Following the advice put forth in these forums, I have finally replaced the CHTS as has been repeatedly suggested by everyone to no avail. The car still surges like there is no tomorrow, and the fuel smell is worse than ever. I really need some help as I am really impressed by the power of this car, but my fuel economy absolutely sucks! Help Me Please!
Ok! I'm gonna try and answer all questions at once. The fuel smell is raw unburned fuel coming out of the tailpipe. I'm getting 16 to 17 mpg at best, and the surging I believe to be the cylinders loading up with fuel and causing the car to bogg down. The beast is still an amazing pain in the [email protected]? to start in the morning, and all of the other symptoms that I have described as well.
surging can be many things. vacuum leaks, fuel pressure problem to name two. Sounds like you will just need to spend some time going through some diags to run this down. Have you checked the fuel pressure regulator to see if fuel is leaking into the manifold? the vacuum tube on the top would have gas in it or smell heavy of fuel. maybe a fuel injector is leaking fuel into the engine (just a guess there).
Alright! This saga involving my car started with the vehicle not starting after driving for a while. After discussing it online with a few people, they suggested that the injectors might need changing, which I had done. Since then, the car has been difficult to start all the time, and it seems to lose power (surge and choke) while driving. In my quest to fix the problem, I have replaced the fuel pressure regulator, the CHTS, TPS, and the IAC motor. After all of this, I determined that I had accidently reversed 2 vacuum lines, between the regulator and the actuator. It runs better, but I am still having problems starting, and the hestation thing still happens at steady throttle on the highway. I have tested the regulator and the fuel pump using the procedures in the FSM, and both are operating properly. Any suggestions?
I had the same problem and basically changed the same parts you did. This car is a beast/nightmare to diagnose and fix.
If you done codes and fix those, than make sure your vacuum system is up to par. Best way to know for sure is to do a vacuum gauge test. This procedure will tell you a lot about your engine! And make sure ALL vacuum hoses don't have cracks on the tip where it connects to the part.
Don't give up because these cars do have potential...
what is your fuel pressure? you need a number not a guess because you pulled a fuel line gas sprayed out means nothing. what is your vacuum. vacuum gage are cheap and vacuum leaks are the bane of fi engines. start there. Don't neglect battery and battery cables. Z's don't like low voltage and poor battery performance creats all sorts of gremlins. Have the battery load tested. Cables tight and uncorroded. Battery grounded direct to the frame and not just to the starter. if you got these clamp on terminals get some real battery cables. those corrode down into the cable under the insulation anc cause problems.
fuel pressure is running at the appropriate 30 psi at idle all the way up to 37 psi at open throttle. Tested the fuel pressure regulator as well and it is operating according to the test set forth in the FSM. I haven't tested vacuum yet, but will procure a vacuum gauge this weeken to facilitate the testing. What is the acceptable range for vacuum?
another possibility is poor ignition performance. New rotor and cap for the dizzy. new plug wires. Look at it while running on a dark and stormy night and see if you see sparkles where they don't belong from the ignition system. study the fsm on the cold start/idle components like the AAC and test them
Thanks to everyone that has contributed information regarding this situation. As of right now, the car has been running MUCH better and that is just by following the procedures for setting the idle mixture in the FSM. I will be doing more as time permits. I do have another problem that I will be listing in another thread if you have any suggestions. In the last week, the car has started cutting out violently at anything above 1800 RPMs. Ironically, it seems to happen in conjunction with when the digi speedometer is actually working, but I'm not sure that this is really related. Any suggestions would be helpful.
Have you done the basic stuff like.....
Measure the plug wires for resistance?
Make sure the PVC valve is not sticking?
All electrical connections under the hood have been taken apart, cleaned & reseated?
All system grounds & clean & tight?
Fuel pressure up to snuff?
ECU edge connectors clean & seated?
Verify timing is not jumping around?
Since mine is doing the exact same thing, I'm gonna check the TPS as well
The function of the throttle position sensor, aka TPS, is to supply information to the car's computer about the position of the car's throttle. The throttle position sensors contain electro-mechanical moving parts which are prone to wear and tear, which eventually add to the cost of car repairs. Malfunctioning of a TPS can result in improper data being fed to the car's computer, which monitors engine performance, in respect to the fuel efficiency of the car. A damaged, malfunctioning TPS can cause variety of symptoms which are also known as symptoms of a bad throttle position sensor.