engine GREMLINS...help me please!!!!

[1991vert]

engine is a brand new 347 stroker.

so i go to check my timing out of curiousity today and i pull the spout and point at the balancer...it's at 10* ATC. so im like okay what the hell? my car does this funky idle thing. it's not the typical idle surge where it revs up and down real quick and wants to die. this is more of a goes from regular idle (950) and then goes up to 1100rpm for a while, then dips down to 950 for a about 3 seconds and then goes back up to 1100rpm and stays there.

i pulled the codes and got one for the secondary air diverter solenoid (EGR system) or something and i went over all of my vaccuum lines. i have re-torqued my lower intake and all of the lines coming off of the intake.

back to setting the timing...so as soon as i go to set the timing my car starts doing the weird idle thing and the timing gun stops blinking! at that point i gave up and came inside.

the timing gun is hooked to plug #1, all the way towards the boot so i dont get any interferance from other plugs.

what would cause the timing light to lose it's signal? it's linked to the engine idling funny because it only loses it when it throws a temper tantrum.

could the computer be the cause of it idling funny? i grounded the (+) cable by accident when i was prying off the timing cover with a crowbar. at least i think it was the battery cable...

 

[HISSIN50]

If you put the timing light on another wire, does the timing light stop working also? It could be more of an issue with the light (most inductive lights have an arrow on the plug wire clip, for instance. Was it oriented correctly?).

While you pulled codes would have been a great time to do a cylinder balance test. This would have shown you if one particular cylinder was not contributing all it can.

Your combo could be the cause of the weird idle (if you have not had the new combo running for a bit, with all quirks ironed out).

And you might want to double check your code and/or definition - your wires are crossed in what you posted above.

Good luck.

 

[1991vert]

it was the secondary air diverter solenoid. the code reader has a definition of inlet air control circuit malfunction, but when checked with a ford book, the code # was the secondary air diverter solenoid.

the timing light is a snap on and it has a clamp to snug it up close to the wire.

no matter what it should always get a spark reading, correct? it only stops getting a signal when it's doing that weird idle surge thing.

im thinking it's surging because of the computer? i've already replaced the idle air control valve. and it's not the dreaded e-cam surge because it never wants to dip down low and die out.


edit: there's about 500 miles on the engine and it's been through numerous heat cycles
is there anyway to check the EEC pins for a certain voltage to determine if the EEC-IV is shot?

 

[HISSIN50]

it was the secondary air diverter solenoid. the code reader has a definition of inlet air control circuit malfunction, but when checked with a ford book, the code # was the secondary air diverter solenoid.

the timing light is a snap on and it has a clamp to snug it up close to the wire.

no matter what it should always get a spark reading, correct? it only stops getting a signal when it's doing that weird idle surge thing.

im thinking it's surging because of the computer? i've already replaced the idle air control valve. and it's not the dreaded e-cam surge because it never wants to dip down low and die out.


edit: there's about 500 miles on the engine and it's been through numerous heat cycles
is there anyway to check the EEC pins for a certain voltage to determine if the EEC-IV is shot?

You're getting it. I saw no mention of EGR in this post of yours.

The clamp question still stands. You're simply trying to rule out user error or tool error. You should have constant spark - that's why I asked what I did (so you don't go chasing an issue that isn't there). If the timing light stops showing spark on all plug wires when it hiccups, it's a timing light issue because all cylinders are not dropping at the same time.

Most often when an EEC goes south, multiple systems fail. It would not be high on my list of things to check, though if you have a spare puter and the inclination, it will rule it out.

WIth the SPOUT connector in, does it hiccup? I'd also clear the old codes (if you didnt already) and let it idle, make it hiccup and pull codes again.

Folks like JRichker will have some very good ideas for you.

Good luck.

 

[1991vert]

well with the spout in it will still hiccup. the code that was pulled was for a vaccuum line that went to the valve that was connected to the smog tube that goes to the back of each cylinder head, which no longer exists. the only stored memory codes i have is from o2 sensors reading lean conditions. i guess im getting those because im running 24# injectors on a 347. my fault for that haha.

that's the thing with the timing light cutting in and out. when the engine's RPM raises i will get no signal. the engine does not sputter or want to die, but it's almost like someone is in the car steadily raising the RPMS. the engine idles smooth. what controls the idle besides the computer? i unplugged the IAC and had the spout out and the engine was still getting hiccups which is why i think it's something electrical?

i appreciate all of your help and i hope you have more ideas to throw my way

 

[bt15]

Are you still running the stock ignition system? When I had a similar problem with my '85, it turned out to be my (aftermarket) ignition box was heading south...FAST. I've also had similar indications from a badly corroded ignition circuit fusible link causing intermittent problems. It was EXACTLY as you've described with momentarily losing my timing strobe and everything. Might be worth a wire wiggle or two.

 

[1991vert]

well i fried the fuseable link to my alternator last year so that's new. i put in a new stock coil and i tried a friend's stock distributor.

i just pulled the plugs and they're the tiniest bit white. you can still see the bronze from the plug though.

the whole losing spark thing has me baffled.

the red wire on the IAC gets 12.25V with the key on, engine off

edit: i had to get a new timing cover so i had to move the ground that originally went in the drivers side of the timing cover to the a/c delete power steering bracket.

 

[1991vert]

ttt