98 Chevy Blazer. Won't idle. The car ran fine, plenty of power, no trouble codes, just a bad rod knock before the motor was rebuilt. I proceeded to pull the motor, have the crank turned, hone the cylinders and install all new rings, bearings, gaskets, and an oil pump. I also threw a full compliment of tune up parts at the motor. The problem now is that the car won't idle. I can start it if I give it some gas, but the minute I let off, it dies. When I drive it, it pings the minute I apply any throttle at all. Also, there is a strong smell of fuel coming from the exhaust. The strange thing is, no trouble codes are present. It has good compression across the board, I double checked the cam and distibutor timing, which are both good. Please help, I'm out of ideas.

 

make sure all the wires are on the sensors or else it may be the egr valve witch is a common problem also check your fuses if all that checks out good either if you have a computer with a functional test u can check it or you can try tapping the egr with a hammer and extension to loosen up the crud thats making it stick good luck

 

Wires and fuses are all good. So is the EGR. Remember, the check engine light is not on. There are no trouble codes at all.

 

What is your fuel pressure reading key-on, engine-off and what happens to the fuel pressure once you turn the key off? It should be around 60psi or better when you first turn the key on and not drop more than 2psi after you turn the key off. You can check out the 96+ Fuel System Diagnosis article for further information.

If everything checks out there, then I would pull the distributor and time it again. There should be no reason for it to ping unless the timing is advanced one tooth. The EDI Engine Timing thread in the Tech Article (DIY) section will give you the steps to help get it timed up properly.

How did you determine that the EGR valve is "good"

Also, what are you using for a scanner? Is it capable of reading the sensor data when you do have it running?

 

I haven't had a chance to test actual fuel pressure, so that could be it, although it ran great prior to all this. Same with the EGR. I am only assuming right now that these parts are ok. I am certainly willing to explore these possibilities, but it seems more likely that I've incorrectly installed something. One thing that definately doesn't make sense is that the Chilton manual I have seems to indicate that in order to set ignition timing, the motor should be turned over until you begin to feel compression on the #1 cylinder, then stop once the FIRST timing mark lines up with the notch on the top side of the balancer on the timing cover. Then the distributor can be installed with the rotor lining up with the 6 cast into the distributor housing. This is what I have done. The distributor installation information you provided me here indicates that the crank should be turned all the way to TDC on the compression stroke of #1, which is 90 degrees past where the Chilton manual says to turn it to install. I've tried it this way and it won't run at all. The best installation I've found was following Chilton and installing 90 degrees before TDC. This is the only installation that will make the car run at all. I've tried advancing and retarding the installation one tooth from this point to see if it gets better but I get a DTC when I do that. Maybe you can help clarify which is the correct installation of the distributor.

 

The thread I linked to above is what I have followed to a T on several occasions without issue. I am wondering if somehow you are not getting 180* out...

 

I wondered the same thing myself, but the only way I could do that is if I installed the rotor in the distributor in reverse, which isn't possible because the rotor has tabs on it which make it so it can only be installed one way. I tried installing it with the timing marks lined up both ways on each rotation of the crankshaft, but still the only way I could get it to run was by lining up the earliest timing mark with the upper tab on the timing cover. that's 90 degrees off on the crank which is 45 degrees off on the distributor. There's no way it should even run like that if it's not right, and even if so, why won't it run correctly when I line up both timing marks with their corresponding tabs on the timing cover? I just went and tried again to install it the way your thread indicates and now it won't start any more. It just bucks and shakes a lot but won't really even try to start.

 

WAY OLD THREAD but I figured I'd post the solution anyway. I took the car to the dealer and THEY couldn't figure it out. $70 for the diagnostic work plus two $60 tow bills later I got it home and just decided to start throwing parts at it. It was actually a malfunctioning crankshaft position sensor. Resistance measured within spec and the ECU didn't throw any codes for the sensor, but it was the cause. It was sending incorrect readings to the ECU, thereby causing incorrect signals to be sent to the ignition system and my timing to effectively be off. $10 at the junk yard solved the problem.

 

Awesome you got it fixed. Thanks for posting a follow up!