98 350 vortec into 95 k1500 timing issues

[fehujber]

Ok I'm about outta ideas, and need some help. I recently transplanted a 98 350 into my 95 K1500 TBI. I bought the GMPP manifold for the TBI Vortec heads combo. I have transfered all the sensors from the old motor. The only thing not changed is the dist gear, hall sensor cap rotor wires all new. Here is the issue. IF I set the timing at the factory 0 degrees( with the timing lead disconnected), it runs like crap, hesitation popping no power, but if I set the timing at 6-8 BTC she comes to life, BUT will not crank when hot. Granted the issue lies in the electronic spark control I have a 16197427 ecu. I was led to believe that there was also a seperate Spak Control Module.....after crawilng around the truck for 2 hours I believe this is NOT the case and the spark control is handled in the ECU, which I am getting ready to replace. Does anybody have any other experience with this issue????

[mytmouz]

I have that set up in a Nissan hard body truck with a different ECM. It ran similar to that until I changed ECM's. I may have done something to that one somehow during installation, as it was running fine in the donor vehicle. Changed ECM's and it ran better, but not all that great. I had a chip burned for it by a board member here, something to do with the timing tables being different between the tbi and vortec engine due to engine efficiency. (I am self tuner deficient) Runs much better now...

[Fast355]

Ok I'm about outta ideas, and need some help. I recently transplanted a 98 350 into my 95 K1500 TBI. I bought the GMPP manifold for the TBI Vortec heads combo. I have transfered all the sensors from the old motor. The only thing not changed is the dist gear, hall sensor cap rotor wires all new. Here is the issue. IF I set the timing at the factory 0 degrees( with the timing lead disconnected), it runs like crap, hesitation popping no power, but if I set the timing at 6-8 BTC she comes to life, BUT will not crank when hot. Granted the issue lies in the electronic spark control I have a 16197427 ecu. I was led to believe that there was also a seperate Spak Control Module.....after crawilng around the truck for 2 hours I believe this is NOT the case and the spark control is handled in the ECU, which I am getting ready to replace. Does anybody have any other experience with this issue????

Vortec starter would crank it right over even at 10* BTDC. That being said the Vortec heads have a much different spark advance requirement and fueling requirement than the TBI engine. Throw the Vortecs cam into the mix and the factory chip calibration is even further off. The 7427 PCM does not have a separate ESC module, the knock filter handling is on the Memcal itself and the knock sensor is wired directly to the PCM. Now here comes the fun part you aren't going to like. You need an adjustable fuel pressure regulator and a different fuel pump at a minimum to feed the engine. Other option would be stock fuel pressure and early model 454 injectors. You need injector flow equivalent to 150 lb/hr to fuel a STOCK Vortec 350 engine, which is 75# per injector. Your stock injectors are 61 lb/hr. I have found the Vortec heads to need between 10* and 16* more timing advance throughout the timing curve and require a lot more fuel overall.

[fehujber]

I hear you,but I have the vortec starter on here, I do have an adjustable regulator. She will run beautiful at the advance I set but cranks like an old lady when hot ( the motor not her). I've heard that 454 injectors would help performance. Right now I'm looking to get the driveability up. This is my spare family rig and also used to pull my 4800# boat/trailer combo. At 63 I've probably done 35-40 motor changes and swaps...never have I had this much grief.

[andy@e-t-d.at]

Hi, i am doing actualy nearly the same, i have a 98 Vortec 350 implantated in a 89 Camaro ecm 1228746 i have the Same Problems, and search about to Fix..
Have you use the correct Sparks (the Vortec Sparks are longer ) i used the wrong one, and Engine would not crank, i changed to the Vortecs, put in a Optima
Battery and the engine Cranks and Run, But the Power is Like a Grandma :-( i have set 20° BTDC for SA Bias (ANLU) Prom..

I have Monitored the ALDL Datastream §61 mask and AFR is going Rich so the ECM put less Fuel. INT around 115, I use Stock Injektors for the TBI 350 Engine.
The Smogpump is always pressing Air in the Catalytic, so i cant pass smog Test -:(

[Woods]

If I understand, you are running a 98 Vortec engine with stock vortec roller cam with TBI, yet still using the stock 95 TBI memcal tune? You need a custom tune with that new combo to run correctly.

[fehujber]

Right now My issue is cranking when warm/hot, but who has the re-calibrated chip? I have got tuner pro but have been struggling to get the needed files. One site "Code59" has just been a disaster.