more DOHC issues

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

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slow'n'steady
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Post by slow'n'steady »

Mach10 wrote:Solve your confusion, and point both cars in the same direction. :thumbleft:
huh? I am not confused. You said YOU where confused. I know what cylinder is what.
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Post by Mach10 »

The only thing I said I was confused about was how to picture valve events in my head since they go at 1/2 crank speed.

My not knowing which cylinder was which wasn't from flipping the document upside-down, or reading the diagram wrong, but from thinking it was the wrong one and never bothering to look it up... To be sure, the problem was when I dropped the crank out of the motor and labelled my cylinders wrong in the first place--while upside down. I just never corrected my bad assumption.

I appologize for having derailed your thread. :salute:
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slow'n'steady
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Post by slow'n'steady »

Well then...

Any other thoughts on why it ouwld run when i timed it thinkng the #2 cyl was the #4 cyl but not now that it is timed correct? What about the fuel injector harness? Is it possible I have the wrong injectors plugs on the wrong banks?

Im gonne try to get the car here ASAP but it wont be for ATLEAST a week or so...
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Series8217
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Post by Series8217 »

Mach10 wrote:Heh... some confusion here... I posted the pic to show I was WRONG, not that I thought I was still right :salute:

According to my pic, #1 is the REAR bank nearest to pulley.
Ahh I didn't read the "front bank" part of your post, just saw "nearest crank pulley" and thought you had it right and was just confused about what bank we were seeing in the pic. Ok then ;-)
slow'n'steady wrote:Well then...

Any other thoughts on why it ouwld run when i timed it thinkng the #2 cyl was the #4 cyl but not now that it is timed correct? What about the fuel injector harness? Is it possible I have the wrong injectors plugs on the wrong banks?
The injectors on the 91-93 3.4 DOHC all fire at the same time, so that's not it...
Could still be the front bank.. get some pics of the front.
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Post by Mach10 »

Thought:

How did you determing TDC on #1 and #4?

There's a mark on the aluminum cover, but it's a fair distance away from the pulley (on which the marks can be "off" anyway).

I'd suggest figuring out TDC with a screwdriver (mark when the screwdriver STOPS moving up, and mark when it STARTS moving down, and mark the exact middle of those points), and starting fresh.
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slow'n'steady
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Post by slow'n'steady »

I did the "screwdriver" method for finding TDC. Well, i actualy used a piece of brake line with a rubber vacuum "cap" glued to the end. I honestly Dont know how it could be the timing. I had an entire thread on here about it. When i get the car here, maybe i will video tape me doing the timing so you'all can see.

Side note: I got my other DOHC V6 running today. The 3000GT that is...
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Post by slow'n'steady »

Shaun41178(2)... did you get my PM about the cam carriers?
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Post by Mach10 »

slow'n'steady wrote:I did the "screwdriver" method for finding TDC. Well, i actualy used a peice of brake line with a rubber vacuum "cap" glued to the end. I honestly Dont know how it could be the timing. I had an entire thread on here about it. When i get the car here, maybe i will video tape me doing the timing so you'all can see.

Side note: I got my other DOHC V6 running today. The 3000GT that is...
It's not that we don't believe you, it's just that the only variable that seems to affect it running is cam-timing. This alone suggests that something is strange here. You get fuel, you get spark... It's about the only think left :salute:

Personally, I'd set the timing, crank the motor over a few times, and verify that the timing marks line up EXACTLY. It's possible something's moving and throwing it out of whack.
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Post by p8ntman442 »

I might be able to answer that questions..... lilferari ? has it right. Rt side cam flats down and Left side up after first rotation. You have to have the cam pullys loose on the left bank to keep the flats up. I made the same mistake and aligned all four flats up on TDC. That is part of my problem. After reading a few different versions of setting the timming I realized I lost step 64 on my proceedure that says to turn crank 360* and then tighten the left bank cams. I was pondering this last night and realized that we are all running waste spark systems. That means that the plug fires every time the piston hits TDC. So they fire on exhaust and compression stroke. You can set the right bank out 360* and it will still run. However if you are running the Multi-port Fuel injection, you're fuel injectors pulse every Three times with the thought of puddleing fuel into two intake valves while one is opening. That doesn't work so well when Mine is Sequential Fuel injection where each injector on fires when the intake valve is open. So in my case, my fuel injectors are out of time with the intake valve. I will be correcting that soon. Check out my thread (3.4L DOHC timming keeps jumping) you may get a better idea why it works but not idea.


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slow'n'steady
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Post by slow'n'steady »

thats one thing that confuses me the most...
When i timed both banks "flats up" with #1 at TDC.... IT RAN
then when timed thinking #2 was #4... IT RAN
but now that everything is right... IT WONT RUN
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Post by p8ntman442 »

get someone else to time it. Seriously. A fresh set of eyes is always a good thing.
The Dark Side of Will
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Post by The Dark Side of Will »

slow'n'steady wrote:It depends if you are talking about the Rear bank in a FWD car or the rear bank in a Fiero... Also when in a fiero are you thinking rear as in when standing there looking/working on it or rear as in the bank closest to the rear of the fiero...
[ass]
The rear bank is closest to the rear end of the car.
Just like "the left" is ALWAYS the side that has the left turn signal.
[/ass]
slow'n'steady
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Post by slow'n'steady »

The car is for sale but IF by some miracle i can get it running before it sells i would LOVE... LOVE to keep it!!

here is a video of what it does now...
http://media.putfile.com/Fiero-023
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Post by The Dark Side of Will »

We've never established that the intake cams are in the intake locations and the exhaust cams are in the exhaust locations.

If you or PO did that, it's basically a reverse rotation engine. Put it in reverse and push start it forward...
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Post by p8ntman442 »

sounds like a plan to me. OR you could jack the car up, switch polarity on the starter, and turn the starter backwards. You may have to wire the selenoid seperate but I doubt it.
slow'n'steady
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Post by slow'n'steady »

cams are good. I got that taken care of, they where actualy there right to begin with...
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Post by slow'n'steady »

C'mon... today is my 21st birthday...
Someone bring me a 12 pack and fix my car

:thumbup:
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Post by The Dark Side of Will »

Have you...

Checked compression?
Pulled a plug wire and looked at spark?
Made sure ECM understands RPM when cranking (IE, using a scan tool)?
Made sure coil pack power AND ground are in good shape?
Confirmed injector pulses using noid light or injector firing using stethoscope?
Gone through the "Cranks but does not start" trouble shooting tree in the SERVICE MANUAL which you darn well ought to have when doing an engine swap...?

What does the tach do when cranking?
slow'n'steady
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Post by slow'n'steady »

the tach bounces like it whould when starting/running.
I want to clarify this isnt a starting problem as much as a running problem. It does start and runs for a few seconds...

checked compression-good
injector pulses and firing-good
dont have a scan tool... Dont have any codes though....
coil pack wires and such are good along with ICM and coils

I have not yet checked the Fuel pressure. I know i can get a kit on ebay for like $26 shipped or at Autozone for like $40 but YEs i am THAT broke at the moment...
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Post by The Dark Side of Will »

Please outline the checks you did on these items. I frequently find that when someone says a component is "good", they've overlooked something.

You need a scan tool or equivalent PC program to know if the computer understands RPM while cranking.

You do have gas in the tank, right?

The tach "bounces"? It should flutter at 200-400 RPM, but it shouldn't drop to zero. Can you take a vid of what the tach does while you crank?
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