Dang, that sounds exactly like my problem. Typically the high rev problem is related to the throttle body. But I have a new AS&M unit.

 

alright i did some testing with the multimeter.i dont have a manual so i dont know what they are supposed to read but heres what i got:

All are in ohms
TPS- 1.5 closed and over 1 open (thinking that this is the problem)
IAT-2.20
MAP-1.4

is my TPS bad like I hope??

 

TPS would be too easy for me. I could just swap one from one of my other LT1 cars and see what happens. Does anyone have a part number for a 3 bar map sensor for the LT1?

 

haha i guess that wasnt the problem still breaks up but it does idle smoother. I am loooooosing it here. about to just sell this damn thing for a dump off price.

 

I have replaced my FPR twice. If the fuel system is not holding pressure, you need to isolate the leak in the system. You could have an injector stuck open, a leaking FPR (hole in the diaphram) or you could have a defective check valve inside the pump assembly.

Did you check for fuel in the vacuum line that runs from the passenger side of the intake manifold to the FPR? If fuel is present, replace the FPR. Another symtpom of this issue is if you get a puff of black smoke out the tail pipe when the car first starts after sitting for a long while (like overnight). This indicates fuel leaked through the diaphram, down the vacuum line and into the intake manifold.

The best test is to follow the procedure in the factory service manual. It outlines how to isolate the 3 parts of your fuel system to determine where the leak is. You will need to pop your fuel lines off the fuel rails and insert shutoff valves in line between the fuel rails and the fuel lines. This will allow you to fire up the pump and then close off each section to see when the bleeding stops. From this, you can tell where the pressure leak is.

Hope this helps. I have gone through it twice myself!

Jeff

 

What have you done about it? As was mentioned earlier, a temp sensor that reads lower than actual temperature will cause the engine to run very rich and very poorly. The sensor can be checked with an ohm meter. There's a table of sensor resistance vs. coolant temp in my Scanner writeup:

http://members.aol.com/InjuneerZZ/ScanMast.htm

Even reading the dash colant temp gauge, and checking the water pump mounted sensor resistance will tell you if the water pump sensor is anywhere near correct. But I can't understand if you know its broken why you didn't fix it. It could be screwed up and not set a code.

Fuel pressure should be read:
-start engine, let it idle, remove the vacuum line to the FPR. Pressure should be in the range 41-47psi. 43.5 is perfect.
-reconnect the vacuum line and the pressure will drop proportional to intake manifold vacuum... a 6 to 8psi drop on a stock cam isn't unusual, less drop on a more aggressive cam.
-tape it to the windshield, as outlined in a post above.

Are you sure you measured your TPS voltage correctly? Doesn't make any sense at all. You are measuring from the blue wire to the black wire, right? Did you also measure from the gray wire to the black wire to verify you are getting +5V from the PCM? You want 0.20-0.90V at idle, and voltage should increase smoothly as you open the throttle, until it reads about 4V higher than the closed throttle voltage, at WOT. I think you measured wrong, or something is really fubar.

1.4V on the MAP at idle looks OK.

 

i took the car to F-Body central in MD about 4 months ago and the sensor was fine, Jason said it broke but because it was just for the guage in the dash that it would be ok. and it the two prong plug for the wire thats broken off. i cant find the prong anywhere.but i hear that only the sensor in the water pump feeds the PCM

as for the FPR i did the test by pulling the line, no gas or anything.

 

You said broken temp sensor on the block, not on the head.

Did you test the pressure while pulling the line, or did you just pull the line to smell it?

You asked me to help, but I'm sensing some resistance here.

 

sorry, it on the driver side right below the header

 

i not tryin to be a pain in the a$$ its just that this is killing me..i love this car and I am getting tired of trying to figure this out since its been going on for a long time and its all i have to drive.

 

I know how you feel. I've been trying to chase down my issue for months and nothing seems to help. At least I don't have to drive my every day. I'm gonna upgrade my map sensor just because it's the stocker and it may help but I'm not expecting any miracles. Let me know if you figure anything out and I'll do the same. The hard thing about my car is that it will run fine sometimes. But most of the time it will idle high, miss horribly at 2k rpm, and random misses at higher RPM. I upgraded the ignition to a delteq with new wires and plugs. I also changed the valve seals which were in bad shape causing excessive oil in the cylinders. Anyway enough about my problems, just try to be patient and stick with it.

 

its just the fact that I am a Marine and we dont make crap. I have put ALOT of money in this car and I cant even enjoy it. i am going to try the fuel pump this weekend. i have a 255 so we will see but if it not that than i dont have the first clue.What bothers me is that I took the car to an fbody shop with this problem and said please just fix it no matter what it costs, but to be honest if its not an LS1 they dont mess with it.

 

any chance that my timing chain may have jumped or something. when i did the rebuild I just used a new chain and gear but not a double.

 

Just checked the FP again. at prime (key on engine off) it fgoes to 37 and falls down below 20PSI. with the car at idle it sits at 37PSI and with the vacuum hose off it goes up to 44PSI.

 

That's normal.