Ok, i am using http://mainstreamtopics.com/forum/in...p?showtopic=78 as my main source of info here, and I am about to go change out the plugs and wires.... would fouled plugs cause a cammed car not to start? or a few burnt plugs? it was idling today at 500 rpms for prolly 20 seconds, and then after that it wouldnt start up again... any suggestions help thanks again!

 

If it cranks then-

Blue corrosion on the opti spark harness (plugs into the top of the harness). Take out and inspect.

Opti spark old and dead (replace vacuum harness to the opti with it).

Dead fuel pump or clogged filter (check fuel bleeder valve with fuel pressure gauge, should read around 38psi)

Coil- remove and check for 5.25 ohms (96-97) or so or 8ohms (93-95 camaros)

ICM, ignition control module (heat sink and computer chip the coil attaches too)

If it doesnt crank at all or really weak.

Battery
Starter
VATS (vehicle anti theft under glove box)
Ignition switch
clutch switch (underneath clutch pedal)

Pull a spark plug, ground it to a header or something and watch for spark. If u have no spark then u know its opti,coil,ICM, wire to the coil/optispark.

A fouled plug or burnt wire will just cause the car to skip a cylinder producing a bad idle, lack of power, and a consistant miss that you'd feel..

 

So you are saying, if it started once, and wont start again, this implies a faulty ignition control module? let me start by saying since the fuel pump is not the culprit this is the next thing i wanted to replace, and I will check it right now, getting 12v test light...
how hard is an ignition control module to replace? I really think this is it, for the same reasons I thought it was the fuel pump... just before it went completely out it would stutter when cold on accel, until it got warm... this is what didnt make sense about the fuel pump going out... not sure if it makes sense w/ a ICM either but we will see. I do have an SES light on, would this happen w/ a faulty ICM?

thanks for the quick response

 

The ICM is pretty hardy, I'd look elsewhere first, although it is easy to replace. Major downfall of the ICM is expense.

The two that I quoted above from ZDriver would be where I'd check first.

The times that mine has exhibited those problems it has in each instance been the cause of the opti's wiring harness being corroded and thus not making connection. That connection is responsible for Low Resolution Pulse signals (among other things), which in turn are responsible for fuel injector timing, which of course is responsible for ignition.

If you do have to replace the opti, and/or that harness then make sure you seal it up with some dielectric grease to help prevent moisture introduction that will cause the corrosion. Mine hasnt failed since but on the third one I made sure to seal it up as well as I could.

If you want to test it the right way, then get a repair manual and systematically test the no start condition. I used a Chiltons to narrow down to the opti harness, and even though I tried like hell to make the problem be anything but that... it always ended at that harness. Chiltons had a nice walkthrough, just double check that the wiring diagram makes sense as it had the wire location into the ICM mismarked for my year. I think all it required was a spark tester, a DVM, and some time.

HTH and good luck.

{edited because I can't type lol}

 

What about a bad TPS? I have heard these symptoms are similar to a bad tps, how can i tell if it is that if i cant get it started to scan for codes?

thanks agian

 

Yes, you scan for caodes with engine off and key in run position

 

If it cranks but won't fire, you can always check the 10A ignition fuse. That's what happened to me yesterday.

 

So what if it cranks but only starts 10% of the time and runs like ****..... could that be the harness???

 

I hope that you find my artcial useful



you will be able to do much better once you get a test light and can see if and where you have spark.

I take it that you have already ruled out the fuel system? did you use a gauge?



I am still amending that artical but one thing I have yet to put is the stuf that makes you go D'oh!! .. like checking all your fuses and making sure that when you turn the key on you don't have a securety light on...

 

I scanned it w/ a scan tool today, and the only code it shows is MIL is off... WTF does that mean?

i also got it started for about a minute today by putting my foot on the gas for a while, it would only stay firing while my foot was on the gas... then it died....

how would i check the IAC? or TPS?

I got the 12v tester... so help again plz

 

what code did you have? MIL cuircut? That will set when you have a wireing problem to the ses light or a burnt out bulb. no biggie.. Does the ses light come on when you turn the key on?


If the car tries to start you have spark and fuel.. not not enough or at the right time..


sounds like fuel or week spark.


follow the artical and test for good hot spark out of the coil with the test light...


if thats good.. check it at the opti end of teh coil wire, if thats good check it coing out of the opti at a few of the wire ports.


if thats good do a fuel pressure test (aslo covered in the artical)


if spark checks out good and you have proper fuel pressure I would have to guess it;s either. plugs, wires, compression or a combo of that

 

Nice, ok...
I have a digital volt reader thing, just have to figure out how to use it now lol...
I will check that after I clean out the TPS and the IAC, already took those off the motor so i might as well clean them up

WD40 for both those and tighten them down hard? should I check the volts or current or resistance or whatever through the tps and iac?

thanks again for your help HBH

 

first of.. you can;t clean the TPS.. and you can clean the IAC with carb cleaner..


once you put them back on you can sweep test the TPS with the multimeter on volts scale. with it in and the key on with the enigine off use the volt meter to find the ground, 5 volt refference, and the PCM signal.

to find a hot with the meter the red lead goes on the got wire and the black lead goes on a ground source, conversly when you look for a ground you put the lead on a good hot source similer to the test light..


now, the TPS is 3 wires, one will be 5 volts, and another wil be a ground. the wire that is neither is the one you want. it will be hot and should be around 0.60- 0.75 ish area with teh throttle closed. then slowly open the throttle and watch for incressing voltage as you open it. it should be smooth with no clitches al the way up to over 4 volts at WOT