How to Delete the Cold Start Injector (Page 1/3)
zkhennings MAR 12, 02:57 PM
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
mcguiver3 MAR 12, 03:15 PM
What is the reason for deleting the CSI?
zkhennings MAR 12, 03:51 PM
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).]

mcguiver3 MAR 12, 04:20 PM
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.
zkhennings MAR 12, 09:46 PM
If you want to delete yours pm me your address and I'll send you a freeze plug this weekend
randye MAR 13, 03:34 PM

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!

------------------

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

mcguiver3 MAR 13, 07:36 PM
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.
Blacktree MAR 13, 09:11 PM
Yes, they are the same relay. Actually, swapping the electrical plugs on those two relays is a common troubleshooting technique.
mcguiver3 MAR 14, 06:34 AM
Thanks, Will try it this weekend.

Bob
zkhennings MAR 14, 11:07 AM
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.