3.4L DOHC Running 8F Code and 42 Lb Injectors HELP

[grandprixgtp_91]

Hi, I am starting to tune now for my 1991 Pontiac Grand Prix Turbo 3.4L DOHC project, only problem is , its my daily driver, and i got myself into a jam. Im hoping someone here knows how to help me. heres what i got

On my 3.4 DOHC I put in 42 Lb/hr Ford Racing injectors

I installed a 2 Bar Map sensor from a 1990 Pontiac Grand Prix TGP (brand new from GM)

Now im trying to run the 8F code but im having serious idle issues, its very lumpy and sparatic. above 2000 rpm seems to run fine i havent driven it yet with the 8f code because im afraid of doing damage to the engine.

i can run the DF code with the 2 bar map sensor and the 42 lb/hr injectors and it runs smooth as glass. i just had to tweak the VE Adder table to richen it up a bit, i think it runs good like this because on the DF code the 2 bar map sensor cuts the Kpa's and the baro in half, so i think it leans it out alot allowing the engine to run fine.

so i know that the engine has the ability to run with the 42 Lb/hr ford injectors, my problem is lying in the 8F code

I have incorporated my Moddified BCFA tables into the 8F code for spark and VE and PE and all that stuff, ive shut off my egr valve and I have lowered the base Pulse Constant to what I find runs the engine the best. and i have lowered the BPW Vs Egr table too .

Like i said it seems to run decent above 2000rpm but idle is all messed up. here is my readings from my Tech 1 at idle

Closed loop
Spark Advance - 10* to 24* ( contstantly jumping between these)
Map sensor - 55 to 58 Kpa ( flutters all over, I think it should be in the 40's Too)
Fuel integrator - 128 ( i played with the VE tables until i got it at 12
O2 sensor - 500 to 700mv
Idle - 950 to 1000rpm

I am using the moates APU-1 emulator and that thing works awesome, saves so much time from guessing and burning, just see the changes instantly. but i cannot get this thing to datalog for the life of me.

I tried tuner pro rt , ive tried tts datamaster, none of them will detect my aldl cable on my APU-1 i dont know why. does anyone else have this problem? ive tryed playing with the switches on the back too with no luck.

also i am emulating with rt tuner from tuner cats, im my opinon its the best and easiest to use. and the car is a 5 speed if that makes any difference.

PLEASE HELP ME!!

thanks

Jake

[Joseph Upson]

Well adoptive brother, I'll help as best I can having worked with the APU-1 for months before I finally got it to datalog using the 8F code.

First make sure your ALDL plug terminal wires are all in the proper place according to the TGP wiring diagram.

Make sure the terminals in the plug are not deformed so that they fit loosely on the ALDL cable plug, mine were and I had an intermittent connection as a result.

Go to the MOATES site and make sure you have the latest driver for the unit, there is also another type of file called "firm ware" that is not mentioned in the instructions but may be necessary to reinstall in order to verify the uploaded bin which also was a problem for my unit.

You can use the help section of Datamaster to help you check to make sure your Moates driver is installed/current, mine was not eventhough I received a message telling me it had been. Datamaster's instructions are very thorough and it was that program that revealed all of the problems preventing me from datalogging including the poor cable connection by flashing a loss of connection message when I moved the plug after it connected to the ECM.

Make sure your switches on the unit are in the right place, there should be no 10 ohm ground switched to on.

Make sure the checksum is disabled under preferences set to AA and 08 in TunerproRT.

Load the proper definition files and you should be set. I had a horrible time getting to the bottom of the APU-1 issue. So far I can emulate and datalog but I can't do both at the same time with the 8F code like the instructions say that I can, I can do it with the A1 code but that's not what I'm using.

I believe that about covers it as far as all the troubles I can recall having with it. I was very frustrated for quite a while.

[grandprixgtp_91]

yeah im looking to emulate and datalog at the same time too, im just lucky i can use the tech 1 from work so i can read that while emulating.

you wouldnt happen to have any idea whats going on with my idle would you?

thanks for the reply, i will try everything you have said.

Jake

[Joseph Upson]

This thread may help;

http://www.v6z24.com/jbodyforum/how-to-tune-tgp-code-t88684,highlight,tune+tgp+code.html

Since you are running the 3.4 DOHC with 42 lb/hr injectors ironing out the idle maybe a bit more challenging since the flow characteristics are a bit different down low than the cam in block engines. I would definately look into a wideband O2 unit or meter to help give a more vivid picture than what narrow band O2 can do.

[grandprixgtp_91]

Yeah i actaully have that article saved in word on my computer so i can reference to it when im tuning on the road, unfortunatly i tired everything it said about setting up for larger injectors and it still doesnt help.

thanks

Jake

[Joseph Upson]

Yeah i actaully have that article saved in word on my computer so i can reference to it when im tuning on the road, unfortunatly i tired everything it said about setting up for larger injectors and it still doesnt help.

thanks

Jake

Then I would turn to a wide band O2 sensor, I used Zeitronix and it helped quite a bit. I still haven't finished tuning yet being away from home. I know my cranking fuel is not correct because I still have to use clear flood mode (pedal to the floor) to start the engine. Perhaps working with idle timing will help some.

[grandprixgtp_91]

How would i hook a wideband O2 sensor up? the ECM only has 1 wire input where as the wideband has like 5 i think. does it use another mini computer to send info to the ecm? also how much did that kit cost and where did you buy it at?

Another thing is too, i am running this $8F code in my stock GTP DOHC computer, do i need to use the 1227727 ECM that is used in the TGP for it to work properly? could that be my problem?

Also does anybody know if the connectors and wiring is the same for my GTP computer and the 1227727 ECM? because i have no problem buying a 1227727 ECM if i need to, but i dont want to switch over all the connectors and re wire it.

thanks

Jake

[93gtpdohc]

your stock computer is fine, when i had my 93 gtp 3.4l dohc turbo running on the $8f program i was using the stock ecm, and i even swaped out the ecm for a 1227727 ECM and had no change what so ever, the main diff between the ecms were ur stock ecm has extra memory and shit to control the electronic 4 spd if u had it, where as the 1227727 was built for car that the tranys were not fully electronic, don;t get me wrong there might more reasons but thats what i found, as for the wireing ur a/c will not work because the $8f program use's different pin location for calling, and engageing your a/c compressor, and if you have a transducer on ur a/c high side, ur will need to wire in a high and low side pressure switchs too, and they use different egr's too,

[Mr_Efficiency]

I'm also curious about the wide band o2 wiring? hows that work?

btw thats a great link, I learned a lot from that. definatly holding onto that one thanks

[bszopi]

People normally just weld in a secondary bung into the exhaust system for the WBO2, and retain the NBO2 for the ECM. The wideband is just there as a tuning helper.

[grandprixgtp_91]

Ok, im going to be looking into that for sure then, heres the one im looking at, any good?

http://www.moates.net/product_info.php?cPath=48&products_id=89

i dont know much about wideband, but it looks alright.

thanks

Jake

[Mr_Efficiency]

So if its not hooked into the ecm how is it a tuning helper? is it just so you can see whats going on when you hook the WBo2 into an air fuel gauge? or is it more complicated than that?

also i have the .bin for a TGP with a 5 speed and a wide band but i can also get it without the wide band patch, so are you saying im better off to stay with the narrow band on the ecm and run the wide band seperatly on the A/F gauge?

sorry but i'm totally lost with this stuff, lol thanks

[grandprixgtp_91]

yeah you have a handheld device that gives you the a/f ratio, which is good for boost, because you should be in the 12:1 a/f area under boost and a narrow band cant go lower than 13:1 a/f so this allows you to tune it properly under boost. what i dont get is what the wideband patch will do if you cant hook the sensor up to the ecm.

Jake

[Mr_Efficiency]

im sure you can hook it into the ecm thats why i was asking how, and if you do can you still run your A/F gauge off it?