7747 Trouble

[Mastiff]

I've had nothing but grief from my TBI conversion. It seems like other people just plug it all together and drive away, but I keep hacking and hacking trying to get my truck to run right. I don't even care about performance, I just want the thing to drive around reliably.

I have a plane jane 350, the only differences being that I have headers, no EGR, no knock, no VSS and "cop car" injectors. I reset back to a factory ASDU bin a few months back, removed the EGR and knock stuff and modified the BPW for the cop car injectors. It runs well when warm, and it starts well in Tucson cold (not much below freezing ever), but it barely moves off the line sometimes when the engine is not warmed up. Occasionally it backfires when trying to accelerate. Any suggestions what to adjust to fix this?

At this point I'm open to buying my way out of this, but I really haven't found anyone providing service along these lines...

 

[4X4HIGH]

Have you checked/replaced the CTS (Coolant Temp Sensor)? Also you should hook the knock sensor and the VSS back up as they are both needed, more so the VSS.

 

[dave w]

I think a few adjustments to PROM would help? I have a few ideas, so I took a screen shot to help explain what some of PROM changes I think might help. I would also disable the emission, knock, and related items in the PROM.

Ultimately, having a data log would be the best way to figure out what needs to be adjusted and how much adjustment.

I would also program a performance timing table. http://coloradok5.com/forums/showthread.php?t=275641

I'm sure it goes without saying, the engine must be in good mechanical condition before re-programming the PROM.

 

[Mastiff]

Have you checked/replaced the CTS (Coolant Temp Sensor)? Also you should hook the knock sensor and the VSS back up as they are both needed, more so the VSS.

I originally had a carb. I converted to TBI and it has never worked quite right. So there is no hooking things back up, as they never existed in the first place. The VSS is not my issue since it works fine warm. Something more subtle.

 

[Mastiff]

I think a few adjustments to PROM would help? I have a few ideas, so I took a screen shot to help explain what some of PROM changes I think might help. I would also disable the emission, knock, and related items in the PROM.

Ultimately, having a data log would be the best way to figure out what needs to be adjusted and how much adjustment.

I would also program a performance timing table. http://coloradok5.com/forums/showthread.php?t=275641

I'm sure it goes without saying, the engine must be in good mechanical condition before re-programming the PROM.

I have disabled all the emissions stuff plus knock. I've also dialed in the basic map. I can take a look at the other things you have up and see if they look comparable. I'm using TunerPro and have a Moates Ostrich. Thanks.

 

[dave w]

I have disabled all the emissions stuff plus knock. I've also dialed in the basic map. I can take a look at the other things you have up and see if they look comparable. I'm using TunerPro and have a Moates Ostrich. Thanks.

I used the ASDU file that is available from a link on the TunerPro website for the screen shot I posted above. I also used the $42 .xdf definition file that is on the TunerPro website. There are several different $42 .xdf files that can be found on the internet, some older and less advanced than the version I used. The timing table I showed in the above post is from my Tuner Cats software. The timing table I posted above will look different in TunerPro, depending on which version $42 .xdf TunerPro definition file being used.

dave w

 

[eagle mark]

Since you can burn a prom I am assuming there are no codes?

Along the lines of popping through TBI unit this can be caused by a lean condition. What is your fuel pressure?

Popping can also be a bad intake valve, what is your vacuum reading? Is it steady?

I have read where guys take the fuel tables from a cop car bin and use them in other chips to start.

Another item to look at is a hot air tube from header to air cleaner. If you take your complaint to a GM diagnostics book it will point to heat riser in exhaust and hot air intake. I have used both these on a few conversions and always worked well in all tempretures.

With headers you usually have no heat riser forcing hot exhaust through intake helping it run when cold. I have adjusted a chip for this but still always used the hot air tube off a header. Maybe you could tune that out too. But I like the hot air tube here in Idaho...

 

[Mastiff]

Since you can burn a prom I am assuming there are no codes?

Along the lines of popping through TBI unit this can be caused by a lean condition. What is your fuel pressure?

Popping can also be a bad intake valve, what is your vacuum reading? Is it steady?

I have read where guys take the fuel tables from a cop car bin and use them in other chips to start.

Another item to look at is a hot air tube from header to air cleaner. If you take your complaint to a GM diagnostics book it will point to heat riser in exhaust and hot air intake. I have used both these on a few conversions and always worked well in all tempretures.

With headers you usually have no heat riser forcing hot exhaust through intake helping it run when cold. I have adjusted a chip for this but still always used the hot air tube off a header. Maybe you could tune that out too. But I like the hot air tube here in Idaho...

I feel pretty confident its a software problem, not anything broken in the hardware. Everything is in good condition. Also, everything runs great once it's warmed up, so chronic fuel starvation isn't the problem. Having said that, I have an open air cleaner and no heat riser. But then, I'm seeing the issue when it's not very cold out, just when the engine is heating up. It never really gets cold here. When I lived in Iowa, carb icing was an issue without the heat riser. That's not is going on here.

My previous bin worked better cold, but it had a really annoying RPM "hunting" thing going on at idle. This bin is great warm but has issue while warming up. I think if I just knew what to change in the file it would work. When I first did this years ago I had the energy to reprogram proms over and over but now I'm getting sick of it.

 

[dave w]

I'm seeing the issue when it's not very cold out, just when the engine is heating up. . .I think if I just knew what to change in the file it would work.

I would change one of these first.

dave w

 

[Mastiff]

My tables look identical to yours at the moment.

I think I need to drive it with the laptop on there and find out if I'm still open loop when the trouble is happening. I don't think I am because it lasts too long into my morning drive, but I'll double check.

It's annoying because I rely on an ancient Windows 98 machine to do this tuning. The thing barely runs and half the keys don't work, but no new machines have serial or parallel ports. How do other folks deal with this nonsense?

 

[dave w]

One option is to update to a new USB OBD I cable ... about $60. http://www.aldlcable.com/

I live in an area where used laptops are very affordable and easy to find. In my area, $200 or so can get a used 3 year old laptop that has been wiped and reloaded with Win 7. Usually a used 5 year old laptop with Win XP can be found for $100.

Maybe laptops are cheap in my area because one of the Intel processor manufacturing facilities is only 35 miles from where I live.

I would think Tucson would be easy to find a good used laptop because of ASU. Intel also has a processor manufacturing facilities in Chandler.

Lots of tech type people live near the Intel facilities, so I'm sure the tech types like the newer stuff?

dave w

 

[Mastiff]

I have two issues: (1) My ALDL hookup needs a serial port and (2) my PROM burner needs a parallel port. Does a USB OBD I cable work with winALDL? If not, what program do you use for watching status/codes, datalogging, etc? PROM burners aren't cheap. So I'm stuck with this ancient laptop just because it has those ports on it.

I keep looking at DynamicEFI and their EBL setup, which is basically a GM ECM with improvements including modernized datalogging and programming using their software. It's not cheap either though, like $350 if I remember right.

 

[4X4HIGH]

I originally had a carb. I converted to TBI and it has never worked quite right. So there is no hooking things back up, as they never existed in the first place. The VSS is not my issue since it works fine warm. Something more subtle.

So what did you do for the TBI wiring harness? EVERYTHING needed for TBI is in a stand alone harness and only a couple wires needed to be hooked up to your existing truck to make it run.

 

[dave w]

I have two issues: (1) My ALDL hookup needs a serial port and (2) my PROM burner needs a parallel port. Does a USB OBD I cable work with winALDL? If not, what program do you use for watching status/codes, datalogging, etc? PROM burners aren't cheap. So I'm stuck with this ancient laptop just because it has those ports on it.

I keep looking at DynamicEFI and their EBL setup, which is basically a GM ECM with improvements including modernized datalogging and programming using their software. It's not cheap either though, like $350 if I remember right.

There are several options to consider for upgrading to a newer laptop.

Yes, a USB OBD I ALDL cable will work with winALDL.

If you decide to upgrade to a newer laptop, one option to resolve the Serial Port ( DB9 connector ) to USB port is with an adapter cable.

From Moates.net
http://www.moates.net/keyspan-usb-to-serial-adapter-usa19hs-p-129.html?cPath=32

The same adapter listed on Moates, but also available at Amazon for less money.
http://www.amazon.com/Keyspan-Speed-Serial-Adapter-USA-19HS/dp/B0000VYJRY

I'm not up to speed on the differences in Parallel Ports vs newer laptops and older laptops. I sometimes get confused if the Parallel Port is DB25 http://www.amazon.com/Syba-SD-USB-DB25-Paralle-Adapter-Prolific/dp/B000JPCAKY/ref=pd_cp_e_3_img or if the Parallel Port is a Printer Port? http://www.amazon.com/Sabrent-SBT-UPPC-Parallel-6-Foot-Printer/dp/B0007UVRVO

The option of adapter cables is an affordable option if you decide to update to a newer laptop, but ultimately the adapter cables add to the cost of updating to a newer laptop.

I have not used DynamicEFI. I'm sure it's a good product.

On the topic of ECM upgrades, I have successfully upgraded to the newer TBI PCM used in the 93 ~ 95 GM pickups. See my post: http://coloradok5.com/forums/showthread.php?t=270253 The newer TBI PCM is "On Par" with DynamicEFI, but requires a VSS. The only real advantage the newer TBI PCM has over DynamicEFI is the ability to operate an Electronic Overdrive transmission.

dave w

 

[Mastiff]

So what did you do for the TBI wiring harness? EVERYTHING needed for TBI is in a stand alone harness and only a couple wires needed to be hooked up to your existing truck to make it run.

I went to this (in hindsight crappy) place called CustomEFIs and they made me a custom harness. They recommended against knock, which I think is fine, and I had no emissions stuff, so we didn't do that. In hindsight I would have just put all the emissions and stuff on so it would be standard, but here I am.

I'm not sure what you mean by a couple wires... There must be half a dozen new sensors, plus relays and all the stuff for the electric fuel pump and heated O2 sensor which I never had. VSS requires a special speedo or some sort of aftermarket sensor. I'm not saying it's unmanageable, but it's not like a Saturday afternoon install.

I did a write-up of my install experience (the link in my sig gets there).

 

[Mastiff]

Regarding laptops, I have a newer one, I just don't use it for tuning. I bought a parallel (printer) port USB adapter and it simply doesn't work. I guess they work specifically for printing, but not for random access to the pins like the PROM burner requires. I don't think there's any escape besides buying a new burner or a new EFI system that just reprograms EPROMs in place. If I wanted to just leave the Moates Ostrich in place I could be done with the burner.

 

[dave w]

Regarding laptops, I have a newer one, I just don't use it for tuning. I bought a parallel (printer) port USB adapter and it simply doesn't work. I guess they work specifically for printing, but not for random access to the pins like the PROM burner requires. I don't think there's any escape besides buying a new burner or a new EFI system that just reprograms EPROMs in place. If I wanted to just leave the Moates Ostrich in place I could be done with the burner.

I was wondering the adapter cables would work. I trust the products available from Moates.net, so it's likely the serial adapter offered by Moates.net should work for the ALDL.

Anyway, there are options to you for reprogramming the PROM.

Getting back on the topic of PROM programming to correct the drive-ability of your Blazer. I'm in agreement the cure to the drive-ability issue is likely in the PROM programming. At this point, I could help better if I had a data log file to look at. If you send me a PM, I'll let you know my email address so you can send me a data log file. You can send me either winALDL or TunerPro data log files.

dave w

 

[Mastiff]

I went out and drove around with my logger on. It's not that cold so the problem wasn't very pronounced. I noticed that the "rich flag" was on almost all the time though, which I'm sure indicates something. I'm confused though because the system was in closed loop all the time and the BLMs weren't that bad (118 to 138 over the short drive). The "old high gear flag" was also on the whole time. I'm not sure what that means. I have nothing hooked to my ECM from the trans. I'll try to post up or E-mail the logs later. It takes some work to transfer from the old machine and my wife is already giving me the stink eye for not watching kids enough...

 

[dave w]

I'd like to share a winALDL data log that I copied / pasted from a .txt file to Microsoft Excel. I have experience with Microsoft Excel, so it's my tool of choice to analyze a data log. The first thing I did with this data log was to "Sort" the data see the picture. The next thing I did was analyze the INT's and BLM's, see the picture for the problem area.

dave w

 

[GMC Truck]

I got a bran new Moates ALDL (USB) cable i'll sell ya for $45.00 plus shipping. I have two now, long story....
It works with great with WinALDL.