I hooked my car up to my computer and used moates software and a customefis cable and got these #s do they look good or is something outa whack? This is from my 92 camaro RS 305 TPI with manuel tranny
these were taken at idle
eng spd-775
Map signal- 1.35
Throttle pos. volts- .53
manifold temp- 142
coolant temp- 189
spark advance would jump from 12-14-17
Knock- 1
Map pres. value- 34.49
Iac steps-40
02 mV- 433
blm cell-4
blm- 140
int value- 128
fine fuel - 128
injector pulse width- 1.79
a/f ratio- 14.26
idle target- 775
battery volts- 13.5

any help will be appreciated.

 

Your BLM being 140 is cause for a little concern...ECM base fueling is lean and it's compensating quite a bit.

 

would an engine miss or a faulty injector cause such a problem?

 

It's definitely under-delivering fuel, clogged filter comes to mind as an easy suspect if yours is old.

Need to know more about your engine and induction system to be of any real help.

 

It is very difficult to analyze one "snap shot" while the engine is idling. What concerns me is the A/F Ratio of 14.26. Was it in closed loop? Typically it should be 14.7:1 (though it may display as 14.6:1 on some scan tools).

Also, was your O2 count oscillating or holding steady? If it is operating properly in closed loop, it should be oscillating above and below 450.

You need more data, as well as other conditions besides idle.

 

I am trying to troubleshoot a problem that only happens at idle thats why I am only showing a snap shot of idle. The fuel filter is new so I dont know why it wouldnt have the right a\f ratio. but since this was recorded I replaced the Coolant temp sensor, the injectors have been Ohm'd out and flow tested as well as I have compression checked all cylenders and they all check out.

 

What is your fuel pressure @ idle with and without the vacuum reference connected to the regulator?

 

I bought a fuel pressure guage last night but accidentally bought the tbi one so ill see tonight;

 

One thing stands out on me from that scan now that i look at it again. You're making great idle vacuum. Cars with a miss at idle will usually show it very readily with a decreased vacuum since you'll have one hole that in essence isn't pulling.

Like i said on the TPI board. Unless this thing is rattling your teeth out, i think what you are calling a miss at idle might be normal idle instability inherent to all the TPI cars i have ever seen. I don't know anyone with a TPI car that idles like glass.

 

I think you might be right. I will try to smog it but I want it to idle like glass I will never give up. lol how many miles does your engine have on it?? has it ever got a new timing chain? If I am gonna change the timing chain should I change the cam too? i mean it is half the job right??

 

Me

 

To add to that statement...don't know anyone with a *fast* TPI car that idles like glass.

 

oooooooohhhhhh burned!

 

Wrong Kev. My car is fast and it idles like glass. So what if it's broken glass ... it's still glass!!! ROFLMFAO!!!

Tim

 

Mine does to Traxion thanks to your help. Its silky smooth even with a 224, 224 cam.

 

Just those that are poorly tuned.

 

when did this post go to hell?? well im sure its not just the rough tpi idle after sitting in the car and hooking it up to the scanner I am convinced that it is missing, it really jerks when it misses and lets a little backfire out too. just like its not firing and the unburnt fuel is beign burned up when it hits the collector and another cylnder ignites it. I guess ill pull terminals today after work to try to narrow it down to one cylinder if possible and if I do then All I have to do is OHM out the plug wire and check the plug and if both of those check out I have a distributor problem correct?

for more info check my post in tpi board Still Missing?? what next?

 

Just good-natured jabs between a guy with a fast car, a guy with a very fast car, and a Canadian.

 

Could idle instability be related to the fact that timing moves around a solid 3-4' at idle for no apparent reason at all?

Actually, a guy i know with CCCS on a ZZ4 noticed that it varied the timing a bit at idle too on a light. He swapped to non-CC a little bit back and it now idles like glass.

 

One think comes to mind after reading your situation. I had a bad distributer. The star on the shaft of the distributer used for the magnetic pick up came loose and was lifting up during idle and during exceleration on my stock distributer. It was making my headers turn beat red because off the detination. What was happening was, the magnetic pick up was getting out phase everytime causing the ruff idle and detination. So if you have the original distributer it will be a good idea to check it. And this how to do it.

1. Simply lift up on the shaft to check for end play. Normal shaft movement between the drive gear and the shaft body is about .015 to .025 ( on my old distributer it was way over .035 ).

Installed the new one from Auto-Zone and it was running alot better.

 

But you forgot to include yourself

 

So what was the problem with your dist. was it the shaft, a bushing the upper bearing?? I will most likely rebuild my dist. this weekend if I dont find something else thats making it miss befor then, but It might also be my cap. I bought a hypertech cap and rotor and when I went to take the coil wire off the terminal came out with it, I jammed it back in and it sticks a little better now but Ive messed with that when its idleing and it doesnt seem to affect it, so I dont think its that but Im just sayin dont buy hypertech anything its all crap.

 

Do you have this posted on the Tech Board? I will be happy to assist you there. This board is primarily for prom burning and this seems more Tech in nature. Go to the Tech Board and describe the "miss". Better yet, can you get a WAV file that you can e-mail?

There are many things that can cause a "miss". Sometimes the sound will give a clue. But sometimes the "fix" can be very elusive. Coking of the TB, IAC, intake, EGR track, and other parts can cause a host of driveabilty problems including "missing".

 

I am gonna see what I can do to fix it. If i dont have any luck this weekend I will post on monday and ill get a wav file and I could also log some data if that would help. But The miss is getting a little worse so it should be easier to find. Im gonna see if all the header tubes get hot from it just idleing and if i have no luck there ill start pullin wires with the car running but i have done this befor with no luck but as I said the miss is getting more defined.

 

He has a couple of threads about this on the TPI board as well Glenn. Probably counter productive to have yet another series on the general tech board.

 

counter productive?? The more help I get the better. But I do need to put some time in befor I waste anymore of your guys time so I WILL FIX IT this weekend. or ill kill it, either way one less worry