New Guy Building a jeep with my boy

**Mr.Magoo** · 04-04-2013

Hi all
Im bulding a CJ 7 jeep with my 16 year old son I have a 350 SBC in it with TH350 trans and atlas transfercase.
I would like to put EFI on The Q jet on now is not to good I don't have a big budget so any help i can get would be appreciated.

**Mr.Magoo** · 08-26-2013

Ok I've rounded up a tbi system off a 87 suburban. And i have a few questions. knock sensor? egr delete? vss? Heated o2 sensor?
Im running outside frame rail headers what kind of o2 sensor should i use?
Will a speedometer vss work on a transfer case in low range with a 5:1 ratio?
Where does the Knock sensor go and how does it work?
Can i make it work without an egr?

**jim_in_dorris** · 08-26-2013

1. The knock sensor is basically a microphone tuned to a specific frequency. Which one you use will depend somewhat on which setup you use. If the ECM if a 7747, then the knock sensor from an 87 surburban will work fine. It goes in the passenger side of the block. Do not over tighten it.

2. A AC-Delco 3 wire O2 sensor will get you into closed loop faster.

3. the 87 surburban VSS was actually driven by the speedo cable. It is behind the speedo in the cluster.

4. EGR delete is simple and it will work fine without it.

**EagleMark** · 08-26-2013

And sorry for the belated...

2. A AC-Delco 3 wire O2 sensor will get you into closed loop faster.

And help keep it in CL, those outside frame rail headers are LONG so the exhaust has loads of time to cool off. To cool and the O2 sensor won't work and you go Open Loop.

Since it's that far back mount it in exhaust pipe as close to header collector as possible. This will get exhaust/heat from all four cylinders. The chip will need an adjustment for moving the O2 sensor this far back. Along with properly deleting the EGR.

Since you don't have any E trans or even a lock up TCC... the VSS does not need to be accurate. Just something so the ECM knows if vehicle is moving or not helps idle quality!

**xtreamvette69** · 08-27-2013

welcome and great to hear that father/son projects havent totally disapeared, nice to see one now and again in this day and age.

looks like most of your questions have been taken care of promptly by these guys but i will add that unless something with the newer ecms has changed i know that knock sensors use to be 305 and 350 specific or CID specific for that mater(diff cid has diff frequancy), just thought i would throw that in to get the right one if thats still the case.
and again welcome and best of luck to you and your son.

**Mr.Magoo** · 09-04-2013

Thank you so much for all the information i need to find some more parts and i am sure i will have more stupid questions

**Mr.Magoo** · 02-27-2014

OK
Wrestling is done time to get to work.

3 wire O2 sensor do you have part# please?
Also wiring diagram for it I have not been able to find one.
Thanks

**lionelhutz** · 02-27-2014

I personally would use a 4-wire O2 sensor. The harness will have a tan wire that comes from pin D6 on the ECM and went to a eyelet that was bolted to the engine. Don't hook this to the block but instead hook to the O2 sensor instead. This will eliminate the connections through the engine block from being a source of possible sensor issues. It gives a much better and more direct O2 signal right to the ECM. It used to be that the 4-wire O2 sensors were the most expensive but they're rather cheap these days.

You could use a sensor from say a '95 F-body. The wires will match the connector terminals as such;
A - O2 sensor ground - hook to the tan wire mentioned above
B - O2 sensor signal - hook to the purple wire that went to the 1-wire O2 sensor
C - heater - hook to ground
D - heater - hook to a switch 12V source

**Mr.Magoo** · 02-27-2014

Originally Posted by lionelhutz

I personally would use a 4-wire O2 sensor. The harness will have a tan wire that comes from pin D6 on the ECM and went to a eyelet that was bolted to the engine. Don't hook this to the block but instead hook to the O2 sensor instead. This will eliminate the connections through the engine block from being a source of possible sensor issues. It gives a much better and more direct O2 signal right to the ECM. It used to be that the 4-wire O2 sensors were the most expensive but they're rather cheap these days.

You could use a sensor from say a '95 F-body. The wires will match the connector terminals as such;
A - O2 sensor ground - hook to the tan wire mentioned above
B - O2 sensor signal - hook to the purple wire that went to the 1-wire O2 sensor
C - heater - hook to ground
D - heater - hook to a switch 12V source

OK thank you I have a acdelco AFS75 4 wire O2 sensor coming and wiring sounds pretty simple

**Mr.Magoo** · 03-14-2014

OK I got every thing hooked up and running set timing and IAC but can't get idle right I talked to the guy i got the motor from and he said that it may be a 5.0 so what now? I have ALDL cable coming can i tune the thing W/tunerpro or do i have to be able to burn chips???

**lionelhutz** · 03-14-2014

It would require burning chips or using an emulator. At least wait until you get the cable so you can see what's going on.

**Mr.Magoo** · 03-19-2014

OK I got the cable and recorded the computer readings and i also got another computer and it idled a little lower but still high. Here are the files...

-The first computer is labeled: jeep efi recording
-The second computer is: new computer test

**EagleMark** · 03-19-2014

The ECM can't change idle. But the chip inisde can! What are the chip BCC (four letter code) on each ECM?

As the engines warms up the idle drops. Having the P/N wire hooked up to ECM helps with high idle and drops when in gear. What did you do with your P/N/D wire?

**EagleMark** · 03-19-2014

Looked at the jeep efi log and it won't help much for 2 reasons.

1. You have the 10K switch on and it puts this ECM in ALDL mode which raises idle and adds spark, ruining the data log.
2. Your overheating, just watched a little bit but started around 245*f and I stopped looking at 230*f

**Mr.Magoo** · 03-19-2014

Thank you Mark
The P/N is hooked to the switch on shifter that goes to ground when in park or neutral.
The 10K switch you speak of that is on ALDL cable and it needs to be off when data logging?
The over heating my CTS is in the head should it be in the intake the temp gauge in the intake is not that high and it has a 195 Tstat should it be a 180?
The BCC on the chips are ASDX & AMUR best i can tell both are 5.7 chips