Bull86

Hi guys. I have discovered i have a standard 4 barrel quadrajet instead of the E4ME. My car is a 1986 Trans Am, 305 5 speed, 3.27 LSD, dual cat back 3" exhaust. The original distributor is still there and the leads/plugs for the E4ME are still there resting on the inlet manifold, it appears the previous owner just swapped carburetor and that's it. The SES light is constantly on. I can purchase locally (i'm in Australia) a reconditioned E4ME from a 1986 trans am but was from a auto car, not manual. Will this carb still suit, can i swap throttle linkages etc.. over from the one i have so it suits my manual car? I really don't know much about these cars or carburetor. Although it has the wrong carby she will spin the wheels in first, second and a bit of third, but i read somewhere that the engine with a non CC carby would make it run like a dog? Anyway, i would like to put her back to original so if someone can point me in the right direction please.
cheers
Bruno

jwfirebird

iTrader: (2)

the way i understand it the electronic portion is for part throttle efficiency. i had a 86 305 with a e4me that i had no computer hooked to and it ran slightly better 1/8th mile than my buddies firebird that the engine came from, only difference being i had better gears

naf

iTrader: (7)

the e4me from the auto car will work fine with your manual. it will likely need to be adjusted for proper dwell once installed on your 86, which should only require a dwell meter (or scanner) and a screwdriver. if the carb has been rebuilt a few other adjustments 'may' be required.

if you need help with the adjustment procedure post back and I can walk you through it when you're ready.

Bull86

Hi naf. Thanks mate, i will let you know when i install the E4ME. I do have a timing light with the dwell/tach meter on the back that i have used on other cars in the past, i have used only the timing light but not the dwell, going to look into 'dwell' a bit more by looking on google and my factory service manual should arrive in a couple of days so i will be having a good read as well. Cheers Bruno.

naf

iTrader: (7)

in short the mixture control solenoid (mcs) controls the primary mixture by moving the primary rods up and down in the primary jets. the dwell is defined as the amount of their time spent down, restricting flow. the ecm commands down time based on a constantly rewritten map of dwell needed for current operating conditions (vac, timing, rpm, throttle position sensor, etc.). the ecm uses the O2 sensor reading to fine tune its dwell requirement for conditions throughout the driving range except full throttle.

dwell is measured witht the meter connected to the green diagnostic lead near the blower motor. the idle air bleed (IAB) is adjusted to get dwell near 50% at idle in drive. this gives the best range - lean to rich- to adjust the mixture over the operating range.

turning the IAB up allows more air into the mixture (leaner)

more dwell keeps the primary rods down in the jets more (leaner)

less dwell keeps the primary rods up more (richer)

when the ecm sees a large throttle opening from the TPS it commands full rich. at WOT the secondaries are your primary fuel providers anyway and are not controlled by the ecm.

let me know when you're there

Bull86

I finally got around to fitting my carb. I adjusted the mixture/idle screws to 3.5 turns out and the motor fired right up and everything seamed to be ok. I got my timing light which also has Tach & Dwell meter on the back, connected it up and now the motor runs terrible, the revs are going up and dropping sharply and just bogging big time. I must have blown something? I'm going to buy a decent dwell tester and try again, but might have to put the other carb back on for now so i can drive it.

sofakingdom

iTrader: (1)

3.5 turns is probably too far in; the threads on those are REAL fine, so they take ALOT of turning. 5 - 7 turns out is more normal.

That said though, they have very little "authority"; best to just set em somewhere, say 5 out, and then adjust the idle air bleed valve for a decent range of control of the dwell. 0° = the ECM is thinking it's rich, and is commanding full lean; 60° is the opposite. Ideally you'd want it to be well away from either extreme both in gear and out.

First though you need to set the solenoid stops. For that, you need a tool that looks about like a slot screw head; needs to be about 1½" long and 5/32" - 3/16" diameter (correct size to fit in the holes in the top of the carb) with a slot about 3/32" wide. I usually find it best to set the lean stop to around 2½ turns up from all the way down, and the rich stop about 4 turns down from all the way up, and then tune from there. Gotta get those right first because they affect the IABV: they control the actual solenoid plunger travel.

And of course the ECM won't have its head screwed on straight if it can't accurately measure the oxygen content in the exhaust; might want to just change out the O2 sensor before trying to tune it, because it's completely hopeless if that's not telling the ECM the truth. Remember, it's a feedback loop; the ECM adjusts the duty cycle of the solenoid based on what it sees from the O2 sensor, which is basically its only "eyes" on the outside world. If it's blind it can't possibly control the mixture properly.

Chuck84TA

Good post.

Dumb question-- (or maybe not )
When you say "turn" with respect to adjustments... Is that a full 360* turn for - 1- turn? So 2-1/2 turns would be 2 full 360* turns and a 180* turn? Sorry about the question for possibly being too obvious...just want to be totally sure I'm doing this right..

Thanks!
Chuck

jmd

iTrader: (4)

Souns like you were running with an ECM-controlled distributor and the non-CCC Q-jet?

It is unlikely the timing was being controlled accurately with the multiple fault codes being set and lack of TPS and M/C solenoid signal.

However, default timing advance (on top of base timing) is addressed in part by the HEI module in the distributor.

Getting to my point, you're probably not running with base timing that is set at a degree which will suit a code-free ECM & Q-jet. The ECM timing advance schedule gives better drivability than "default" provided by the module.

Base timing can be set by disconnecting the 4-wire plug going to the distributor, starting the car, and setting base timing. Usually between 0 and 6 deg BTDC depending on few things. Your octane rating of the fuel may allow for more or less than what I can guess from here.

After set, key off, reconect the 4-wire plug and you should be set. Excess advance can lead to surging. I think one of the earliest times I messed up the timing on my car, I had it at 19deg. BTDC which is going to give erratic running, idling, etc.

I'm not familiar with whether you are doing this to suit the emissions regs. in your area but carry on and good luck with your repairs.

naf

iTrader: (7)

yes. 360 degrees for one full turn.

Bull86

I have done away with the CC Quadrajet i installed on it as it had a cracked and broken area on the carb (hence why i got it cheap on ebay). What a shame as it looked brand new. I found too many other problems with sensors and other things under the hood that i decided to go with a non CC carb (i just rebuilt), new vacuum advance distributor, headers (having problem fitting RHS one as steering shaft in the way, my bird is RHD), deleteted the Air Con as it didn't work well anyway, i can actually see my engine now! The car was originally from California so it was full of your smog stuff, the smog pump seized and my V belt melted off so i just decided to take most smog items off (all i need here is EGR & Charcoal Cannister pretty much). The front of my car looks like it needs lowered springs now Thanks everyone for your help, i will let you all know how she runs.

Bull86

What a nightmare this has been. Purchased a new $50 Procomp Distributor with Vac Adv that has caused me nothing but grief! The distributor made the engine run terrible, fouled my new plugs, made my quadrajet backfire several times and catch fire and the list goes on! I put my original CC Distributor back on and it runs fine again! I was unable to fit my new stainless headers (these came in a box with my car) because the drivers side (RHD) hits the steering shaft so i have to make some mods to them (need to find someone who can weld stainless, i tried and failed). I always wondered why my secondaries on the quadrajet would not work, well the damn thing is warped! The top doors rub when open so i will have to do a bit of filing around the walls and try and flatten the air horn sections, or purchase something newer?, my carby is a quadrajet 17058282 and going by one i saw on the net is a 1978 800cfm type (overkill for my 305). I have pretty much only used the primaries really, which is why i have had such great fuel economy and power has still been fine too.

midias

Found your problem

naf

iTrader: (7)

try loosening the screws holding the air flaps on and adjusting them for a better fit before filing anything.