Motor down on power, what am i missing?


Check the TPS as well, when on the Dyno the DME may not be seeing full throttle to engage the wide open throttle map in the DME. This can be an easy tell by the dyno graph.

Id also do a smoke test to see if there are any vacuum leaks. It may sound good but that doesnt mean there isnt a leak somewhere.


And make sure the throttle is opening up all the way.


Did this issue ever get resolved? If so what was the solution?


I put a car together two years ago using an 89 IS vert for a donor. The engine and trans had 185k miles. After putting my car together it dynoed at 132 whp. I only changed the oil, plugs, plugwires, rotor and cap. After the first year I put a 220k mile engine in the car, don’t ask. I dynoed the car at a different dyno facility but still on a Dynojet. It dynoed at 133 hp. I did compression tests on both engines. The cylinders were within 5-10 psi of each other. However, I did a leak down on both. My first motor’s valves and rings leaked bad. The second engine’s valves were tight but the rings were leaky. I’ve since decided to rebuild the first engine. For some reason I ha e a feeling the rebuilt motor is going to put down the same power and I have something else going on with the car than the engine itself. Both motors had brand new injectors and fuel regulator as well. My A/F was around 12-13 with no dips.

How do you check the TPS?


There’s an electrical test in the Bentley.


Yeah, I saw it on another thread in these forums. Thanks.