454 TBI for '98 350 Vortec

**rsicard** · 03-01-2015

Just found out the mystery of the situation. The CHEAP plastic 0-15 psi fuel pressure gauge is way off and was saying (pegged) 15+ psi. Put a 0-60 psi Summit Racing gauge from the pickup on the run-in stand. It reads little better than 10 psi which is FAR MORE realistic. Now I can change regulator springs again and adjust the fuel pressure regulator and get what I need for pressures.

**rsicard** · 03-02-2015

Removed altered spring from fuel regulator and installed stiffer spring. Now the fuel pressure is at 15 psi which is the maximum force the Mallory 4110 fuel pump can exert. Still no fuel being bypassed with this stiffer spring. Weather closing in on us today. Will try lighter spring and much stronger MSD in-line fuel pump. Looks like I need to install a stronger fuel pump in the Chev Pickup fuel tank in order to achieve 18-20 psi. If so, may need to go to the 454 injectors and higher pressure at the throttle body. Higher pressure at the injectors should yield better fuel atomization? Awaiting shipment of assortment of regulator springs.

**rsicard** · 03-04-2015

Well, I just got the 350 Vortec running with the 454 throttle body and supposedly 65# injectors which were purchased off of Ebay and part numbers are NOT MARKED. Set the fuel pressure regulator to 20 psi. Started it up and it is running VERY RICH. Backed down the fuel regulator to 12-14 psi and it is still running rich but the engine has not come up to temperature. Need to get Laptop and TunerPro into the act and see what is happening to coolant temp and other parameters. Disconnected the one lead from the Dist to ECU and set the timing to zero. Reconnected and fired up again. Now timing goes in the retard direction? And then little later, engine slows down and wants to quit. Not sure what gives with these. Will post binary loaded into the Flash Mem chip in the ECU to run the engine on the run-in stand. Just getting started at the tuning.

**brian617** · 03-04-2015

You need to calculate the amount of fuel pressure to get the required PPH your engine combo needs. After that you need to set your fuel pressure, corresponding flow rate in the .BIN and forget it, then get started working on your VE tables. Trying to adjust fuel pressure on an engine stand is pointless. I also strongly recommend GM injectors that have actually been flow tested, otherwise you have no idea what PPH you are working with.

These are things i learned the hard way. Hope that helps.

**dave w** · 03-05-2015

Apples, Oranges, and Bananas ... What an injector is rated to flow (Apples) ... What an injector is actually flowing (Oranges) ... What flow (BPW) is programmed into the PROM chip (this parameter drives me Bananas

)

dave w

**rsicard** · 03-05-2015

Apart from the injectors, after running the engine and getting it warmed up, for some reason that I do not yet know, the wide band AFR from Innovate goes from 10 quickly up to 18+ to 1 and the engine dies. The fuel pressure remains the same so that is one thing that can be ruled out. The only thing I can surmise is that it is going closed loop and onto a different much more lean table in the binary? Need suggestions as to any other possibilities for this situation. It has repeated 3 times. Cannot find open/closed loop indication on TunerPro RT. Display of MAP appears to be unavailable. Just a newby at this stuff. Need suggestions.

Hate to go purchasing another set of injectors. Just have to do it. Perhaps received a bogus injectors from Ebay that have NO part number marking on them. The outfit that supplied them is in Austin TX. Better go to someone more reputable. Anyone have suggestions where to obtain Cop Car fuel injectors? Please advise. Thanks.

**rsicard** · 03-05-2015

Originally Posted by dave w

Apples, Oranges, and Bananas ... What an injector is rated to flow (Apples) ... What an injector is actually flowing (Oranges) ... What flow (BPW) is programmed into the PROM chip (this parameter drives me Bananas

)

dave w

I believe Dave W. has got it right. There are multiple aspects to this situation concerning injectors. If I was so inclined, would set up a pulse generator and high current DC switch circuit to fire the injectors in the fuel pod and into a calibrated vial to measure the ACTUAL fuel delivery of the injectors with calibrated fuel pressure and calibrated pulse frequency and pulse duration. Pick three different pulse widths low, medium and large and measure delivery under these three different situations at one pulse frequency in the middle of the RPM range. I think that I will hook my PC based Oscope to the injector leads at the throttle body and see if when the engine dies that it is commanded to do so via the ECU. Hopefully getting at the root cause of this action.

**rsicard** · 03-05-2015

Originally Posted by dave w

Apples, Oranges, and Bananas ... What an injector is rated to flow (Apples) ... What an injector is actually flowing (Oranges) ... What flow (BPW) is programmed into the PROM chip (this parameter drives me Bananas

)

dave w

Dave: Need help with TunerPro RT. Can the ADX file be expanded to include such parameters as Open/Closed Loop, MAP etc.? Need to diagnose why after warming up the 350 Vortec goes from rich to lean and then dies. Fuel pressure remains stable during this event. Your recommendations on these aspects would be greatly appreciated.

**Fast355** · 03-05-2015

Originally Posted by rsicard

Apart from the injectors, after running the engine and getting it warmed up, for some reason that I do not yet know, the wide band AFR from Innovate goes from 10 quickly up to 18+ to 1 and the engine dies. The fuel pressure remains the same so that is one thing that can be ruled out. The only thing I can surmise is that it is going closed loop and onto a different much more lean table in the binary? Need suggestions as to any other possibilities for this situation. It has repeated 3 times. Cannot find open/closed loop indication on TunerPro RT. Display of MAP appears to be unavailable. Just a newby at this stuff. Need suggestions.

Hate to go purchasing another set of injectors. Just have to do it. Perhaps received a bogus injectors from Ebay that have NO part number marking on them. The outfit that supplied them is in Austin TX. Better go to someone more reputable. Anyone have suggestions where to obtain Cop Car fuel injectors? Please advise. Thanks.

Generally three things are happening as the engine warms up. The startup/choke air fuel ratio is starting to lean out. The engine is getting some heat in it and the coolant spark compensation is starting to retard the ignition timing. Finally the idle speed is starting to drop. The Vortec head spark advance requirement is vastly different than the TBI head tuning. I would also check your minimum air rate which is the base idle with the IAC fully closed. Its often too low forcing the IAC to behave much like a vacuum leak.

Going from open loop to closed loop is going to force the ECM from whatever air/fuel ratio it is looking up in the open loop air/fuel ratio tables to whatever the closed loop stoichiometric air/fuel ratio is programmed to, usually 14.7:1.

Try unplugging the o2 sensor and warming the engine up to see if it is an issue with the base tune or an issue with the closed loop side.

With a wideband attached, I do alot of open loop tuning then come back and enable closed loop and tweak the closed loop operation to my liking.

**dave w** · 03-06-2015

Originally Posted by rsicard

Dave: Need help with TunerPro RT. Can the ADX file be expanded to include such parameters as Open/Closed Loop, MAP etc.? Need to diagnose why after warming up the 350 Vortec goes from rich to lean and then dies. Fuel pressure remains stable during this event. Your recommendations on these aspects would be greatly appreciated.

Please refresh my memory, which ECM / PCM are you using?

dave w

**rsicard** · 03-06-2015

Originally Posted by dave w

Please refresh my memory, which ECM / PCM are you using?

dave w

Dave: The ECM is a 16197427 with BJYB binary loaded into the Flash chip. I suspect that there may be a vacuum leak between the throttle body and 4 barrel adapter or between the 4 barrel adapter and the 4 barrel manifold. The adapter plate is steel and 1/4" thick so the holes are threaded for the bolts with the 454 throttle body with supposed 65 Lb/Hr cop car injectors. They came unmarked to I really don't know the actual flow from them. I did not drill into the 4 barrel manifold for the TBI bolts. At this configuration, the open loop runs at 10 - 11 AFR as read on a Innovate Motorsports LM-1 and wide band sensor. Apparently when up to temp and going into closed loop, after a short amount of time, the AFR goes from 10 or 11 to greater than 15,, 16, 17 and then the engine dies. Also the idle is very high approx 1900 RPM. There is NO idle adjustment screw on the 454 throttle body. This has repeated 3 times already.

Next step is to drill clearance holes in the 4 barrel manifold for the throttle body bolts which at present have many washers that do not allow projection into the 4 barrel gasket between the manifold and the adapter. Then apply sealer to the 4 barrel gasket and to the throttle body gasket to make certain there are NO vacuum leaks.

Then run the engine again with the same binary. Also have a factory binary for the Vortec with TBI for export trucks. May try the latter binary later.

**Fast355** · 03-06-2015

Originally Posted by rsicard

Dave: The ECM is a 16197427 with BJYB binary loaded into the Flash chip. I suspect that there may be a vacuum leak between the throttle body and 4 barrel adapter or between the 4 barrel adapter and the 4 barrel manifold. The adapter plate is steel and 1/4" thick so the holes are threaded for the bolts with the 454 throttle body with supposed 65 Lb/Hr cop car injectors. They came unmarked to I really don't know the actual flow from them. I did not drill into the 4 barrel manifold for the TBI bolts. At this configuration, the open loop runs at 10 - 11 AFR as read on a Innovate Motorsports LM-1 and wide band sensor. Apparently when up to temp and going into closed loop, after a short amount of time, the AFR goes from 10 or 11 to greater than 15,, 16, 17 and then the engine dies. Also the idle is very high approx 1900 RPM. There is NO idle adjustment screw on the 454 throttle body. This has repeated 3 times already.

Next step is to drill clearance holes in the 4 barrel manifold for the throttle body bolts which at present have many washers that do not allow projection into the 4 barrel gasket between the manifold and the adapter. Then apply sealer to the 4 barrel gasket and to the throttle body gasket to make certain there are NO vacuum leaks.

Then run the engine again with the same binary. Also have a factory binary for the Vortec with TBI for export trucks. May try the latter binary later.

I have NEVER seen a GM throttle body that did not have an adjustment screw. Both of my 2" bore TBI units had capped off adjustment screws.

**brian617** · 03-06-2015

Originally Posted by rsicard

Also have a factory binary for the Vortec with TBI for export trucks. May try the latter binary later.

As far as I remember that "Vortec/TBI/Export" .BIN floating around is a hoax. I compared it with a BJYL .BIN and found no differences in the fuel and spark tables.

**Fast355** · 03-06-2015

Originally Posted by brian617

As far as I remember that "Vortec/TBI/Export" .BIN floating around is a hoax. I compared it with a BJYL .BIN and found no differences in the fuel and spark tables.

Its not a hoax, just not much different. The Mexico trucks have larger injectors and the calibration is not even changed for them! I have pictures of the 96+ TBI Vortec engines in mexico with vortec accessories on them. Even the vortec timing tables are not that much different than the TBI. My Vortec engine really woke up after adding timing to it. I added 12*+ in some areas without running into knock on 87 octane. In some areas I gained over 40 ft/lbs of torque.

**brian617** · 03-06-2015

I'll have to open those .BINs again and look, but i'm almost certain I laid the two maps on top of each other in graph mode and there was no difference. I manually added a vortec table in and it was seriously different shape. I've seen the pictures too, but the proof was in the pudding, I saw no differences. Didn't think to compare the AE stuff though.