Number one cyl exhaust is cooler

[gn dennis]

I was checking my exhaust temps at the manifold cyl. one is about 125 to 150 deg. f cooler. The other 5 are about 400 f the coolant 180 deg. What does this mean? Thanks Dennis

 

[dank GN]

That your #1cylinder is rich . If u had a sd2 chip or a aftermarket Ecm u could pull fuel in that cyl till it was closer to the others.

 

[WSLN 6]

You shouldn't have to pull much , if any fuel on s properly running engine. Check your spark plug against others, swap cylinder 1/3 injectors around and see if the problem moves around. Easy to do for starters.

 

[gn dennis]

That your #1cylinder is rich . If u had a sd2 chip or a aftermarket Ecm u could pull fuel in that cyl till it was closer to the others.

Thanks Dank I was wondering what was going on. I did pull the plug and number 5 they both look the same, no smell of gas. I do get a little Knock in third gear. car has a TT chip and 42 injectors from them. Thanks Much

You shouldn't have to pull much , if any fuel on s properly running engine. Check your spark plug against others, swap cylinder 1/3 injectors around and see if the problem moves around. Easy to do for starters.

Thanks WSLN6 I will try that and see if it makes any difference.

 

[turbo87adam]

Have you performed a compression test to ensure all cylinders are mechanically sound?

 

[NY Twin Turbo]

What tool are you using to check the temps?

When using an accurate measuring device and at varieous RPM ranges, I'm sorry to say that this may be typical of most Turbo Regals.

Surprised?

I was.

Pleases read through this thread below. You will understand.


https://www.turbobuick.com/threads/individual-cylinder-monitoring.449546/

 

[Mr.Spool]

I was checking my exhaust temps at the manifold cyl. one is about 125 to 150 deg. f cooler. The other 5 are about 400 f the coolant 180 deg. What does this mean? Thanks Dennis

Then that cylinder is either not getting the air or its has too much fuel.does the car have an rjc powerplate.

 

[turbobitt]

I was checking my exhaust temps at the manifold cyl. one is about 125 to 150 deg. f cooler. The other 5 are about 400 f the coolant 180 deg. What does this mean? Thanks Dennis

How are you measuring it ? I'm assuming this is at idle and maybe a surface temp with a heat gun since the "Others" are at 400F. That seems low and I see typically about 800 F with EGT probes in the gas stream. There are a few considerations, if you are measuring surface temp with a gun, the header primary tube length variations could heat sink differently. Also to my knowledge individual cylinder correction is shut off at idle, at least on the aftermarket XFI.
AG

 

[gn dennis]

How are you measuring it ? I'm assuming this is at idle and maybe a surface temp with a heat gun since the "Others" are at 400F. That seems low and I see typically about 800 F with EGT probes in the gas stream. There are a few considerations, if you are measuring surface temp with a gun, the header primary tube length variations could heat sink differently. Also to my knowledge individual cylinder correction is shut off at idle, at least on the aftermarket XFI.
AG

Using a temp gun.....Car doesn't have an RJC plate....Checking like this does give me some idea that that cylinder is cooler. Thanks everyone

 

[Ttype6]

Your number 1 cylinder is receiving less air than the rest of them. This is very typical of these engines. The RJC air distribution plate is made to address this issue. I altered my plate to help number 1 receive even more air than the plate was designed to give because my number 1 cylinder was still my most rich cylinder after installing the plate.

 

[gn dennis]

Your number 1 cylinder is receiving less air than the rest of them. This is very typical of these engines. The RJC air distribution plate is made to address this issue. I altered my plate to help number 1 receive even more air than the plate was designed to give because my number 1 cylinder was still my most rich cylinder after installing the plate.

Please give me the run down on how to install an RJC plate and what I need to go with it? Thanks vary much for your help. Dennis

 

[Ttype6]

Please give me the run down on how to install an RJC plate and what I need to go with it? Thanks vary much for your help. Dennis

It is sandwiched between the lower and upper intake plenums. Nothing else needs to be done.

 

[NY Twin Turbo]

Please give me the run down on how to install an RJC plate and what I need to go with it? Thanks vary much for your help. Dennis

I'm simply not convinced that the RJC plate works throughout all possible RPM and Map conditions. I'm not saying it's worthless. I have no personal expeirience with it. It may help some. It's just that I know it may or may not correct the problems of unequal airflow where you need it the most. Besides, I have seen many cylinder No. 5 and 6 blown head gaskets and melted pistons when others have used RJC power plates.

The flow characteristics and variations in injector flow change based on rpm, map, fuel flow, and pressure. This seems clear to me when using individually correction on the XFI. And these findings apply to all of us, weather you have a stock computer or aftermarket.

Corrections CAN NOT be made across the board to make things equal. This tells me things change with RPM and Map. Furthermore, even with RPM based individual corrections made to the fueling, still it is impossible to get it very close. So, the best strategy is to get it close under load (boost) and hope it's within range at the same RPMs without boost. Because it is less likely that damage will occur when your not making power.

So what is the answer?

Well first, make sure all is working correctly. Fuel pressure, injectors etc....
Then, make sure your temperature readings are accurate.
Then, possibly have your injector's flow checked.
Then, put the injectors that flow more in the hotter locations.
Maybe then get a power plate.
Then you tune against the leanest cylinder.
If nothing else, maybe this is all you can do.

And this is more then enough for most. I mean, at some point you have to let it go and enjoy driving the damned thing!

When your combination becomes to expensive to risk the possibility of burning it up because one cylinder was 1700 degrees and the rest were 1500. Then you go with 6 EGT probes and aftermarket engine management.

 

[Pronto]

It is sandwiched between the lower and upper intake plenums. Nothing else needs to be done.

I highly advise longer 3 flange head bolts and 2 exhaust studs. The pp is about 5 mm thick and the stock bolts/studs don't have enough threads left for good engagement. After 15 years my studs finally let go after removing the upper plenum for maybe the 5th or so time. They had a nice ring of aluminum in the threads. Some go with Helicoil but I had plenty of threads left in the hole so I just went longer. Bolt size is m8 30mm. Chased all the holes with a M8 tap and all was good. Gave the gaskets a light coating of copper spray too.

 

[gn dennis]

I'm simply not convinced that the RJC plate works throughout all possible RPM and Map conditions. I'm not saying it's worthless. I have no personal expeirience with it. It may help some. It's just that I know it may or may not correct the problems of unequal airflow where you need it the most. Besides, I have seen many cylinder No. 5 and 6 blown head gaskets and melted pistons when others have used RJC power plates.

The flow characteristics and variations in injector flow change based on rpm, map, fuel flow, and pressure. This seems clear to me when using individually correction on the XFI. And these findings apply to all of us, weather you have a stock computer or aftermarket.

Corrections CAN NOT be made across the board to make things equal. This tells me things change with RPM and Map. Furthermore, even with RPM based individual corrections made to the fueling, still it is impossible to get it very close. So, the best strategy is to get it close under load (boost) and hope it's within range at the same RPMs without boost. Because less likely that no damage will occur when your not making power.

So what is the answer?

Well first, make sure all is working correctly. Fuel pressure, injectors etc....
Then, make sure your temperature readings are accurate.
Then, possibly have your injector's flow checked.
Then, put the injectors that flow more in the hotter locations.
Maybe then get a power plate.
Then you tune against the leanest cylinder.
If nothing else, maybe this is all you can do.

And this is more then enough for most. I mean, at some point you have to let it go and enjoy driving the damned thing!

When your combination becomes to expensive to risk the possibility of burning it up because one cylinder was 1700 degrees and the rest were 1500. Then you go with 6 EGT probes and aftermarket engine management.

Do you think my knock could be caused by this issue? I don't know how old the chip and injectors are the . You give me lots to think about . I will let yall know what I do. Thanks

 

[gn dennis]

I highly advise longer 3 flange head bolts and 2 exhaust studs. The pp is about 5 mm thick and the stock bolts/studs don't have enough threads left for good engagement. After 15 years my studs finally let go after removing the upper plenum for maybe the 5th or so time. They had a nice ring of aluminum in the threads. Some go with Helicoil but I had plenty of threads left in the hole so I just went longer. Bolt size is m8 30mm. Chased all the holes with a M8 tap and all was good. Gave the gaskets a light coating of copper spray too.

Thanks for the detailed install. Vary good information. Thanks

 

[NY Twin Turbo]

Thanks for the detailed install. Vary good information. Thanks

A reading with a heat gun of a very cold cylinder at idle can show you a few things. But not really translate to what's happening at WOT.

For example. If it's cold because it isn't squirting any fuel, then chances are with just that little fuel, you are going to feel it long before you smash the pedal down.
Or, if it's not getting any spark, again, chances are your going to feel it before WOT. Because an injector this clogged or a spark having problems jumping will certainly be worse when asked to do more.

The temps you check at idle are most likely going to be used to diagnose your problems at idle. Not WOT. Because these kinds of problems will become amplified under load and RPM long before.

But as Turbobit mentioned earlier, only very drastic temperature differences are worth anything with a heat gun because there are a lot of reasons for inaccuracies. My EGT probes also read around 800 at idle. But when using a heat gun, in this case, if a cooler combustion is actually occurring, it is probably better to take the reading on a warm engine about an inch away from the header flange. Because the cooler one may never really get that close to the others

On a cold engine, with a serious problem, you can use your finger to find a dead cylinder. At least for a very little while..........Ouch!

 

[Jerryl]

As stated: The exh surface temp is not the correct data to rely on to make adjustments.
There are too many variables impacting the reading, including but not limted to the angle of attack, and, accuracy of the gun itself in the lower range.

As stated earlier: A rich mixture increases temps since excess gass is burning in the exh. A lean mixture can do that as well since not all gas is burned. This can be due to misfire, timing or other variables.

To rely on EGT data in a decision making process, the data has to be accurate. The focus area of adjustments should be at max VE where combustion pressures are highest. For a given mechanical setup, spark plug gap variation, injector flow variations, fuel pressure variations, impedance, etc. will in theory also impact the readings.

 

[Ttype6]

Do you think my knock could be caused by this issue?

The knock that you didn't mention until now?
If you're getting knock below 17 lbs of boost with 93 octane fuel,I would first suspect the injector harness since number one is you richest cylinder. The heat from the egr is known to mess with the wires that pass by the egr on their way to the number one injector causing that injector to stay on too long. The next things I would suspect are the injectors,so you should do what WSNL6 suggested. Swap the injectors of your coldest and hottest cylinders after you determine that the harness is ok after checking the resistance of each wire in the harness. If the temps move with the injectors,get them cleaned or replaced.
You will still have an air distribution problem and the RJC plate is the solution. Jason,at RJC told me that he was very surprised by the fact that the air moved the same at idle and WOT during their testing to develop the plate. Then he advised me on how I should modify the plate to get even more air to my number one cylinder and it worked. My number one cylinder had the darkest colored spark plug. It doesn't anymore.

 

[gn dennis]

I have my work cut out for me. This is a great post lots of great information !! Thanks Dennis