Tbi and Feedback quadrajet compatibly
Well I've been around the forums for awhile now and I've finally decided to join, tons of great info.
Anyway, I recently picked up a 1989 Caprice wagon that was converted from a 305 tbi to a 350. I was told the 350 was from a 1986 suburban. Its mated to a 200-4r. While I'm fairly experienced mechanically I'm not to great with electronics, I've been stumped by a few things. The problem I'm facing seems to be do to the swap. The car is sluggish, seems to run rich and the secondaries don't open(its not because of the choke lock out, no vacuum leaks either). It has a quadrajet (17087130 0717 JSD) which decodes to an 87. The engine could be from a later suburban or the carb is replaced, but that doesn't really matter. From what I can tell the carb is somehow hooked up to the original ecm.
I read somewhere that on some of the quadrajets off of 80's trucks had a dual capacity pump solenoid in stead of a mix solenoid. If this is so, how can I tell? I don't think it can be a mix solenoid since I believe that requires input from the O2 sensors, which are nowhere to be found on this car.
Unfortunately I can't really drive the car much to tell if the converter is even locking up at highway speeds, That could be a clue if the ecm was working with the carb. (not registered or insured, plus its fenced into my backyard under a tent for now).
In the end, I'm looking to correct the car since the swap seems to be done wrong. I know I'm lacking details on the on problems and the set up of the car. My main question is, Is it possible for my quadrajet to be hooked up to this ecm correctly?
Is there anyway to see if the setup is right from observation? ( I haven't driven it more than five miles and driving more isn't really an option.) I'm trying to get the car ready to drive it to and from school twice a week. I'm staying with a quadrajet. I think I'm going to just buy a non-feedback quadrajet to rebuild , a new distributer and wire a lockup switch.
What do you guys think? I might be a prematurely assuming problems and the carb might just need a little tune. What options do I have? The biggest question is the one above. Can it be hooked up correctly to the original wiring and ecm? I know that I might be lacking too much info to to answer this question but any help or guidance is greatly appreciated. I know there is alot knowledge on this forum, looking to tap some of that.
PS. I've searched alot! Don't be too hard on me!:D
First, here is a page on the dual accelerator pump Q-jet. There, you will be able to see what a full-on feedback Q-jet looks like and can compare that to what you have.
If you have a feedback carb but no computer controlling it, it will run excessively rich and will be a slug for the most part, although WOT shouldn't be that bad- but you cannot drive everywhere wide open, at least not for long. You cannot judge the secondary operation by revving the engine in the driveway, either. I'm not suggesting you take it out anf run WFO, either. Just saying.
The '89 Caprice w/a 305/350 SBC used TBI- the computer will be different, as will the connections, etc. The only carbed engine was the 307 Olds.
If you do not have emissions testing, I would use a non feedback Q-jet carb (a non feedback dual capacity accelerator pump Q-jet would be fine), along w/a HEI distributor.
Thanks for the links. I unfortunately have feedback q-jet. I understand that the secondaries require load, not just rpms. I've done a few WOT runs(I can't help it) , I didn't hear the distinctive sound or feel any difference. That's okay though, I figure it out, there's plenty of tuning info for q-jets out there.
I never thought of it being the 307, I'll have to look. It could have been. However, the connectors for the tps and mix solenoid are just spliced into the wiring and there is an abundance of left over wires/connectors doing nothing. The swap was done wrong. I'm going to just switch to a non feedback q-jet and switch the distributer. Since I have a th200-r4 I need to install a lock up switch, right? I'm assuming this is the easiest route to correct my car. Going to TBI would be an expensive nightmare. I guess I could wire in a feedback ecm and harness but it wouldn't be worth it with the need to install all the associated sensors and what not. Thanks.
The TBI and CCC computers are completely different, as are the wiring harnesses. The CCC Qjet secondaries are not computer controlled, so any problem there is unrelated, however as noted, you are unlikely to see the air valves open if you are simply reving the engine in park.
Does the engine have an oil fill tube at the front, above the water pump? If so, it's an Olds 307. What is the eighth character of the VIN? If the car was originally equipped with a 307 Olds (as most B-body wagons were in the late 1980s), the eighth character will be a "Y". If it is, the car was never TBI from the factory.
The CCC system can be made to run very well, but it takes a LOT of effort and the carb adjustment process in the factory service manual must be followed EXACTLY. Any small leak in the miles of vacuum tubing on the engine will be cause for poor performance.
Like I said, I know its a 350. I knew the computers were different, I just wasn't sure if certain sensor inputs for a ccc system could be obtained from a TBI. It doesn't make sense that it could but it that's what the previous owner thought. I wouldn't mind having a properly tuned ccc system, I hear they are great for fuel economy and decent performance when tuned right. For simplicity I'm just switching to a non feedback set up. The engine is temporary anyway, in two years I'm switching to a 4.8 or 5.3 vortec.
I'd agree a non feedback Q-jet carb and HEI distributor will be by far the easiest way to get up and running. Be sure to recurve the distributor. Most times you can use the original weights and the springs from an HEI kit from Mr. G, Crane, etc. Just use the medium springs or one medium and one light spring to bring in the mechanical advance quicker (all in by about 3000 rpm). Be sure the total advance doesn't go too high- all you need is about 36 degrees, not counting the vacuum advance. This is covered in the link above, including how to make a timing tape in case you don't have a dial back timing light.
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