So, let me run this by you guys.

Since the T5 swap, I've noticed smething like a "miss" at above 3000 RPM. Not really a miss, but more of a coarseness as revs increased. It was there with the 700R4 but became much more apparent with the T5. I bought a new cap/rotor/coil for it, which are still sitting on my workbench, uninstalled.

Anyhoo, I just happened to have a bottle of Techron Concentrate on the shelf and put it into about a 1/4 tank of gas. I know some folks don't believe in magic elixors, but some knowledgable people swear by Techron. I also have purposely been revving the motor higher to keep it in the 3000 RPM and above range. I burned through the 1/4 tank and refilled with Shell premium and now that "miss" is apparently gone, or at least so diminished, I can't detect it.

So what happed? Was my cat clogging? Carbon on the back of my valves? Intake runner carboned up?

What do you guys think?

 

It was all in your head!!!!





That's what people keep telling me when I say something similar.

 

Who the heck knows.....might be.

 

You may have had some carbon build up in the intake and heads. next time use seafoam as well. I have used chevron with techron and it cleaned my injectors quite good. My spray pattern was much better after using it.

 

That car has guzzled lots of Seafoam since I've owned it, both in the tank and down the TBs. In fact, the TBs were black when I first got it.

 

Which version of seafoam did you use ?

 

Both regular Seafoam and Deep Creep. The Techron seemed to have made a more dramatic difference. But I noticed yesterday, that it stumbles at low RPM when cold now - wonder what that's all about.

We'll see what it does today.

 

So, I have to say after my morning commute, that in general the car runs much better. Really, I'm not kidding. Smoother. Eagerly revving to kiss it's redline - like a smallblock should, where before it felt like you needed to flog it to get up there.

But....it still has an occasional stumble. And not just when it's not warmed up either. I'm going to have to figure that one out.

During the 5 years I've owned the car, I've run several cans of Seafoam through it, (I also use it as a fuel stabilizer when in winter storage), at least one can of Deep Creep, and a can Berryman's.

This is the first time I've used Techron in this car and I must admit, it made a fairly dramatic difference. I can only theorize that maybe a valve or two were so carboned up that they just weren't closing or opening completely.

 

Rough ride home tonight. Major stumbling on the way home. At a red light, it'll sometimes drop a few hundred RPM like it's going to die and then catch itself. It's like some carbon or something got knocked loose.

So, I cleaned up my IACs, ran some Deep Creep through a vacuum line and dropped in another bottle of Techron to hopefully dissolve whatever is in there. Weird. When it's not stumbling or feeling like it's going to die, it runs great.

 

how bout quit dumping **** in it and change the plugs? that much seafoam and who knows what else has surely fouled them out

 

Yeah, probably a good idea to pull a plug and get a look. But fouled plugs would make it run crappy all the time. This alternates from running better than it ever has, to crappy and back again.

 

I've had astonishing luck with both seafoam and Techron. I've torn down engines that ran seafoam religiously and the intake ports looked like fresh cast iron, I couldn't believe it.

Although your problem is intermittent, I'd do the cap/rotor/plugs and wires if it needs it. I assume the O2 is fairly new? If it persists, I'd start looking at throttle position sensors and their adjustment, coolant temp sensor, and MAP sensor. I got water in my MAP sensor on my TA one time and it would go from running great to running horrible. If you're going to keep that thing you really should replace the stock ECM with Rbob's EBL with HAM board so you can appropriately diagnose problems like this in the future. Or I'll do the swap for you when we build your new motor. (just had to get that out there LOL)

Either way, I'm glad you are enjoying the car. Sounds like the swap has transformed your experience with that car. Mission accomplished!

 

Yup, I replaced the O2 with a new Delco unit a while ago, the TPS has been properly adjusted. The MAP is on my suspicion list.

 

Got my LU5 out for the first time this year. Started and ran great.

 

Let's see some pics!

 

Sure....Owned since 1987

http://www.camaropacecars.com/1982/8...PhilBorris.htm

 

Nice car!

 

I think my MAP is bad. When it runs bad now, it's REALLY bad. I was messing around with the MAP tonight, and it runs better with it disconnected. When I reconnect it, car wants to die.

I'll pick one up tomorrow.

 

I'm anxious to see how that turns out. The MAP sensor is critical, and if it's been skewing fuel delivery for who knows how long, you may have a new car again once it's replaced.

 

No codes in the ECM from the MAP sensor?

 

Nope. Computer is probably too stupido.

 

Welp, it's not the MAP sensor. I put the new one on with a new vacuum hose. Started the car, ran really nice like it's been doing when it runs nice. Then it started hesitating again and died a couple times. Shut it off, started again, ran nice for a few minutes and started the same crap again.

 

Open loop to closed loop maybe? Sounds like something is wrong when it switches to closed loop - bad O2 sensor?

 

Fairly new AC Delco O2. No more than 3 or 4,000 miles on it.


When I let it run, it'll idle normally, then it seems like it's going to die and idles down to 500-400 RPM and then catches itself and then goes back to normal for a while. Wonder if the ECM is bad?

 

Possibly ECM. I switched my computer out due to the fact that my 82 computer wouldn't operate the hood louver solenoid. So I switched it to an 83 ECM. It seems to idle better with the new computer. I haven't taken it for a ride yet though, but I had a low idle issue with the old ECM and now it starts and idles up to 1000 rpm and settles in to 750 rpm once it is warmed up. I can't wait to take it for a ride tomorrow to see if it runs better with the new ECM.
BTW - the hood louver now works in diagnostic mode. We will see how it works on a drive at WOT tomorrow.

 

Wonder if I were to replace the ECM, if it would be worth going with an '84 manual trans Vette unit. It carries the part number 1226430. The auto '84 Vette and my ECM carry the same part number, 1226026.

 

You would have to find out if there is a wiring difference between the two computers. See if you can find a wiring diagram for the two cars. The Corvette manual computer controls that 4+3 trans, so it may be different. Your prom also might not work in the other computer.

 

82 - good points. It's strange that a manual and auto use a different computer, typically the dfifferences are only in the chip, and if the manual does need any special wiring, it would simply use the unused auto pins.

Although the problem described may be the computer, the problem was there before the tranny swap. I think Chazman needs to get a scanner on this car and follow some data while the problem is occurring.

Chaz: And if you haven't already, install that new cap/coil/rotor.

 

The 2 computers physically look the same. The pin out in the auto computer controls the OD on the 700R4 and on the stick computer it controls the OD portion of the 4+3 trans in that it shifts it into the extra gear - very similar to the auto function. I don't think you would benefit from it as you would need to use your prom anyway, and that is what contains all the tuning parameters.
Eseibel is right. You probably have a problem elsewhere. How about your EGR? If that opened at the wrong time it could cause your issues. You should test the valve and the solenoid for proper function.
BTW - my TA runs awesome with the 83 computer. It definitely has a better tune in it. The 82 computer would hold TCC lockup too late forcing me to smash the pedal to get the car to downshift to unlock the TCC and every once in awhile that would cause a backfire because the car was chugging a bit. That problem is gone. It also idles smoother and feels a bit quicker according to the butt dyno. Oh - and the hood flap works now.

 

Charlie - just for the heck of it - try disconnecting the vacuum line to the EGR and plugging it with something and drive the car around. See if you still have the problem. That would help you diagnose the EGR solenoid as the issue.

Also - like Eseibel said - change out the ignition parts. You want to eliminate it as a cause.

 

Cap/rotor/coil is on my 'to do' list for this weekend.

I'll look at the EGR, 82tarecaro..

eseibel67, this particular problem is actually new. It's gotten bad enough where I don't feel comfortable driving it anywhere.

 

BTW, shouldn't I get a code for a bad EGR?

 

You will throw a code for a faulty egr circuit. But if the solenoid is weak and letting vacuum pass you will probably not get a code.

 

Wonder if that also might explain my high idle, (950 - 1000 RPM)?

 

I thought this 2 weeks ago but have never done it on a xfire car. Do you know the datastream definition to do it with TunerPro5 and the Autoprom? The other problem is that the refresh rate is going to be so slow that it may be hard to catch whoever is lying to the ECM unless they are doing it constantly and we can see it in multiple frames. If the cap and rotor don't fix it, and if Charlie can't get it fixed soon I'll go over with my equipment and help diagnose, that is if my equpiment will work, I've never tried it on those old ECMs.

 

Okay, went for a ride with the EGR disconnected and and plugged. No change.

I did see something though.

This:



The top of the injector by the yellow connector is moist with gas. This on the front, passenger side injector only. Also, I happened to be under the hood when it started to struggle to keep running. The same injector stopped injecting fuel. Just a small tug on the throttle cleared it's throat and regained a normal conical pattern.

Other than the high idle and this issue, the car runs awesome.

 

Is my problem in the fuel meter accumulater?

 

Could be o rings and seals on the injector pod. You should pick up a rebuild kit. It only costs a few bucks and comes with everything new including the regulator and accumulator seals.

 

I'm sure a rebuild kit won't hurt anything, but I wouldn't be surprised if that fuel is from reversion in the intake because of the engine running rough. Some possible explanations for the injector totally dropping out could be, bad injector drivers in the ECM, the ECM could be losing crank signal from the distributor or the injector itself could be bad.

 

Wouldn't they both go out if crank signal was lost?

 

Just to clarify, the front injector isn't leaking or dribbling gas or anything, the fuel meter is just moist with gas, where the back one (driver's side) is dry.

 

Also, considering how the TB goes from off to a perfect conical spray pattern, syncronized with the back TB, I wouldn't rule out an electrical component either.

 

Sounds like a short somewhere - possibly the ECM. Do you know anyone who has a spare ECM they could lend you? Maybe someone who has a Crossfire car and you could try their computer. It doesn't take much to pull it out.

 

Congratulations, you've found the cause of the rough running/high idle problem. You now have a much shorter list of possible culprits. ECM is definitely a possibility. And as with any intermittent electrical problem, open up and clean all the electrical connections in the affected circuit (everything inbetween the ECM and the TB). If it still does it, wiggle the wires in that circuit and see if you can get the problem to surface. If yes, you might have a wire that is starting to rub through somewhere.

Another item I might suspect is the actaul TB unit since it alternates between flooding and nothing. A bad rubber piece might be the cause. As mentioned earlier, get a couple of rebuild kits and do them both at the same time.

 

Looks like the front injector is actually INJ "B" or injector #2. The white wire will have a constant 12V from the INJ 2 fuse with ignition on, the dark green gets ground pulses from the ECM in order to fire the injector.

If you have to, check out those wires.

 

any one got link to a cfi adjustable fuel pressure regulator kit and tbi rebuild kit ?

 

Not sure on the regulator, but the Crossfire TBI rebuilt kit is Standard Motor Products # 1640. Any parts store should be able to order it easily.

 

Had a busy day at work yesterday so didn't spend too much time on the car. But I did briefly poke around at the wiring and connectors under the hood.

Coupla thoughts:

1) I'm not really sure that this is the cause of my high idle.

2) Still wondering if there's some loose chunk of carbon hiding somewhere. It's just too coincidental that this new issue started the day after using Techron Concentrate.

 

Wondering about that, too.

 

I used this rebuild kit. He is a member here. The kit is very thorough and he has great customer service. I called him for advice and he sent me additional seals I needed for nothing.
http://www.ebay.com/itm/Crossfire-Injection-Rebuild-Overhaul-Kit-dual-Regulator-/261219261201?pt=Motors_Car_Truck_Parts_Accessories&hash=item3cd1e19b11&vxp=mtr
I made the fuel pressure regulator adjustable by removing the block off plate and then I bought the adjuster tool from DCS.