Last spring at the strip car blew a head gasket on the track put coolant on track filled up inside with steam, pulled it home started on the rebuild. had crank polished heads checked out ok new 8.75cr pistons, reused rods. reused cam, new timing set went ahead and put new opti on thinking it was causing it. Filled the number 8 cylinder with coolant and other than normal wear nothing else apeared to be wrong. Number 4 cylinder seems to be dead header is not hot to touch after running while others are swapped injectors, and still missing, have pulled plug wire and plug and is sparking. fuel pressure is good. I'm at my end with this and its almost been a year any advise will be appreciated. I can only think somehow i bent a valve also rockers look by the naked eye to be traveling the same as others. valve springs? bent rod? cam lobes? I did not have my computer retuned and before had stock cr pistons in.

 

So throw a comp gage on it.

 

well looks like I need to do that first, could my compression change from 10.4 to around 8.75 without changing anything in my computer cause this? The block was in tolerance and had it honed. The valves are opening and closing on the dead hole. I just don't want to pull the motor back out to find something simple I'm overlooking.

 

Any code?

My thought is that having fuel pressure doesn't mean the injector is actually firing

On the 96, a shorted injector wire causes the PCM to shut down that injector. If that happened, you should be getting two codes. I don't know if the 94 is the same though.

Hopefully someone with a 94 will chime in and give you more specifics.

Jake

West Point ROCKS!! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

In OBD-I there is a code for faulty injector circuit(s) = DTC 18. That's all.

 

No codes, the spark plug is wet with fuel after the engine has been ran. I'm sick of missing lt1's. Any other suggestions? I pulled the intake off everything looks ok (rockers pushrods, lifters I'm thinking maybee the rings are broke, could a bent rod cuase a miss? Has spark, fuel its just missing also the plug is black not new like i would think for a brand new plug that has not fired. Does the number 4 header tube heat up slower than the other ones?

 

Don't see why but remember you need fuel spark and compression.

So what was the compression? both cold and hot.

Forget rings being the issue cause you have no visible oil on the plug.

Assuming you have fuel, you need to check spark while the engine is running with an inline spark tester.

 

I took the intake off hoping to find a rag stuffed in a intake runner or something like that. I have not checked the compression yet but the motor has new pistons, rings and honed and was in tolerence. Has anybody ever insalled rings and not staggered right? Maybee I did that and its loosing to much compression. Also it apears to be idleing fine but is kinda hard to tell with the blower and cam. when it gets under a load the miss shines. I'm wondering if I'll ever figure this out.

 

Fuel
Spark
Compression

It takes all 3 to run properly. The proverbial "rag" you were looking for would have had an effect on compression and you would have seen such with a simple compression test. But when I asked about a compression test your response was "but the motor has new pistons, rings and honed and was in tolerence". Indicating to me that you don't want to do the test.

Well I have news for you. Rings and such are NOT the only things that effect compression. In fact most of the time the valve train is the problem with compression. In order for rings to effect compression enough to have an effect on running, oil burning would be the result.

The reason you test compression is to eliminate it as the problem so you can move on to either spark or fuel. WHICH I also mentioned to check in my earlier post.

If you look logically at the results of what you witnessed, your course of action to start would be compression and spark since your plug was wet. SO if you eliminate compression then you next move to spark. I agree that compression problems are not as likely as fuel and spark issues. However, if you were to focus on spark and didn't find a problem, you would be right back to compression. And you could eliminate that being the cause real quick and not have to worry about it.

It comes down to where to start and how broad a test to start with. With a perplexing problem like this, you must start out broad and then sharpen the focus. So start with a system and end up with a component.

FWIW compression is more likely the culprit of changing with heat. Since all your other cylinders are good after warm up. It's not as likely that fuel for one cylinder or spark for one cylinder is changing after it's warm. However, of the 2, spark and fuel, spark would be more likely to change when warm than fuel would. So see, we're back to the same 2 again.

BTW if you haven't figured out by now. You need compression numbers both cold AND hot. Better buy mechanics gloves.

 

Thanks for the advice speedy, what was i thinking? I checked my spark with an inline tester, tested my injectors with a noid light, both are good. however i got a new code reader my old one was aparently broke and got some codes now don't worry i will do a compression test as soon as i can but for now i have code 23, 33, 34 and 84 any thoughts on those? And if your wondering why i did'nt just do a compression test its because i have a 2 year old son who has to be by my side at all times while I'm outside working on it and a 1 year old daughter who wants me inside while I'm outside.

 

The 23 is the IAT sensor and the 33 and 34 is the MAP sensor. They both use the same sensor ground point to the PCM with a black wire going to the black connector pin B16. Since they both use the same ground pin and both have a problem, that's the best place to start.

There should also be an effect on 2 air conditioning sensors but either the ac system is gone or not being used at this time.

 

DTC 84 means the skip shift solenoid has been disconnected. Unless you just recently disconnected it, the code should have been present when you made your earlier check, but you reported "no codes"????

 

I was getting no codes because my code reader was crap got a new Autoxray 3000

 

Number 3 Cylinder has no compression. Number 1 went from 150 on second stroke to above 160 on the third. I then checked the one I thought was missing the number 4 and it hit 150 on second stroke and then above 160 on the third stroke. Went on to the number 3 and it has no compression. done this with engine hot. It has zero compression!

 

How did you check compression? In other words did you disable the fuel system so it's not squirting in the cylinders? That screws up all the compression readings. Did you have the throttle plates wide open? That has an effect too.

If 3 is a bonafide problem, take the valve cover off. More than likely something is going on with the valve.