BigJohnson

Hello,

I recently swapped my carbed Vortec 350 over to TBI fuel injection. I was going to go the kit route but in the end decided to build a kit myself. In a way I started out with some more advanced hardware that dosen't compliment my novice skill level. Here are the specs on my system.

Bone stock Vortec 350 w/ Edelbrock Performer RPM intake
16197427 PCM BJYK 0D
Bored 350 throttle body w/350 injectors and modified pressure
regulator
Walbro in-tank pump 255 lph high pressure version (this is overkill I know not sure if it is hurting anything though)
HEI converted for use with EFI with corvette ignition module

The chip has a fresh copy of the BJYK 0D bin with the EGR disabled.

I have no EGR or speed sensor. I do have a knock sensor installed but the ESC is not working properly. So to keep from being extremely long winded, basically I got it all together and fired it up and it doesn't run well at all. It will crank and run, at a high idle, and then when it goes into closed loop it leans out and dies.

I understand that since I built this system using new and used parts and may not have wired/installed everything correctly there are many, many combinations of things that could be wrong and contributing to my problems. To help me in troubleshooting journey I attached a datamaster file in hopes that someone could point out some possible obvious problems with my setup.

I thought that the stock BJYK 0D bin in the 7427 would be driveable and be a decent place to start tuning. However, I don't know if it is the stock program or other problems that are causing me trouble.

Any input or suggestions on where to start troubleshooting would be greatly appreciated. I have a factory manual for a 95 van with the 7427 and a full set for 1991 trucks at my disposal. At this point I am a bit overwhelmed with the amount of unkowns in my system. I need a few known quantities to start with to troubleshoot the others.

Thanks

Grumpy

Take an ohm meter, and go point by point from every ecm pin, to where it plugs in. Then do it again. Also, double checking the that sensor/whatever matches what the ecm is looking for.

Then go thur all the mechanical stuff, bolt by bolt, hose by hose. Then do it again.

More often then not, new fire up problems are self inflicted.

If you have an original memcal, then try that.

And if you used any aerosols, or RTV, in cleaning or assembling things, you may have killed the O2, and it will read false form silicone posioning.

HaulnA$$

What wiring harness are you using? Did you make your own or use a 94/95 truck harness? Since your ESC is not working and the engine runs bad, I agree with Grumpy that it is probably a memcal issue. HTH

BigJohnson

Thanks for the replies.

I just found this post today. I didn't know I had submitted it I was still drafting the post and trying to figure out how to make a website to post the datamaster file on. Oh well…

The link to my site is here.

There are a few pictures of my swap and a link for the datamaster file.

Grumpy, I feel kind of stupid now that you mention that about the o2 sensor. I had trouble starting the motor at first, didn’t get the distributor in correctly, and used starter fluid while trying to start it. I’ll pick up a new o2 sensor today From what I’ve read AC Delco o2 sensors are the way to go, right? When I can get someone to help me I will ohm out the harness to ensure all the pins have good connections.

HaulnA$$, I built the harness myself using 94-95 computer connectors and the other connectors from various TBI vehicles from junkyards. I ordered the wire, weather pack connectors and tools from Waytek. I made my harness similar to ones I have seen from CustomEFIS in that I cut the factory harness at the computer connector and spliced in new wire for the entire harness. If I had it to do over again I would have found a place to buy the computer harness connectors and used new wire all together and not spliced anything. CustomEFIS seems to have good luck building harnesses that way so hopefully I will as well. There are pictures of my harness on my site.

I will also try to locate a new memcal today. The one I am using now I removed the old EPROM and soldered in a 27SF512. It is very possible I damaged something in the process.

Also, I was looking in my van manual and it used 2 knock sensors. Did the 7427 PCMs use two knock sensors and if it did will it function properly with just one?

Thanks again

Grumpy

A/C, GM only.

There's nothing wrong with a spliced harness done right. Soldered, with heat shrink, and you're equal to oem. The only thing to watch is if there's a soldered joint where the harness flexs, like at the firewall to engine tie ins. Even then with a little thought even considering that issue, and some tape would be a cure.

HaulnA$$

It will function properly with one sensor if you match the sensor and Memcal. The '7427 only used two knock sensors on the 4.3 V-6 applications. All of the V-8 stuff used only one sensor mounted in the block near the starter. Use a single 3.9K Ohm sensor from a '94 or '95 350 truck. HTH