Misfire on new motor

[pontiacgta2002]

Hello,

Installed a new GoodWrench 350 into my 99 gmc yukon. New dizzy, wires, plugs spider MFI. I set the cam retard to 0 and the cap is turned all the way to the right and touched the intake to reach 0 degress. I'm getting the biggest misses on number 2, with number 4 then number 3. The misses havent been enough to throw a code as of yet. Here is the head scratcher i have. The crank learn test wont register the sensor. I run it up to 5k and let off as the scanner is waiting to see it. I have two shims on the sensor is that to many for it to get a reading? Another odd thing to mention is when the dizzy is set to reach 0 cam retard it's pointing more to number 3 cylinder. If i stab it pointing to number 1 cylinder i can only get the cam retard down to +8. I have also heard that GM is saying to run plug gap at .45 instead of .60, is this true? Mine are at .60. Any ideas would be great.

 

[SunlitComet]

i suggest you re read the install procedure for the dizzy you need a proper scanner to set cam_retard. you can not set it to zero and say it is pointing at #3. your our doing something really wrong there. as i read it anyway, but i am very tired at the moment.

---------- Post added at 10:16 PM ---------- Previous post was at 10:15 PM ----------

and.060 only. your are reading info that does not apply to your vehicle engine.

 

[noJeepshere]

Yup, get the proper scanner and redo exactly like the install sheet says.

 

[pontiacgta2002]

Im using a Solus scanner by snap on. I was able to get the CPK learn completed. The cam retard is at 0 and Im still having a miss on #2 cyl. Its pretty frustrating that I'm having this miss issue.

 

[Phone Man]

I think you have to have your foot on the brake at the same time your raising the rmp. Should cut out at 4k.

 

[pontiacgta2002]

Okay, I'm going to restab the dizzy tomorrow so it points to #1 cyl. At that point what should the range be for 0'ing out the cam retard?Should you see a range from say +10 - -10? On the old motor had 180K on it and I was having a misfire on several cyl. I seem to have the same issue with the new motor. The things that i brought over to the goodwrench 350 long block were the lower intake, MAP, MAF, EGR, ESC, CPK sensors. The misfires dont cause the CEL to come on but i see them on the scanner. I have cleaned the MAF and checked resistance and voltages on the other sensors all check out okay. Could the ESC cause a crossfire? i am thinking i could be dealing with a crosfire issue. #2 cyl is taking most of the misfires with #4 and #3 having fewer. Where should i try to eliminate the issue at?

 

[SunlitComet]

With engine at tdc on at beginning of power stroke, crank pointing at 0 timing mark the dizzy rotors should rest on the 8 mark ( may look like. Pyramid too) on dizzy housing with the cap towers pointing sideways with a slight clockwise maybe. Once aligned clamp it down slight. At hot temps for a 99 unit check the cam_retard at 2 and 4000 rpm. Adjust as need at 2000 rpm to achieve 0.0 degrees but you go 2.0 higher or lower. Verify at 4k. Clamp for good. Any crossfire after that is misplaced wires or dAmaged cap. Missing could be bad wire or .plug or bad cap. Once retard is set properly and you don't "feel" misfires perform your crank relearn again. You may have set it with a mis alignment causing false errors. Rinse and repeat as needed till you are proficient.

---------- Post added at 04:08 AM ---------- Previous post was at 04:07 AM ----------

BTW use Delphi or delco caps and rotors.

 

[Gzes]

Plug gap is at .035 or .045

 

[Phone Man]

I'm curious as to what you find as a solution. I've been having misfires for a year and have changed everything. Spark gap at .045 was worse than .060 for me.

 

[SunlitComet]

Vortec 350 are platinum 41-993 pregapped at .060, DO NOT ALTER the gap. If your vortec 350 will not operate with that then something else is wrong.