My engine is flooding cylinders 1,4,6,7 based on the fouled out spark plugs on my 350TBI 91 Camaro, I had a spair TBI intake and scopped it out and saw that the driver side injector feeds these cylinders while the passenger feeds the others.

1. I took a know good injector off of another 305 TBI unit that I had laying around and swapped it in place of the one i thought to be failing and still fouling.

2. I took the "bad" injector and placed it into the passenger side and it was not fouling out the other 4 spark plugs.

Between all 3 scenarios I cleaned out all 8 spark plugs.

Info on the car is that it was originally a 91 rs l03 305-700r4 combo. It is now a mild 350 punched over .030 with a mild cam and a wc t5. It was somewhat prom tuned and ran until I had an exhaust shop do some work. The shop is out of the picture now, I cannot take it back it is my problem. I have all new o-rings, gaskets and injector filters on my TBI unit.

Is there a different injector feed that might be messed up or is there something I am missing.

 

I don't know how they work but maybe take OHM or volt readings of each side? Being that they work off some sort of signal from the ECM maybe there's a bad signal?
Sorry it's no real help. 2cents & I owe you 1 1/2 back lol

 

Each injector has it's own driver in the ECM. They also have their own wire between the ECM and injector. The ECM grounds the injector to turn it on.

So, it may be that the driver in the ECM is bad. Or that the wire is pinched (shorted) to ground.


Note that the fuel pump will only run for 2 seconds at key-on. So can also hot wire the pump to help with this diagnostic.

Take off the air cleaner and do a key-on (no cranking). Does the one injector spray fuel? If so then unplug the ECM.

Need to hot wire the fuel pump on as without the ECM it won't turn on. Then key-on again. If the injector sprays check the wiring for a pinched wire.

If now no spray, then try another ECM.

RBob.

 

RBob,

I have no injector leak with or without ecu, and I tried a spare ecu I had laying around from a prior problem I was trying to solve. Both ecus were tested in a friends car a week ago and both ran his car no problem. Both ecus had my tune on the prom chip.

The tune ran the car perfectly prior to the exhaust shop, but I have the problem now.

I should also add that I replaced the cap, rotor, wires with MSD stuff and the plugs are brand new AC Delco double platinums all gapped properly (I don't remember what I gapped them to tho)

Is it possible that I am looking at the wrong point and this is a weak coil that only shoots a strong spark every other time?

It may not be evident looking at cylinder numbers, I actually posted it up wrong in my first post, I will edit that now, but every other cylinder in the firing order is fouling out. 1-8-4-3-6-5-7-2 All in bold are fouling.

 

After an other day of messing with it, I still have no clue what is going on.

I have an egr block off plate and my dad recomended I check the gasket to see if it was blowing by. Since the gasket was only $.24 new from Autozone I threw a new gasket in. I cleaned all 8 plugs again, which requires unbolting the driver's side header. Fired her up and thought that I had actually fixed the problem. It idled good,02 readings were tolerable but after about 15-20 minutes of it running it started to sound rough again and got a little surge of between 650-725 according to WINALDL. I currently have true duals with dynomax bullets, which I am going to re-think after i get it running, and I noticed my passenger side exhaust was considerable cooler than the driver. Slowly but surely it started dieing out and my 02 readings were getting closer to 1 volt.

Because of how loud the car is I don't work on it past 7pm but I pulled one of the plugs and it was fouled out. It wasn't one of the ones that was fouling out before either.

Could this be something to do with the ignition system? Coil? Ign module?

Sorry for the long story and I really appreciate everyones help.

 

One last check for injector issues: swap the injector connectors between the injectors. This is the electrical connectors. If the problem stays with the same cylinders then it doesn't have anything to do with them.

I have a feeling that it won't change.

If so, I'd look for something such as a clogged EGR passage on one side. Or maybe the distributor shaft has too much side play, or the star wheel is loose on the shaft.

Or there is a vacuum leak in one side of the plenum. Doesn't the brake booster feed from the drivers side plenum?

RBob.

 

I will try swapping the injector wires tomorrow.

When you talk about the distributor having too much side play I am not entirely sure what you mean. Like if I were to take the cap off and try wiggling the rotor and dizzy shaft left and right?

Is the star gear the gear at the bottom of the dizzy shaft that is driven by the cam?

The line for the brake booster is on the driver side but I am not 100% sure if it feeds off of the left side because the bore goes down for the driver side and the passenger side bore is on top and the booster connector is closer to the top, but I will look at my spare intake tomorrow and will probably just cap it off just to be 100% sure.



If my first post I forgot to mention that the car gave out a code for about 20-30 seconds while it was dieing slowly. It was the High MAP code, I think that is 33 but not sure.

 

Yes, side to side on the distributor shaft. Can grab the rotor and see if it moves side to side. Saw one in the JY the other week that was so bad it ground most of the star wheel and reluctor points away. Must have had 1/2" of play (should be none).

Note that up/down play is normal. About 1/8" is typical. And the rotor will turn as the shaft is moved up or down.

The star wheel is attached to the shaft below the rotor. Has 8 points on it that align with the 4 points on the reluctor. The star wheel sometimes come loose from the shaft.

Malf 33 is high MAP. This can be caused by the engine not running correctly. I wouldn't replace the MAP in this case as if it were bad it would affect all cylinders. Although it never hurts to check the vacuum line between it and the TB.

RBob.

 

Thanks for the info RBob, you have really been a help throughout this headache.I have had a busy weekend but I will get out to the car after my class in the morning.

I am pretty sure I don't have any side play, thats the type of thing I would hope to think I would notice when I was putting my engine together.

If the star wheel or reluctor is worn, is it time for a new dizzy? Factory replacement or is this a good time for a forced upgrade?

So the star wheel is supposed to be attached to the dizzy shaft and the reluctor is stationary on the base of the dizzy? If I am thinking of the right thing my reluctor wiggles a little bit, would that be a problem or is it supposed to have a little bit of play?

I am not the type who sees a sensor out of range or throw a SES or CEL and replace it but thanks for the advice on checking the vacuum, I just gotta track down my buddy who I lent my vac. gauge to a couple years ago....

 

RBob,


I do have a tad of dizzy play, I can't see it move but i feel it. The dizzy most likely has about 140k-ish on it. I would call it less than a 64th of an inch. Is that enough to cause the problems I am having?

My star wheel is still attached to the dizzy shaft well, but the outer ring around the reluctor can be turned from side to side a bit, is this normal?

And yes, the brake booster is fed off directly off the driver side injector bore.

Thanks in advance.

 

The slight side play is not likely to cause a problem. There is a shield over the pick up coil which will rotate some. This too isn't an issue.

The reluctor with the four posts sticking up in the air. This must not move. IIRC it is pinned to the distributor body. So if it moves something is wrong.

RBob.

 

RBob,

It is just the shield that rotates, the actual reluctor wheel is very firmly attached to the dizzy body.

In the PM you sent me you said my problem may lie in the cylinders that are fed by the plenum with the clean spark plugs, what could be effecting it. I currently have 2 vacuum lines hooked up to my engine, the map sensor and the evap can.

So you believe that this has nothing to do with the ignition system, my coil, and modules? When I did the 350 swap I wasn't 100% sure if I needed to change my ESC or knock sensor, so I didn't. I assumed it wasn't a problem cause the car ran good initially.

Jeff

 

It may be that the AFR is lean on the clean spark plugs plenum. This in turn will cause the BLMs to increase causing the other plenum cylinders to run rich.

It doesn't seem to be an ignition issue. Every other plug having a problem. But I tend to not rule out anything.

RBob.

 

Rbob,

Are you saying that there could be some fault in my tune? If so would it be alright if i posted it up here and you took a look at it?

Jeff

 

I doubt it is in the tune. What was the work the exhaust shop did on the car?

It may be that something in the EGR is foobar.

How bad does it flood out on the the drivers side plenum? What are the BLMs doing?

RBob.

 

Drove the car in with a good running rebuilt motor and open headers. He ran duals all the way back and that was that.

When you say something in the EGR is fubar do you mean the ducting in the intake/heads? I don't know if i posted it on this thread but I do have an EGR delete with a fresh gasket on it.

The cylinders fed by the driver's side plenum foul out really quick.

I will run my dataloging either tonight or tomorrow because I am not home right now.

Thanks

 

Rbob,

It takes about an hour to clean out my plugs after they foul out because of my cheap-o headers so before I start it up again just to get a reading I want to verify this reluctor wheel/star wheel possible issue.

/

Is the spur looking thing that has the rivets the star wheel? It has 8 points.

And

Is the part the 8 points "mesh" with the reluctor wheel?



The reason I ask is that after looking again it looks like both parts are spinning with the dizzy.

Sorry for the blurry pictures, camera phone.

 

Attached pic has the shield off. The star wheel with the 8-points rotates with the shaft. Note that if loose on the shaft then timing issues will occur. It is pressed on and needs to be tight to the shaft.

The reluctor is the piece with the 4 uprights on it. That is pinned to the distributor body and must not move.

The shield which is not shown in this picture will rotate some.

The white piece nestled down inside of the reluctor is the pickup coil. The brown stuff is what is left of the wrapping on the coil. Common for this to peel off. Can see the white & green wires exiting to the left. These go to the ignition module (which is not present).

RBob.

 

Thanks that picture clears alot up, my reluctor wheel and star gear are nice and tight on the dizzy body and shaft, respectivly.

I will run my data logger later tonight and get the BLM readings for you.

Thanks.

 

Ok, had a few things come up but now I am back on the car.

I just ran it to datalog and collect data. It only ran for 7 minutes and my BLM stayed at 128 the whole time. Is there any other data I should post up that could be helpful?

 

Did it go into closed loop and learn mode?

RBob.

 

I am fairly certain it didn't but I can't keep it running long enough. Is there any way I can force it to?

 

Bumpin it back to the top

I'm hoping to drive it once before the snow hits. If the rain holds out I am going to run a vacuum test tomorrow.

 

My dad came out and we spent the day on the car adjusting the valves, replaced the spark plugs, checked all connections, tested all sensors for proper range. The only thing we didn't do properly is set the timing cause the timing light crapped out out on us.

My problem has changed from my fouling out spark plugs to now I have an idle of 2300-2500 RPM. Like I said, timing it will come tomorrow or Monday because I need to pick up a new timing light. We did try advancing and retarding it a little bit from where it was set and it on lowered the idle one way but the car instantly died when the gas was tapped.

I do not know what we did to turn my problem from what it was to what it is now, is there anything other than timing that could cause my new problem?