Hi everyone.

I'm fairly new to tuning, but willing to learn (so please go easy on me) - here's the deal, my dad is restoring an 82 El Camino. For years he had a MPFI 305 from an IROC-Z. Originally MAF, then we converted it to speed density and was running the AUJP bin with a 730.

With the restore, we're swapping the 700R4 for a 4L60E. Everything has been connected to a 7427 and running a BJLK Bin. I found information on how to make the PCM in "MPFI Mode" by jumping the two resisters in the PCM (saturated verses peak/hold) and the jumper wire in the memcan to fire the injectors on the 4th distributor pulse.

I have a Pocket Programmer II and running the free version of TunerPro. I have the Moates adapter and some EEPROMs. I found a document that had some data related to a conversion with a 7.4l, but I found a lot to not match up or be confusing.

At the moment I have the stock BIN in with the PFI mode flag checked, nothing else. The engine will start, runs super rich and very doggy on the throttle.

If someone has any guidance as to where I could start to learn, that would be fantastic. I'm not looking for anything wild here, just a nice running 305 with a 4l60E.

Thank you so much!
Kris

 

Any help here? I've done a lot of looking online and I just can't seem to find a good place to get started. Right now the vehicle runs, but it is very rich when cold, so we don't want to wash the walls down and trash the engine. When the PCM was not modified (didn't have the resistors jumped and didn't have the jumper in the memcal) it ran great, just rich.

Anything to help get started would be fantastic! Eager to learn, just need to know what to look for here.

Thank you!

 

You can start by leaning out the open loop air/fuel ratio table from the pig rich 9.5 and 10:1 values to something around 13-14:1. If it is a value richer than 13:1, it needs to be reduced. TBI needs a richer mixture when cold, TPI does not.

 

Ok, awesome. I will start there. I know that if I trick the PCM into thinking the engine is warmer (resistor across the water temp sensor), it will run a lot better and get into closed loop faster. Last thing I want to do is trash a fresh rebuild because I'm learning! Thanks much, I'll keep everyone posted!

 

Hi! Just now getting back to this (work full time, plus school full time, etc) - anyway, plan to burn a chip tomorrow after work and try this out.

I found another bin that someone had converted to MPFI, but that used a MAF. I did a compare in TunerPro and decided I was probably better off starting with my own, since we're not running a MAF. Before the PCM mods (sense jumpers and the DRP jumper), it ran really good under closed loop, so I'm hoping it won't take too much to get this going. Biggest deal now is to get something that works decent as the vehicle needs to go to the frame shop to be straightened - last thing we want is someone else to try to move it around and flood it out, ruin a fresh rebuild.

Anyway, I looked in the BJLK BIN and saw that the open loop AFR ranges from 12 at -40c to 14.6 at 104c. I have changed the bin to start at 14.1 and then transition to 14.6 at 44c where the bin was already set.

The second thing I did was set the CPI/PFI flag to ON.

I changed the Cylinder Volume to 38.13 (305/8) and the injector flow rate to 19.9 lb/hr (which is what the stock injectors are) I didn't change the flow rate. It is set at 2.39 gms/sec - I'm sure this will have to change as well?

I guess that is where I shall start. Hopefully before the weekend is going, I have it running halfway decent.

Thanks for the help!!!

 

A bit frustrating night. That bin didn't work at all. Could NOT get it to even start. I found one last night that was already set for MPFI, but it used a MAF, which doesn't really help me.

So, I went back to the stock BJLK bin and started one setting at a time. So far I have the bit checked for CPI/PFI mode, I have the injector flow rate set to 19.9 lb/hr and I have the bit checked that fires the injectors on a DRP during crank (without this, I couldn't get it to start at all). This seems better, but a little lean. Since I went back to the stock bin, I left the a/f table alone. That table isn't that bad - with the coldest being about 12.5; most of the range this vehicle would ever start in is 13 or above...so that should be ok.

When I read over the "TBI TO MPFI" document, there were a bunch of settings that were changed for BPW and such. And while I understand the electronics side just fine, the concept piece is a bit over my head, especially when the document talked about double pulse, etc, etc.

Tomorrow morning we're going to try again, maybe we'll find a way to get it just a little richer and see if that helps. I keep looking for more examples online, sample files or documents and not finding much that seems to help me. The immediate need is to get the frame to the frame shop, after that I pretty much have all winter to try to get it tuned in and be ready for spring.

I appreciate any advice!!! Thank you!!

 

Update. A little better this weekend. Went back to the stock BIN for the BJLK, set the MPFI mode, put in the BPW parameters I had read from the "TBI TO MPFI" file. Had to set the bit that pulsed injectors on each DRP on crank. Without that it would not get any (or enough?) fuel to start....however, with this set, I'm actually getting TOO much fuel. If I disconnect the fuel pump prior to start (there's a switch under the dash past the relay) and crank, then apply the fuel pump - it will start nice and easy. If I just crank on it, it's flooded. It will eventually start, but it starts hard.

Run-wise, not too bad. Maybe a bit lean on open loop, however it lacks some low end. I can't even break the tires loose.

Any suggestions from here? Right now I'm looking at making a pigtail harness that would plug into the harness we made for the car that would allow the engine to use the 7730 computer and the 4L60E to use the 7427 computer, just so it runs right in the meantime. That way it can be driven during the week - then on the weekends figure out how to get it to run right on one computer.

Any suggestions, things to try, examples - all appreciated.

Thanks!

 

Still running the truck timing map or the 305 TPI one?

 

Still using the truck timing map. I didn't change any of those tables. The TPI is using the larger distributor with the coil in it. Should I copy what the AUJP bin had? Will it line up, or am I going to have to take an educated guess to fill in the gaps? Driving down the road with the scan tool installed it did seem the timing was a bit off...

 

Making progress! After swapping in the timing tables (and doing a little math to fill in the gaps) the vehicle drives AMAZING! I have two issues left before I change from "need to get it going" to "now we tweak' It even broke the tires loose shifting from 1 to 2!

The biggest is the starting fuel. No matter what I do, I can't stop it from flooding on start. Like before if I begin to crank, then turn the pump on - it'll start right up. If I shut it off by turning the pump off - all is well. If I turn the key off normally and then start it right back up, it'll crank and try to puff off one time, then it just floods and floods.

The second issue, which isn't as big at the moment, is that the TCC won't lock up. I think the transmission is a 95 (rebuilt from a few, but we tried to make sure items were of the same vintage). I found a flag for PWM TCC, checked that, but no difference. Our scan tool says the clutch is on all the time - which isn't right either.

Any ideas? Attached is my latest bin I'm using (renamed to .txt). If I can get the start fuel issue resolved..or better, we're smooth sailing for a bit.

Any ideas where to look next??

Thanks!
Kris

 

I havent had a chance to mess with one yet, but I think there are some minor differences in the 4l60e and 4l80e control schemes. Also there may be some changes depending on what year the transmission is. Might double check to see that you have the correct code and corresponding pinout for the trans in use.

 

Look closely at all the tables related to start-up, especially cold start. I seem to recall that on SAUJP ( I know that's not what you're using) you can pick which DRP's to skip or not to fire the injectors while cranking. Also there is a 2D table which enriches the cranking fuel based on temperature. Your computer should have those settings plus many more.

 

Kris,

Not sure if any of this will help because I am using a different PCM and mask. 16168625 and $E6. This is a speed density system out of my 93 K1500 Silverado with 4L60E. And have also made the TBI to TPI swap, and have began tuning with TunerPro RT.

I read and used the same information about the resistor modification, and the memcal jumper. I also found an .xls file that compiled a lot of settings inside the bin file, but for $E6, $OD, and $OE masks.

I think your using the $31 mask and am unsure of which parameters will interchange, however it may give you some things to look at in your bin & mask.
If you would like to look at it I can email it to you, as I don't think I can insert an .xls file here? I's an OpenOffice (free program) version of Excell.

My system is running very well, but have a similar restart issue. Anytime after the first cold start up I have to depress the throttle 1/2 way to the floor to start it up.
And if it does flood, push the pedal wot during cranking to initialize "clear flood" mode.

I see in my scanner, that the initial turn of the key to crank I get 12ms injector pulse, then it drops to 3 to 4 ms (with my foot 1/2 way down on the pedal) and it starts.

I too am looking for this "fix" and if I find a way to correct this I will post it up.

HTH
Keith

 

Kris,
I took a screen shot of the page in this .xls file that may be of some help.

 

Kris,

I did manage to get my hard start issue to go away.

In my mask, there is a parameter very similar to what The_Punisher455 suggested.

Crank BPW vs Temperature Scalar Table. My stock bin setting was 123.49.
I put in 50, and the checksum corrected it out to 51.22.

Saved this change, and tried a warm start. Perfect start up. No throttle added. Turn key to crank and got a nice clean start.

Now will try a cold start this morning!

I hope this helps you.

Keith

 

Keith! I know this is months later, but long story short we experienced a cracked block, then my dad (who's building the car) had to have major shoulder surgery. That said, we're back in business...and I mean it!

I modified the Crank BPW vs Temp scalar to 50 and it was MUCH better. A setting of 35 makes it start better than it ever has before!

So, the engine starts perfect, runs fantastic, shifts great except for the TCC.

Did a bunch of looking this weekend. The trans is indeed a 1995, so it is PWM. We have a PWM signal coming out of the E11 on the 7427. E10 will not engage the TCC solenoid.

I have copied all the 4L60e parameters from a 1995 (BHMC) bin running the same 0D mask. From what we can tell, we think that some condition is not being met which is causing the TCC to not engage.

At first we thought it was the 4wd low switch (2wd vehicle) needed to be grounded, but all that did was make the RPM slip on the scan tool go wild.

So, that said. Attached is my BIN and some scan tool pictures. Everything to us looks in check. The speed shown on the scan tool matches that of the speedometer and matches that in real life. The "output RPMs" seem strange. Both 2000ppm and 4000ppm from the DRAC have been supplied to the ECM.

I'm sure whatever it is, it is simple. Like I said, I think some parameter is not being met causing the TCC to remain unlocked. It says unlocked on the scan tool and an LED on the output pin states the same.

Thanks so much for your help, sorry it has taken this long to get back to the project.

Kris

 

Do you have 12vdc power inputed to the brake switch pin via a brake switch that opens when the brakes are applied.

 

Kris,
First, I hope all is well with your fathers shoulder. I had rotator cuff surgery once and the rehabilitation is the worst part!

I am unsure of what the 7427 PCM is capable of in TCC circuit control. A simple on/off, or duty cycled control.

Fast355 suggestion is the next logical step.

I remember from many years ago, grounding the TCC pin in the aldl connector was an easy test to check the TCC circuit.

Found this thread relating to this test:

https://www.thirdgen.org/forums/v6/2...terminals.html

Hope this helps

Keith

 

Hey guys...thanks for the tips, I think we're on to something. What I saw on the scan tool is exactly the opposite of what Fast says, so I bet the ecm thinks the foot is on the pedal the whole time!!

Keith - the TCC will engage if we ground the solenoid itself. The pwm is working, jut not the engage...and I bet this switch issue is it. I will try in the morning and let you guys know.

Yeah, his recovery was close to 4 months. A metal mesh and screws...drove him crazy to not be able to do much for himself. So far everything is working as planned.

I'll let ya know if this worked! Thanks again!!
Kris

 

Let me clarify the brake switch pin has to recieve 12 volts going down the road ot the TCC will not lock.

 

Success!!! The wire to the ecm was on a normally open switch. Once we switched it to a normally closed,it locked right up!

Thank you so much, happy to have things working. Now to tweak parameters

Kris