I've had a similar problem that you have, the car would hesitate and not want to go above 2000 RPMs, execptionally worse at highway speeds. There was no codes on the computer and the car always started and ran okay otherwise. It did burn more fuel also. I changed the opti once and then put in a Deltec, plugs, wires, fuel pressure regulator, fuel injectors, fuel filter, PCV valve, cat, cleaned the air filter, none of this stopped the problem. I bought a scanner and started analyzing the computer while it was running and I realized that I was getting knock retard and alot of knocks where getting sensed. The knock retard comes on at the same time the car hesitates. I figured it was in the valve train, so I readjusted the stock valves and it still got the knock retard. I also noticed that I could hear tapping out of the drivers side valve cover, but only when I revved the car up from under the hood and was standing right there. I couldn't hear it from inside the car while driving. I then figured it was a lifter, so I bought new ones and decided to put a Hot cam in too since it was going to be apart. Sure enough, when I took it apart, I had to bad lifters that where flat on the end, and the cam had two knicked up lobes. I just finished the install last week, but I didn't get it tuned yet, but even with out the tune it doesn't have the hesitation anymore. So I would say that the knock retard is definately the problem, you just have to figure out why its getting it. A good running car will get 0 knock retard. Sorry this was so long, but I thought I'd tell you all the things I replaced for nothing so you don't make the same mistake.

 

Thanks for the advice, I'm going to disable the knock retard and run the car and see if it still stumbles. IF it doesn't with 0 retard, then your right I'll have to check to see why it's making alot of noise. My engine is noisy though, thanks for the tip that makes alot of sense.

Brian

 

should it get 0 retard at wot? just curious

 

mine used to

 

Are you sure that your wires arent arcing? My car started running like total crap and I was getting up to 5 degree of KR. Checked out the engine in the total dark and there was a pretty fireworks display

 

I'm going to do alot of checks on this bad boy when it stops raining like a ****, and this is one of the things that I will do. I'm going to solve this thing, i will not be defeated

But I"m pretty sure the plugs and wires are good, I mean i replaced them 100% and it ran exactly the same, I seriously doubt both sets arching the same way. I also use dialectric grease to.

Brian

 

I just also replaced the knock sensor with a 100k resistor to ground, it is pulling timing EXACTLY the same as before? How does it know to do this even with no sensor?! Any help, can this be a computer problem? ALso, I hear NO DETONATION just the car stumbles and misses under load, the knock retard increases as I increase throttle almost linearly.

UPDATE: ordered a new KS will install it and tape it out of the way, see what happens. I'm getting a hell of alot of knock retard and no detonation and I should not be at all(run premium, stock engine), i want to get 0 knock then start from there is my new direction on this problem.

Brian

 

Not trying to hijack your thread, but my "what happened" post is about the same thing. Even when I unplug my knock sensor, I'm getting knock retard avg 5degrees. HOW IS THIS POSSIBLE????

 

if you unpluged it, there is no resistance there i would expect that. You need to put a value so it "sees" something. In my case, i had 100k ohms there yet it still is pulling timing but my computer is OBDII. I either have

A)bad KS
B)bad knock module
C)bad PCM

I don't see any other reason how my computer will pull timing.

Brian

 

Since the KS is essentially an AC generator, you would be better off just unplugging it then putting a resistor in it. In addition, you are wasting your time unless you scan it. Once the PCM sees a KS system failure, it sets a DTC and pulls timing. What I'm not entirely sure of is whether the PCM resets after some number of cycles or has to be reset.

I also saw where you posted in someone elses thread that you have an ABS INOP light. My question now is how many other problems do you have that we don't know about? The reason I ask is a faulty alternator can cause wierd stuff to happen if the diodes are defective and leaking AC voltage on the DC supply line. You may want to visit the Helm web site and purchase a set of shop manuals.

And the last question is why does your signature keep showing up and then disappearing?

 

If you are getting an ABS INOP light then you probably have a bad ground. Check the ground that goes from the battery to the passenger fender.

 

I just go tback from a work trip to Yuma AZ, so I haven't had much time to look at the car. I'll dig into it this weekend.

I have a scanner, there are no codes. I will unplug it then plug in a new KS, see if that helps. I will also reset the PCM after I change the KS.

i COULD have a bad ground, sometimes in the morning when it's cold all my interior lights flicker and my chimey thing goes crazy, i'll look into that to. I checked the engine ground bolt ground thats good but I'll do some more lookin.

I have the shop manuals as well. And my signature, I only use it when I post the first message in a thread, if there is any other problem beats me

 

I'm curious why you replaced all the ignition parts when you have an OBD II and a scanner. Can't you just look at the miss count and see if it's missing, and if it's not then the problem is not the ignition? By the way, just as general knowledge to anyone who reads this, you cannot rely on the scanner to tell you about the fuel system. I put LTs on my 94 a couple weeks ago and forgot to plug back in the number 8 injector hidden in the back there. It was running rough and stumbling so we put my Dad's Snap-On scanner on it and let it idle and drove it, and the friekin' thing read BLM 1280. ie, the O2's claimed that the car was not running rich or lean, but right on target. So of course my Dad, who's been a mechanic for 25 years plus, and I said "fuel's fine." Then we saw the injector was unhooked and asked each other, "didn't the scanner say the fuel was right on?" I plugged the injector in but the car still runs about like yours, stumbles and runs rough under load. Did your problem appear overnight or did it come on gradually or did you do some work after which it started?

 

Isn't it fun playing Sherlock Holmes.

 

it got worse and worse gradually