Hi All,

I've just purchased an 82 Firebird with Crossfire and I guess I didn't do my homework on what I was getting myself in for haha. When I got the car it would start fine, but idle at 500rpm, often stall and would bog when I punched the gas while driving. Sometime it will backfire too.

So far I have replaced:
- o2 sensor
- Coolant Temp Sensor
- Throttle body gaskets
- Intake manifold "lid" gasket
- PCV
- Spark Plugs, Leads
- MAP sensor
- Injectors
- Fuel Filter

I have also:
- Verified fuel pressure (i'm getting 20PSI pre-filter with engine off. Not sure if this is correct?)
- Simplified the vac hose situation by deleting all hoses apart from the MAP sensor hose and the hose for the brake booster.
- Tested all cylinder compression.

The only "smoking gun" that I've found is an exhaust leak between the exhaust manifold and the down-pipe. As this is before the o2 sensor I can only assume its throwing off the readings. I havent been able to fix this yet, but as the exhaust is so crusty, I'm wondering if I should just replace everything including the exhaust manifolds?

I also have a couple of other questions as I'm not familiar with these older engines.

1) Whats this next to the distributor? It has 3 pins on it, but has been unplugged on my car.

Whats this?


2) I'm thinking about re-sealing the lower part of the intake manifold. I've already emptied the coolant from the engine, but would like to know what else is involved in order to remove it? It looks like the distributor would also need to be removed? If so, are there any gotchas i need to look out for?

Thanks in advance guys

 

I also own a 1982 Trans Am with Cross-Fire, it's been in the family since it was new.

Check the evaporative canister purge valve, that can cause poor idle, low idle, and shaking. It's often overlooked. Also check your hose connections to the evaporative canister and make sure the hoses have no holes or damage. After you run your Trans Am for 20 minutes or more then turn off your engine and remove your gas cap does your tank make a pressure release sound? If yes then you have an canister/purge/evap related issue.

Also have you checked all your engine vacuum hoses? All it takes is a small pin hole and they can cause idle issues.

Are you getting a check engine light? Have you hooked a code reader up to the computer port to see if your computer is throwing any codes that may help with your troubleshooting?

 

When I bought my '83 LU5 it ran like absolute crap.

It felt like 90 horsepower and backfired through the TBs. Did you ever see a fiberglass hood bend? Of course I replaced sensors, cleaned and lubed the IACs and all that. In the end though, it was the vacuum leaks which made it so terrible. The top plate of the intake can be a HUGE leak. Make sure all the bolt are tight. Make sure the TBs are bolted down tight on the intake, that's another trouble area. And then just replace all the vacuum lines. Just replace them all - like nuking from orbit - it's the only way to be sure.

 

thanks for the reply LU5. The previous owner has actually removed the charcoal canister and has capped off all the vac hoses that go to it!

All I’m left with is a hard line that comes up the drivers frame rail and terminates in the engine bay venting to atmosphere. There is also this part which is plugged in but has no vacuum or other lines going to it:




As for codes, I will need to look into that. I assume it’s pre obdII so will need a special reader?

 

I will pray for you tonight. Good luck.

 

Good luck. 99% chance vacuum leak. When I was younger I had an 82 Pace Car with CFI and fought it til I got so aggrevated I pulled the whole engine and swapped it with a carbed 350. Should have swapped it the first day I brought it home.

 

well I made good progress today




Have got all new gaskets to seal this all back up and have deleted almost all of the vac lines that were for emissions, cruise control, a/c. Did a compression test on all cylinders (150psi across the board) and will start putting it back together tomorrow

 

Verify timing? Often overlooked...

Now make sure you plug all those removed vaccum lines!

 

i didn’t realise timing was manually adjusted. I thought it was all done in the ECU. I have a lot to learn about these cars!

Is it done just by twisting the distributor? What am I aiming for?

 

That was pulled right off the canister and with the canister gone its definitely going to be causing you some issues. The Cross-Fire engines are engineered to run their best with all the emissions control equipment intact and proper operation from the computer reading input from the engine and related sensors. That doesn't mean you can't run it without the emissions system/evaporative system (canister) but you'll have to spend a lot of time trying to tweak it to work. You will be further ahead returning the emissions system/evaporative system back to 100% stock. Not to mention the resale value of your Trans Am will be more with the emissions system intact and functioning properly. I recommend this 1982 Firebird Service Manual, it has everything you need to keep your 1982 Trans Am and it's Cross-Fire system running properly, it was the manual the mechanics used back in the day at the Pontiac dealership service departments when servicing 1982 Trans Ams and Firebirds:

https://www.ebay.com/itm/322393177201

I'll take a picture in a few hours of my canister and the wiring and post it here for you. If you need a canister, I may still have a spare one (I'll have to check), however it may need to be restored. This requires cutting it open at the seam replacing the charcoal (with fish aquarium charcoal) and sealing it back up with a sealant/glue.

 

I know you will need a timing light, and with the car running you adjust it by twisting the distributor, but first you need to disable the computer from electronically adjusting the timing, there are several threads on this on this site.

 

jimxms,

For timing adjustment this I would recommend getting and reading the 1982 Firebird service manual (I put a link in my previous post), the timing system with Cross-Fire uses Electronic Spark Timing along with Electronic Spark Control. The manual has all the info you need to do this and troubleshoot the entire Cross-Fire system. Along with the great help that's in this TBI section of Thirdgen.org I would also recommend that you also join the 1982-1984 Firebird Zone Facebook Group:

https://www.facebook.com/groups/1630957793853931

there are many very knowledgeable people in this group (just like on this forum board) on the Cross-Fire system with many having been in the same predicament as yourself with a Cross-Fire system that's missing some or all of the emissions or other engine accessories. There is always somebody in this Facebook Group who has a part that you need and can assist you with troubleshooting and fixing an issue. Since this Group only concentrates on 1982-1984 Firebirds/Trans Ams it has a lot of Cross-Fire owners and experts.

....

 

Thanks man, this is all a massive help. My car is missing a LOT of its accessories. It has no A/C, No cruise control, no evap system and I'm pretty sure a lot of other stuff is missing too. It's pretty much just the engine and power steering.

I'll finish putting the engine back together and see how it runs. I just noticed that the fuel injectors were missing some o-rings (previous owner again) and the lid of the intake manifold was sealed with what looks like glue (certainly not proper sealant or a gasket!)

 

Here's the picture of the canister and the wiring you'll notice that solenoid with the two little hoses connected to it is mounted in the area on the inside front part of the front fender and you can see how it's connected to the evaporative canister. You'll notice that the canister number is 17075825FB which is the original canister that the 1982 and 1983 Trans Ams and Camaro Z28s with Cross-Fire used (carb equipped cars used another model canister). I am still looking for a spare canister (17075825FB), I have a few more old part boxes to go through in my garage which I'll go through in the next day or two to see if I can find it. If you need me to take any more pictures of anything in the engine bay or anywhere else let me know. Also the link to the 1982 Firebird service manual above is a rough one, I found one that's a little bit more money but appears to be in much better condition: https://www.ebay.com/itm/334093361660

 

Yes, you'll need a bent paper clip. https://www.thirdgen.org/forums/tech...des-paper.html

 

Realize that "codes" are the bare-azz beginning of diagnosis. So, yes, you can get codes with a paper clip, but that's still pretty meaningless.

You need a scan tool capable of reading the data stream, and interacting with whatever on your vehicle can talk to a proper scan tool. With newer vehicles, it's the engine, transmission, ABS, air bag system, instrument cluster, and more. Older vehicles may only have engine data.