wideband o2 reading questions

[kkchevy3]

While driving around town my gauge reads 14.7ish (+/- .4) On WOT its goes to 13.1 but as the rpms get around 3500 it starts to go lower towards 11. Also after 3500 the motor has no more power. Im running the lunati 63500. mustang injectors. no map changes. ears cut off the dizzy. ive also had a pinging problem for months that i cant figgure out but ive given up on that does this seem normal?

[Muad'Dib]

Usually for me at WOT, AFR will be around 13.2-.5 and start to work its way richer as the RPM's get higher. 14.7 is stoich and is what you should see at idle or normal cruising.

If your losing power above a certain RPM, then there is an issue. You mentioned pinging which is never good. It can cause serious engine issues if that's what you are truly hearing.

Are you sure the distributor has been indexed correctly? That's usually the cause of losing power over ~3000 RPM's.

Additionally, how was the cam broken in?

[Cheromaniac]

On WOT its goes to 13.1 but as the rpms get around 3500 it starts to go lower towards 11.
Also after 3500 the motor has no more power.
ive also had a pinging problem for months that i cant figgure out but ive given up on that does this seem normal?

Definitely not normal. The three symptoms you've described above do suggest that the dizzy might not be correctly indexed (as well as being deaf ) as Muad'Dib mentioned.
Also make sure that the vacuum tube from the MAP sensor is properly connected all the way to the intake manifold with no cracks/leaks.

[kkchevy3]

Does anyone have the correct procedure for obd1 distributor install? Im going to grab a dizzy from the auto parts store with the ears on it and retry. My idle also sometimes goes down to around 600 and gets rough. All of my symptoms are random and come and go so I really don't have solid info. The motor has about 20k miles on the stroker. It runs well enough that someone that isnt car savy would think everythings normal. Its not like its undrivable. The whole thing is very frustrating because i don't have all the specs on the work done since the guy that built the motor passed away. I was thinking about getting the injectors cleaned also

[danimal]

I'm having almost identical drivability issues, so please keep us updated on what you find.
Is there any good way of checking to see if the distributor is indexed properly, maybe with a timing light? i assume checking the timing in the higher rpm's might show if it isn't advancing as far as it should? Just a thought.

[danimal]

So I went out to check out my distributor indexing and I noticed my distributor shaft had tons of side to side slop. I'm talking .05" or more. Threw in a new one and it runs MUCH better now. I can finally hit redline easily. Just something for you to check on yours.

[jsawduste]

Indexing the OBD1 is simple enough. Engine at idle in closed loop. Turn the dist. CW/CCW till you find the sweet spot in the middle. Some engines have a fairly broad spread while others are a bit more sensitive.

Another trick I`ve found, especially if your running a bit more cam then stock, is to add an air bleed to the throttle plate. Start SMALL allow the ECM to "learn" and see if your drivability at coast down and idle improves. On my stroker I`ve found that a 7/64`s (.1094) drill bit fits right into where the engine wants to be. Have run as high as a #33 drill bit (.1130) but think the engine is a little better with the 7/64`s. The change is significant and I highly recommend it.

[Cheromaniac]

So I went out to check out my distributor indexing and I noticed my distributor shaft had tons of side to side slop. I'm talking .05" or more. Threw in a new one and it runs MUCH better now. I can finally hit redline easily. Just something for you to check on yours.

Good call. Sounds like the drive gear on your old dizzy was badly worn.

[atias]

Indexing the OBD1 is simple enough. Engine at idle in closed loop. Turn the dist. CW/CCW till you find the sweet spot in the middle. Some engines have a fairly broad spread while others are a bit more sensitive.

thats not a good way to index the distributor. you should do it like dino's way http://www.angelfire.com/my/fan/dist_index.html
the ecu reads the sync sensor only in start up and then he is ignoring him and uses only the crank sensor, you can even disconnect the sensor while the engine is running with no effect.
BUT if you turn the engine off he wont start without the sync sensor connected again.

thats true for almost all OBD1 ecu except for the very very firsts and old ones that do need the sync sensor all the time.(they came with the gray rubber under the 60 pin connector).

[danimal]

So I went out to check out my distributor indexing and I noticed my distributor shaft had tons of side to side slop. I'm talking .05" or more. Threw in a new one and it runs MUCH better now. I can finally hit redline easily. Just something for you to check on yours.

Good call. Sounds like the drive gear on your old dizzy was badly worn.

Yea it wasn't pretty, nor was the bushing in the distributor. The rotor was hitting the cap at some times. I do believe it was responsible for the shaft on my last oil pump seizing just before building this motor.

[kkchevy3]

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well got the new distributor. didnt have to shave the ears this time. set up the motor tdc, marked the dizzy 3 cm clockwise from the rubber opening (blue mark) its closer to the 3cm then it looks. put it in. Starts up fine, runs the same and still pings. At least its in there now with the ears still on. not sure where to go from here. And checked my vacuum hoses. any ideas guys?

[sly-jeeper]

hmmm when does it ping?

[atias]

the distributor is still a little off. you need that 3cm mark to be in the center of the rotor.
turn the crank clock wise to the 0 mark (index the pulley only in clock wise to keep the timing chain stretched),
drop down the dizzy and hold the rotor counter clock wise (to take out the slack in the gears),then index the housing to the rotor.

what fuel ?
did you tried premium to check if the ping goes away?

[kkchevy3]

always run premium. It pings going down the road at mid throttle. on the highway also. does ping at wot sometimes. overall not very loud pinging but can still hear it. tdc was set correctly. from what ive read with an aftermarket cam the dizzy wont line up exactly to 3cm? gonna clearance the forks a touch so i can rotate it a hair more

[RenoF250]

always run premium. It pings going down the road at mid throttle. on the highway also. does ping at wot sometimes. overall not very loud pinging but can still hear it. tdc was set correctly. from what ive read with an aftermarket cam the dizzy wont line up exactly to 3cm? gonna clearance the forks a touch so i can rotate it a hair more

What is your overall build - cam, pistons, etc?