I am reposting this issue in the TPI forum in hopes of getting a broader response.

Alrighty, I'm still fighting this stupid "miss" (most recent thread: https://www.thirdgen.org/forums/te...-thinking.html (I Lie Awake Thinking About It.....)) which is actually only on a hot car after a restart, and had only happened at 1000rpm-1200rpm. Also the stall at low-mid rpm (1500-2000rpm) rolling, usually in 2nd or 3rd gear.

Here's what I've done so far to no avail:
-replaced spark plugs (1500 miles on them)
-visual plug wire, cap, rotor check (3000 miles on them)
-ohmed fuel injectors; 16.7-16.9 cold, 17.9-18.0 hot
-checked fuel pressure; 28psi KOEO, 36psi engine running, no bleed off

I bought a circuit tester (that's a noid light, right?). Tried the household tester w/ the 2 leads and that din't work, hence the new tester. I've been told to test the injector harness? Is that one connection or do I have to remove each connector from the injector and hook my tester to it? Can I do this while the car is running (preferreably when it's "doing it")? I will also use this thing to test each plug wire at distributor for spark.

I read a post that stated "it's either fuel or spark". Here's what I really cannot grasp: if it is only "doing it" at certain rpm, why would I need to check for spark and injector pulse? Obviously they are both present, only absent at a particular rpm or situation. I do better with stuff if I understand WHY things should or shouldn't happen, can someone explain this to me? Last, I had a couple folks tell me it's my cats. That also bewilders me as my cats are 1000 miles old. And wouldn't they be more of a persistent, not intermittent problem?

Thanks again guys....
Eric

 

Problems like that after a restart bring to my mind either leaking down injectors or maybe a distributor pickup coil breaking down after heating.

 

I run an MSD 6A, Blaster GM coil, MSD cap/rotor/wires; the coil is seperate from the cap. Can you tell me where the pickup coil is in my distributor and how I can check it?

How fast should the injectors be leaking down or how long should I leave the fuel pressure guage hooked up to determine a leak? I left mine on for a minute and saw barely any leakdown.

 

It has been way too long since I have dealt with either. Your probs just sounded familiar. My car acted a bit like yours in that I could drive 20 miles fine, then park for a few moments and wouldn't start for an hour or two.

GM shop diagnosed my injector probs so I don't really know what they did for a test. They wanted a fortune for repairs so I yanked them and sent them to Rich at Cruzin Performance and he sent back a flow matched set balanced within 2%. One of the best things I ever did.

I remembered a read about erratic chugs and misses. Seems the pickup coil is wrapped in a paper that breaks down after a few years. I recall it giving people fits because they changed the cap, coil, rotor, plugs, etc. and all the obvious things but the pick up coil was an overlooked culprit.

I wish I could help you more but I would put a call out for Vader or someone more expertise in this area and see if it is worth your diagnosing.

 

I'm having a similar problem. When the car gets to op temp it starts to have a chug and the motor starts to work its way up to 220 also if I get on it i have alot of black smoke out the back but only if I'm really on it. Where is the pickup coil located? I have the msd coil wires plugs cap and rotor along with ngk plugs

 

Here ya' go. Vader has already provided a picture at another thread about the Pickup Coil.

Click Here and Look At #24

You're looking for a part at the bottom of the distributor that kind of looks like this:

 

haha Ever since I read Michaels post, I have been researching ignition modules and pickup coils (about 5 hours now) and so far I'm going to replace the ICM. Thought about getting an MSD Pro Billet distributor, but I've noticed I can just replace the ICM and/or PC for about $60 vs $300 for the whole "dizzy".

Thank you for the pic MikeinAZ. This solution makes a whole bunch more sense to me that the ones I have been considering for the last 2 weeks.

Edit: I just read that post "#24", THAT's sooo helpful!!

 

It may or may not solve your problem. But it is not money thrown away. The majority of 3rd Gen cars are cruising with deteriorated pick up coils. Guys nickel and dime themselves to death replacing every thing thats "not" the problem.

I spent 500 bucks and 10 months fighting a Code 44... reached up one day and tightened 4 manifold bolts.... bingo. Look for the simple.

More and more of our parts are discontinued every day. Things like gaskets, o-rings, pick up coil, rubber products, etc. should be replaced with no guilt cuz' they may not be available next month.

 

You're right about that. I like to get all the use I can out of stuff so I've decided just to rebuild my distributor. I'll check back in a week or so and unload the results.

E.

 

ok another symptom is that she doesn't like starting in the morning but any other time its fine or like if it sits all day and I try to start it at night its a bitch to start.

 

Investigate the cold start injector and temp switch.

Also ohming injectors only verifies the electrical side, they can still be leaking.

later
Jeremy

 

yea but we go right back to it running great till the motor warms up to op temp
once at op temp you have your foot to the floor and it acts like its running on 4 cylinders

 

Do yourself a favor and take the GM distrib out and throw it in the trash can. If it is the original , it is worn out and you can rebuild all the electrical you want and it probably won't solve your problem. I use MSD distrib, but any quality unit will work.

I have seen it time and time again where idle and missfire problems are solved using a new distrib even tho the original had all new electrical parts. Save yourself money and agravation and just buy a new one. The GM units wern't designed to last 20 years and excessive milage.

Gary
Kingston,NH

 

Ok do me a favor then. Send the 300+ my way to purchase a new one.

 

Don't buy one and be stuck with a crappy running car. your choice. These things are 20 + years old. nothing lasts forever. No one ever said this hobby was cheap. Good luck!