Ive researched the archives and didnt quite find the perfect answer for my problem.

1) When my motor is cold after sitting all night I turn the key and she fires up instantly.

2) If I drive it for awhile and get it warm then turn off for say 5 minutes. She starts back up pretty quickly... not as fast as cold.

3) Now if I drive it and get it warm then let it sit for an hour or so, it takes 3-5 seconds to start and I normally pump the gas some then get a nice puff of burnt fuel smoke out the back.

From reading the archives is a fuel related problem. I did some tests. With a fuel pressure gauge hooked up, I turn the key on and its at 40 psi. After turning the key off, its down to 20 psi within 2 minutes.

Next, I blocked off the return line, turned on the key to get pressure and its back at 40 psi, within about 2 minutes again, Im at 20 psi.


Does this lead to leaking injectors or the pressure regulator? Or is there additional tests I should perform?

 

nice car, but i am not familar with superramm at all.

just a thought, check your ignition system.

 

Thanks, ignition is good and a complete tune-up was jsut given.. this is an ongoing problem that Im determined to solve or set the car on fire.

 

Anyone?

 

I have the same problem. i read on another post about a month ago that the fuel system may not be venting at the vapor canister. I asked how to check for this but got no response. I think the post was called "does this happen to anyone after fueling up?"

 

I had the exact same problem and it was the injectors.

 

That sounds like your injectors. If it were your fpr, pinching the return line would prevent the pressure from bleeding down.

 

Uggg, with a Superram, Im not looking forward to taking it off again. The injectors were cleaned and tested about 2 years ago. i jsut want to make sure thats the proper diagnosis before going thru all the work.

 

I had EXACTLY the same symptoms.... it is your injector(s) leaking down. The reason it gets hard to start after sitting for a period (less than overnight) is that the injector or injectors is leaking gas down into the cylinder, causing it to flood out. That is also why the fuel pressure drops - because gas is simply leaving the system and going into the cylinder.

It's a lot of work, but what I did to confirm was pull the plenum and runners (I have no idea what this will look like on a superram), then pop the entire fuel rail and injectors out - leave the whole works connected and brace it so it sits on top of the manifold. Then put a small piece of paper under each injector and turn the key on - DO NOT START. This will pressurize the system. After a few seconds turn the key off and watch what happens. In my case, seven out of eight injectors leaked, causing the paper to get wet. In a couple of instances I had pools of gas for on the paper.

I then pulled it all apart and had the injectors cleaned and flow tested and balanced and it is good now.

Good luck

Eric

 

I have this same problem and I just had my injectors cleaned and flow tested only 3 months ago.

 

Well unless another idea comes up. Im yanking my plenum this weekend. I can avoid the runners on the superram setup so its not too bad. Ill check them out.

 

Sounds like the exact same problem I have been having for a long time except now it has gotten to the point the car will not start except 15-20 turns of the motor. I am going to put in a new dist with a new pick up coil and see if that helps.
Hey Lock, could smell gas when your car was trying to start? I can, even if I do not touch the pedal.

 

I have the same problem off and on. I think what it is that dirt gets in your gas. even though it shouldn't. everytime I run through some injector cleaner it works fine afterwards.

 

I agree with Eric. I don't know much about superram, but for a standard factory TPI or V6's MPFI, when you block the return line, and turn the key to get pressure, the pressure should be 60 psi- the "dead head pressure" (or, "max pressure") of the pump. You say you're only getting to 40 psi. That fuel's going somewhere it shouldn't be- unless you didn't crimp the return line completely.

My wild *** guess as to why the car starts great when cold is because your cold start injector is kicking in, and adding extra fuel for startup. Or, the fact that, on a cool motor, a crack (such as one inside an injector?) would not be as wide as on a hot motor. Just like a crank sensor on a distributorless ignition system- the sensor can have a crack in it, and the car will run great when cold- as the motor heats up, the sensor heats up and the crack expands- and the sensor doesn't "sense" anymore.

Let us know what you find!

 

Maybe this'll help too
When I had leaky injectors if I let it sit for 30 minutes it would be a hard start. I would also smell gas AND once it started it would run like it was flooded (extremely rough).
new injectors fixed my problem.

 

What is an easy way to block the return line? I do not want to crimp or damage my hardlines. Are you talking about crimping it between the car and the take sending unit?

 

I crimped the rubber part right near the steering box.

 

Yeah. Squeeze the rubber part with channel locks or vice grips. Be careful though. I believe the stock fpr can be damaged over ~60psi.

 

As a follow up, I pulled off my fuel rail last night. Powered up the fuel pump and sure enough, I had leaking injectors. Three were leaking. One I could actually watch drip!

Off to buy new ones now. I needed bigger ones anyways. Hopefully Ill have nice clean smoke free startups this weekend

 

Does anyone have any followups on this topic? I am considering buying a set of 24lb injectors off of ebay. Does anyone know if I would have to get my PROM re-done to make the injectors work correctly?

 

Oops, I meant to come back for a final follow up. My car is running better than it ever has wit hthe new injectors, they solved all my problems I talked about in this post.

I dont know what your putting 24# injectors into... my prom is setup for 22# injectors right now but I will be changing it for the 24's I just put in. Yours might be setup for 19's though depending on what car you have.... so it may run but will probably be running rich and you should adjust it on your chip or maybe you can get by with a lowering the pressure on a AFPR.

 

hey
well you may want to run an additional test, pressurize the system and block the return and feed line, if pressure drops its the injectors, if pressure is stable and does not drop then its the fuel pump check valve that has failed.

 

24# on a 350 will work. I'm having no problems with mine. It runs a little rich but it's still better than the leaky injectors I had.
24# on a 305 is too much. You'll have to play with the prom and maybe the afpr to get them to run right.
I read on hear somewhere that the computer can compensate for ~20% diff in injector sizes. It's prolly true since I run rich but I don't blow any smoke.