The car starts fine but when you give it a little gas it may make it up to 2 grand and begin to fluctuate. Sometimes it will make it to 3 grand but tries to die. If you suddenly floor it it will die. If you put it into gear and try to drive it forget it. It had failed for clogged egr and egr system failure. The egr valve was pretty clogged up and the upper intake was removed and cleaned out. Now heavy vacuum from the egr port. Seemed like a vacuum leak but none was found. All gaskets that were affected had been replaced. No codes come up since it won't run long enough to set any. I checked PID data and found the Absolute throttle position value to be at 5.1%.Pressing the accelerator does not change this value at all. Ran the same test on my Mustang and a newer Kia and the TPS values would rise with the accelerator . It looked as if the TPS was no good and since Honda in all their wisdom decided to make the TPS part of the throttle body, they also wanted $400 for a new one. We tried two different used bodies but the same symptoms. The TPS value always at 5.1% and never changed. I metered the TPS and according to the book there should be a variance from .5v to around 4.5v when the throttle is open. I only get .4v to 2.24v. Someone mentioned the EGR but if that were the case it would idle badly if at all but would still be able to increase rpm's. The IAC was completely cleaned out. I am going to try to meter the IAC tomorrow but I am not going to hold my breath. Any Suggestions?

 

Yes the TPS should go from .4v-.5v all the way to 4.5v. If it does not do this then there is a problem with the TPS or the wiring. Have you tested the three wires to make sure they are in good condition? There should be a 5v supply, a ground and signal wire. Somewhere in this circuit there something that is causing a resistance and not allowing the full signal to pass through the TPS.

Where you said you have tried 2 other throttle bodies. I would suspect the chassis wiring or the connector.

 

Back probing shows a 5v ref. The PCM supplies it. The signal returns to the PCM. One thing I just thought of is I didn't check the ground signal. A good friend was a Honda tech years ago and is letting me use an old shop manual on this car. The problem is , is the wiring color coding in the book does not match whats hooked up to the TPS. Or maybe we have been just unlucky with the throttle bodies sent to us. I'm rechecking the wiring. Thanks.

 

Found it! Car came to me with a p0401 and P1491. I told the guy he would probably need a new EGR and a cleaning. The car was not running right at the time. After I found the problem is when I was told someone else had tried to work on it before. After studying the Honda schematics and a little thinking I discovered the TPS and MAP sensors use the same type of connector. Idiot design. I think drugs were involved. But the only way to ensure the right connector goes to the right sensor Honda has one blue and the other Grey. They were reversed. I mean at least any layman should know right away the blue always goes to the TPS and Grey to the MAP. I switched the plugs and low and behold I had that sucker doing 60 on my dyno at the shop. He still needs an EGR though. Pending P1491 sets after 1 mile of driving. But at least it drives. Thanks for the replies.