Jay_rich

iTrader: (4)

60k Mile Stock 1987 LG4 auto car (canadian, no air tubes etc), only mod is a catless 3.5" from where the cat was back. I have put around 600km on the car since the exhaust change and bought the car last fall.

Issue I'm having...

Fire the car up, let it warm up for like 5 minutes, hop in and toss it in reverse and the car stumbles then dies. The car fires back up and runs/drive no problem.

Couple days later the same issue but this time I listened when it was idling and every now and then you would hear a hesitation in the exhaust note. misfire?. So hop in the car, stalls once it goes into gear. Fires back up and drives no problem. I ended up going through a drive thru so was creeping forward barely touching the gas and I could here the car misfiring/stumbling. from idle to 1000rpm. Now it does not do this in neutral.

Pulled the cap off the distributor and it looks fairly new, cleaned it up anyways (same results, stumble in gear)

Swapped the coil from my buddies car (same results)

Changed the Plugs (same results)

Looked over all of the vacuum lines and I cannot see any issues, no dried out or cracked hoses. However I'm going to try to spray some quick start on them and see if I get a change in idle.

Now the wires appear to also be fairly new but I will not rule them out, maybe swap a new set on, I will also pickup a fuel filter for cheap insurance.


I should add accelerating normal and WOT it seems to run fine.


From what I have read, would maybe the Idle Air Bleed need to be adjusted since the exhaust is more free flowing? I assumed it would be fine catless since it still has stock mani's and the stock Y.

Thanks for any input!

Jay

ex-x-fire

Make sure the egr valve isn't getting vacuum at idle/low engine speeds.

naf

iTrader: (7)

If the cap/rotor/wires haven't been replaced in 50K or so miles, do that first. If your tachometer is jumping at all it's a sign the pickup coil is going out.

Does your model have the ccc-qjet as an export model? Small cap HEI dist?

Jay_rich

iTrader: (4)

I also read that today about the EGR. I will definitively look into that.

I have only had the car for not even a year so No idea when the last tuneup was done but from looking at everything (cap/rotor/wires) All appear to be newer.

Mine has the Coil built in/on top of the distributor. and yes it is the CCC Q-jet.

Jay

naf

iTrader: (7)

when in doubt, swap it out.

failed EGR will usually cause more severe issues but I'd check it anyway.

best way to check your vacuum lines is with a mityvac or similar tool. disconnect the line at the carb or manifold and put some manual vacuum to it.

interesting that it's an export 87 with the large cap and ccc-qjet.

not recommending you go crazy with replacement parts, but I've found that a new dizzy for a near 30 year old piece can solve a lot of minor issues and bring some peace of mind.

Jay_rich

iTrader: (4)

Ya from what I have read it was an option in canada.

Well good thing is I have 2 spare dizzy's My buddy had a couple sitting on the shelf from his old Monte SS's

So last night checked all the wires. All seem to be giving me close to the same OHM reading. So no broken wires.

Tried spraying some quick start on the intake and all the vacuum lines with no luck.

Tonight I'm gonna try swapping the Cap and Rotor in it just for ***** even though mine appeared to be fairly new. (buddy gave me 2 of those also). May as well stop and pick up a fuel filter also.

If that isnt it, I will just drive it out to my fathers and use his manual Vacuum pump and timing light and check it all over. I may bump the timing up a bit anyways. He also had an LG4 84 Z28 (now 383 sbc) so Ill see what he thinks. He is the family carb guru. I tend to stick with FI.


Im starting to wonder if its a fueling tip in issue from the 3.5" and no cat. Its basically mufferless also since it has a dynomax straight through since.

Anyways I will try to keep this update with my progress.

Jay

naf

iTrader: (7)

Exhaust system may require an adjustment to IAB settings to reaquire the proper dwell range. If it's far enough out the motor may not be going into closed loop and you'll experience some tip in stumble. Get 100% on the ignition, check your TPS then plug in your dwell meter.