So I did this recently and I found some of the information scattered in the forum and some on my own, but I haven't seen a full write up so I decided to do this quick.

I will edit this weekend to add pictures and part numbers when I go home.

There are 3 components to the cold start injector, the fitting on the fuel rail that feeds the injector, the injector that is in the lower intake manifold located below the distributor, and the cold start injector switch, located next to the fan switch next to the Thermostat housing.

So three things need to be plugged, the injector hole in the intake, the fuel rail where the fitting is, and the top of the lower intake where the switch is.

I bought all the parts at NAPA

The injector hole gets plugged with 7/8 inch steel freeze plugs, they are a sealed power part # (edit for part #) NAPA can only get these in packs of 12, so I am sure you can find them online, but they only cost $6 for a 12 pack so I just did that.
I just used a big wooden dowel (like broom handle sized) and a hammer to seat the freeze plugs in the intake. They fit perfectly and are shallow enough to not be blocked by the smaller hole (this is not my picture)

The fuel rail fitting gets plugged by a 12 x 1.25 Metric bolt that will always be too long, so cut it down to the length of the original fitting once it is removed. Make sure the rubber gasket stays in place when the bolt is installed. Mine has not leaked so as long as it looks OK I would use it again. the fitting is on the end of the fuel rail next to the regulator (also not my picture)

The switch hole gets plugged with a 3/8 NPT brass plug. I got one with a square on top and if I could do it again I would get an hex head or allen fitting instead. I just removed the injector switch and screwed the plug in. It is a little tight and only went in around halfway which is fine, but the size may be closer to 5/16 NPT, both sizes were listed as the size of the thread on the actual switch, so I went with 3/8ths, but 5/16ths may work too and look a little nicer. I then just cut the wiring out of the injector harness, but be careful what you do with the wire that is coming from +12v source (starts at a splice in the solenoid wiring on the starter, might be different for other people).

And that is it, it looks really clean compared to leaving the switch and injector in place which many people do, and it is cheap, around 10 dollars all together (even ordering 12 freeze plugs)

And I will add Pictures!

Zach

What is the reason for deleting the CSI?

Upgrading ECMs don't need it anymore like the 7730 which has a choke like feature, and also it can be a source of vacuum leaks, or the CSI itself can get leaky and cause rich conditions. They aren't super cheap to replace, the metal line is a hassle when removing the fuel rail. Also it is not really necessary anyways even with the stock ECM. Maybe a second or two more cranking time. It just simplifies things, less things that can go wrong. I have had a bunch of problems with mine when the o-ring in the fuel rail broke and it sprayed gasoline everywhere.

Your racecar definitely doesn't need one.

[This message has been edited by zkhennings (edited 03-12-2013).]

My ECM is not running the fuel pump on initial start up and I have a momentary switch
installed to run it to start so I can probably delete the CSI with no issues.

If you want to delete yours pm me your address and I'll send you a freeze plug this weekend

quote Originally posted by mcguiver3: My ECM is not running the fuel pump on initial start up and I have a momentary switch installed to run it to start so I can probably delete the CSI with no issues.

Energizing the fuel pump is not an alternative to the CSI or using a newer ECU such as the 7730

The OEM CSI is energized when the STARTER is engaged and when the cold start switch senses coolant temperature below normal operating temp.
When energized the CSI shoots fuel into the LIM center passageway for just a few seconds.

Simply energizing your fuel pump with a momentary switch arrangement before or during startup will NOT activate ANY of the regular injectors OR the CSI

When swapping in a newer ECU such as the 7730, it is programmed to "bank fire" the regular injectors during starter cranking, thus eliminating the need for the analog controlled CSI originally on the engine.

If your fuel pump does not run when you turn the ignition key to the RUN position, then your fuel pump RELAY is very likely faulty not your ECU and it is only the oil pressure back-up switch that is energizing your fuel pump once the starter turns your engine over enough to build oil pressure and activate it.

Replace your fuel pump relay!

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[This message has been edited by randye (edited 03-13-2013).]

Is the AC relay the same as the fuel pump relay?
I know they are side-by-side and I done need the AC relay.
That way I can just switch them to try it.

Yes, they are the same relay. Actually, swapping the electrical plugs on those two relays is a common troubleshooting technique.

Thanks, Will try it this weekend.

Bob

There is a clearly audible click when the key is turned to on, and an audible click 2 seconds later if the fuel pump relay is working correctly.

quote Originally posted by zkhennings: .... The fuel rail fitting gets plugged by a 12 x 1.25 Metric bolt that will always be too long...

Not necessarily. Take your cold start injector to Advance Auto, and go through their assortment of oil drain plugs.
Find one that resembles your CSI. I think mine came from a Honda. Be sure to use the washer, to prevent leaking.

I'm in a huge toss-up whether to do this or not while I'm swapping valve covers. Thanks for the how-to.

I can tell you right now that in my 35* garage my car starts in what seems to be the same cranking time as it did before. I'm sure it is a little slower, but at least for me it was nothing drastic at all.

Swapped out the relay and things work as expected.
Thanks to all who chimed in.
I did not think the relay was the issue but apparently it was.
Zach, thanks for trying to send the plug.
When you do get the chance to resend it I will PM you when I get it.

Bob

Thanks for the feedback, and being in MA you're in a climate similar to me.

Question about the freeze plug, is it just friction fit when you hammer it in? I just don't see any threads in the photo of where the injector goes.

The hole you see in the side of the lower intake manifold in the first picture I posted is where it goes. The distributor is right near it. And yea freeze plugs are a press fit type deal.

Zach,
What are you doing up at 1:30 in the morning dude?
Get some sleep

Haha I am a mechanical engineering student at WPI so I get little sleep. You sleep when you can on the busiest days, went to bed at 4am, woke up at 6am, took a nap from 5pm to 7pm... Also I work crazy hours when I work on the fiero, I usually do a 20 hr work day if on a time crunch. I have been outside at 4 am before wrestling with the engine on the gantry trying to get it back into the transmission...

I'm having a serious issue where my car will not start up, and runs rich when i hold the pedal to the floor. I believe this is the problem. What should I do to troubleshoot the csi?

Hey all I am in the process of Deleting my Cold Start Injector.
The NAPA Part# for the 7/8 Freeze plug is 381-3029



At my local store you can by them one at a time.

[This message has been edited by buga8tr (edited 07-12-2014).]

Just wanted to thank zkhennings and Raydar for the hot tips in deleting my Cold Start Injector. It has been inoperative since before I bought the car, due to someone using the thermal time switch location to house a mechanical temp gauge sender. When currently replacing my fuel injectors, I wanted to delete the whole apparatus.

Just wanted to add:

1. I managed to install the freeze plug without removing the distributor (to avoid having to reset the timing), but had such a battle it might have been quicker to pull the distributor. If you're thinking of using an expansion plug, there's an uneven ledge behind where the freeze plug will seat.

2. A good candidate for Raydar"s drain plug would be: https://www.amazon.com/dp/B...dt_b_product_details It has the perfect length and thread, and a wide flange head to seal. But don't trust the gasket. Use the o-ring imbedded steel washer that GM used. I bought a whole assortment kit, imagining all the future uses it would have: https://www.amazon.com/dp/B...dt_b_product_details Thanks again for the help, and I hope my input might help even more for the next guy!

Contact Spade Customs https://www.facebook.com/SpadeCustoms or spadesluck on this forum.
He has a kit with everything you need to delete the cold start injector.

[This message has been edited by fierofool (edited 04-20-2024).]