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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more DOHC issues

Post by slow'n'steady »

well, i keep having issues and keep having issues so the car is up for sale however i doubt i will be able to sell it so, ONCE AGAIN i need you'alls help.

It hardly ever starts, when it does it will run for may be 5 seconds, it baclfires and just over all SUCKS!!
I did the timing again a while back and i am now 100% sure it is correct!!
do you guys have any other ideas? Also if anyone is interested i will pay for someone to get the MF'er running right!!!
whipped
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Post by whipped »

Kohburn sez: "Check for bent ECM pins"

:thumbleft:
slow'n'steady
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Post by slow'n'steady »

did that last time around...

Just went out to try again... would turn over no problem but wouldnt start... I planted the gas pedal to the floor and it started, kept it held to the floor, it wouldnt go past about 3K RPM then it died....
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Series8217
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Post by Series8217 »

Error codes?


Also take the intake tubing off and have someone start the motor and hit the gas. Does exhaust come out? Maybe you swapped the intake and exhaust cams :-P
Mach10
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Post by Mach10 »

Either you've boned the ignition timing, or the cam timing is off.

Check your plug wires first, if they are all good, do your cam timing again.

Backfiring certainly suggests your cam timing is off...
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Series8217
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Post by Series8217 »

Oh yeah, make sure your plug wires are on right. Ignore the markings on the coils, they could have been replaced or switched. Follow the diagram in the service manual.
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Shaun41178(2)
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Post by Shaun41178(2) »

I too am wondering if you have the plug wires mixed up.
Boscolingus
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Post by Boscolingus »

fuel pressure?
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Blue Shift
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Post by Blue Shift »

I juuuuuust got my swap on the road, myself and ran into some of these issues on the way:

- Sometime early in the project, I took my coilpacks off the ICM to inspect, and put them on in the wrong order, and put the plug wires on according to coil markings. I had 1 coil correct, so 2 cylinders were firing. It was doing just what you describe.

- I also had a problem with the CPS to ICM wire, the purple and yellow one. Make sure the pins aren't fucked up.

- Check your C203 connection and pins, it's been widely known to cause intermittent issues.

- The ICM should start your motor on its own until the ECM takes control - Darth/Sinister knows more about it than I do. You can do that test to rule out other problems.

- Don't get the order of your cams wrong - it does happen, and it sucks toilet water.

- Make sure your MAP, TPS, and CPS sensors are good. Make sure all your sensors are good - bust out a voltmeter and backprobe shit.

- A million other things.

Good luck, man.
Mach10
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Post by Mach10 »

Honestly, you're better off parking it for a few days and cooling off. Selling it won't fix it, and you're just going to regret it later.

When you're calm enough that your hands aren't shaking, start from scratch. Pull out your multimeter and test all your ECM connections. Check that each coilpack is actually sparking, pull all the plug wires off and rewire from scratch.

Redo your cam timing.

When you've got the cams pinched down, put some alignment dots on the cogs so you can make sure nothing's moving when you're wrenching around. After you've timed both, spin the motor a couple times with the starter, line it back up to 0º and check your alignment dots.

I'm almost positive it's something stupid. We're all guilty of it sooner or later! :salute:
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Post by Kohburn »

Boscolingus wrote:fuel pressure?
yeah in my case the bend pin cause the backfire that killed my stock fuel pressure regulator.

aftermarket FPR later and it all works fine
slow'n'steady
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Post by slow'n'steady »

OK, wires are right...
timing has to be right (unless P.O. has cams backwards)
threw a code 21 which IIRC is TPS?

im gonna head back to work and soend $18 for a new TPS and see where that gets me.
slow'n'steady
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Post by slow'n'steady »

TPS didnt fix anything at all

plug wires are as fallows: (from the side of the ICM with 2 plugs going to the side with a single plug)

143625
chuck
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Post by chuck »

When I got my car on the road I thought I would do the timing before it bit me and I had a set of 95 cams so I installed them on a 92 engine. The car ran but had valve train noise. Out of spite I pulled the engine for a 3400. After removing it, it appeared the lifters didn't have enough range to take up the slack so the cams were loose. It still ran but not well. It may not help your situation but I figured I would mention it just in case.
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Series8217
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Post by Series8217 »

95 cams are identical to 92 cams (I'm running them in my motor with the 93 lifters). Sounds like someone botched the valve job on your motor or you had collapsed lifters.
chuck
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Post by chuck »

If by identical you mean not the same, then yes, they are identical.
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Post by Mach10 »

I've got a pair of both 95 and 92, and I measured both

The cam profile is identical, the only change is the switch from lockrings (t3h suck) to split washer (t3h aw3som3).

Putting 95 cams in the 92 heads will work just fine... Better than fine 'cos it's even easier to degree the cams.

96 had a slightly different profile (nicer idle, less power) to go with the newer head design (better flow) for a net gain of zero.

In any case, the WHOLE range of LQ1 cams have exactly the same max lobe lift. If your lifters (also the same) weren't taking up the slack, you had OTHER problems (like collapsed lifters).
"Oh, this is too good. She thinks you're a servant... Cause you're black! This is greatest moment in my miserable life... Sooo-ey! I LOVE RACISM!"
Blue Shift
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Post by Blue Shift »

slow'n'steady wrote:TPS didnt fix anything at all

plug wires are as fallows: (from the side of the ICM with 2 plugs going to the side with a single plug)

143625
According to the Chilton (yeah I know, they suck) book, it says from left to right, left side being the side with 2 connectors on the ICM: 1-4, 6-3, 2-5. I hooked it up that way after having the 1-4 and 6-3 coils swapped, and boom, fires right up.

As for the cams, I'm running 91' cams in 91' motor with a set of 95 cam cogs - and they kick major ass.

Now if I can just figure out what I'm seeing in my oil... we'll be all good.
slow'n'steady
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Post by slow'n'steady »

Well, just went to check it out and i guess i switched a couple numbers around when i was typing because how you have it listed is how it is...

keep the idears comin...
and THANKS
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Series8217
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Post by Series8217 »

Mach10 wrote:I've got a pair of both 95 and 92, and I measured both

The cam profile is identical, the only change is the switch from lockrings (t3h suck) to split washer (t3h aw3som3).
That was not a change to the cams. The split cone washer setup uses the same cam nose as the earlier ones.
Putting 95 cams in the 92 heads will work just fine... Better than fine 'cos it's even easier to degree the cams.
Just swap the cogs. The cams are the same.
chuck wrote:If by identical you mean not the same, then yes, they are identical.
I've measured the cams. They are the same.

The alloy of steel or (perhaps the heat treatment?) used on the later cams is a bit different, hence the slightly more golden color, if thats what you were going by. The castings and machining are the same so dimensionally they are identical.
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