Charlie - I could see the flow to the injector blocked and the injector spray pattern gets weak but if you say it totally stops spraying it sounds like an electrical/ECM issue. Could be a short, a loose connection or a problem inside the computer. That's why it would be nice to swap out another computer to see if it eliminates the problem. But I would try to get hold of a used one or borrow one just in case there is nothing wrong with yours.

 

What ever else is happening, it definitely looks like an O ring or gasket is leaking on the forward TB injector.

 

That would definitely rule in or out the ECM. Now to find one.






Have you done the stacking two injector pod gasket trick? It's supposed to increase flow and low end torque.

 

Thanks I have bought my egr block off plate from him great guy

 

What roller rockers will fit my CFI 305? I need to replace my rocker arms.

 

No - I was tempted but I left it alone. There is a member here that made a spacer out of wood. Could it possibly make a difference?

 

On non-CFI TBs it is said to be worth 4 hp and better throttle response.


So tonight, I rechecked the TPS setting and let it idle for about 30 minutes or so, checked all the wires and connections - nothing. Ran smoothly.

 

Took it for a drive. Started off running great. Then got crappy. Barely got it home running on back injector only. Front injector appears dead.

Is there a solenoid in the actual injector which can go bad? It'll start right up after it cools down, but the front TB goes dead again after it runs a little.

 

Ok, I posted this in the TBI section, but might as well post it here as well for those following along.


Okay. All 3 amp fuses are good. I pulled out the ECM - and even though I really don't know what the hell I'm looking for - everything is connected and nothing looks fried. As far as I can tell, it seems all the electrical connections are good.

So, I HAVE A THEORY. Let me run it by you guys. As I said, I just noticed that the front TB has a leak. The leak is on top, above the injector, right at the electrical plug. Is it possible that as gas pools up there by the plug and pins, that it eventually shorts and kills power to the TB? That might explain why it takes a while for it to shut off and then restarts normally after it's been sitting.

Does that make any sense at all?

 

It may sound stupid of me, but I'm not sure if fuel conducts electricity or not. If it does it could cause a short, if not it won't matter.

It is a common failure path for injectors however to stop pulsing when they get hot. You could probably test that by checking the resistance across the injector terminals when the engine is cold and check again when it's acting up. It is possible the the coil in the injector goes open circuit when it's hot.

 

As I've found out, gasoline is not a conductor. A failing coil in the injector makes a lot of sense to me.

 

Well, my neighborhood car pals came by today to see what's what with my Crossfire. Since I had the cap/rotor/coil on my bench, we decided to throw that stuff on first. BTW, the stuff we took off was date coded 10/82. Yup original to my 12/82 build date car. Took it for a spin, ran awesome for about 5 minutes, then the same thing happened. I limped the car home, and all of us were thinking about our next move. My friend Bob, who came with his very cool, Pro Touring-esque '69 Camaro, says, "Charlie, this is the reason you invited me, because I know a guy".
This "guy's" name is Lou, and he was a Corvette Specialist in the service dept. at a Chevy dealer for many years, owned an '82 Corvette Crossfire and is very familiar with the system. He walked us through the diagnosis on the phone and we are 99% sure it's a bad injector - even though everything I've read says they never go bad. Better the injector, than an unknown bad ground or bad ECM, if you ask me.

So, anyone know where I can buy an AC Delco injector? They don't seem to be easy to find.

 

Charlie - you could swap the injectors in their pods to see if the injector does the same thing on the opposite side. Then you will know for sure if it is bad.

 

BTW - Rock Auto sells new and rebuilt injectors.

 

Yeah, I saw those. I'd prefer a new, AC Delco part number GM5234255.

 

Unless you find NOS there is a good chance the AC Delco units will be reboxed brands - possibly the same ones Rock Auto is selling.

 

mhmm, and cost more, gm tax lol

 

Hey do you have a part number for the injectors ?

 

Yeah, I could.

But what our man Lou told us is, if you give it a tap with something and it fires up again, it's the injector. We did that a couple of times to confirm it. I knocked on the pod by the injector with a screwdriver handle, it fired right up 2-3 times. He also said that the fact that it's leaking makes it suspect. According to Lou, step one is replacing the injector. Step two....he said, you won't have a step two.

 

If I can't find an AC Delco, I'm probably getting this one from Rock.

https://www.rockauto.com/catalog/mor...700&cc=1035447

 

The GM part # for the front one is: 5234255

 

I think you should be fine with that injector. GM probably sourced out the injector manufacturing anyway. All the later port injectors were brands like Bosch and Motec. Interesting how to test for a bad injector. I have to remember that in case I ever have that issue.

 

It's Multech not Motec.

 

Oops - you are right. Motec makes ECM's

 

Just an FYI, there are no AC Delco units available any more, not even from GM. I elected to order a remanufactured AC Delco injector from GB Remanufacturing, through Rock Auto. I also ordered the rebuild kit through dctrumpet on ebay....

 

So anyways....

Today is my birthday. My wife says, why don't we drive up to Lake Geneva, have lunch and spend your b-day there. I said, how about we stay home, you cook something special for dinner and I can put my injector in.

So, that's what I did today. I put the injector in and the car ran strong, really strong. If you didn't know any better, you'd think there was a healthy TPI under the hood. After a few minutes, it's stumbled a little, quickly cleared it's throat and ran better than ever again. No more than 5 minutes later it almost died, like it has been. I quickly pulled over and popped the hood, and the new injector was dead - like the old one. I limped it home. Obviously now, it's a short/electrical issue. On a good note, at least the new injector doesn't leak.

I gotta get "Lou" out here!

 

I'd try an ECM next if you can "borrow" one. I don't see how a wiring issue would cause what you are having happen. I can see a solder joint or a failing component in the ECM causing your symptoms.

 

Charlie - I have the computer from my 82. If you want to borrow it, just cover shipping and I can mail it to you. It worked fine, other then the hood louver function. It would be good for testing.

 

I've wiggled, jiggled, fiddled with every electrical connector I can get to, so maybe I DO need to scrutinize the ECM again, Jeremy. Do you think it's odd that only the front injector turns off though?

When I pulled out the ECM previously, I got the impression that someone had been there before. There was a non factory looking zip tie on it, which I had to cut off, in order to pull it out.

 

only dropping one injector is why I think it is time to look at the ECM again. The problem doesnt seem random enough to be a straight up wiring harness issue, although it suppose it could be. It seems like whatever it is gets hot, stops working, then cools off and starts working again. The injector drivers are separate devices on the ECM board as far as I know (I'm really at the limit of my knowledge here so I may be wrong) It seems plausible that there is a component or connection on the ECM board that gets warm, goes open, then closes after it cools off again. Again, I'm referring to the board INSIDE the ECM that has connections you can't see.

 

I would think it is an injector driver in the ECM also. Just my 2 cents. I may also have a spare ECM if you want to it. I have a whole stack of GM ECM's. Just let me know what the part number is of the ECM you need.

 

Hey there Brian.

1226026 is the part number for an '83 Crossfire ECM. It's the same part number as the auto trans '84 Corvette.

Incidentally, the manual trans '84 Corvette ECM is 1226430. Not really sure what the difference is.

 

This is a plausible explanation. Of course a tester ECM would confirm it. Before I did this however, I would still do one more check for light corrosion on all electrical connections for the affected injector.

When it's acting up, a quick test would be to check for 12v at the white wire on the front injector. This would eliminate another possiblilty and get you closer to condemning the ECM.

 

The 1226026 was repaced by AC delco service number 88999109. I will check for both of these numbers to see if I have one. Also, the newer AC delco unit under 88999109 is relatively cheap and can be bought for about $80.00 to $100.00 online but let me see what I have. I will check on Friday for you.

 

Any luck, Brian?

 

Charlie, here is what I have in stock for ECM numbers, I went through ever one and could not find either of those numbers. Looks like I never ran into a cross fire car or GM car that ran the same number in a wrecking yard all of these years. I like to keep spares in stock for diagnostic purposes but no luck with those numbers.

Sorry

Numbers I have:
16198259 (MAF TPI)
1228079 (4 barrel CARB)
1227730 (Speed Density)

 

No sweat Brian. Thanks for looking.

 

The computer from my 82 works fine...

 

Thanks so much for the offer. I'll keep it in mind. I want to see if I can borrow one locally, if possible.

 

Okay, I just ordered a remanufactured ECM. If this doesn't fix it, I'm driving the **** into Lake Michigan.

 

Drive it over to South Bend before you do that Charlie. :-)

 

It's alive sucka's!


I put the new ECM in today, and have been driving it around for a while. Still runnin'. For now.


Do I dare risk taking it to work tomorrow?

 

so how did it do?

 

Well, drove it about 50 miles round trip to and from work. So far, so good.

 

Glad to hear it's running again. A new ECM can really change the car sometimes. I have helped a few members locally from the board with tracking down weird issues and many cannot believe how much the revised ECM can change how the car runs overall. Did you get the AC delco unit? They are the best Reman out there. I have pulled the complete cover off of them to compare to the old models and every AC Delco has had a completely redesigned board in it. I think they correct a lot of older know bugs with the Reman's.

 

Yup, an AC Delco remanufactured unit. I pulled the covers off of both of them in order to keep the original covers, since they had all the mounting hardware. I'm not sure what I was looking at, but the guts looked different. The original one had some goopy stuff encasing some of the circuits.

 

Should be a conformal coating. The remanufactured one didn't have any kind of coating on the circuits? It should have been replaced as part of the remanufacturing process.

 

I'll post a pic of it tonight.

 

Where did you get your Reman ECM?

 

Ebay.