I bought a computerized carb from a 305 on ebay its number is

17086004

the one that was in my t/a (swapped out by someone else) is also computer controlled but the carb number is:

17087124 will this carb still work and run right on my t/a? I have a carb on it now from a 86 monte ss and it runs like **** until warm but still runs rough.

 

Should work fine as long as it's in good working condition. You might want to give it an overhaul before putting it on the engine, though. Definately tune it or have someone tune it for you because it most likely won't be tuned out of the box.

From the PN you gave us, it's a Quadrajet carb from an 86 Chevrolet vehicle with an automatic transmission and 49-state emission compliant. It's definately a CCC Qjet, because unless I'm mistaken GM switched all their carbs to computer controlled for emissions after 81 or 82... somewhere around that time. You might have just paid for another Monte Qjet from the sound of things.

However, I'm pretty sure the carbs are completely identical. You should have no problems as long as you overhaul the carb and tune it correctly.

 

Thanks for the info , the monte carb I have on it now was pulled from a ss (got it for free) which had center bolt heads I found that odd. Also on the monte carb there is no computer plug at all everything is manual. My t/a runs with this carb but takes forvere to get started and needs to warm up first.

 

Hmm... the carb you have now should be CCC because the PN claims it's an 87 model (170 means quadrajet, 87 means made in 1987). Are you sure it doesn't have any connections for TPS, ect.?

 

I think ive got you a little mixed up here The carb that came with my 86 T/A is the 17087124. The owner swapped the original out for some reason. I bought the 17086004 from ebay. The monte carlo ss carb I dont ahve the number written down but its all manual no plug to be found.

 

I'll take a stab at this...if your running a non feedback carb on a CCC system then I'd expect it to run crappy on warm up. The ECM is looking to go into closed loop operation and cant because it has no data from the TPS and is getting no response from the M/C solenoid that it thinks is there. It's seeing the coolant temp rise but is getting out of parameter data from the O2 sensor. It's pulling back the timing to protect from detentation until a point where it goes into a default open loop operation. Also it's turning the electric choke feed on and off , and maybe in this case not at all, which would produce an extremely lean cold start condition.

Does this sound like the problem? or am I misunderstanding which carb you're using.

 

yeah thats about right , i runs like crap and you can clearly see exhaust smoke fromt he tail pipes even when it warm.

 

Trucks kept non-computer Q-Jets in some applications up through 1990.

 

I understood what you meant, I was just looking at the part numbers. The first two (or three) digits--usually 70 or 170--identify the product as a Rochester carb. The next two numbers represent the year it was built. You said the carb on your '86 has the numbers 87 on it, which means it was built in 1987. The other numbers are for emissions, division of GM and auto/manual identification.

Fast355 has corrected me though, so you might have gotten a non CCC carb from a truck.

 

I have the exact same carburetor, 17086004, I have a Mustang 302 engine that I would like to put it in. Anybody know if it's possible? Do I just need an adapter plate, or what?

 

My 86 5.0 LG4

 

Hi @all,

I found this old post ... got more or less the same problem. If I go with my car (year, brand, engine) I'll come to a UREMCO 33699 .... the one on my car has following number : 17086004 (so must have been replaced already, since it's been manufactured in 1986).
My car is a 1984 Recaro Trans Am with a L69 H.O.

What would be the right carburetor ?

Thanks for any help.

Ernest.

 

Hi,
Canadian models in 86 had a non CCC carb. These Rochester carbs are referred as: M4MED or M4MEF. This has a solenoid with just 2 wires to help with acceleration when the motor is cold. The solenoid takes its signal from a thermal switch.
US cars had a CCC carb (E4MC or E4ME)

 

Mine was originally sold in the US (Ohio). My car has quite a bad cold start. Could it be that the mounted carburetor is the wrong one ?

 

It's unlikely that an 86 US car will have this Canadian style carb, it was used on some GM trucks in the US back in 86, but not on 3rd gen cars.
The solenoid is not to help with a cold start but to help with acceleration when the motor is cold.

Check if you have the CCC under the dashboard on the passenger side, and if it is connected.
are there any wires coming out of your carb?

 

First step would be to check and make sure the choke is working properly.

 

And no major vacuum leaks.

 

 

This is the E4MC carb, and it wouldn't run very well without a functioning CCC (but the car should be drivable).

On a cold choke, I will expect the choke plate to be closed quite a bit farther than in this photo.

 

Well, the car was in a private collection for more than 10 years, didn't drive for even longer. I had everything checked, but they couldn't adjust the carburetor anymore, apparently it's worn out. That's why I just wanted to put a new one on the engine and then go from there. No leaks, choke is working.

 

Ok, what is the difference between R4-E4ME and the one on my car ? Could it be that my carburetor is the wrong one since its number says the year 1986 an my car is from 1984 ?

Thank you.

 

I don't know what are the differences between the E4ME and E4MC, both require a functioning CCC.
I would imagine that the car will run quite well with both E4ME and E4MC carbs assuming everything else is correct.
The CCC takes TPS , O2 and temperature readings and calculates output to the solenoid and ignition timing in a closed loop, So it should be able to correct for a slightly different carb.

I will first check that the CCC is reading correct inputs, and can drive the mixture solenoid.
If you don't want to deal with the CCC, you can always install a non-CCC QJet (M4MC or M4ME) and a vacuum advanced distributor. You are looking at $500 in parts and a few hours of work.
The car will drive very well but will use a bit more fuel.

 

This is NOT correct.

is also WRONG. The carb in the photo clearly has an electric choke, therefore is the E4ME.

Model names:
E = Electronic control, M = "modified" (had provisions for an aneroid that if installed gave it automatic altitude adjustment, and was also used for a cold start enrichment solenoid)
4M = Q-Jet. Originally there was no letter prefix. The most typical 60s Chevy Q-Jet was model 4MV. The previous Rochester 4-bbl model was the 4G. It was much smaller and had 4 vents pointing together horizontally in the center of the air cleaner flange.
E = Electric choke, C = directly heated choke (stat mounted on the carb), V = divorced choke (stat mounted on the intake and connected by a linkage rod)

carb numbers:
70 = 1st 2 generations; from intro in 65 up to some time in the late 70s
170 = next 2 generations

Next number is the generation or version:
2 = the original, from 65 to about 71 or so; started with 70, i.e. 702
4 = 2nd gen; was adapted to the emissions standards of the day; also started with 70; from early 70s to late 70s
5 = 3rd gen; even more emissions; started with 170, i.e. 1705
8 = 4th gen; includes the E4M series
There were none with 0, 1, 3, 6, 7, or 9 for this digit. 702 carbs weren't produced for 1920s cars. For example one of the best all-around carb cores you can get for a performance non-E Q-Jet is 7029202, which came on 69 Chevy 350s with double-hump heads.

I avoid ALL 704xxxx and 1705xxxx carbs for ANY performance application I'm building, if at all possible. Several of the internal passages are sized MUCH smaller than a 702 carb, especially in the idle circuit, therefore are utterly impossible to properly calibrate with a big cam (low vacuum). 1705s are even worse than 704s. Obviously a 1708xxxx is required for an electronic-controlled application.

Next number is the last digit of the year it was introduced. A few especially back in the early days were used for more than one year but that ended by the time the 704 series was introduced. Some 69 cars for example had 7028xxx carbs.

Next number is the car line. Most 49-state Chevy cars have a 2. Different divisions and CA applications are identified by that digit. Chevy trucks had this digit different from cars. In 83, carbs for our cars for example, had numbers 170832xx.

Last 2 are the application. Odd numbers are for manual transmissions, even for auto. Similar applications are often sequential; like 201 for a manual, 202 for the same car with an automatic.

In 86 they started doing something weird. Lots of carbs had a 0 for the division; I don't know which or how many or why. 17086004 is a typical one for our cars.

There is very little difference in the 1708 series from one year to the next, for the same application. A carb from 83 will work fine on a 86 car, and vice-versa. There's more difference, mostly in rod sizes, between applications; L69s for example got considerably more generous calibrations this way. 305s had a little nub of casting in the secondary air valve bores that prevented the valve from opening more than about 2/3 of the way while for 350 and larger the valve could fully open. Lots of similar applications but in different chassis also have very similar carbs; so for example a Monte Carlo SS (L69) and a Z28 L69 carb are very much alike. Not sure that they're absolutely identical but I do recall my late little bro's 87 Monte Carlo SS carb worked perfectly on my 83 L69 Z28 when he was trying to troubleshoot a driveability problem one time. (turned out his problem was the ignition module) I couldn't detect any difference in how my car ran compared to the 83 carb. If memory serves, he even put my carb on his car, and it worked fine as well as it could at the time with his other issue going on.

Last year for the Q-Jet in our cars was 87. It continued at least until 88 in the MC SS, which was still a L69.

When you buy a "rebuilt" carb, all bets are off as to what it REALLY is. I've seen some pretty unbelievable Frankencarbs come out of parts store boxes, even some where the 2 metering rods weren't the same on both sides. If you have a 17086004 (which is for LG4 if memory serves) on a L69 it's almost certainly not the right one, and if it's on a 84 it's absolutely not right; while it will "work" "fine" assuming it isn't sodomized somehow, it won't have quite the response or power that the right one would. It would probably be possible to turn it into a L69 carb, or at least pretty close, by changing the metering rods, especially the secondary ones. No telling whether it's REALLY an exact match for a factory 17086004. It's certainly NOT "the right" carb for your car, but if it was a 86 L69 carb, it would be virtually indistinguishable from a 84 l69 carb other than the stamping.

 

Thats some Input ! Thank you !

What carb should I buy ? My car has 29tmls, and I want to keep it 100% original.

Regards,

Ernest

 

To keep it original, look for somebody parting out a 84 L69 car that is known to have never had the carb changed. Buy that, and rebuild it yourself. Not an easy task but it's the only way to be sure you're getting a carb that's RIGHT and isn't already buggered before you start. Note that there are a number of adjustments that will be disturbed during the process of "rebuilding", and for those (lean stop, rich stop, and idle air bleed) you need to carefully bottom them out while counting the turns that it takes to do so, before disturbing them in any other way, then removing them all for cleaning; then put them back afterwards at the same number of turns out from being bottomed. These adjustments are critical, and obviously are inevitably disturbed during a "rebuild"; which is why you want a carb that's never been touched, so that those adjustments are all still where the factory put them.

Be aware that there's more to "rebuilding" a carb of this age, than merely disassembling, cleaning, and reassembling it. In particular, they suffer from dissimilar-metal electrolysis corrosion, which causes adjacent metal parts to EAT each other. This results in serious leaks in critical places which are often not addressed even in "industrial" rebuilds.

See some old posts on this matter, with photos.

https://www.thirdgen.org/forums/carb...6-ccc-tps.html
https://www.thirdgen.org/forums/carb...4-trans-2.html
https://www.thirdgen.org/forums/carb...n-replace.html
https://www.thirdgen.org/forums/carb...-starting.html

 

Thanks for that advice ... now, what would I have as a second option if i'm not gonna stay original. At the end I just want the car to be driveable..

Thanks,

Ernest

 

Fix up the one you have now.

 

Well, that's my problem. I have no clue about these carburetors ...
And over here in Europe there's practically nobody who has any idea of these things.

 

I had a question about this, my 87 trans am came with the 5.0 and I believe a ccc carb, number is 17087160, was told it had a 350 swapped so curious if this is the original carb. Also if that was the case, how difficult is it to tune them? Also curious if the ecm controls lockup on the 1987 700r4 non tpi. Appreciate any info. Been reading up.

 

]An 87 LG4 automatic in a G-body had a 17087130. Some carb numbers were used across multiple model lines (F-body, B-body, G-body,). Others weren't. I don't know if yours was original. Learn the carb and it will probably be absolutely fine with minor tuning.