Hey all I am new to the third gen list here I have been on the second gen one for a long time.. this one is pretty cool as well.

Ok my concern is this... I bought a 1985 Z-28 with the LG4 and when I got it the motor was staggering on it's last legs,.. I planned on doing the motor anyway when I got it and did so, doing a fresh healthy rebuild on the 305. When I bought it the EGR was blocked off and he had a Edelbrock carb on there. He kept it and I put the carb off another 305 1985 camaro on, the feedback Q-jet. When I pulled the motor aprt every piston had the compression ring broken into peices like chiclets.. not cool. Well when I put the motor back together, everything is fine but I have a spark knock condition that presents itself whenit pleases,... not fun. I replaced the EGR with a Delco one straight form the dealership, and as far as I know I have all the vacuum lines routed correctly. When I got it is was a mess but I HOPE I have it sorted out. Had anyone heard of what may cause this? I have the timing set at 0 degrees, set it with the 4pin connector disconnected, and also rebuilt the carb the other day,.. all seems oko. It will drive fine it seems, no SEs light or anything, but also seems like a light miss at idle sometimes intermittantly? I am an auto tech and I have talked to a few older techs,.. they are all at their wit's end.. when I hooked it to a snap on scanner I had nothing really obvious jump out at me. The o2 sensor was not switching really wide though, though I figured it was from being in open loop yet. I am thinking I will replace it anyway as good measure, since when I freshened the motor I replaced all sensors ( Knock, temp, temp unit, oil pressure, etc) When I jumped the a/b connection, I have a code for rich exhaust, lean exhaust, and a MC solenoid code. I did not replace the MC solenoid though now I wil lprolly as well. When the spark knock occurs, I can accel thru it and it goes away. it usually starts at light pressure on the go pedal, then worsens a bit as I step into it easily. if I tromp it-> poof it goes away. Most times I will be driving and it is fine no noise or anything. It just does it when it wants. CAN ANYYYYYYYYYONE HELP ME OUT?!?! or has ANYONE heard of this?? THANKS in advance for ANy help you may give...............

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1980 Camaro- (sub) frame off resto, my drag car

1985 Z-28 - My newest toy and driver

1967 Camar - to be purchased SOON!!

 

i am getti a code tht says lean exhaust as well, and am having a problem with noise from my engine. What does the spark knock noise sound like? Is it like a clicking noise? If so, maybe that is my prob, im havin a tough time figurin whats wrong with my car, and any imput would help me a lot. I also dies sometimes when i try to strt it.

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1986 Metallic Blue IROC-Z
80k miles, 305 TPI
Mods:
-Edelbrock Hi-Flow baseplate
-Dynomax Cat-back
-gutted MAF
-K&N's
-airfoil
-shiftkit

 

Spark knock is detonation, pinging,.. everyone has a similar name. it sounds like pebbles in a coffee can, or also like a diesel engine under heavy load kinda that knocking/pinging rattle noise it makes. In a car it is more hollow sounding. Hope I didn't confuse you more than I helped.

 

Supposedly a non-functioniung egr can cause ping. But you say the egr is probably OK. Ping can also be caused by carbon buildup in the cylinders or on the piston face. The carbon could be glowing hot and pre-igniting the gas. You say you set the timing to 0. Not sure what an LG4 is supposed to be.
Techron Concentrate is good for cleaning out carbon. And lightly spraying a mist of water into the carb with engine running will clean out carbon too. You need to use at least a cup of water, and it takes a while, too. Be careful not to put too much h2o in at once, which could be harmful to the engine.
Running lean causes ping too.



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88 GTA 5.7 TPI Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

 

Water fed into intake? Old Wise mans' tale. DON'T DO IT. Water bad for engine. Already been through this at college. Very bad consequences.

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1987 IROC,305 TPI Slush box G80,G92,143K+:Mint condition,K&N Filters, ADS Superchip, Stock Exhaust, Virgin Engine and transmission.

1968 SS Camaro, 350 built and shaved, Holley 750 Dual line double pumper, TH-400, 3.73's

Two other Thrid Gen Camaro's for parts ('84Z and '85Z TPI)

 

What, a whole bucket of water? A mist doesnt hurt anything and cleans up the inside real nice.

As for the knock, if you have a code for both lean and rich exhaust something is wrong. Check the wiring to make sure its not grounded where its not supposed to be, that its grounded where its supposed to be, and make sure the choke isnt hanging up at all. Just as a guess since the previous owner had replaced the carb with a non-CC carb and blocked off the EGR, its probably an issue with the fuel delivery on that carb, possibly the MC solenoid thats bad. Those carbs also have to be adjusted right or they will just dump fuel like mad, I have seen more than a few that someone didnt know what they were doing and just made a mess of things. The screw right at the back of the choke horn under a plate (for the life of me I cant remember the name) is critical.

 

madmax... are you talking about the air bleed screw???

zroc

 

Hey all,.. I tuned her up a little more and all I have left of spark knock is at light tip in at cruise, usually when I am at the bottom of a hill going up. It is still running rich though, and I'd love to find a book out there on tuning q-jets. Anyone know of a good one?

Also, I have a goofy electrical gremlin,.. OK. When I put the motor back in, I know I reconnected every connector to where it was when I received the car (which is not to say the previous owner didn't switch a few around or whatever in the name of high performance,.. ) with the only exception being that at the rear of the passenger side head, I ran the ground strap from the body to the back of the head, to the top of the intake along with a ground from the harness in that area as well. When I drive the car, my choke light flashes, and it seems to be in time or sync with the MC solenoid, and if I hit the brakes or turn a turn signal on, it changes the pace the light flashes or makes it go away completely. After a bit the light stops flashing, but usually when I come back to around lower rpms it starts up again. Is it possible that not having the grd go to the head instead of the intake would do this or something? I am not totally afraid of it , but it still isn't correct you know? Anyone have somethinglike this happen before to them?? TIA

 

I know QJets pretty well. If you are running rich it is usually as a result of a bad O2 sensor, or the mixture control solenoid is not connected or bad inside the carb. The CCQJet defaults to full-rich if not receiving a correct signal from the ECM.

The choke light is also the alternator light on these cars. Don't asky why, I don't know. Make sure your alt. voltage is good at idle, low RPMs.

OR........ if your choke really isn't working that could certainly cause the car to run rich. Makes sense, no?

Makes sure the choke plate is totally vertical (open) when the engine is warmed up. If not, then maybe you really do have choke problems.


[This message has been edited by Damon (edited November 21, 2001).]