No Codes, Timing Advances, Ridiculously Rough Idle
 

I have a '90 Iroc-Z with a 5.0L TPI and I'm having Isues. I changed the Cap & Rotor, Ignition Module, Coil, and Spark Plugs thinking that would solve the problem. That didnt help so then I changed the Knock Sensor and MAP sensor. After that I found out that the Timing was off. Every time I set the initial timing to 6 degrees like the specs ask for the car runs beautiful with full power for about a mile or so then it gives and runs like crap all over again. The computer advances the timing for some odd reason. The computer isn't throwing out any codes NO matter how much of a rough idle it has. Now the car wont turn over at all and after cranking it over so many times trying to figure out what's wrong, I fried my starter solenoid and I waiting for my replacement. I'm looking for any other sugestions as well.

Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

You might want to doublecheck that new ignition module. Make sure the plugs from the engine harness are still connected good and also check the plug that hooks to the module inside the distributor. Nine times outta ten, the module is the problem when you can't get any spark. Also, if you bought an Accel module or one of those cheap Wells brand ones, that could be the problem as well. The only modules worth a damn are the orginal AC Delco ones. I've seen guys go through 3 or 4 Accel modules in less than a year. Did you make sure to smear some dielectric grease on the bottom of the module before you bolted it down to the distributor? They'll overheat and short out if you don't put the dielectric grease on the underside before installation.

Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

Yeah, the Accel Module came with a little package of die electric grease... I made sure I put the whole tube on it...

Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

The only thing that worries me in your last reply is you mentioned the name Accel. :eek: If you still have your original module laying around, you might want to put it back in and see if it makes a difference.

Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

I ordered it from Summit... They sales rep over the phone suggested the Accel over the Mallory and the stock AC Delco Ignition Module.... Do you have any idea of what this Beige thing is in this picture ...? It's located behind the fuel tank

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Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

That's the vent for the fuel tank. When too much pressure builds up inside the tank, the valve inside that thing opens to relieve the excess pressure. That tech rep at Summit oughta have his damn neck wrung for recommending an Accel module over the AC Delco one! I had a local buddy that went through about 3 Accel modules in less than a year, and there's tons of old posts on here from members who've also had problems with them. The module may not be your problem, but I'd still try putting your old one back in to see if it makes any difference. The module does adjust the amount of spark advance to the distributor, so it could be causing your problem.

Re: No Codes, Timing Advances, Ridiculously Rough Idle
 

Ok... So I got the engine running again... The gave me a knock sensor for a 350 instead of a 305. After changing MAP sensor, External Coil, Cap & Rotor, Spark Plugs, Ignition Module, and Fuel Filter, still have no luck on what causes the timing to advance after setting initial timing at 6*. The odd part is that sometimes it'll advance the timing and sometimes it'll retard the timing.... I'm stumped on why the random adjustments. I followed the instructions from the Chilton's Manual on the Timing adjustment procedure but still NO Luck... I grounded the ALDL, disconnected the EST, and set the timing. It ran good for about a mile then advanced and ran like crap. Again I grounded the ALDL, disconnected the EST, and set the timing. It ran good for about a mile then it retarded itself. I then disconnected the EST but left the ALDL alone and set the timing and it still seemed to do either advance or retard. Any Suggestions would be greatly appreciated...