2M6 1985 SE Just finished a 2.8 to 3.4PR swap with CompCam 260H, new Magnum 1.52 roller-tipped rockers , 3.4 DOHC pistons, donor engine 3.4l Camaro (1994) 117k miles, Block was honed Crank was polished. Machine shop said all was within specs. New Timing gear and chain set. New #19 lb Accel injectors. Bearing/rings etc.
The valves were adjust three times to make sure I got it right. TDC #1 / #4 valves set per service manual 1 1/2 turns after 0 lash. Ran compression test with plugs removed and starter engaged. 160 +/_ 5 on all 6 cylinders 5/30 oil with CompCam Break in oil, engine oil primed. fuel pump runs sec with key on. timing set at 10* rotor set at #1
Engines cranks but will not catch. bad coil / crack in case. Replaced with MSD Street Fire.
Timing light on plug 1 cranking and still nothing. Jumped A / b wire on ALCL rotated distributor until a hit. Engine would not run below 2,500 rpm rough exhaust turned red within seconds......... Did not like the situation did not want to damage engine , stopped cranking . pulled engine
Looking for possible vacuum leaks. Reset valves, insured all manifolds were torqued and gaskets were good. all vacuum tubes are sound. re-installed engine.
set timing at 10* A / B jumped at ALCL fuel pump on at key on No codes but 12 Rotated distributor while cranking started. Engines idles at 1,100 - 1000 sounds great. Timing at mark is off the charts maybe 20-25* attempt to rotate dist back to 10*. engines starts to cough and sputter miss , rough idle.
I hope this video is helpful......
If I turn back to where it was running smooth. Pull A/B jumper.... engine dies.
Well that is where I am. Video attached but not sure you can hear the backfire, pops, and missing above 2,000. Not sure where /what to try next...... In the video I pulled the temp sending unit to the ECM and the smooth idle went rough.... not sure this is right or not. pushed back in and idle went smooth again.
Any thoughts? hopefully electrical......
------------------ Mark In the Great Northwest!
[This message has been edited by NW-Fiero (edited 04-27-2014).]
With 19lb injectors you will run rich without change to the ECM. If you have SMOG tests in your state, you probly won't pass with the 19lbs. Are you sure the distributor is not 180 off? It will run 180 out but very badly and the manifolds will get red super fast. Do you have the right timing marks on the balancer? Did the rubber in the ring of the balancer move? IE throwing off the marks. did you verify TDC on the timing mark?
Do you have any way to scan it?
Also, your idle will be bad untill you drive it over 25mph for a few seconds and then stop and turn it off then back on and that will reset the idle in the ECM.
I did use the the 3.4 balancer but transferred the timing mark and verified the mark when the heads were off.
Pulling the engine again this evening and checking to verify that the cam and crank alignment dots are where they belong.......Kind of hoping the cam is off a tooth.....would make the disassembly worth while. In my mind it is the only way I can see the timing mark being off 20+ BTDC and the engine idling fine, but falls apart above 1,500
Cradle on ground. now waiting for timing cover gasket set to show up in morning. Dropping this engine is getting easier every time. just wish I could move on to the "next big thing"
Take pics, then you don't have to disasemble. try the stock 3.4 injectors if you have them. check fuel pressure if you can. check ALL your grounds and make sure EVERY sensor is pluged in. Do you still have the metal sheilds on the spark plug wires? if so throw them out, they leak spark alot. take your IGN control module to any parts store, they will test it for free. Make sure you are on the compression stroke when setting TDC. It will run 180 off, I know that for a fact, I even have video. the first time I started my first 3.4 swap it was 180 off.
While you have it out, you may want to verify that the (new?) cam is timed right. You may be able to look at the cam chart and see if the fully open degrees match what they should be. Cams (really hot ones) produce very little vacuum at idle and will require lots of static advance, I am not suggesting it is because of the cam selection but because there may be some error in the indexing of the cam when they drilled the mounting holes. A cam running really retarded will act like this. But don't get fixated on this when you are trouble shooting, there are probably many more reasons for the problem. Larry
I can safely say it's not the 19lb/hr injectors causing this. My build is practically identical to this, running on a stock ECM, and it ran beautifully the first time. Noise you hear is the y-pipe heat shield rattling. Tightened it down, and it went away. Having since driven the car, this setup loves the injectors. Integrator and BLM are always very near 128.
My advice would be to beg borrow or steal to get a scan tool to see what's going on. Each sensor has a certain range of values that a good running engine should fall within. I can't imagine it just being a sensor issue. It could be something in the primary ignition electrical system for sure. You replaced the coil, for a seemingly known fault. What are the plugs, and how are they gapped? New wires, or known good used ones? What does the timing mark show when you hook the light to #4 cylinder? The FSM protocol for setting timing involves taking the reading of #1 and #4 and making an average of the two readings.
My experience is that an engine will not truly "run" 180 off. It may seem like it wants to crank and fire, but very poorly. Yours is running way too well to be 180 off.
Unfortunately I'm much more of a hands-on diagnostician, rather than being able to do it easily over the internet. I'll do my best to help though.
[This message has been edited by ManMadeChickens (edited 05-02-2014).]
This may seem elementary, but forgive me, I'm grasping at wild ideas; you did transfer the widest mark on the old balancer, for #1/#4 TDC, right? There are a couple of marks on a stock 2.8 balancer.
Odd thing is that when he gets it to run, pulling the jumper kills it. It is like something is telling the computer that something is in a position that it really isn't in. Larry
I transfered the Timing marks from the 2.8 to the 3.4 Damper. I verified with the Crank timing mark (dot) at TDC and with the marks on the Timing Cover
New plugs, wires cap rotor.. hits on all 6 when idling.
The point that Trotterlg is making:
quote
Odd thing is that when he gets it to run, pulling the jumper kills it. It is like something is telling the computer that something is in a position that it really isn't in. Larry
Is what I have been eluding to as it being an electrical issue.. But from which module/sensors? or could the computer be the culprit.....how to test?
Engine should be in this weekend for another round of........who knows
Will also pick-up a fuel pressure tester from ORielly's and see if they can test the Distributor module.
------------------ Mark In the Great Northwest!
[This message has been edited by NW-Fiero (edited 05-03-2014).]
Are you sure you are on the compression stroke with the rotor pointed at no1 ?
Also when you jumper the ALDL, the check engine light should be flashhing if it is in Diag/Ground mode.
It really sounds like timming. I got a 3.4 running today and it didn't want to run at all really, I had to give it gas, long cranking to start it, couldn't start it in ALDL mode, etc. Timming was at 0, set it to ten and now runs great.
FYI grounding pulls alot of timming, so by grounding and un grounding you can kinda see where you need to be.
When you jumper the ALDL terminals, the computer stops advancing the ignition timing. The only timing advance is from the distributer adjustment. That's why you have to jumper the terminals when adjusting the distributer, to keep the ECM from confusing the readings. The amount of timing advance that the computer adds, even at idle, can be pretty significant. So if the engine runs fine while the terminals are jumpered, but dies when you remove the jumper, it's probably because the ignition timing is too far advanced.
[This message has been edited by Blacktree (edited 05-03-2014).]
So if the engine runs fine while the terminals are jumpered, but dies when you remove the jumper, it's probably because the ignition timing is too far advanced.
Totally agree but the engine is only running at jumped A/B 20* as per the video. ..
That is a fairly mild cam, but it will take a little more advance to run right than stock. I would try getting it to run any at all at around 10 to 15 degrees and then pull the jumper and see what you get. My cammed up 3100 won't idle any at all with less than 15 degrees static advance. The red exhaust is just a lot of unbruned fuel burning in the exhaust system. What does the timing light show while cranking with the jumper removed? Larry
[This message has been edited by trotterlg (edited 05-03-2014).]
Originally posted by NW-Fiero: Totally agree but the engine is only running at jumped A/B 20* as per the video.
Suggestion: set the distributer back to 10 degrees BTDC. Then remove the jumper, and go from there.
You seem to be trying to make the engine idle smooth while the ALDL terminals are jumpered. You're not supposed to do that. You'll end up adding too much timing advance. The computer will add enough timing advance to make it run properly after you remove the jumper.
Put the engine back in last night. Put a fuel pressure gauge on the rail and got 43 lbs at key on... Took distributor ICM in to have it tested andn it fail all tests.. I think when the coil failed it shorted out the ICM.. Replaced the ICM and the pick-up. Put the Distributor in at 10* jumped A/B and it fired right up and went to an 800 rpm idle. Timed verified # 1 and #4 both spot on 10*.....Shut down and removed the jumper. Fired right back up without hesitation.
NICE! I always test the ICM when things are weird, free test, lifetime warranty, and always carry a spare. Don't froget to use thermal paste, always have them test new ones too , I had 2 in a row bad out of the box, did I mention always carry a spare.?.
Glad you got it resolved! Sucks you chased down this issue so thoroughly when it was something seemingly so simple. Alas, such is Fiero ownership sometimes.
