Recent content by ned pepper

navy man, the "D" threw me off, plus ref to "primary coil." I thought you might have one of those gimmick boxes that people bolt/connect into the system, like MSD, whatever. I may be wrong about the spark color IF using the GM tester. FSM does not mention color in that test, but does refer to...

navy man, the "D" threw me off, plus ref to "primary coil." I thought you might have one of those gimmick boxes that people bolt/connect into the system, like MSD, whatever. I may be wrong about the spark color IF using the GM tester. FSM does not mention color in that test, but does refer to...

cali navy, you lost me. I threw in a new primary coil and it's the same issue, so I'm looking at the pick-up coil and the ignition coil now. do you have the stock HEI? one ignition coil, one pickup coil? I admit that I do not know what a "Distro" is. but I am quite familiar with the HEI...

I read the page a while ago, refers to "weak coil," also "proper ignition coil output voltage." I think there are various reasons for weak coils, either pickup or secondary. will have to read it. I USED to know it. long time since I been into that. added: any spark has to be blue/white, yellow...

you meant volts instead of ohms, right? or am I terribly confused? .6v to 5v WOT.

been there, been there! anyways, good catch on the k ohms. I can quit wondering how it worked most of the time, since it is not adjustable, can't get loose easily. also should not cause backfire. still meditating on ignition, coil, coil grnd, whatever. open EGR is an option, if you have it...

hardware stores have them, like a round steel brush with a stem that fits an electric drill, or use a bristle bottle brush, something that will not cut the aluminum or damage threads. my instinct says it is residues and not metal that is causing the tight fit. shine a light in it.

I would use the one GM uses, not sure whhat your LT1 takes. you will get a dozen different opinions, all of them as good as another.

ok. I would brush it, lube the bolt and try it. if you cut new threads, which is not likely, the threads should be loose, not tight. should be able to look inside with a bright light.

good analysis! the 91 is supposed to have the non adjustable TPS, so it may be defective.

is the hole full thread, into water jacket, or blind? meaning it has a bottom. I would run a wire "drill" tool thru it to brush it out, no reason to use a tap. it is aluminum head. some bolts on the runners are blind holes, use shorter bolts. not sure about intake.

did you test fire/spark with a comparable GM tester? if it was a bit weak, a low output coil can be part of this problem, per 6e3-6 section, "Symptoms." esp backfire. that tester is a severe test for spark, and the spark would be blue if I set my timing at 6, est out, and rev engine slightly...

added comment I failed to mention that IF this is just an overnight or long time between starts issue, and I assume it starts fine -less than 3 secs crank otherwise- it points to a slightly leaking injector. a fuel pump can leak pressure back to the tank if the check valve is failing, but pump...

it may be lean or rich, either will do this. if so, most likely rich due to injector leaking. the book says: try the "clear flood" method; hold pedal to the floor while cranking so that the ecm will lean out the injectors. if it is "lean" it could be lack of fuel to the rails. the fuel pump...

you won't get the same smooth timing advance curve with the ecm as you would with a centrifugal advance. ecm uses rpm, load, and engine temp -rpm, MAP, CTS. 6e3-c4-1. not sure that revving the engine as you did will result in the max advance. may be.