Running on 5 cyls?

[we4Mateo]

Here it is. Car was raced Sunday, everything was great. Drove it 50 miles yesterday, everything was great. Left Jimmie John's last night, everything still great, but then half way home, it just started to run like crap. I started running through the SM numbers and everything seemed good but my BL's were higher than normal. I thought maybe a plug wire came off or something, but everything is good there. Here are my thoughts: I think I have an injector that took a dump. That would explain the higher BLs as the other 5 injectors are running richer to get the AFR to where the computer is happy with the overall mix and also why it runs like crap ie: rich and on 5 cylinders. Everything else on the SM is normal for my car and no MAL codes. Any other thoughts? I have a guy who I'm taking it to to diagnose further as I just don't have the time right now with my new biz, but I wanted to collect some ideas before taking it there in case my thought process is off.

TIA guys and gals!

 

[we4Mateo]

I have about 50k miles on these injectors too. Maybe I should check the injector harness too, but I'd think it'd come back in and out if there was just a short.

 

[kidglok]

Could've lost a spark plug?


Posted from the TurboBuick.Com mobile app

 

[we4Mateo]

Could've lost a spark plug?


Posted from the TurboBuick.Com mobile app

I was thinking that too, but wouldn't the BL's stay the same or even go lower from the excess fuel in the exhaust system from not being burnt properly?

 

[kidglok]

I was thinking that too, but wouldn't the BL's stay the same or even go lower from the excess fuel in the exhaust system from not being burnt properly?

It would add fuel thinking its lean from the excess oxygen not being burned


Posted from the TurboBuick.Com mobile app

 

[we4Mateo]

It would add fuel thinking its lean from the excess oxygen being unburnt


Posted from the TurboBuick.Com mobile app

Ahhh, yes. I hate that back one on the pass side, but maybe I'll get lucky and it'll be one of the other five. I should at least pull the other five before towing it up there. Tow charge is minimal though.

 

[kidglok]

Ahhh, yes. I hate that back one on the pass side, but maybe I'll get lucky and it'll be one of the other five. I should at least pull the other five before towing it up there. Tow charge is minimal though.

That's one thing I like about not having heat or a/c, tons of room lol


Posted from the TurboBuick.Com mobile app

 

[750H.P.V6]

Do a compression test and see what you find.

Neal

 

[we4Mateo]

Do a compression test and see what you find.

Neal

Really? It's not smoking or knocking and it happened at cruise and not under load. That's what makes me think it's electrical and not mechanical. I haven't seen too many mechanical failures yet at cruise, but there's always room for a first time! Electrical happens to me a lot though and always happens all of a sudden, just like this. I don't want to jump to conclusions though. Thanks for the input. I'll def do that if the plugs and wires all check out. I'll check the TR6 box as well, but it's not showing any diag codes and that thing is sensitive to things being wrong.

 

[jdsgnx]

I was gonna say check injition module and coil pack....

Good luck!!!

 

[Pronto]

MAF?

 

[Nick Micale]

The simple and easiest check is to use a laser heat "gun" to check the temp on each cylinder to see if there is a issue in a specific one.

The next step,as was mentioned, a compression check will tell the condition of the plugs as well as each cylinder integrity or not.

 

[750H.P.V6]

I'm not trying to tell you it's one thing or another but headgasket failures in Turbo Buicks are fairly common, not all the failures are the same. It is possible to have a head gasket fail to the outside of the block thereby creating a dead miss with no coolant or oil spraying around and no additional crankcase pressure. It makes sense to check the electronics first then pull the plugs to check condition and then do a compression test.

Neal

 

[kidglok]

What plugs you running? And are you still on the same coil pack with .050" gap on the plugs?


Posted from the TurboBuick.Com mobile app

 

[NicksTurbo6]

If you don't have access to an infrared heat gun as Nick suggested, Get a spray bottle and fill it with water. As the car is running, spray each primary tube with water. The cylinder not firing will have the water evaporating the slowest.

 

[TurboTdr3.8]

The simple and easiest check is to use a laser heat "gun" to check the temp on each cylinder to see if there is a issue in a specific one.

Nick is right about that , That is a very easy way to check what cylinder you have not up to par , Keep it Simple !

 

[we4Mateo]

What plugs you running? And are you still on the same coil pack with .050" gap on the plugs?


Posted from the TurboBuick.Com mobile app

NGK UR5's at .040. Less than 2000 miles on them and probably 20 or so passes. I really appreciate the help. I'll use the heat gun idea first. I am running the same coil pack I got when I installed the TR6, so that should be good, but obviously I'll check that spark plug on the cylinder I find to be dead. I'd be surprised if it was a HG though. I run a no knock and conservative street tune and the HG's were new less than two years ago. I'm open though, especially with these cars. Help much appreciated, and I'll report back what I find out. FYI, I've only been running it at 22-25psi lately. The times in my sig were from BG last October at 30psi, but I would think the HG would have let go down there or on the 600 mile return trip.

 

[we4Mateo]

MAF?

AF readings are normal and turbo still spools, but poorly, and AF climbs as it should. I only ran it to 1psi when it started acting up, but I wanted to see the SM readings on the AF side of things. I have an LT1 MAF and translator.

 

[Nick Micale]

NGK UR5's at .040. Less than 2000 miles on them and probably 20 or so passes. I really appreciate the help. I'll use the heat gun idea first. I am running the same coil pack I got when I installed the TR6, so that should be good, but obviously I'll check that spark plug on the cylinder I find to be dead. I'd be surprised if it was a HG though. .........

The signs point to a head gasket or possibly worse?

Not all blown heads gaskets are complete blowouts, most start with a head lifting and "tracks" the gasket. It may be miles later before if lets go or is noticeable?

In my experience your plug gap is way too large especially with an extended plug which is a prime target for a hot spot in the combustion chamber. When a hot spot develops, you immediately cause pre-ignition which is much more damaging than detonation, and it will not show up as a knock reading.

 

[kidglok]

That's why I like these plugs. Recessed tip with a cut back ground strap.

Posted from the TurboBuick.Com mobile app