tspooner1985

i have a 1985 camaro with 305 Qjet 4bbl i cant figure out what is causing a code 41. The car stumbles at low rpms just cruising and goes away when you get on it, when you try to go wot it bogs down and will die if you keep it at wot. it also has a hard time starting. some one please give me some advise thank you

tspooner1985

does anyone have a clue pickup coil??module??ecm??

Tuned Performance

iTrader: (92)

ecm or prom would cause a code 41

naf

iTrader: (7)

I've run into an issue with the tach signal code before, it may have been a code 41 on that one. Wiring harness from dist was bad on that one. ECM basically didn't know that the motor was running.

Best to hook up a scanner to it and see what the ECM sees while it's running. Beg, borrow or acquire an Autoxray or the equivalent and it'll show you the (semi) real-time data.

Your WOT behavior is NOT due to any ECM/sensor issues. Focus on fixing the computer controlled primaries first though.

Tuned Performance

iTrader: (92)

Is the code 41 not for 41 CYLINDER SELECT ERROR (FAULTY OR INCORRECT MEM-CAL) for the 85 ccc ? Wot fueling is done bye the secondary metering rods they may be incorrect to lean or to rich or the secondary air valve in not opening all the may contaminants in the float bowl.

naf

iTrader: (7)

I don't recall, only that I had an ignition wiring gremlin that tripped a 4X code. The ECM wasn't seeing RPM on that one (among other things). In my experience, the codes don't help much on the ccc-qjets (except for a few common ones). Often you'll get wonky behavior without even tripping codes. Hooking up the scanner while it's running, or even while you're driving, is the best way to sort things out.

RBob

iTrader: (1)

Code 41 on the CCC set ups is what is know as a "tach input error." LIkely something wrong in the distributor or between it and the ECM, or possibly the ECM itself.

RBob.

tspooner1985

it has a rebuilt q jet on it next im going to put remanned dist if that doesnt do it then it must be mem-cal or ecm right???

RBob

iTrader: (1)

Don't forget the connectors and wiring. Connectors are the most troublesome areas of electronics. I try to avoid designing them in whenever possible.

RBob.

naf

iTrader: (7)

A reman dist is always a good idea for a piece that is old and of unknown quality. Like said above though, inspect the wiring closely, especially the small harness that goes from the module in the dist to the cap in coil connection and the four-wire connector.

A reman should come with a new Ignition Control Module. Before you turn in your core, pull out your old ICM and keep as a spare. Can't hurt and they'll never notice.

Do not jump to memcal/ecm without scanning the data. Unless you've got a no-cost one laying around just as a check.

tspooner1985

This really sucks i put the dizy in and the car still bucks alittle at low speed with low rpms the wot issue i think was just not enough gas could it be anything else? does the differential pressure sensor have anything to do with this? its such a nice car i dont want to give up on it

danclemts

iTrader: (1)

Fuel filter clogged?

tspooner1985

the connectors all look good too

tspooner1985

nope fuel filter is new and i checked it

danclemts

iTrader: (1)

Does it start right up after dieing at WOT? plugs fouling? usually too little or too much fuel, Does it die like key turns off? or more and more misfiring till it dies, If its immediate shutoff, I'd look at electrical stuff, if gradual, then fuel related more likely. General rules, but something to start

naf

iTrader: (7)

Did you set the timing to near 0 degrees WITH the four wire connector to the distributor unplugged?

There should not be a differential pressure sensor. There is a vacuum sensor on the driver's side near the brake booster that is connected to the carb by a hard vacuum line. There is also a Barometric (Baro) sensor on the opposite side that looks identical but should have NO vacuum line connected.

tspooner1985

yes i set timming with it unplugged at 0 then plugged back its at 8 and i have a map sensor in there right now is that bad

naf

iTrader: (7)

Timing should be much higher than 8 with the EST connector plugged back in at idle.

Not sure what you mean by map sensor. Is this a semantics issue?

tspooner1985

where the vac sensor is i have map sensor from advanced they gave me that it must be wrong and for timming at 8 what do i do or what do i replace.... where should it be???

naf

iTrader: (7)

If the part looks the same, plugs up the same and has the vacuum line fitting, it's probably the same part. They just didn't know what to call it.

Double check your base timing and make sure the distributor isn't moving. Timing at idle should be 'around' 20 degrees or so with EST connected. They'll be no marks there so exactness is lacking.

tspooner1985

when i unplug the est its hard to start i get it running an put it at 0 then shut it off plug the est back in an it only idles at 8 degrees so should i put base at 4 then plug est in cause this gets me to almost 20 degrees at idle??

naf

iTrader: (7)

Sure, try a little more base timing. See if it runs better.

tspooner1985

OK the timing is good now I'm getting a code 44 lean it also popped out the carb today I also noticed it ran worse after the ses light came on any ideas for that?

naf

iTrader: (7)

Was it running fine with the reman carb before the dist issue came up?

tspooner1985

no it ran alittle better with reman carb but was still throwing code 44 before an after the code 41 hasnt came on so i think thats fixed do the idle mixture screws on the front of the carb have something to do with this, if so wihich way do i turn them to make it run more rich?

naf

iTrader: (7)

Ah. Any carb swap may require some adjustments. Probably all yours needs.

Don't tinker with the idle mixture screws though. Adjustment requires a dwell meter, or scan tool, to read dwell of the mixture control solenoid. The IAB is adjusted to get dwell nearest 50% at idle. Get ahold of a meter and I can walk you through.

tspooner1985

Ok i have a dwell meter how do i set the mixture? An also i had flowtech headers on my 91 tbi 305 i was wondering if those will fit my 85 305 4bbl?

naf

iTrader: (7)

With the timing good and TPS voltage set:

Start with idle mixture screws each at 4 turns out. Set IAB at four turns out. Warm up the engine and connect the dwell meter to the green diagnostic lead near the blower motor. It is a single wire lead that comes out of the ECM harness just past where it comes out of the fender. The other lead for the meter should go to ground.

If it's in closed loop the needle will waver back and forth slightly as the ECM adjusts for O2 voltage. You want to adjust the IAB 1/8th of a turn at a time until the dwell hovers nearest 50% or 30 degrees on the V6 scale. If it's not moving try turning the IAB in 1/8 turn at a time until the dwell either responds or the engine begins running worse. If no luck try it the other way not to exceed 7 turns out.

If you can't get it to go into closed loop (needle wavering) set your idle mixture screws at 2 1/2 turns out. Go through the full range of turns with the IAB starting at 2 1/2 turns out on it. Turn it 1/8 turn at a time, give the motor a chance to respond then open it a little more. If it doesn't find a sweet spot after you've gotten to about 7 turns out on the IAB, start over at 3 turns out on the mixture screws. In the end you want to be nearest 4 turns out on each, not over 7 turns on anything.

Once in closed loop, turning the IAB OUT will allow more AIR IN, leaning the mixture and the dwell meter should respond RICHER (lower dwell). Higher dwell means the rods are in the jets a greater percentage of the time, restricting fuel.

The dwell will change with engine speed and load even in open loop. You'll only know it's in closed loop when the needle wavers slightly back and forth as the ECM adjusts for small changes in O2 readings.

Those headers should work fine as long as they have an O2 bung.

tspooner1985

ok so i did the dwell its set but now the car will red line in park no problem but in drive it wont go past 3500rpms even if u go slow into the throttle. like ill be driving at about 60 at around 3000 rpms if i try to go faster it bucks bad like its not running then it is. Also if i try wot (at 3000 rpms) it makes a loud bogging sound like the secondarys are wide open and the car will roll to a stop if u held it at wot ive never see anything like this ive put a feul pressure gauge in an it stays at 6 7 psi the hole time its doing this so i dont think its fuel all the ingnition is done wires new dizy and plugs are good what the hell is wrong with this thing!!???