Computer controlled Q-jet to a non Computer one?

[capriceowns]

The carb on my car still has serious problems with it, all cause of the poor rebuild I did (also my first) I dont have the 400$ to buy a reman one. But I have a Edelbrock reman q-jet I got with the heads and intake from a dads friend (all free)

The guy said the carb has less than 1000 miles on it, still looks new.

Can I switch over to the non computer carb without any problems like driveability and such?

[silicon212]

You will lose some performance and lower your economy, but it can be done. You MUST replace your distributor with a mechanically-controlled unit or your car will have the performance of a misfiring Yugo coupled with the fuel thirstiness of a diesel-electric locomotive.

[capriceowns]

Originally Posted by silicon212

You will lose some performance and lower your economy, but it can be done. You MUST replace your distributor with a mechanically-controlled unit or your car will have the performance of a misfiring Yugo coupled with the fuel thirstiness of a diesel-electric locomotive.

would I still have to get the mechanical disturbtor if I use this carb on my 350?

[silicon212]

YES - if you remove the electronic carb and replace it with whatever one you have, you will lose the use of the computer period. With no functional computer system, you will not have a computer controlled spark curve. With no computer controlled spark curve on a fully electronic distributor such as what your car has, your timing will always be at the static level. This is usually 6-8 degrees BTC, whereas optimum performance and economy tend to want 28-32 degrees BTC. depending on conditions.

I can tell you that on my own car, with its 350, when the computer went tango uniform last year, performance dropped to the level of a V6 and the car averaged about 2 - that's two - miles per gallon over the two days I drove it like that. You can expect that same level of performance and economy with the electronic advance distributor and no computer.

To further put it in perspective for you, that's about half the economy of an 800hp NASCAR Nextel Cup car at 180 mph.

[capriceowns]

Originally Posted by silicon212

YES - if you remove the electronic carb and replace it with whatever one you have, you will lose the use of the computer period. With no functional computer system, you will not have a computer controlled spark curve. With no computer controlled spark curve on a fully electronic distributor such as what your car has, your timing will always be at the static level. This is usually 6-8 degrees BTC, whereas optimum performance and economy tend to want 28-32 degrees BTC. depending on conditions.

I can tell you that on my own car, with its 350, when the computer went tango uniform last year, performance dropped to the level of a V6 and the car averaged about 2 - that's two - miles per gallon over the two days I drove it like that. You can expect that same level of performance and economy with the electronic advance distributor and no computer.

To further put it in perspective for you, that's about half the economy of an 800hp NASCAR Nextel Cup car at 180 mph.

woah thats serious. I didnt think my carb was that important.

I think im gonna stick it out with my ill Q-jet on my car now for a while, and sell the non computer one for a Reman computer one.

Ebay and summit goes for about 300$ replacing my carb sounds easier then the whole dist mess.

thanks silicon

[Blue Bowtie]

Unless the main body is broken or someone has hacked it beyond the point of no return, it should be repairable. Throttle shafts can be bushed easily. Dip tubes can be replaced. Air bleeds can be replaced or peinned closed and re-drilled. Leaking well plugs can be sealed easily. Nearly everything else is a removable/replaceable part.

What, exactly, is wrong with the current E4ME?

[capriceowns]

Originally Posted by Blue Bowtie

Unless the main body is broken or someone has hacked it beyond the point of no return, it should be repairable. Throttle shafts can be bushed easily. Dip tubes can be replaced. Air bleeds can be replaced or peinned closed and re-drilled. Leaking well plugs can be sealed easily. Nearly everything else is a removable/replaceable part.

What, exactly, is wrong with the current E4ME?

Ill try to list all the problems, I know its fixeable, but I have no clue how to do any of it.

is there some book out there that would tell me how to fix all the stuff you listed BB?


Problems
1: Runs real rich
2: has an extremely hard time starting after engine is warm(some times needs starting fluid)
3: when its warm out the fast idle on the choke never turns off, so the car idles extremely fast, makes it hard to stop.
4: if i give it any pedal past 1/2 throttle its bogs so bad it never gets going again unless i let off. it will never let me accel with the pedal that far down no matter how long i hold it or how warm it is.
5: vaccum leaks from the base of the carb/butterflies. if i spray carb cleaner or water down there it bogs/races for a second.

[Blue Bowtie]

It seems that there may be multiple problems, some of which may not at all be the fault of the carburetor, while some may be on the carburetor:

1. Potential causes of your described problems which should be checked at the carburetor:
   • The rich condition is important to solve, and could be related to some of the other problems you are experiencing.
     1. The choke plate not opening fully could be a problem, and will also cause the high idle cam to remain engaged.
        • Make sure the choke and linkage are moving freely:
          1. Clean the choke plate, choke thermostat linkage, and high idle cam and linkage on the right side of the carburetor with a spray-type carburetor cleaner.
          2. After the cleaner has dried away, apply a light lubricant to the linkages and choke pivots. Even WD40 can be used for this temporarily, but it won’t remain there for long, so plan on using a real lubricant eventually.
        • Since the choke should be electrically heated, make sure the choke thermostat heater element has 12V when the engine is running. If not, that could indicate a problem with either the charging system or the choke heater relay.
        • Once power is there, allow about five minutes for the choke thermostat to completely warm up and open the choke as far as it can. If the choke is not fully opened at this point, rotate the choke thermostat housing to just the point where the choke is fully opened. This may require either loosening the three mounting screws around the thermostat ring or loosening the rivets.
        • ”Blip” the throttle once the choke is fully opened and see if the idle PM returns to something more normal. If not, inspect the high idle cam and linkage to make sure they are not holding the throttle open. Further adjustment of the choke thermostat position or linkage may be necessary to fully disengage the high idle cam, but usually is not unless it has been tampered previously.
     2. The float/fuel level problem could also cause a rich condition. However, the float position doesn’t usually change, and this can be diagnosed by observing the secondary fuel nozzles with the engine running, and briefly after it is turned off. Manually open the secondary air valve and check for fuel spillage out the nozzles. The presence of liquid fuel there can indicate a float or inlet valve problem. If that is not apparent, disregard the float/fuel level adjustment for now.
     3. Lacking any other obvious cause for a rich condition, the main and secondary metering well plugs on the underside of the main carburetor body are known problem areas. Any fuel leaking there goes directly into the intake and can significantly enrich the mixture, drain the bowl after shut down, and cause flooding and hard starting. These can be cleaned off, peinned closed, and covered with a fuel-resistant epoxy to seal them against fuel leakage.
   • Another primary item of concern is the apparent vacuum leak. Insufficient vacuum will kill carburetor performance, since the carburetor does not have the correct vacuum signal from the engine. As previously stated, a leak can also affect the ECM operation via the MAP/vacuum sensor.
     1. You remarked that there is a known leak at the base/butterflies. That needs to be investigated to decide if it is one or the other (or both).
        1. If the leakage is at or near the base, there may be a problem with the mounting flange or gasket/spacer. You'll probably have to remove the carburetor and raise it enough to remove the gasket. You can inspect the gasket to determine its contact pattern, and hopefully identify and mismatch or leakage areas.
        2. If the leak is not through the base gasket, inspect all vacuum lines and fittings where they attach to the carburetor throttle body for damage or leaks. Repair any problems found there or replace suspect or poorly fitting vacuum lines.
        3. Check for play or looseness of the throttle shaft where it enters the throttle body. Any play of more than a few thousandths of an inch can indicate the need to install bushings in the throttle body to restore it. However, play less than about 1/16" should not create a vacuum leak sufficient to cause all your described problems.
     2. Any other vacuum leaks, internal or external, can create problems. These include the power brake booster, PCV valve and system, EGR system, all other vacuum lines, and any gasketed joints.
     3. A vacuum leak can cause the MAP/Vacuum sensor to “fool” the ECM into thinking the engine has more load than is actually does, and the ECM would react by either enriching the mixture or deactivating the M/C solenoid completely, as previously described.
   • Adjustment is very important. The carburetor needs to be properly adjusted. The lean- and rich-stops of the mixture control solenoid travel, the Idle Air Bleed adjustment, curb idle adjustment, and throttle position sensor adjustments are crucial. Those adjustments should be performed in that order once he ECM is in control and functioning.
2. Other potential causes for improper operation need to be checked. For the system to function properly, the ECM needs to be in control. Any ECM problem which prevents normal operation can cause the system to revert to Backup Mode. In this mode, the mixture control solenoid may be inactive, allowing the carburetor to operate solely on the rich stop adjustment of the mixture control solenoid travel. ECM problems can include failed, weak, maladjusted, or disconnected sensors. Proper operation will require some that some sensors and devices are connected an operating
   • The oxygen sensor must be active and reporting to the ECM.
   • The throttle position Sensor will also have to be set within a reasonable range of adjustment and able to vary its output voltage.
   • The mixture control solenoid must be connected so the ECM can pulse it.
   • The MAP/vacuum sensor must be connected to full manifold vacuum and wired to the ECM.
   • The Coolant Temperature Sensor must be connected and reporting within a reasonable range.
   • A 1987 may also have a Intake Air Temperature Sensor, and if so it must be connected and reporting to the ECM.
   At a minimum, all these things need to function so the ECM can control the mixture properly. The ECM must also have a valid PROM/MEMCAL installed and have power. The fact that the Check Engine” lamp is remaining on while the engine is running indicates a problem with the system which may disable ECM control.