and the plug tips to. try it (somebodys gonna argue my point, but fact is we use it at my job for home fuel oil and it works wonders we added it for a problem sludge oil flow, we come back a year later for the annual service and the oil is clear. fuel oil is some thick dirty **** and if it can clean that itll do wonders in your fuel system. also raises your octane as well) give it a try, as for your leaky valve seals befor eyou dig into the heads give valvoline max life a try with that lucas oil additive, cheap try so give it a whirl, let me kno whow it works, i personally approve of this . worked wonders on my car.

 

You would also need to disconnect the fuel pump for this thing to work. In any case, taking them out for testing would tell if the injectors were good or bad and what they flowed. One might need more cleaning than the other or the filter might be full of debris that won't dissolve.

 

I am having a similar problem with my F body. I changed from a 305 TBI to a 350 TBI, and ever since then, it has taken a long time to start. Usually around 3 seconds. I have installed the 350 throttle body with the bigger injectors. I think it might have something to do with the PROM not letting the injectors fire long enough. Any ideas?

Also, I did happen to run it out of gas once, and now every once in a while, after the car has been run for a while; if I shut it off and then restart it, it tries to die as soon as I put it in gear. It idles around 300-400 rpm, drops and if I feather the gas for a minute, then it picks up again.
The only other symptom that I have noticed; is that every once in a while, when I go to put gas in the tank, the cap does not always hiss when I take it off.
People are telling me everything from replacing the fuel pump to the injectors. I have already had the TBI apart and cleaned everything. I also used Wynn's fuel injection cleaner.
My next step before replacing the fuel pump is to replace the fuel filter again. I replaced it once right after I had swapped the engine, but not since I ran it out of gas.

 

breakthelawinaz-

It's normal for pressure to drop off a bit over a few hours, and can drop to zero overnight.

Also there is a check valve in the fuel pump that keeps the line primed when the pump isn't running. If it's a faulty valve it can cause extended startups after the car has been sitting awhile because the fuel is draining back into the tank. Otherwise it's not a big deal and doesn't affect performance.

There are a couple of quick tests you can do to isolate a bad regulator, leaky fuel injectors, or a faulty fuel pump check valve, without taking apart the car.

To see if you have leaking injectors, pressurize the system. Clamp off the rubber pressure line and return line in the engine bay and see if the fuel pressure drops. If it drops off you can assume the injectors are leaking since the fuel has nowhere to go (unless you have a leak somewhere).

If your injectors aren't leaking, remove the clamp from the return line. You may have to repressurize the system if pressure has dropped off some. If pressure drops fairly quick then the regulator is bad....fuel is getting past the regulator too quick.

From the sounds of it though, you might have a bad coolant temp sensor....maybe incorrect temp values vs. resistance. The ECM uses the CTS values during startup.

 

I agree with everything iroczz3 says. If you want to see which injector is leaking, take the plenum and runners off, then the 4 bolts that hold down the fuel rails. Pressurize the system (don't start car) and gently lift the fuel rails and injectors. The leaky injector or injectors will be dripping.

 

So how do you test the CTS?

 

if you want your injectors serviced right and have the flow rates 3% of each other i would send them to: http://www.cruzinperformance.com/ Rich recently did my 19 SVOs. i couldnt imagine dropping injectors into a fresh motor and not having tem flowed and matched. he will be able to tell you which ones are bad, leaking, not up to teh correct ohms and so on.