FalconZ28

I've been working on an '88 firebird while I work up the motivation to upgrade the ECM and burn a chip for my Camaro.

Rebuilt the engine, bone stock all the way through. Just wanted a solid runner for fun.

Got the engine all back together, and after some other debugging, cylinder #1 is not firing at all. I have verified that it is getting spark (timing light, and watched the plug spark sitting on top of the plenum) and I have verified that it is getting good compression. Which leaves fuel.

I figured it might be a plugged injector, so I swapped it out with another one I had lying around. No change. I switched injector plugs to see if it was specific to that plug wire. No change.

At this point, I'm wondering if the fuel rail is clogged. Any other ideas? My next task is going to be removing the fuel rail and blasting it out with carb cleaner unless someone has some other easier options to try first.

Thanks!

86Z

iTrader: (4)

why would you say the cylinder is not firing? each side fires all injectors at the same time. i doubt the rail is clogged

FalconZ28

After the engine reaches operating temperature, I can put my hand on the exhaust manifold without it burning me.

Spraying the exhaust manifold with water from a squirt bottle, the only area that doesn't vaporize the water is by cylinder #1.

Also, pulling the plug, it's black as night and all others are the gray-white color. I took these all to mean it's not igniting.

86Z

iTrader: (4)

ok so you verified spark, from your description you must be getting fuel.. is the spark plug wet smelling like fuel?

FalconZ28

I do not think I am getting fuel. When I pull the plug it is not wet, even after running up to operating temperature.

I suppose it's possible that the injector I replaced it with is also clogged. Perhaps when I tear into it again I'll swap the #1 and #3 injector to see if this is the case.

ploegi

if its black, it is at least getting some fuel......

Swap the injectors on 1 and 3, and see if anything changes.

FalconZ28

The engine ran before I rebuilt it (bad rod knock), and I used the old plugs that came out. So I'm pretty sure the soot is from before the rebuild. I intend to take your advice and swap the injectors. I'll also blast out the rail with carb cleaner while I'm at it, couldn't hurt and it might help.

FalconZ28

I dug into the intake and blasted carb cleaner through the fuel rail this evening. Didn't appear to be clogged with anything. I swapped injector #1 and #3 to see if that would make a change and bolted it all back together.

Cylinder is still not firing.

Trouble codes from ECM:

22 - TPS voltage high or fuel cutoff relay circuit open or shorted to ground.

34 MAP voltage high or low vacuum/ high pressure or MAF voltage high/ low flow.

I could see the car not idling because I fudged some vacuum lines. But I'm baffled as to why I'm still not getting a fire out of cylinder 1.

ULTM8Z

Try swapping the injector plugs between 1 and 3.

Maybe the wiring harness is bad to the #1 injector.

At least you can put your finger on the injector and feel if the solenoid is operating. EVen if the injector was clogged, the solenoid should still be clicking on and off...

FalconZ28

Already tried swapping injector wires, I will do it again to make sure I wasn't dreaming or something.

Next, I plan to put my hand on the injector as someone cranks, to see if I can feel the solenoid clicking. After that, I'm going to unplug the spark plug wire and run up to operating temp, pull the plug, and check to see if it is wet/ smelling like gas.

Also, I might be chastised for this, but my "test" to verify I had compression was pulling the spark plug and having someone crank while I plug the hole with my finger. I couldn't keep my finger in the hole, as the cylinder pushed it out with each stroke. I know this isn't as good as a true compression tester, but since I lacked a tool I figured that was good enough.

Not sure if this is significant: but when pulling the injectors this last time I noticed the stacking of the O rings was reversed... Is this normal? Or is it some manufacturing anomaly? Since I switched the injectors and it didn't make a difference, I'm assuming it's fine. Pictured are injectors 1 and 3, (3 is in 1's slot, and vice versa, i.e. I already switched them).

ULTM8Z

When you say "not firing", is this all at idle speed? Does the problem go away while driving?

I fought an idle misfire for a LONG time before a leak down test revealed an issue with stuck piston rings.

The misfire went away at higher rpm as the proportion of air leaking past the rings became a lesser percentage of the total air moving through the cylinder.

Fortunately a can of oil additive freed up the rings after about ~100 miles of driving.

ULTM8Z

Edit: disregard... I see you already noticed the O-ring thing. But if you swapped injectors already with no change, then that can't be the issue.

RBob

iTrader: (1)

Replace the spark plug it is fouled. Most likely the spark is leaking down the center porcelain.

RBob.

FalconZ28

RESOLVED!

Last night, after properly hooking up all vacuum lines, I was able to get it to run at a low enough RPM (1K) and I noticed that it sounded like it was backfiring into the intake manifold.

It occurred to me that I may have set the rocker arms too tight on #1, thus causing what would essentially be excess valve overlap. I didn't think of this first because it was getting partial compression, enough such that I couldn't tell it wasn't strong enough with my finger plugging the spark plug hole.

I backed off the rockers on #1 and it started firing. Woohoo! But it still wouldn't idle...

Hmm. If I made the mistake of overtightening #1, perhaps I did them all a little too much and cylinder 1 was just the worst one?

My assertion was spot on. This morning I did the due diligence of removing both valve covers, and setting them all in sequence (1-8-4-3-6-5-7-2), starting again with #1 to make sure I had it perfect, rotating the crank 90° and going to the next one in the firing order.

The procedure I used for tightening was:

1.) Back the nut off enough for the rocker to be loose.
2.) Tighten in small increments until I could no longer feel any lateral play in the pushrod.
3.) Tighten a 180° turn beyond that "no play" point.

By my assumption, ALL the rockers were between 360° and 720° too tight.

And that adds up to make your car run like a turd. Lesson learned. Hope my struggle helps someone in the future. Thanks for all who gave input.

86Z

iTrader: (4)

i had the same thing with my car except the valve springs for cylinder 2 were broke.