It seems like i have more power right after my car has just started while its still cold vs fully warmed up.

Is it just me or could their be a reason for this? Is the startup sequence different than after its warmed up? Such as a different fuel/air ratio while cold?

89 305TBI 700r4

Adjustable FPR
Injector pod spacer/throttle body spacer
Full emissions delete including egr
Full tune up with msd blaster coil
Headers, y pipe, no cat

 

When first started, the O2 sensor is not warm enough to provide appropriate signal. The ECM runs in "open loop" mode. The coolant sensor, at ambient temperature but slowly climbing, calls for a richer fuel mixture than would be correct for a fully-warm engine.

Between the ECM being in "open loop", and the richer mixture due to the coolant sensor, the engine can run differently when first started.

First Guess: There's something wrong with your engine/computer management, it's fixable, and I would start by connecting a scan tool to look at the data stream.

Second guess: You've screwed-up the emissions system, so you're going to find a lot of screwed-up data with the scan tool. I hope you're able to re-program the ECM to account for your modifications--or--you're going to have to fix or reinstall the emissions devices.

 

As Schurkey mentioned about the"open and "closed loop" procedure.....
If you sit in your car and start it when its cold you should actually hear and feel the car go through the "open loop" process into"closed loop".
It starts out with higher RPMs in the beginning then as the car warms up it will drop RPMs all at once. Its noticeable.

 

Most likely the ign. timing is allowed to advance more (less chance of spark knock) when its cooler.

 

Small block chevrolet engines like to run cool to make their power. I always ran a 160-170*F thermostat in my TBI and TPI engines. Even my 1997 Vortec 350 Express van I have run a 170*F thermostat in for years. When the engine heat soaks to 190*F and beyond it loses more and more power.

 

When I used to race my old TPI car I would let it get to cold temp leaving the hood open and chilling the intake with ice and run up to starting line with it in open loop and it would trip at several tenths faster when I would do this. In hot weather my car was anywhere from 2-3 tenths slower. SBCs love cooler temps no doubt.

 

What he said ^^^^

 

Yeah, yeah, yeah.

Look how the OP describes his vehicle: The poor thing has been scalped, with ZERO evidence that the control systems have been modified to account for the missing/defective equipment.

ALL engines appreciate cool intake air/fuel temperatures, the SBC is no more susceptible to this than any other engine. The problem isn't the engine temperature, the problem is almost certainly ****-poor control over fuel and spark, therefore combustion. I bet the knock sensor is going nuts without the EGR functional.

 

Ill look at getting a custom chip to make up for all this. I have one now but it was a while ago and i dont believe he modified anything to do with emissions. As far as i know it just has a timing advance curve.

So it seems like my car is performing better in closed loop since when out of closed loop my sensors are going nuts missing all the emissions equipment.

However i wouldnt call it a "poor thing" everything i removed is unecissary. It runs great just with a seeming lack of power. At the moment i do about 0-60 in 7 seconds which i dont think is terrible for a 305 with 2.73 gears.

 

Your car is performing better in OPEN loop, when it shifts to closed loop you complain about poor power.

Ummmm...no. The fact that it doesn't run right in closed-loop is evidence that there is SOMETHING WRONG, and it's not just the thermostat rating like some folks want to believe.

EGR does a great job of dampening detonation; therefore unless you've re-tuned the engine to fix the detonation caused by the missing EGR, your spark timing is probably being retarded by the knock sensor. Removing the EGR didn't gain you power, it probably cost you both power and fuel economy. This was NOT the sharpest thing you could have done.

I don't even want to speculate on what else might be screwed-up without seeing the data stream with a scan tool. There's just too many things that could be "off" to make guesses. It's going to be really hard to "burn a chip" if you don't know what's wrong in the data stream before hand.

For that matter, I haven't seen evidence that the cranking compression or cylinder leakdown is acceptable, or that the engine would pass a cylinder-balance test. For all we know, you could have leaking valves or stuck rings--although that would probably affect the engine as much when it's in open loop as it would in closed loop.

 

Ill look into putting a new egr valve on.

 

Get a scan tool on that vehicle so you know WHAT ELSE is going on. You could easily have multiple problems, fixing one of them may not make much overall difference.