Carbon build up in intake ports

[Tim]

I was a GM person for most of my life. I never really trusted Ford to be reliable. This is probably because of spark plugs breaking off in the head (I thought this happened with all Ford engines) and other issues that I picked up while watching car shows in addition to “Found on road dead”, “Fix or repair daily” that I had heard even as a kid in elementary school.

So far, the Ford has been trouble free and this forum has been impressive with advice, how to’s, general information and lack of condescending attitudes found on some GM forums.

Being able to adjust settings using Forscan rather than trying to deal with dealer service departments is an added benefit.

Overall, my first experience with Ford has been a good one.

My last truck was a 2017 GMC Sierra RCSB with a 5.3 engine.

The GMC had direct gas injection that came with rumors that the intake ports would eventually clog with carbon because the valves were not being washed by fuel.

Beginning with the first oil change at 1,500 miles and with every oil subsequent oil change, I would use CRC valve cleaner on the GMC engine in an effort to prevent carbon build up.

The Ford Coyote engine has direct gas injection and port injection. I have not used CRC valve cleaner on the Coyote engine thinking that port injection would keep the intake clean.

Question: Has anyone who has had the intake manifold off maybe to install a supercharger or for other reasons noticed significant intake carbon build up on Ford Coyote engines with direct injection and port injection?

Sponsored

 

[TexasTruck]

I was just as curious as you actually; does PI actually do anything to keep the intake runners clean including the backside of the intake valves.

I waited till ~9500 miles before installing my FP/Whipple. I felt it best to let things settle in together before hand. I only run 93 octane since new.

While I don’t have a picture (I know pic or it didn’t happen) of the detail down inside the intake runner I will tell you I was pleasantly surprised! I expected it to be shined new, that it wasn’t. What saw is the usual darkish yellow fuel staining, evenly distributed all the way to the intake valves. There wasn’t any carbon buildup whatsoever!

I’ve read here that the PI is used most of the time on our 5.0 and the DI kicks in at higher RPMs.

Anyway, sorry I don’t have any actual pictures of it, but I rest knowing PI seems to be doing its job.

 

[randc42460]

I was just as curious as you actually; does PI actually do anything to keep the intake runners clean including the backside of the intake valves.

I thought that was the whole point/advantage of having port injection. The injectors are in the intake runners and shoot fuel from the runner into the combustion chamber and that spray helps clean the runner and, more importantly, the backside of the valves.

 

[Snakebitten]

There are many benefits to adding port injection to a direct injection engine, beyond washing the back of the valves. But that is indeed one of the benefits and I personally wouldn't worry about carbon buildup.

Welcome to the dark side, by the way. But fair warning, we do reserve the right to take a shot at GM every once in a while. It's America, after all.

 

[TexasTruck]

I thought that was the whole point/advantage of having port injection.

Yep they spray right down in there. However, my doubt was do they spray enough or is DI active most of the time. Like I said, it was very clear they must be used enough to keep things clean down in there

 

[JExpedition07]

Welcome to the Ford club, the increasing power demand by consumers as well as emissions compliance have necessitated the addition of direct injection into naturally aspirated engines. Direct injection is key to getting power out of a naturally aspirated engine, as the use of high static compression ratios extracts more power out of the fuel. Direct injection is used to keep knock down. You could never safely run a 12:1 compression engine like the 5.0L V8 does from the factory on 87 octane in the past, this kind of compression was strictly for the drag strip or track. Now, direct injection can cool the incoming intake charge which prevents detonation or knock. The direct injectors on the 5.0 are always active. They just vary on degree of blending. In low loads and low rpm they are 10% of fuel blending. In high rpm or high loads they are 90% of fuel blending. It’s not as simple as rpm, if the ECU knows the engine is under load the DI increases as dominant over the PI. At low loads and speeds PI is primary. Overall the induction system should stay significantly cleaner than an engine without PI.

 

[TexasTruck]

The direct injectors on the 5.0 are always active.

Learn something new everyday, thank you!

 

[Tim]

Question answered.

One less thing to think about

Thanks all.

Sponsored