Need guidance GM TBI install 1228747

[jlsmith]

Recently installed TBI unit in 83 Jeep CJ-7... Complete donor engine and TBI system from a 89 GMC G3500 Box Van.. ECM 1228747

Got it running after setting initial timing with bypass unhooked. Plugged bypass back up and it surged on idle. After checking several things I unplugged MAP and it idled much better. Checking senor with vacuum pump and referencing against chart (inHg/Volts) it functions properly.

[dave w]

Recently installed TBI unit in 83 Jeep CJ-7... Complete donor engine and TBI system from a 89 GMC G3500 Box Van.. ECM 1228747

Got it running after setting initial timing with bypass unhooked. Plugged bypass back up and it surged on idle. After checking several things I unplugged MAP and it idled much better. Checking senor with vacuum pump and referencing against chart (inHg/Volts) it functions properly.

Maybe you can record and post a TunerPro RT data log .xdl file of the TBI engine running for us to look at?

dave w

[EagleMark]

So it's a complete TBI System on a Jeep engine or the complete GM engine transplant? What size engine.

Unplugging MAP and it runs better is not good? With MAP unplugged, MAP kpa goes max and adds fuel. So check fuel pressure.

MAP hose should be plugged into hose barb between fuel lines on back of TBI. (Just checking it's in right spot)

[drowning in tbi]

I would check manifold vacuum with a gauge, if it's below 17", look for anything that would make it low-proper timing marks, vacuum leaks, restricted exhaust etc... How many miles on this engine? Possible late cam timing.

[jlsmith]

21-22" at about 750-800 RPM... No vacuum leaks.. Timing looks correct, set initial timing with bypass unplugged to 0 degrees. Turned engine off plugged bypass back up, cranked backup and ECM to over, which advanced to 12-13..?? don't recall actual number but was right according to documentation. Don't have complete exhaust on yet.. just headers, so there shouldn't be any restrictions. I don't know how many miles this engine has because it was a GM Performance replacement from the donor vehicle. The transmission had went out for the second time so the guy just parked it. He thought there was like 30-40K miles on the engine. I did measure the bore several years ago when I got it and it showed virtually no wear.

What do you mean by possible late cam timing?

[jlsmith]

So it's a complete TBI System on a Jeep engine or the complete GM engine transplant? What size engine.

Unplugging MAP and it runs better is not good? With MAP unplugged, MAP kpa goes max and adds fuel. So check fuel pressure.

MAP hose should be plugged into hose barb between fuel lines on back of TBI. (Just checking it's in right spot)

I installed a complete 5.7L GM Motor and fuel/spark management system ecm (1228747 not 1227747) from a 89 GMAC G3500 Box Van.

The MAP Sensor tube is plugged into the middle vacuum line in the rear of the throttle body. I will have to check the fuel pressure, currently don't have provisions for that right now, but will this weekend.

I did eliminate all the EGR Controls from this setup. I did leave the EGR Valve bolted up until I can obtain a block off valve. Also I didn't plug in the knock sensor but did leave ESC hooked up to the system. Will any of this effect anything.

[Fast355]

I installed a complete 5.7L GM Motor and fuel/spark management system ecm (1228747 not 1227747) from a 89 GMAC G3500 Box Van.

The MAP Sensor tube is plugged into the middle vacuum line in the rear of the throttle body. I will have to check the fuel pressure, currently don't have provisions for that right now, but will this weekend.

I did eliminate all the EGR Controls from this setup. I did leave the EGR Valve bolted up until I can obtain a block off valve. Also I didn't plug in the knock sensor but did leave ESC hooked up to the system. Will any of this effect anything.

Yes it definately will throw things off.....The HD TBI setups were also open loop idle which the headers can affect the idle mixture.

[EagleMark]

I Also I didn't plug in the knock sensor but did leave ESC hooked up to the system. Will any of this effect anything.

Yes, hook up the knock sensor. With it disconnected it usually creates a constant knock count and thus knock retard, so your loosing advance timing for no reason.

With O2 sensor also disconnected means this system is running Open Loop, just what is programmed into ECM. Should be plenty rich. So disconnecting MAP just makes it richer, but in your case makes it run. So I'm still thinking low fuel pressure. Or maybe there is a wiring issue or collapsed vacuum hose from MAP sensor to TBI?

[jlsmith]

Fast355, So are you saying the HD TBI setup it will never go into closed loop at idle then revving engine up even at normal operating temp.

EagleMark, I will hook up the knock sensor, thanks.. I downloaded WINADL and see the knock signal.. What is normal count (0)? What is normal advanced timing? I temporally installed the O2 Sensor up in a section of pipe below the header collector. When should I see a closed loop situation what is the criteria. I will absolutely check fuel pressure this weekend.

Thanks to all for the help.. You guys are awesome.

[jlsmith]

Maybe you can record and post a TunerPro RT data log .xdl file of the TBI engine running for us to look at?

dave w

Don't have TunerPro RT.. I do have WINADL will that work.. Not sure that I need to do any tuning yet because it is all original engine with original fuel/spark system.

[dave w]

Don't have TunerPro RT...

In it's day WinALDL was a good tool. TunerPro RT is more than a tuning tool, TunerPro RT is an AWESOME Diagnostic Tool!

dave w

[jlsmith]

In it's day WinALDL was a good tool. TunerPro RT is more than a tuning tool, TunerPro RT is an AWESOME Diagnostic Tool!

dave w

thanks I will check it out.. Do you burn your own chips or do use a EEProm setup?

[dave w]

thanks I will check it out.. Do you burn your own chips or do use a EEProm setup?

I have the ability to UV Erase and Burn the original EPROM chips. I have modified ECM's for EEPROM's (http://www.gearhead-efi.com/Fuel-Inj...-%2827SF512%29). I also own an Ostrich 2.

dave w

[EagleMark]

Fast355, So are you saying the HD TBI setup it will never go into closed loop at idle then revving engine up even at normal operating temp.

EagleMark, I will hook up the knock sensor, thanks.. I downloaded WINADL and see the knock signal.. What is normal count (0)? What is normal advanced timing? I temporally installed the O2 Sensor up in a section of pipe below the header collector. When should I see a closed loop situation what is the criteria. I will absolutely check fuel pressure this weekend.

Thanks to all for the help.. You guys are awesome.

It may go into CL if the engine is totally warmed up and revved up for awhile, but will soon go back OL. It will/should go CL after warmed up and driving. In the TunerPro Data Acquisition file there is a Loop Status bit that will change to Closed when this happens.

Knock counts on these old ECM does not always start at 0, so when looking just see that it is not moving, adding counts as engine runs. It may start at 1 or 79 or? It's an accumulator more then a counter.

There is no Spark Advance in the data stream of this ECM.

Here's the info thread for the 1228747 ECM with files needed for TunerPro RT, also some wiring diagrams and stock chip/bin files
http://www.gearhead-efi.com/Fuel-Inj...Information-4F

[dave w]

Attached is a TunerPro RT screen shot of a bad VSS. Look at the erratic MPH chart vs. the engine RPM chart vs Injector pulse width (milliseconds). Classic smoking gun diagnosis on a bad VSS.
Based on price, there is not a comparable diagnostic tool that can provide as much useful technical information for such a low cost! Ok, the only possible downside to TunerPro RT is needing a good laptop computer, which are abundant and low cost also.

dave w