On a bmw 2000 540i im only getting 2500 rpm out of motor with full throttle n a code of p1637 p0100 where do i start checking please advise me as what this relates to.

With out see it running on a scanner. Maybe the IAC or throttle body. Does it have any codes. Did you erase codes after rebuild? Any time I do a rebuild on engines and transmission, the codes have to to erased. Other wise you are trying to run a new part on old PCM codes. Codes have to be erased.

Clean inside the throttle body and idle air control motor. Should clear it up.

Disconnect the MAF sensor and see if it changes rpm's. Pull off the big boot at the intake. Is the throttle valve wide open? If it is, the throttle body assembly needs cleaning-maybe it is stuck?
Have you scanned for trouble codes?

Without checking your car physically, its not possible to give you any idea what it could be or not

CODE P1637 - GENERATOR L TERMINAL CIRCUIT MALFUNCTION CONDITIONS. CODE P1638 - GENERATOR F TERMINAL CIRCUIT MALFUNCTION CONDITIONS. POSSIBLE CAUSES FAULTY GENERATOR WHICH IS ALTERNATOR.CHECK GENERATOR POWER FEED WIRES AND CHECK GENERATOR VOLTAGE REGULATOR WIRES FOR LOOSENESS AND DAMAGE. MAKE SURE BATTERY VOLTS ARE 12.6 VOLTS. IF BATTERY WEAK DUE BAD GENERATOR VECHICLE WONT START.

P0100 is "massair flow sensor circuit malfunction" and P0116 is "coolant temp. sensor circuit range/performance problem. Acceleration/starting issues? Replace both if the answer is yes. Great cars. The last one I drove was up armored.

E90 6-cylinder VALVETRONIC Engine This is a collection of pictures of the new upcoming 6-cylinder engine for the new E90 3 Series from BMW. It is reported to make approximately 258HP @ 6600rpm and 221lb-ft torque at 2500 rpm, a notable upgrade to keep competitive with other vehicles in this class. If the torque peak is really that low in BMW's notoriously flat powerband, it will be really fun to drive. It utilizes a new magnesium-aluminum alloy crankcase shaving off about 22 pounds. It makes 12% more power and consumes 12% less fuel. It will also be seen in the new 630Ci, X3, X5, Z4, and more. There are numerous other upgrades to this moto thanks ben

actually it works in battery. check the coil associated with the RPM meter or if your battery charge is low recharge it. You ll get it fixed :) Please rate this!!

The throttle position sensor has an idle switch in it that tells the car's computer that the throttle is positioned at idle. If the idle switch sticks in the idle position, the computer will not allow the engine to rev more than 2500 rpm. In your case, I think the switch is stuck.

First, see if you can get the trouble codes to come up. Rig a jumper wire and jump between the "T" terminal and the "E1" terminal in the car's "Diagnostics" box. It is a small black box on the driver's side of the engine compartment near the battery. Open the lid and on the inside of the lid it has a map of the terminals.

Once you hook up the jumper wire, turn the ignition switch to on but do not start the car. If there are codes, the check engine light (orange) will blink the 2 digit code. It blinks the first digit, pauses, then blinks the second digit. The code for the throttle position sensor is code "41". That is, four blinks...pause...then one blink. If this code comes up, change the throttle position sensor. (If there are no codes, the check engine light will steadily blink once per second until you turn the key to off.) Don't forget to remove the jumper wire when you are finished.

check operation the throttle control motor or cable if used ( broken /missing return spring