My Turn....injector upgrade madness

[CptnVortex]

I just swapped out my stock injectors for some rebuilt 19lb Ford Type 3's. Install went well, fired right up, was rough for about 30 seconds then it ran great. Went for a little cruise about 25km and it was running great. That was last night. This morning however, started up ok, and ran rough the whole drive in to work, about 15km. The whole drive it was running as though only on 4 or 5 Cylinders, and shook a ton on throttle and idle. I thought it would get better after install...not worse! I checked the harness connections and all is on tight, no smell of fuel or any visual cues, and spark plug cables are all on tight. Thoughts??

[jlevie]

Was a chip tuned for 19lb injectors part of the "upgrade", it should have been.

[CptnVortex]

Not just yet...... that is coming Friday..... Miller Prostreet Kit is what I am going to go for. I must be running super rich eh?

[jlevie]

Yep!

[akorcovelos]

With stock chip it doesn't matter how big the injectors are (to a point) they will just run as stock size injectors. So with 19lb injectors and stock chip it will just reduce the tine the injector is open so its still adding the same amount of fuel as the stockers.

Where these used injectors you installed? Could be one is clogged.

[CptnVortex]

Yes used, but rebuilt, new seals. Like I said they ran fantastic last night.

Maybe they will be fine when I drive home....we'll see.

[German Audio Specialties]

Was the car healthy before, or did you do this upgrade to attempt to address an issue?

[Q5Quint]

I think I had to fiddle with my afm a bit since I dont think the car self adjusts injectors with the throttle closed. I was using a m30 afm and 19lbers and it worked great~ the o2 sensor will adjust the mix while your cruising around but the afm adjustment will change the idle mix.

Since I wasn't using the stock afm though things could be different.

[CptnVortex]

The car was healthy before, yes. I was just upgrading to be ready for the Miller MAF setup. Car is completely drivable its just not what I would call smooth.... sounds pretty nasty too... I might just park it until I get the MAF and chip just in case it gets worse.

[whodwho]

If it changed running behavior it could be the adaption(but it usually help) you can try to disconnect the battery or ECU to reset and see if it helps.

[jlevie]

If you stuff in larger injectors and don't also install a chip tuned for those injectors the engine will be running rich because DME doesn't know about the increased flow rate. If the O2 sensor is good learned adaptation will eventually get the mixture where it needs to be, at least for 17lb injectors. The DME may run out of fuel trim when 19lb injectors are used.

A chip tuned for larger injectors just has the maps adjusted to account for the increased flow rate. So the net effect of larger injectors is pretty much zero. The mass flow though the engine is essentially governed by head and only very small gains are possible by messing with the throttle body, intake, etc. Those gains are easily within the range of the OE injectors, so there isn't any advantage to larger injectors. Well, later design injectors have a better spray pattern and that can result in slightly better mileage.

[Gregs///M]

Make sure your injectors are seated correctly and sealed. Spray some carb cleaner over each injector where it means the cylinder head. If your has a reaction to spraying on one of the injectors, there is a bad seal.

You can also check for clogs by pulsing a low current 12 volts source through the injector while pressurized carb cleaner or fuel is running through it.

[CptnVortex]

Thanks guy for the tips, will try these steps out and see what transpires!

[CptnVortex]

Well, got the MAF and Chip and all installed, its working great now.

That being said, follow installation instructions correctly and dont plug the damn MAF harness on upside down.... Worst driving experience EVER! hahaha