Hi Guys happy easter!

Ok so spring is finally here and the roads are clear of salt so I decided to get round to finding out why my bird is running so rough. As you can remember (see previous post, Jan 06) I took my Firebird out in January to make sure she was running ok and found out that she wasn’t!
After some useful ideas from guys I decided to start with the easy stuff first, so seeing how I’d never changed the distributor cap, rotor, plug leads or plugs I’d start there just in case I had an ignition problem.

The cap duly came off and I was greeted by rust! The rotor was in a very poor state being burned and pitted, and it looked like at some point that it has hit one or more of the contacts inside the cap because they are all deeply grooved with metal pulled off in the direction of rotation!! The spring inside the rotor that holds it onto the distributor shaft had completely rusted away and that’s what made me think the rotor had possibly “wobbled” on the shaft and hit the contacts.
The carbon brush inside the cap didn’t spring up and down like it is supposed to it just went up and stayed up in the top of the cap when I pushed it! And it looked like it’d almost worn through the rotor. (Did the previous owner EVER service her????)
There is rust (surface) on the magnet and the pick up coil, but I wasn’t able to change them as I’d not anticipated the condition inside the cap and had not bought spares. The module and the wires to it and the pickup coil look ok but I didn’t disconnect them just in case!

Ok so I’m thinking that’s got to be the trouble I was having, wrecked cap and rotor causing a weak spark hence the misfiring. I replaced the cap the rotor the plug leads and plugs and finally put my battery back in for the summer to test it out.

What can I say, it run’s even worse now!

I turned the ignition and it usually starts first time. This time it would only start with my foot quarter way down on the gas holding about 1500rpm. It will run quite smooth with a very light misfire right down to about 500rpm with your foot on the gas but as soon as you take your foot off it stalls. I’ took the number 5 and number 6 plugs out and both were very dry black and sooty only after about five mins!

It was suggested that when I changed the fuel tank last year and let the fuel injectors go dry it caused blockages in them resulting in the problems I had. I did notice that as I was checking round I saw that the number 2 and 4 injectors were wet under the plenum. So I guess that’s the next thing on my try list!


All the best Speed.

 

Ok, black and sooty means running rich. Maybe several things.
I did not catch how many miles it has, but if 120K+ you really need to have the injectors cleaned. Not just add a bottle cleaner, really taken off and professionally flow cleaned.
Also did you replace the fuel filter? just juding by other condidtions stated... just some prevention stuff...

Now, did you check your timing while you were doing all that ignition stuff? (I know I harp about timing in every poor running thread but it's usually 80% of the cause or is off anyway)

If your new rotor and cap have physical damage I suggest pulling distro, removing the cam gear and checking the shaft for trueness. Something happened to cause the impact. It will also give you the opportunity to replace alot of the other parts, compasitor, pick up and such.

It sounds stupid but did you put wires back on in correct order? #1 drivers front...
Did the plugs have the right gap in them? (actually gap them, not just take out of box and install)
Has the EGR port been cleaned lately?
Has the EGR been tested lately?

Start with that list and see what happens.

 

Yeah I changed the fuel pump and filter at the same time I did the tank and they appear to be running ok. I’ve not got a timing strobe but I can get my hands on one. I feel that seeing how it’s got markedly worse since I changed the old stuff and found that the pickup coil was in such bad condition also due to water ingress I’m feeling that it might have something to do with that. I took the new cap off, and it along with the rotor are in still new condition. I think the other rotor came loose when the metal spring in the old one rusted away. I’ve gapped the new plugs to 0.045inch 1.143mm which it says in the book. And run the wires the same as I took them off. I’ve been looking up some other posts and another guy had exactly the same problem as me and it too was due to water rusting away the pickup coil and module. As for the EGR, it’s never been off the car as far as I can tell so I’m sure it’s neither been cleaned nor tested.

Is there any way of checking if the injectors are blocked? I can send off for new one’s if needs be but I’d like to make sure that it is them before I pull em. Oh by the way the cars done 70,000miles, but for the last two years it’s only ever been used in the summer (Oct-Apr it’s in the garage)

Speed.

 

you do not need new ones (injectors) you can send them over the pond if no one there actually flow cleans them. I will have to search for the name, but there is a company here that has a good rep, and are cheap ($10 an injector), but the S&H will get ya.
Injector Cleaning Steps

But yeah, if everything was really rusted, then yeah. Rotate the engine to #1 TDC before removing and then pull, tear down, clean and rebuild. 1/8" pin holds the cam gear on.

 

Normal, and will work fine as long as there isn't a bridge.

Probably due to the misfiring. Dry black soot indicates rich, which it probably is, especially if its not firing all the time. Is there any way one of the plug wires could have shorted against the exhaust or perhaps melted onto it?

Double check the firing order, then triple check it, and for good measure, check it again. Have someone else check your work too. Its way too easy to get one set crossed or hook them up the wrong way round.

Ignition coil is suspect and should be cheap enough to replace, might save you having to do the distributor.

Ignition module is suspect too, those wires are really easy to have an intermittent connection.

This is really a hack, and not much worth the effort - Pull one injector (its a chore to do), find a can of fix-a-flat or some aerosol can with the clear rubber hose coming off, take the top portion off (you want the button and the hose), now take a can of throttle body cleaner (carb cleaner or brake cleaner even) and remove the top button and replace with the button and hose from the other can. Now cut the fitting off the end of the hose, insert one end of the fuel injector into the open clear hose and secure in some fashion (small hose clamp) - Now the tricky part - press the button on the throttle body cleaner, and at the same time apply +12V across the terminals. You'll need 3 hands. Tap the +12V never leaving it on for more than an instant. (tap, tap, tap, tap), you should have a conical spray pattern that isn't interrupted. Actually doing this you are cleaning the injectors in a way we Americans call - the ******* way.

Edit: LOL, R3DN3CK is starred...

 

Thanks for the input guys,

Bobdole369 your idea of cleaning the injectors sounds way scary guy! I think I’d be better off just paying for the shipping and handling to the U.S. rather than blowing myself up with some fix-a-flat and TB cleaner!! Thanks for the idea though.

I think I might be better just letting someone who knows what they’re doing clean the injectors like v6sucker suggested. I’m looking now at some places over here that might be able to do that sort of work but any you know of over there would be appreciated.
As far as I’m aware the new plug wires I put on are in the same order as the ones I took off and are well clear of any exhaust components but I’ll give them another check tomorrow. I also rotated the engine to TDC on the number 1 plug to verify its position before I pulled the cap so I’m pretty sure I’ve not mixed anything up.

The more I think about it the more I’m leaning to the thought that I’ve got a bad pickup coil and module in the distributor, it really was quite bad in there and from what I saw there had been quite a bit of moisture in there at some time. From what I’ve seen of pickup coils, they have what looks like plastic tape round the copper wires protecting them? Well mine doesn’t have this, in fact the wire is pretty corroded and looks in poor shape.

Can this cause a week spark hence the fuel not being burned? And would it cause the car not to idle at all and only work with your foot on the gas?
Just out of interest why are there 3 cables on the throttle body? I know one is the accelerator cable but the other two go under the plenum and I can’t work out what the hell they are for, cold start perhaps?

Cheers Speed.

 

you can test the coil.
Test for resistance, and output with a screw driver and a dark area (night cranking). Place a long screw driver in the sparkplug end of wire. Have someone crank while you hold it close to a ground (body). It should jump to ground revealing a color. Anything but white/blue is bad.

An easier way to clean the injectors yourself... a very simple and basic flow bench.
1. Have a small liquid pump able to handle fuel type fluids. LPH rating is not THAT important, but you do want a good bit. 20-40 minimum. Sealed aquarium pumps can handle alot of this type of duty.
2. Buy an injector harness plug.
3. Buy a 9 volt battery connector at an electrical parts store. like radio shack type place.
4. Solder the 9 volt battery connector to the injector harness plug. Please use heat shrink tubing...
5. Get 4-5 feet of 1/4" clear tubing and some clamps to fit.
6. Have some sort of liquid container with carb cleaner type solvent. If like gallon dip buckets here, your fine just use that.
7. Now play connect the dots with tubing pieces. Container to input of pump, output of pump to top of injector. Bottom of injector to container.
8. Put the injector harness on (with 9 volt battery plugged in-this will open the injector), turn on the pump and let it run for a while. It will pump with the injector full open.

I suggest putting a clamp on the output of pump and input of injector, that is the pressurized side of things.

And yes the 9V is enough to trigger the high impedence injectors on the 3rd gens.

TB cables are as follows...
one Throttle
one trans kick down
one cruise control

 

To answer your last question and get it out of the way - 1 is the cable from the cruise control servo, the other is likely your TV cable (TV stands for Throttle valve, aka (quite incorrectly) kickdown cable, passing cable, etc. The most obvious use is that when you punch the gas, the car downshifts. It does a whole lot more than that (regulates pressure to the entire transmission).

Absolutely a corroded pickup and magnet can cause a weak spark. And absolutely a weak spark can make the car run like garbage so you must have the accelerator depressed to have it run. So can a bad ignition coil. If your going far enough to pull the distributor to do the pickup you may as well get another coil on there too. Beware, the coil on my car was riveted on, needed to be creative about getting the rivets out

 

i put a msd coil on a while back, taking the old one off was no prob, just grind one side of each rivet away (dremel) and pry it off, but bolting the new coil back in that spot was PITA, no room to hold the tiny nuts(heh..) behind the bracket...if cursing at it got the job done, it would have been done in 5 minutes

 

Hi Guy’s

I can’t thank you all enough for the help and suggestions over the last few days but guess what? Yeah she’s running like a dream now!
Don’t know how I did it to be exact so I’ll describe what I did and see if you can work out what it was I did.
Ok well first I re checked to make sure the plug wires were all routed the right way, then I did it again and yeah they were all where they should have been. Second I made sure I got #1TDC in the first place and rotated the engine on the pulley bolt until the white timing notch matched with the #1 plug. (By the way I have two notches on my crankshaft, one white and one orange, I know the white ones TDC on compression stroke but anyone know what the orange one is for?)
Anyway, then I went round and pulled all the plugs and re checked the gaps. I had set them to 0.045inch which it says on the label on the bonnet but I noticed they were not as tight fitting as the plugs I took out so I matched them with those (what the hell!)
I took the distributor cap off and made sure the rotor arm was on properly and then went round checking all hoses and wires were tight and fitting correctly. I also, and I don’t know if this matters, but I swapped ends of the coil wire to distributor head. It looks exactly the same and theirs no mention that it has to fit a specific way, but I did it anyway. And that was it, that’s all I did, I got in the car turned the key and it jumped into life as quick as that! I’ve driven her 50 miles today, stopping switching off and then on and not a problem. It idles at 650rpm without hesitation it’s a smooth as silk and accelerates like a dream!

All I want to do now is give her a good wash tomorrow and try and get rid of a full tank of 6 month old gas!

I suspect it might have been the plugs but there now gapped to 0.043inch, can that make the difference?

Anyway, I’m a happy bunny again (for now!) so thanks for all the help and suggestions it’s nice to know there are guys out there with the knowledge.

Speed.

 

Gratz on fixing it!

The gap isn't as critical as it might seem. Its important but as long as its close and it works!

A tighter (smaller) gap requires less electricity (well voltage actually) to bridge the gap effectively at the expense of your coils longevity (the difference is negligible), and completeness of the combustion cycle. A smaller gap presents a smaller "surface" for the compressed air/fuel to ignite against.

I have a feeling your coil wire (the one between the coil and the distributor cap) may be on its way out, or maybe it just worked its way loose over winter. A loose or failing cable would cause the following to happen:

All your spark gets used up getting through the coil wire (perhaps a 0.010 gap due to a break in the wire, or maybe if the connector were ever so loose). It would actually spark inside the wire or connector. Thus weak spark at the plugs and a terribly running motor.

You can compensate for a failing coil by reducing the plug gap. This is a way to get the car home if your coil suddenly developed problems (like a small internal short).

 

Yeah I get ya, the actual plug wire is brand new so I’m hoping it’s ok. The actual coil looks like it’s been in there from new so I might just replace it just to be on the safe side along with the old pickup coil and module.
Thanks for the help bob it’s appreciated.

Speed.