So I have just dropped my rebuilt motor in the car and am trying to tune with the FAST coimputer.

However, after much investigation it appears that the 1 and 8 cylinder are dead.

What I mean is that though there is definately SPARK to the plug, it is NOT working. We tested by spraying the headers with water. On the other 6 the water evaporates immediately, but on the other two headers it stays wet and is cool to the touch.

Any ideas for me? We have fuel, as the problem plugs are wet and the other plugs indicate a rich condition- although the Wideband O2 sensor says it is running lean *scratches head*

Any ideas? opti?

Note we have triple checked all the plug wires that they are on the right plug.

 

if you're positive you have spark going to the spark plugs, then your opti is not at fault. There are three things required for ignition...

• Spark
• Air
• Fuel

You know you have spark, you probably have air...do you have fuel? Your injectors could be clogged?

However, I'd doubt this, but I guess anything is possible. You're absolutely positive you have spark on those two wires?

 

If you have spark to the plugs you need to check fuel and the third thing is compression. If the plugs had spark and they are wet then they don't have compression. do a compression test and then do a leak down test. Chances are you have a valve problem. Leak down will tell you which valve is the problem.

What's up wit the heads. Seen too many with grindings in the guides and causes the valve to stick.

check it out

 

AFR 190 freashly ported. grindings in the valse guide. Hmmmm.

But number 1 and number 8??????
Have spark for sure. have fuel because they are wet. getting frustarted. i cannot tune the car with the FAST until I get those two holes working

 

BTW he has fuel also from i have heard.

just wo dead cylinders. He is trying a re-lash on number one to see if he can pick it up now

 

I changed some injectors to see if it helped. No luck though

I did a compression test on the 1 cylinder. Got 100 psi. This is a brand new motor with 8.9 CR

 

pull your valve covers and watch the intake/exhaust rocker arms on 1 and 8. make sure they are opening and closing like the rest.

easy way to rule out alot of things.

 

yes, make sure your rockers are adjusted right.Make sure those wires are good also.

 

Dang it.

I took a 'new wire' from the opti to the number 1 cylinder. No luck.

We took the valve cover off and watched the number one rockers go up and down. They seem to be working fine. We backed the rockers off a 1/4 off a turn just to see it it helped.

By the by, the 100 psi compression. That seems a little low. It is a new motor though and 8.9 compression. Is that 100 #'s alright?

As I say, the major clue is that the air fuel ratio is running super lean in spite of any tuning efforts. Also, the number 1 and number 8 header are NOT getting hot. The other 6 get hot enough to evaporate a water spray.

When we pull a plug we can see spark though. The plugs are also wet. HAS to be compression right? Valves or rings? God I hope it not the rings. My friends and I have spent 10's of hours to get to this point

 

Just a suggestion,see what you get for compression on a couple more holes.Just to compare.Maybe try a new plug?

 

If you have the blower on the engine currently, take it off to get back to normal condition. [B]Do not run the engine long with this problem[B/] but we need to do some things to find out where the problem is.

I do not believe the F'ing computer your using since the plugs you say show it is rich. If you know what your looking at, then plugs never lie. Let's get some things straight right away. Even at 8.9 100 pounds is low. Have the rings had time to seat?

Did you find out what the rest of the cylinders are at? Have you done a leak down test yet?

Have you pulled the plug wires to these cylinders while they are running to see if has any affect on the running of the engine?

 

Yeah I need to update this thread. Especially after about 15 hours of testing and chasing.

Firstly, I did a compression test on three holes and they are all 100 psi. *shrug*, That seems low but until I have run it around the block a few times i continue to hope it will be fine.

Next, I HAVE found out that the 1 and 8 injectors are NOT firing. - I'm not sure why it is that when I pulled the plugs they appeared to be wet. For the moment I will just say that I was wrong.

In trying to dihanose if the wiring is an issue - and it appears that is not, I found that three pins in the PCM are 'fried'.

NOW the penny has dropped. I had previously, and mistakenly, attached a wire to the starter motor and it blew a fuse - the O2 sensor fuse. Upon investigation I found that it was a ground wire - whoops - and fixed it.

Now that I have looked at a schematic of the wiring harness to try and find the injector problem, the ground wire in question is for the PCM, thus I had power going THROUGH the PCM.

NOT a good thing.

The next thing to do - as the wiring for the injectors DOES test as being good so far although I'm suppose to test it under load as well - is to change the PCM and see what happens.

I hope that fixes THIS gremlin.

Thanks everyone, I'll update this thread with results.