Wasn't sure if I should post this in the engine tech or TBI....

Basically my L03 went from running great to $h!t over night. So I'll start by saying the temperature dropped well below freezing last night. When I started my car in the morning, I let it warm up for about 10 minutes. I gave it a little gas and noticed a "clicking" sound. Now I know the clicking sound is a bad lifter hitting, but it usually only does this when in drive, and never sounded as bad when in drive as it did in park this morning. I also smeeled unburned gasoline. So I put it in drive to go home, and the engine bogged horribly at anything under 2000rpm, and the lifter sounded even worse. The overall acceleration was gone as well. So I get home and check the TBI. My K&N smelled of gasoline. The TBI injectors seemed to be spraying a bit much, as gasoline was actually bouncing off the TB blades, and landing outside of the bores.
I do not have an adjustable FPR, but it is an obvious assumtion that my injectors are spaying to much fuel.
Has anybody ever had this happen to them. I would guess gas may have froze inside the injectors and messed them up, causing them to flow rich.
Could this cause my bad lifter to hit that much more?
And finally, if it is the injectors, should I get some new ones, or go with the Holley 670 for 305, or go with the one for 350s and adjust the fuel pressure?
I appreciate any help. Thanks, Roy

 

I have had simular problems...minus the clicking.

When the temps drop below freezing the combination of my 160 deg stat/Ram air (sucking in ice cold air)/aluminum intake caused me to go lean on tip-in acceleration. Also the car was never reaching operating temps so my mpg was crap because the ecm wuold be at "full choke" while I was cruising down the road. The injectors could not compensate for the cold charge because the car would not go into closed loop for the 02's to start yelling lean. The ecm was basing all its "'choke" on the coolent temp and the TPS sensor. That is why once you get on it, the TPS tells the ecm that the throttle blades are opening so it needs more fuel. It was always either too rich at idle, or too lean on tip in accel, that is why it bogs heavy. I fixed it by going to a 180 degree stat until it warms up and I go back to my open element filter when it gets below freezing.

As for the clicking, my best guess is your valve lash might need some tweeking but I'm not sure...hope this helps!

 

btw I run 12psi of fuel pressure

 

Thank You!

 

Anybody else, any thoughts???

 

sounds like it could be an injector leaking or not working properly. I've heard that the best ones are either mustang injectors or chevy replacement ones. put in the adjustable fp regulator too.

I don't think that the rich condition would cause your lifter to clack any harder, its probably just that it worked its way too far out of adjustment.

Look at the injector first, then after that pull of the valve cover and fix the lifter. You can see if the injector is leaking just by putting something under it over night, let it collect. that'll tell you if its leaking or just working improperly.

later,
mike

 

Thank You! I'll give it a try. Also, injectors arre kinda expensive ($160-$200), and I can get a Holley 502-5 for $300 new. Is there any reason I shouldn't? Thanks, Roy

 

umm.. I haven't changed throttle bodies yet, I've heard that the Holley injectors that come with the unit are junk and that you would probably want to put in GM injectors anyways. I've always said to get lower injectors (or keep the ones you have) and turn the pressure up. That'll cause the spray pattern to be better instead of a trickle you'll get a nice cone effect which will help with the atomization. I would think though that unless you were planning on changing to a 350 the holley unit might be a little excessive. The chevy unit is good up to like 330 hp the way it is. (its actually a holley unit, but GM hosed holley when they designed it) the main difference is that the Holley unit has bigger bores.

Also, check your oil, that'll tell you if you have an injector leaking since gas will get into the oil system. That could cause the lifter to make noise...

Mike

 

Well, accourding to a post on this sight, holley has been using Delphi (???) GM injectors for about the last year and a half. And I believe the 670 Holley TBI comes with an adapter to fit the 1 1/16" intake, which I would assume lowers the cfm of the 670 to that close to the stock TBI, so I hopefully won't get to much air flow. I'm gonna keep my fingers crossed!