I have been working on a 89 16v non turbo 740 GLE for a few weeks on/off. The car came in on a hook due to intermintent starting and lack of power. I found no spark so I replaced the amplifier and gave it new wires/plugs/cap/rotor (way over due). So then it started and idled fine but still no power. If you give it gas in neutral the rpm goes up to 2k and falls down and it does this over and over. I had some good used parts laying around so I changed the Air flow meter, RPM sensor with no luck. I then found the fuel pressure regulator was shot (spraying fuel out of the vacuum port) and changed it and it still wont go above 2k. After searching this site it seems like either the knock sensor or TPS could be doing this ( I don't have spares of these laying around to swap in)? Does this sound possible? I also swapped ECU's and no change. Is there a control loop in the ECU that would shut down the FI pulse at 2k? I don't have a pin out / voltages of the ECU yet so I guess I need to get a manual next.
Ideas?
Thanks

 

Was any other work done to it before you got it?
Maybe a rear main seal?

 

Thanks for the quick reply. That is very interesting you asked about the rear main seal. The car was at a transmission shop before it came over to me. I'm assuming they pulled the trans since I think the customer said there was some issue going into high gear. What are you thinking?

 

If the Rear main seal was done and the Flywheel was not marked and installed in the proper spot then the car will not run properly.
The flywheel has to be in a certain spot for the speed sensor to pick up properly.

If that is all good I have seen a coil do the same as well.

 

I will give the customer a call in the AM and see if the flywheel was removed. In the mean time I went back out and checked the codes from the diagnostic port. No ignition codes but there are two fuel.
223 and 232 I have read the other posts and it sounds like there must be a vacuum leak for the 232 code. Could there still be a leaking injector per the code? The 223 (signal missing to/from IAC), could this cause the rpm's to cut out at 2k? I know above idle the IAC shouldn't really shouldn't do anything but not sure if the Volvo setup has something different.
Thanks

 

The idle motor is Bypassed over idle doesn't do anything at all.