7747 running issues

**kacy** · 01-01-2017

heres an update with egr and air reconnected. Using these

**mmigacz** · 01-01-2017

Did it run better??... The BLMs were way better... Also, did you have an error code when the EGR was unplugged? The o2 voltage was still swinging on the low side (350 mv), which is lean. On my Camaro I changed the swing to something closer to 600mv. It was happier when it was a little richer than stoich... BTW when you are datalogging, you don't have to have a bin file loaded into tunerpro. Currently, you don't know what your bin is, so its not worth posting something that is not installed in the ECM...

**kacy** · 01-01-2017

Originally Posted by mmigacz

Did it run better??... The BLMs were way better... Also, did you have an error code when the EGR was unplugged? The o2 voltage was still swinging on the low side (350 mv), which is lean. On my Camaro I changed the swing to something closer to 600mv. It was happier when it was a little richer than stoich... BTW when you are datalogging, you don't have to have a bin file loaded into tunerpro. Currently, you don't know what your bin is, so its not worth posting something that is not installed in the ECM...

so the AMUR code on the outside of the chip is irrelevant? The CEL did come on before this recording, it runs worse with those connected I have a spring that is rated for 12-20 psi at wot with a regulator made adjustable that will be installed when I get my gauge.

**mmigacz** · 01-01-2017

Originally Posted by kacy

so the AMUR code on the outside of the chip is irrelevant?

For datalogging, yes. Just because the chip has an AMUR label on it, it doesn't mean the original AMUR tune is still on it. It could of been flashed/retuned by somebody previous to you.

**jim_in_dorris** · 01-02-2017

I think something might be being ignored here, and that is the consequences of merely removing the EGR instead of disabling it in the tune. Because the tune doesn't know you don't have an EGR, when the EGR goes active in the tune, it expects to see the fueling lean out. if it doesn't, it will subtract fuel, making it lean. I think that you should get an ASDX tune with EGR disabled in the tune and go from there. ASDX is what I am currently running in my truck and it works quite well. Find someone to burn you a chip, it will be money well spent. I actually had a 305 tune in my truck and someone installed a 350 without changing the tune. I chased a lean condition for years before figuring out I actually had a 350. An unfortunate result of running lean is burned valves, so I am in the middle of doing a valve job now. Also, if the sticker is still on the chip, odds are extremely high that it is the original AMUR bin. To change the tune, you have to use a UV lamp to erase the chip which requires removing the sticker to expose the quartz window. 2732 chips are getting harder to find, but are still available.

**kacy** · 01-03-2017

Originally Posted by jim_in_dorris

I think something might be being ignored here, and that is the consequences of merely removing the EGR instead of disabling it in the tune. Because the tune doesn't know you don't have an EGR, when the EGR goes active in the tune, it expects to see the fueling lean out. if it doesn't, it will subtract fuel, making it lean. I think that you should get an ASDX tune with EGR disabled in the tune and go from there. ASDX is what I am currently running in my truck and it works quite well. Find someone to burn you a chip, it will be money well spent. I actually had a 305 tune in my truck and someone installed a 350 without changing the tune. I chased a lean condition for years before figuring out I actually had a 350. An unfortunate result of running lean is burned valves, so I am in the middle of doing a valve job now. Also, if the sticker is still on the chip, odds are extremely high that it is the original AMUR bin. To change the tune, you have to use a UV lamp to erase the chip which requires removing the sticker to expose the quartz window. 2732 chips are getting harder to find, but are still available.

I would agree with you except the truck runs better with it disconnected and it takes a while for the CEL light to come on. What did the ASDX bin used in?

**jim_in_dorris** · 01-03-2017

ASDU is a 350 700r4 bin for trucks 3.73 rear gears. Eagle Mark and I did quite a bit of work on it documenting it before he passed. The EGR valve only comes on during certain conditions, closed loop cruise mainly. So until you reach those conditions, the EGR valve is not active. The CEL won't illuminate until the EGR valve is activated and it fails to go lean by the amount called for in the test. I currently have my EGR valve removed and a block off plate installed for test purposes. I do get a CEL but am okay with that. When I put the truck back together after the valve job, I will reinstall the EGR valve.EDIT!!! ASDU Is the correct bin I put ASDX BY MISTAKE. Looking at your symptoms, you either have a vacuum leak, a pre- o2 sensor exhaust leak, or incorrect injectors would be my guess. Try smoking or if you don't have a smoke gun, propane can help locate a vacuum leak. Also, verify your injectors by looking at the numbers stamped on them

**kacy** · 01-03-2017

It always smells rich at 750 rpm idle and 500 in gear, feels like it has more power than other tbi trucks. could I use a stock bin for a 350 1 ton because they didnt have emissions to rule them out?

**jim_in_dorris** · 01-04-2017

A stock bin for a 1 ton truck would most likely not be a very good idea, the 1 tons mostly had th400's for transmissions. it could be made to work, but why bother. Get ASDU with EGR disabled. I am not sure if AMUR is an open loop idle bin or not. Watch your data stream to see if it goes closed loop at idle.

**kacy** · 01-04-2017

Originally Posted by jim_in_dorris

A stock bin for a 1 ton truck would most likely not be a very good idea, the 1 tons mostly had th400's for transmissions. it could be made to work, but why bother. Get ASDU with EGR disabled. I am not sure if AMUR is an open loop idle bin or not. Watch your data stream to see if it goes closed loop at idle.

Everytime I look at it at idle it is open loop and only thing the ecm controls is lock up and i put that on a toggle switch.

**jim_in_dorris** · 01-05-2017

ASDU is closed loop idle, much easier to tune for some people, others prefer open loop all the time. If tuning open loop. You need a wide band O2 sensor. With closed loop, a wide band is a big help, but not necessary. There is a lot of discussion on open loop tuning, but I like closed loop feed back systems. I cannot guarantee that ASDU would fix all your problems, but it might help, and certainly won't hurt.

**ony** · 01-05-2017

whatch the o2 voltage an see if it is getting hot enough at idle for closed loop. you may want to use a heated o2 sensor. my v6 4.3 would go open loop at 25-30 mph in 4th gear when it was cold in texas ,with a new sensor put a 3wire heated o2 in fixed the problem got better milage too.

**kacy** · 01-05-2017

the truck runs great when cold so if the o2 was open loop it should run great. I know it does run great with o2 disconnected i drove it like that for about 10 miles as a test.

**jim_in_dorris** · 01-05-2017

Ok, new info. If it runs ok in open loop, get a wide band O2 sensor and tune the open loop fueling to 13.5 AFR. Many people run open loop tunes. Not best possible fuel economy, but will run fine. If you want fuel economy, you will have to tune closed loop.

**kacy** · 01-05-2017

Originally Posted by jim_in_dorris

Ok, new info. If it runs ok in open loop, get a wide band O2 sensor and tune the open loop fueling to 13.5 AFR. Many people run open loop tunes. Not best possible fuel economy, but will run fine. If you want fuel economy, you will have to tune closed loop.

i dont want to throw parts at it to attempt to fix it or cover the real issue. If that is the case ill pull the factory efi and go aftermarket efi.