I am transplanting a 1985 TPI engine/transmission into a 1955 Chevrolet build and have a question regarding the CSI and the potential possibility of disregarding it all together. I know the difficulty of finding one....when I got my injectors back from testing the CSI came back as "pulsed one time then quit...suggest replacing ". I planned on using a block-off plate and eliminating it, but the gentleman making me a Stage 2 Custom Chip doesn't think he can eliminate it on the 1985 ECM.

Question #2....with the chip programming the lock-up on the transmission, will I need to use a 4 terminal brake switch, or can I use the stock 2 terminal switch?

Any thoughts?

Mike

 

The csi help with cold start. But I wouldn’t waste a dime on using ghe870 ecm. Goto Larry’s electric and get a 1227730 speed density harness and ecm.

 

Already have a Painless harness installed....I'm not really well-versed in TPI and certain benefits of any updates. Saved the engine from my wife's '85 IROC and putting it in this '55. I have plenty of manuals that explain specifics, but sometimes it is nice to be able to run questions to someone in-the-know. My current problem is do I replace the questionable cold start injector, or can I use the block-off plate and update the chip (if at all possible). Wish there was a local professional I could have get involved!

Mike

 

There is no significant support for using the 870 ECM from the 85 cars. So if you plan to use it then you will need to fix the CSI. If you want to switch over to the 165 ECM or the speed density 730 ECM then you can either burn a chip to delete the CSI or in the case of the 730 it already doesn't require it.

GD

 

As far as I know painless only makes a stand alone harness for tpi maf 1227165 ecm and 1227730 ecm. You might consult your instructions but I don’t think you can use your 85 870 ecm.

 

When I purchased the harness I was told it would work with the 1985 engine, and I verified directly with Painless. There is a provision for the CSI on the harness. What would need to be done to upgrade to a 1227165 ECM?

Mike

 

Here's what I have...

 

That harness is for a 1227165 ecm. I’m not sure if the 85 maf sensor can be used. Could always give it a try . It’s considered digital and 86-89 uses analog. You should get a memcal programmed for 89 without vats.
this world not use the ninth injector. There are block off kits available on eBay or hawks thirdgen.

 

Painless was mistaken. That will not work with the 85 computer or MAF. You will need to get a 1227165 ECM, matching 86-89 MAF sensor, and as Tuned Performance mentioned you will need an 89 PROM chip or custom chip to delete the CSI.

It has the CSI injector provisions because those were used on 86-88 models as well as 85.

GD

 

In my experience, the 1985-version FM output MAF cannot be used reliably with the analog input scheme used in the 1986-89 ECMs due primarily to linearity at the higher output end - The "dumb" input buffer cannot reliably translate thr FM output to the required analog voltage. You could build a rudimentary converter using a 0808 and divider to get the supply voltage to 5V (or a regulator IC), but it is probably just easier (and possibly cheaper) to get a later design analog MAF.

Once the MAF issue is resolved, the use or elimination of the CSI is easy, and well-documented here, many times.

Been there:

 

Thanks for all the input...trying to put something together.

Doesn't mean I won't be back!

Mike

 

You might want to look into dynamic EFI's flash. Setup it's the same harness as a '165 but allows you to eliminate the MAF and cold start.
or if you want I have my old '165 ( 88-5.7 Auto with 2:77) chip cheap. I probably have the old cold start stuff but would have to look for it.

 

It will, what it won't do is work with your ECM. I have went the EBL route as mentioned above. It was a lot easier than you would expect and allows you to do flash based tuning. This includes removing the 9th injector and the old MAF that like to go bad and cause code 36 frequently.

Side note on the 9th injector. Since you have what looks to be a fair weather hobby car, you could probably block off the 9th injector and do nothing else. If you are not driving it in the cold, won't matter. One thing that didn't get touched on here, is the ECM does not control the 9th injector. It is only powered during cranking to give extra fuel when it is cold. The later cars just opened the cranking pulse width, Ideally you get a chip with the updated tables, but if you only drive in nice weather, you wouldn't notice it is gone.

 

I have decided to update to th 1227165 ECM so will need the ECM and compatible MAF sensor. Shoot me a pm if you want to get rid of your ECM.

The harness is wired for the CSI...what do I do with that connector? It is connected to the right side injectors.

Mike

 

Thanks...appreciate your help. This group has been very helpful in guiding me in the right direction, and for that I am extremely grateful.

Mike