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1982 Chevrolet Citation 2.5L I4 : Engine racing and transmission slamming into gear

Hello all,

 I have inherited a vehicle and need to get it on the road as a daily commuter as soon as possible. After extensive searching on the web, I have been unable to find any substantial information regarding this model car. It seems that some of the problems I am experiencing are fairly commonplace, but I need more info to find a solution.

 As stated above, the engine tends to race at idle, seeming to stick after pressing the gas. After pulling the air cleaner and watching the throttle return? pull back to normal, I have decided to replace the whole carb, as it is showing its age after being in storage for 13+ years. Prior to the racing engine problem, the car tended to choke out and die when left at idle for more than a few seconds. A mechanic tuned the idle up to prevent this problem, but obviously this was a band-aid fix. I ordered a complete carb from RockAuto, and took it out to replace it. Here's the rub: the carburetor from RA is a 2 barrel unit, for this model year. The carb on the car is a frankenstein throttle body fuel injection setup which I can't seem to find anywhere. Not even a picture. Does anybody in the community have any info regarding this setup? I'm curious to know if this is a half-year thing and I need to look to a later model year to find parts?

 Possibly related to the racing throttle issue, the transmission seems to slam into gear when shifting from park to either reverse or forward gear. The shift is barely noticeable when traveling at speed. I also noticed that the entire engine seems to shift up or down an extreme amount when putting the car in gear, sinking at least a few inches when shifting into drive. Is this a normal occurrence, or a symptom of some other problem? I have little experience with older vehicles such as this, and I immediately notice that there is a suspension mount of some sort bolted to the top of the engine block, effectively isolating the engine from the body of the car.

Thanks in advance for any help!

You have inherited one of the worst automobiles EVER produced

No offense, but investing money in this X body car doesn’t make any sense to me

I just looked at the GM heritage center website, and your car was apparently produced with throttle body injection. For what it’s worth, that is an official GM website, and I believe it’s pretty accurate.

And now you’re planning to ditch the TBI, in favor of a carburetor

I’m not sure how you’re going to explain that to the guy at the smog station . . .

I believe you simply ordered the wrong part. It’s possible you mistook the TBI for a carburetor. A non car guy might make that mistake.

I’m not sure why Rockauto even lists a carb for your engine, but the company does list wrong parts, from time to time

I’d call rockauto and suggest they made a mistake

Have you already tried cleaning the throttle body and the idle air control valve?

In the words of King Arthur in a certain movie: “Run away!”

And forget using this dinosaur as a daily driver. It is long past it’s time. The fact it still runs means it is decent enough to tinker with. But to try and depend on it is asking for hurt. As you noticed, parts are getting hard to find. This thing is 32 years old!

I do remember working on these TBI’s. The idle air control solenoid is screwed into the side of the TBI housing with a large hex on the body. It’s like a 1-1/8". The plunger gets crudded up and sticks, leading to high idle problems. You can try to unscrew the IAC and clean out the port to fix this.

And yes, RockAuto does list a carb as well as TBI parts for this vehicle.

Thanks for the reply db!
I don’t intend to replace the tbi with a carburetor, as keeping it stock makes things easier for someone ignorant of cars such as myself to maintain. Cross referencing this model year reveals that the “Iron Duke” I4 used in the citation and other GM cars like the Skylark had several intake setups. The tbi was one, as was the 2 barrel carb, though more commonly on the V6. Several parts websites I visited listed the Rochester 2 barrel for this model, sometimes as a Canadian model, sometimes not. Interestingly, some sites showed both carb and tbi parts for the same model years, hence my confusion. The Heritage site was unknown to me, but quiets my fear that the engine may have been swapped in the past. I have yet to attempt a cleaning, as i thought a full replacement would be easier than disassembly and reassembly.

Wow! Lots of replies since last refresh! @NYBo - European or African Swallow? Lol.
@BustedKnuckles - Several parts have already been replaced in the recent past, the master cylinder was done as were several brake components front and rear. The car starts easily since the new battery, body condition and interior are decent though not excellent. If the IAC valve is the large disc like shape between the valve cover and air cleaner, that part is new as well. I admit some nostalgic affection for it, but I do have a dollar limit on repairs.

Thanks for the interest guys! Anyone have any thoughts on the transmission issues?

I suspect that the high idle and slamming into gear are related

When your idle is back to normal, it probably won’t slam into gear

@BeardAl, the IAC may apear new, but did they clean the port? A new part in a gummed up port will still stick. And, you just need a large cresent wrench to take it off and know for sure.

The large disc between the valve cover and air cleaner is likely the EGR valve. A vacuum leak will cause a fast idle. The engine moving forward and rearward when shifted into gear indicates a faulty motor mount. And believe it or not the TBI fuel system is simpler than the carburetor with its ancillary equipment. The car is becoming a relic though.

Thanks everyone for the helpful comments! Today I checked as many of the suggestions as I felt safe performing. The IAC valve is new, I pulled it and checked the plunger per @BustedKnuckles suggestion. It appears to be clean and free to move. The PCV valve is dirty, but still moves freely in the housing. The car has a new vacuum canister, and after tracing all vacuum lines under the hood, none appear to be cracked and all have a good seat on corresponding ports. The EGR valve appears new, and I can’t seem to figure out how to remove it for a visual check. The MAP sensor doesn’t look new, but all research tells me that a faulty MAP would create a bad idle, and hesitation on acceleration. Those sound opposite of what I am experiencing. After checking all these items, I started it up and noticed that at first crank and for a couple minutes afterward, the idle sounds normal, then accelerates and stays there. Again thank you to everyone for the help!

High idle speed can be caused by a number of potential things and takes a good amount of patience to get to the bottom of it. You just have to go through all the things one by one that can cause it. The experts here on the forum helped me through a similar problem on my early 90’s Corolla. The Corolla is electronic port fuel injection so the process won’t correspond exactly for you, but it might be worthwhile for you to read how my Corolla’s high idle speed problem was eventually diagnosed and fixed in the thread below. Best of luck.

A typical problem on these cars of this vintage is a broken wire between the computer and the IAC valve causing the idle to increase but never settle down. Very light wires for what they do. While the engine is “idling” move the wiring around, push the wires into the connector and see if there’s any change.

1982 x body are all considered past the end of useful life. So you are beating the proverbial dead horse here. Even in the day when these cars were not too old they were cranky poor running cars. Look for vacuum leaks as the cause of your high idle. Evap smoke testers are great tools to find vacuum leaks. Look at the throttle cable and throttle lever crank system carefully. Stuck open throttle was common on this engine.

If the high idle is not caused by vacuum leaks and sticking throttle then look at the electrical, in particular the coolant temperature sensor, throttle position sensor and check for bad grounds at the big bolts where the engine and trans bolt together.

I agree with all the previous commencts. This car is the equivalent of a white elephant the Thais give to someone they want to punish and or bankrupt. The elephant is a sacred animal in Thailand and you just have to take care of it until it dies. The white elephant has a voracious appetite but won`t do any work.

Youre lucky; you can get rid of the Citation X-car before it either bankrupts you or drives you crazy. My brother had aits sister` car, an Olds Omega (last letter of the alphabet) and it was a complete dog; the rack & pionion steering, a GM first was trash, the transmission, their first for a FWD car, as well.

This car has mulitple weak spots much like the 1957 `thrown together Chrysler products, and is only suitable for a guy who is a mechanic or buys it as a hobby car to learn repair work.

This car will never be a reliable daily commuter, no matter how much you spend on it!!!

Heed the ancient wisdom of @Donick all roads lead to the scrapyard.

Speaking of vacuum leaks, on this ancient piece of iron it would be good to go over every vacuum line and piece of rubber tubing under the hood and likely replace most of it. It’s likely all dried out and inflexible and if it doesn’t have any cracks now, it likely will soon if the car is pressed back into service and undergoes heating/cooling cycles and everything flexes a bit.

Thanks to everyone for their input! After considering the amount already invested, and the fact that having a mechanic navigate the rabbit warren of debugging would likely cost the equivalent of the total value of the car, I have decided to retire this vehicle. Best of luck to everyone in future endeavors!

That was a wise decision

Step right up and get your 300 bucks at the junkyard! Wise, indeed.