I'm currently working on a 3.4 PR engine rebuild and since I live in Florida where "cold" is usually 50 degrees, I decided to delete the cold start injector on my 3.4 rebuild.
This should work well for the 2.8 as well since all the mods are obviously the same for both.
Once the engine swap is done , I'll know how well, (or how badly), this works, but the good thing is that it's reversible, so the CSI can be re-installed if needed.

The first thing is to stumble across this fuel injector rail:
I had planned on simply capping the CSI outlet port on the 2.8 fuel rail, but I found this rail on my parts shelf.


I have NO CLUE what engine it goes to, so maybe somebody can do some detective work with this part number on it:


Note that the fuel rail has NO port on it for the CSI....nice and clean
Note also that the fuel inlet ports are correct for the Fiero fuel inlet block!

[This message has been edited by randye (edited 04-29-2007).]

The next problem to tackle is the CSI port on the lower intake manifold:


I measured the hole and found that it is just a little under 7/8 inch, (.864), so......


A nice 7/8 inch diameter freeze plug fit just dandy in the port and is just about perfect in heigth.
The plug is coated with a thin bead of RTV sealant and then tapped into the port using a suitably sized socket and a hammer.
I tapped carefully as I was concerned about cracking the manifold if it was too tight, but this is a spare manifold I had, so worth the test
The plug fit very snug so I'm not worried about any vacuum leaks.
The tapped hole for the old injector flange is a blind hole, so it can just be left as-is.

[This message has been edited by randye (edited 04-29-2007).]

You should not have any problems with it. I disconected mine about 3 years ago when I did my swap. It starts right up in the dead of winter with only a slight stumble when it's below 20* and the engine is ice cold. After 5 minutes of run time, it does not stumble anymore.

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Next order of business is to deal with the CSI switch on the other end of the lower manifold:
Pretty simple. Just a 3/8 NPT pipe plug and a little sealant:

The old broken fan switch was stuck in to remind me which hole to plug, but I think you could plug either hole and just move the fan switch where you like.
The fuel inlet block from the Fiero is installed on the new rail and sits just where it should

Here's the opposite end, with the stock fuel pressure regulator in position.


Here's another view with the manifold plug inplace:


I'll also be deleting the coolant lines to the throttle body, so this should help clean up a lot of the clutter.

If this is "old hat", and has been posted before, my apologies, but I was just pleased with how easy this turned out to be...with the exception of finding the fuel rail, so if anybody can PLEASE identify it from the P/N it could be a better option than capping the 2.8 fuel rail.

Randy

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Everyone thinks I'm psychotic,
except for my friends deep inside the earth.

[This message has been edited by randye (edited 04-29-2007).]

I did something similar to mine, when I built my 3.2 stroker last summer. I drove it all winter with no cold start, no throttle body heater, non-functional EGR, no trunk blower, and custom PCV setup. I haven't had a problem yet. I went so far as to delete the wiring for the CSI system.

The truth of the matter is that here in Florida, the cold start injector might actually activate 7-10 days out of the year, at the very most. And that's assuming you start the car late at night or early in the morning.

[This message has been edited by Blacktree (edited 04-30-2007).]

Ok few things that I think should get some clarification, the cold start injector fires whenever the engine temp is below operating temp and I believe has nothing to do with how hot or cold the outside air is. Which means that at even 100f the cold start would still come on.

Now playing devils advocate here, I have removed my cold start, EGR, fuel tank vapor canister, throttle body coolant lines, and a whole whack of other things on my last several builds. Even in winter temps of -13C ( roughly 5F ) the car always fires up just fine. It really cleans up the engine bay removing all that stuff and getting to the dist hold down bolt is a piece of cake now. I have never had a throttle body freeze and I don't think I have ever heard of one freezing from these mods. Oh if you do an EGR delete just make sure to get a chip that electronically deletes it as well. When the computer thinks the EGR is active it alters the ignition timing. So you need the chip to stop it from doing that.

Oh one last tidbit, I don't remember the exact size, but a chrome metric Honda drain plug fits the cold start port on the fuel rail perfectly, for those that don't have access to a fuel rail with CSI delete.

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85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics Yellow 88GT 5spd Stock.

quote Originally posted by Capt Fiero: Ok few things that I think should get some clarification, the cold start injector fires whenever the engine temp is below operating temp and I believe has nothing to do with how hot or cold the outside air is. Which means that at even 100f the cold start would still come on.

Ahoy there Capt.!
You are correct. However, the 87' Factory Service Manual *does* state that the CSI will activate whenever the engine temperature is below 95F, so supposedly it wouldn't squirt at 100F
If I read it right, the max. activation time at very low temperature is approx. 8 seconds, and only while cranking....one onethousand, two onethousand.....count it out for yourself or look at your watch...that's one long crank-over. Again, if I understand correctly, the ECU adjusts the activation time of the CSI according to temperature, so I'm guessing that the CSI total activation time while cranking on a 70 - 80 degree day would be mighty brief. Thanks for the info on the Honda drain plug. With that and the 7/8 freeze plug it would still clean up the clutter and look good.

Still don't know where the fuel rail came from, but I'm not exactly losing any sleep over it....

quote Originally posted by randye: Ahoy there Capt.! You are correct. However, the 87' Factory Service Manual *does* state that the CSI will activate whenever the engine temperature is below 95F, so supposedly it wouldn't squirt at 100F If I read it right, the max. activation time at very low temperature is approx. 8 seconds, and only while cranking....one onethousand, two onethousand.....count it out for yourself or look at your watch...that's one long crank-over. Again, if I understand correctly, the ECU adjusts the activation time of the CSI according to temperature, so I'm guessing that the CSI total activation time while cranking on a 70 - 80 degree day would be mighty brief. Thanks for the info on the Honda drain plug. With that and the 7/8 freeze plug it would still clean up the clutter and look good. Still don't know where the fuel rail came from, but I'm not exactly losing any sleep over it....

The CSI system is self-contained - the ECM doesn't control or know anything about it. The CSI thermo switch is a thermal time delay switch; when it's cold the contacts close. Power is only applied to the CSI circuit when the engine is cranking. Current to the injector heats the thermal delay; when it gets warm enough (about 95) it opens.

The injector works for varying amounts of time depending upon the temperature of the switch; when it's very cold, it takes longer to heat the element enough to open the switch. When it's hot outside, it only takes a fraction of a second to open.

It's really only valuable when outside temperatures are below zero.

quote Originally posted by Whuffo: The CSI system is self-contained - the ECM doesn't control or know anything about it. The CSI thermo switch is a thermal time delay switch; when it's cold the contacts close. Power is only applied to the CSI circuit when the engine is cranking. Current to the injector heats the thermal delay; when it gets warm enough (about 95) it opens. The injector works for varying amounts of time depending upon the temperature of the switch; when it's very cold, it takes longer to heat the element enough to open the switch. When it's hot outside, it only takes a fraction of a second to open. It's really only valuable when outside temperatures are below zero.

Thanks Whuffo.
Thats what I get for using the Fiero shop manual for bedtime reading when I'm tired.
I had the essentials, but was confused about the ECU.

One thing remains. I am assuming that I can simply trim the CSI injector cable short in the harness if I want?

is that the fuel rail for the 3.4? looks familiar but i cannot find mine at the moment. i think the lower intakes were pretty close as well. i'll have to take a look again.

quote Originally posted by shawnkfl: is that the fuel rail for the 3.4? looks familiar but i cannot find mine at the moment. i think the lower intakes were pretty close as well. i'll have to take a look again.

Shawn,
It's not the original 3.4 fuel rail. The 3.4 rail has provision for the inlet and return lines to bolt directly to the rail and does not use the "block" that the 2.8 does.
Here's the 3.4 fuel rail for comparison:


Here is how the 3.4 original fuel lines mount to the rail:

Oops! I mistakenly thought the CSI only activated below 32°F.

quote Originally posted by shawnkfl: is that the fuel rail for the 3.4? looks familiar but i cannot find mine at the moment. i think the lower intakes were pretty close as well. i'll have to take a look again.

Shawn,
Stick with the 2.8 lower manifold on your 3.4
I'm convinced that the oil splash shield on the bottom of the 2.8 manifold is worth having, (the 3.4 lower manifold doesn't have one), plus the concensus I've been able to get from PFF posts is that the 2.8 lower manifoild may even flow a tad better.....(who knows, but the difference is likely marginal).

The upside is you don't have to plug the 3.4 manifold, but I tossed mine out before I thought about deleting the CSI

Is that possibly a 3.1 fuel rail? My Beretta and my Lumina 3.1's both did not have the CSI. I can't remember what the rail looked like tho'.....will have to check at Harry's U-Pull-It this weekend.

um - one question: where did you relocate the IAC too? if I remember right - it too uses that lower intake bypass that the CSI uses.

The IAC bypass port is still intact. Note that the hose fitting on the lower manifold is still there, (no hose connected)
The 7/8 inch bore that the freeze plug fits into does not intersect the IAC port opening, so it isn't blocked.
I checked that before I installed the plug

quote Originally posted by randye:

[This message has been edited by randye (edited 05-03-2007).]

quote Originally posted by randye: The IAC bypass port is still intact. Note that the hose fitting on the lower manifold is still there, (no hose connected) The 7/8 inch bore that the freeze plug fits into does not intersect the IAC port opening, so it isn't blocked. I checked that before I installed the plug

oh, right - shoulda remembered that...I just put my upper plenum on yesterday....