Performance questions.. (Hot vs. Cold)

[VW_Factor]

Ive never owned a car with so many sensors, etc..

Otherwise.. Something Ive noticed after having this 89 for a while..

If the engine is still fairly cool (just started moving the temp gauge), you can romp in the loud pedal and it will light up the tires.. First and second gear..

After the engine is fully warmed, into the "ma" range on the gauge of "normal" it will no longer light up the tires as such.. It requires some clutch work to light them up..

This tells me that perhaps a sensor is not allowing something to happen in the intake.. (Like the secondaries not opening, or opening too soon, allowing no low end torque)..

Is there a sensor that is normally attributed to this behavior? Or is this just something normal that this SHO motor does?

 

[yamahaSHO]

The secondaries should not be affected by temp... In fact, you should be able to hear them open around 4000 rpm.

If it is not a sensor, it could be the fact that the engine bay gets so warm, that the air in the intake heats up rather quickly and thus your lack of power.

If you want to replace a sensore, check your ETC.

 

[VW_Factor]

Forgive my ignorance.. ETC is the Engine Temp Control??? I dunno..

My neighbor works on the city fleet of cars for a living.. He was kind enough to bring and use his handy dandy Snap-On tools engine computer (it was like 8g's he told me)

(As a side note, I never knew the computers in 89 were this advanced, KOEO test his tester honked the horn, wiped the wipers, flashed lights, etc..)

Otherwise, the car had no "hard codes" or other trouble codes stored.. If there is a code that pops up, it happens while driving during warm engine operation.. The CE light never has lit in the car. Kinda just wondered if there was something that may be not out of spec, (computer wont notice) however, could cause what I have noticed..

 

[yamahaSHO]

Correct on the ETC... This one is found just aft of the t-stat... the one in front of the t-stat is for the guage... Most likely, you are losing power due to the warmer air. Where does you temp needle normally sit?

 

[AutoSHO]

Psst... guys, its the ECT, Engine Coolant Temperaute sender. 2 wires, 1" Hex.

 

[yamahaSHO]

D'oh... I was trying to do to much at once... Yes, you are correct.. You know what I mean, I have replaced enough of them wink

 

[drivinhard]

The spark map is different for cold warm up vs at temp cruise. On the WOT vs ECT table, you get 10 degrees of added spark advance at 0 degree coolant, which is ramped off to 0 degree add by 50 degree on the ECT. At 250 degree it pulls out 5 degrees.

 

[VW_Factor]

My temp gauge when I would suppose it to be fully warmed sits at the MA in NORMAL on the gauge..

It hasnt gone past this point, so I would venture, this is the reading for fully warm, and ready to go..

Just after feeling the difference in low end between hot and cold temperature, I figured something was amiss, that wasnt tripping a code in the computer.. I would figure that normally, the power output wouldnt be this adversly affected.. I much prefer more power of course.. I'll replace that sensor, and see what changes..

 

[sdpatt]

Just for the record, you can read the codes yourself with just a short jumper wire and the ignition key. You can visit the links in my signature below to learn this simple process.

Before the engine has reached normal operating temperature, the engine control system is functioning in "open loop" mode where the spark and fuel are controlled by a preset table of values or "map." In this mode, the emissions output is at its highest because the fuel mixture is overly rich (hence the power), the catalytic converters have not heated to their 850F minimum operational temperature and the signal from the oxygen sensors is not used to "close the loop" to control the fuel:air mixture at the optimum for emissions control.

On a side note, if the engine has not yet reached the normal operating range, you should not be digging deeply into the throttle. This is very ******* a cold engine when all of the parts have not reached their operational clearances and the oil is still thick with the oil pressure high.