Fellas, I drove a friend's 82 recently and it feels like it has more pep just off idle. Seems to spin the tires very easily.

Symptoms I'm having:
Mine hesitates slightly coming off idle no matter how hard I come off idle. Pretty hard to spin my tires.
Before I replaced my cam sprocket and chain my engine would often die upon coming to a hard stop or it would almost die and barely recover. The new cam chain and sprocket set has reduced this symptom and my idle is consistently steady, locked in at spec.

I have balanced my throttle bodies in the last 2 years per the procedure given on this forum.

Might I need a pair of IAC's?

Thanks,
Steve

 

IAC, is Idle Air Controller. Just that. It's for idle. Anything off idle is not the IAC.

 

Fuel pressure spot on? Dirty injectors? Does the car run properly at other levels?

 

You might want to read through this article
http://www.superchevy.com/how-to/468...system-tuning/

 

I would definitely suspect a fuel pressure issue, but it may be more than that. Do you know where the FP is set at? That's the first thing to check and move on from there.

 

Yes which is why I included the symptom of almost stalling. It makes me wonder if my IAC could be sticky or worn because it won't respond quickly enough when I come to a quick stop. Does that sound possible? I was thinking of pulling them out and cleaning or replacing them.

 

I just replaced the fuel pump last year after wasting a year trying the 85-87 fuel pump (40 psi). That was a disaster. So I'm back to stock. I don't have an inline fuel pressure gauge. I will get one if I have to. I was just looking for validation that the IAC could give me the symptom of nearly stalling due to being sticky. As for the off-idle response, it hesitates some. I don't know if that could perhaps be related to the sticky IAC.

 

Thanks. I hadn't seen that before but I used the balancing procedure set by the local pro on this forum about two years ago.

 

Like Buccaneer says.....fuel pressure first. One of the biggest things that cause issues. Check the TPS voltage next......there is a idle voltage....it is in the Super Chevy article above. Read that article as it covers timing too.....which should be checked as well.

Jebby

 

Just wondering why it was a disaster with the other pump? Can you elaborate a bit more on that? Switching over to the 85-87 pump should not have been a disaster. 40 psi is not the output of the pump since pumps are not rated in psi. PSI would be the regulated pressure. All you are looking for is good is a steady pump output "flow" in lph especially at WOT at a solid 13psi so it will keep feeding the motor all the way to redline and not go lean. If you regulated 40psi in-between the TBs, I can ASSURE you you had a huge mess on your hands and fuel was going everywhere since the regulator would have burst. However, with that said, you would NEVER be able to achieve that pressure with a stock TB regulator...EVER. Besides, I only run 28psi with my 383 now with an external FPR, 40psi is out of the question for stock CFI. Sorry, just wanted to clear that up a little.

 

I stuck the 85-87 fuel pump in after reading about 50% positive remarks on it here. My results were consistent with the other 50%, though. I had a slow fuel leak on top of my manifold, but the performance was all messed up. The idle was always searching, but I stalled a lot too. There was surging during steady speed driving. I have never had a fuel pressure gauge on it. But putting the stock pump in solved all those performance issues. THEN I had to replace my timing chain and sprockets. That smoothed things out a bit more, such as my idle. But I still suspect the IAC's because of the near-stall on hard decel. If I imagine them doing their job, they should open up when the throttle is closed to continue supplying enough air for the idle. If they do so slowly I think it could explain why the idle drops to about 250 before recovering to the steady 600. I performed the throttle body balancing a couple years ago, my TPS is set at .5V at idle and is 5.0V at wide open throttle, my timing is set at 8 degrees with the distributor/computer connector pulled. Of course I had to set timing after replacing the timing gear set. The slack in the old chain had my distributor way out.

Anyway I have 221,000 miles on it without ever rebuilding the throttle bodies. I have had the manifold off to replace the intake gaskets between it and the heads. My engine was swallowing water directly into the crankcase because the gaskets were almost gone at the water jacket ports. There was gobs and gobs of dirt in there, too. Why it still runs at all is a tribute to the old Gen ! SBC. My plan is to re-engine in the near future with a crate SBC with good internals and EFI for about 350 HP. The problem is that the "future" keeps staying a couple years out because of other projects and obligations. That's why I was hoping I could regain some performance with a pair of IAC's or at least cleaning them. I am thinking about pulling the Injectors as well for a cleaning or replacement. I was just given a wake up call when I drove the other man's 82 and it felt so much stronger just off-idle with no hesitation or stumbling.

 

BTW I was just informed of a fairly newly built 383 for a low price. Don't know if I want to risk my tranny, though. My budget is not unlimited. But I've spent enough money keeping it on the road this many miles and years to have bought a new C6. Crazy, I know.

 

OK, that baffles me a bit about what you mentioned. One thing you MUST do is check your fuel pressure...period. These motors ARE fuel pressure sensitive. If you do not know what it is, you are completely shooting in the dark IMO and experience trying to figure out what is going on. Get the fuel right and move on to the next item(s). Something was amiss when you installed the other pump, but I don't know what that was since I wasn't there.

You shouldn't have had any issues with that install. Most people that have issues is because they did or didn't do something else. If you have NEVER rebuilt the TBs, that isn't good if they are original. You are literally playing with fire. If the regulator were to burst because of age your 82 WILL go up in flames. Hot engine and fuel going everywhere equals instant fire. I would carry an extinguisher with you from now on. I have done dozens of 82 and 84s with this install with no issues. Set the fuel pressure where it needs to be and the motor runs perfect. If you have surging, hunting or stumbling you have other issues like a vacuum leak, IAC issues or something else.

If you think you have spent a lot of cash so far, you are in for a shock if you plan on installing a 383 now in your 82, jus sayin'. Get your wallet out and jump in that rabbit hole, but have a parachute on. You are literally at a crossroad with what to do. Rebuild your motor and do it right or buy a 383 and spend even more money before it's over. Just remember, the more HP you put to the rear, the more the rest of the drive-line will have to cope with, the weakest link will be found quickly.

Don't read into this reply. I'm not trying to beat you up in anyway, just wanting you to know that something isn't right on your 82 and that's just my 30+ years of working on a CFI motors experience telling me this and working on, 82/84 vettes and 82/83 camaro, firebirds and trans am. I don't think I'm necessarily an expert, but I have seen and done and designed a few things for and on the CFI engines. Just when you thought you have seen everything, something makes you scratch your head and you start to get a headache. If you were close to me, I'd say drive it over and I would have a look and see what's going on. I'm sure I could figure it out...

 

Oh, pleased to meet you! I saw your website many times and dreamed of upgrading with the manifold, opened TB's, the 383, etc. Was still raising the family back then, not enough money. I've always been able to keep it on the road myself, though. My tools love me.

I didn't take it as a beat down in any way. Your logic is sound. I defer to your expertise, of course. I am sure that my TB pressure regulator was not up to the task of the 85/87 pump. As I said, I still have not rebuilt the TB's in 221,000 miles. Have the rebuild kit, have balanced the TB's, removed the manifold and had a shop clean it in a tank. I left the pump on for a year wondering what else I might have to do to get it to run properly, not really looking into it until late last year. Then I just put an original back in and suddenly those symptoms were gone.

As for my current issue (hesitation compared to my friend's 82) I think I will pull the injectors and clean them or replace them. Same for my IAC's. Probably cheap, probably ready for a swap anyway. My hand may be soon forced into the rebuild. My problem is I hate down time. I bought it to drive it and I clearly have developed a fondness for that.

I had a 5.3L LM7 rebuilt and ready to install in my Vette. Then we decided to buy the house we've been renting so I sold the 5.3 to help raise down payment. I was also getting cold feet thinking about the down time as I figured out how to interface that engine with my analog gauges and other issues. Now I'm thinking GM crate motor, another 350 maybe up to 350 hp. I want serpentine belt drive this time. But I also want to be able to plug and play. I fear the 383 would eat my R4700 which has been rebuilt 3 times since I owned it. I have time to consider all this because our money is first going into a 10x20 Amish-built shed to help me empty the garage and lots of stuff in the house we can't store indoors.

 

I don't know how much similarity between an '82 IAC valve and its control system to a more modern one but isn't cleaning the pintle and seat the very first thing to do? A buildup of crud on either will reduce the air passing through. A modern system will detect that the valve is fully open but idle speed is still to low, set a service code and illuminate the "CHECK ENGINE" light.

 

DO you have a parts list for an in-line fuel pressure gauge for my 82? I'm thinking you've been there before and can save me a ton of parts research.

 

If you are referring to me, I do not have anymore 82 fuel pressure assembly's. I had some last week and they are all gone now and will send out the last two on Tues. If you keep checking back to the site, I will have more somewhat soon.

 

Yes Buccaneer, I need that. Can you give me your web site?

 

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