Changing Injectors from SFI to MPFI

[laveryt]

I finally got my new 3400 delivered to drop into my 89 Z-24. It came out of a 2001 Impala. My question is, how do I rewire the injector harness to work with the 2.8 ECM? Does anyone have a schematic to show how to rewire the harness? Also, what should I do with the cam position sensor? Just leave it unhooked?

[bszopi]

I have a schematic around here somewhere, but I'll have to find it...

[bszopi]

Here ya go:

http://60degreev6.com/hlperf/Beretta/ECM%20Project/MPFI-Inj-Wiring.gif

http://60degreev6.com/hlperf/Beretta/ECM%20Project/SFI-Inj-Wiring.gif

[v6h.o.]

i dont get why you guys keep playing with your injector harnesses in these swaps.

use the original 2.8L/3.1L harness, run the stock injectors from that harness,
the MPFI harness works fine, it routes properly and the injectors at least from a 3.1L are more than addequate to supply enough fuel.

[laveryt]

Here ya go:

Thanks for the schematics.

i dont get why you guys keep playing with your injector harnesses in these swaps.

use the original 2.8L/3.1L harness, run the stock injectors from that harness,
the MPFI harness works fine, it routes properly and the injectors at least from a 3.1L are more than addequate to supply enough fuel.

I have the 2.8 injectors. Will they flow enough for the 3400 or would it be better to convert the injector harness?

[Guest]

Colin's not talking about the injectors, but the harness. You have a harness that will work in your car already, it plugs onto the injectors and into your existing harness. I am actually using the same harness in my truck, works fine. You just have to pull the upper intake off and everything you need to access is right there.

[3100 MPFI]

I believe that the 3100 that he has has the smaller PINTLE STYLE injectors, and the connectors are differant. If you can get some of the older 3100, or 3400 injectors, you can use them with the STOCK WIRING from the 2.8. That is what I did with mine. I am using stock 3100 injectors and my programming is 1993 with a custom chip by Ben.

Laveryt..... If you have the REALLY SKINNY injectors (not the fat ones that the 2.8 should have), you will need to put in the fat injectors (if you put in the 2.8 ones, you might need to get a custom chip. I also think that the spray pattern is differant from the 2.8, and the 3x00, so if I were you, I would try to locate some of the older 3x00 injectors). The other thing that you can do is just cut off the connectors to the smaller injectors, and solder them to the wires of the old 2.8 wiring harness.

I will send you a PM with some other suggestions that will help you out in teh long run.

[v6h.o.]

it really depends on what injectors your new Gen 3 engine has.

if its the old style regular injectors (same physical shape as the 2.8L and 3.1L ones)
then your ok.
IF its the MULTEC 2 style injectors. well then i'd suggest to use the 2.8L ones or a set of 3.1L or whatever that are the older style injectors.

as then with the multec's you have to convert the harness... that and you have to use a custom chip programed for the multecs as they are a different kind of injector.

2.8L injectors might work. i just dont know what the rating of those were. for some reason i dont think they were the same rating as the 3.1L injectors.

[3100 MPFI]

2.8, and 3.1 are almost Identical. The 3x00 ones have a differant spray pattern. I recommend just getting a set of 3x00 injectors, and using the 2.8 wiring harness.

[3100 MPFI]

forgot to add that my 3100 MPFI ran better with the 3.1 injectors than the 2.8 injectors, but it ran the best when I put in the 3100 injectors. It seemed like that 2.8 injectors were not putting in enough fuel.

[Cliff8928]

i dont get why you guys keep playing with your injector harnesses in these swaps.

use the original 2.8L/3.1L harness, run the stock injectors from that harness,
the MPFI harness works fine, it routes properly and the injectors at least from a 3.1L are more than addequate to supply enough fuel.

Well, i wanted my 3400 to look like it belonged there, harnesses and all (right down to the CS130-D alternator) Plus, i kinda like the all-in-one design of the injector harness (99 and earlier has the injectors and MAP in one harness, the Coolant temp in a small one next to it... 2000 has the injectors, coolant temp, map, and the other crank position sensor (or is it the cam sensor) all in ONE harness IIRC) Oh, and i didn't want to take the plenum off the 3400 to install it...

Cliff Scott
89 BerettaGT
89 Volvo740

[laveryt]

Ok... I have a 2001 3400 out of an Impala, so I assume that it has the Multec 2 injectors. Is it really a pain to get these injectors to work with the 2.8 ECM?
I was planning on buying the swap kit from JBP, and it includes a chip reprogram. Will that reprogram work with the Multec 2 injectors or am I just screwed with them? I really didn't want to have to take the intake plenum off unless I really had to.

Also, while in the process of swapping over some sensors, I found that the oil pressure sensor on the 01 motor only had one pin in the connector and the one from the 2.8 had 3 pins. So...what difference with the sensors? I could use the 01 sensor but two of the pins wont connect to anything. Does anyone know what the other pins do for the 2.8 sensor?

I also found that there is no place on the 3400 for the temperature sensor that screws into the head onto the 2.8 engine. This sensor has only one wire. Is this sensor used only for the temp gauge? What can i do to work around this?

Thanks,
Tom

[bszopi]

Ok... I have a 2001 3400 out of an Impala, so I assume that it has the Multec 2 injectors. Is it really a pain to get these injectors to work with the 2.8 ECM?

Yes, it is.

I was planning on buying the swap kit from JBP, and it includes a chip reprogram. Will that reprogram work with the Multec 2 injectors or am I just screwed with them?

IIRC, he was using older injectors, therefore the program was probably written for the older injectors. I can't say that is 100% correct though...

I really didn't want to have to take the intake plenum off unless I really had to.

Its 6 bolts and then 2 bolts for the fuel rail... Not like its really that hard. You can probably even reuse the plenum to manifold gaskets.

Also, while in the process of swapping over some sensors, I found that the oil pressure sensor on the 01 motor only had one pin in the connector and the one from the 2.8 had 3 pins. So...what difference with the sensors? I could use the 01 sensor but two of the pins wont connect to anything. Does anyone know what the other pins do for the 2.8 sensor?

I'm in the process of looking this one up...

I also found that there is no place on the 3400 for the temperature sensor that screws into the head onto the 2.8 engine. This sensor has only one wire. Is this sensor used only for the temp gauge? What can i do to work around this?

The 3400 uses the temp sensor in the thermo housing for the guage cluster and the PCM. There is a harness that allows for this, and I want to say it is mentioned in Korbendallas's 3400 swap guide. I'll see if I can't look that up for you as well (for part numbers and such).

[bszopi]

As far as the oil press sender goes... the only thing I can find is that perhaps the 3400s don't use the oil pressure sender as a fuel pump relay like the 2.8/3.1 and early 3100s do. IOW, even if the fuel pump relay doesn't work, once oil pressure is built up inside the engine, a contact closes which allows for the fuel pump to kick in. That is what 2 of the pins are for. The other pin is for the oil pressure signal (either a pressure for the guage or for the idiot light). So I would recommend using your old sensor.

http://60degreev6.com/hlperf/60V6%20Site%20Files/Oil-Press-Wiring.gif

[v6h.o.]

on the old 2.8L's some used two oil pressure senders.

one for the cluster

one for the fuel pump relay.

you want to retain the one for sure for the fuel pump relay! or wire both that are to run oil pressure together off the one sensor, use the two wire? IIRC?

for the coolant sensor there are two things you can do.
with the 3X00's they used only one sensor to monitor engien coolant. the info went first to the PCM then was sent to the IPC for the gauge.
now on our old engines there isthe one for the ECM that goes into the Lower intake manifold. and then our One wire coolant sensor that used to go into the head for the gauge

GM also used on the 3X00's a 3 wire sensor that can be used to work for both functions of ECM and Cluster info.

OR
http://www.domesticcrew.com/colin/hybrid_comparison/ look up the coolant sensor pics.
pics of where i tapped my heads for my Autometer and stock Coolant sensors in the 3100 heads.

for the stock sensor you'll need a 1/8th? or 1/4 NPT tap. and corresponding proper drill bit to drill the right sized hole, take your sensor to an autoparts or tools store and you can find the proper tap for this.

any other info you will need to know can now be found at: http://www.domesticcrew.com/660/index.html we have info for swapping these components into Jbodies for you guys now.

i also have heaps of pics in my parent directory in the link i provided with my pics.