4age running rough, I'm stumped, pls help

subiedrake
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4age running rough, I'm stumped, pls help

Postby subiedrake » Mon Dec 12, 2016 7:44 pm

Alright guys, time to swallow my pride and resort to asking for help. Any and All help is appreciated as i just want to be able to track my car already. So onto the details!

4age swapped SR5 chassis. Still running SR5 tank and lines with a Walbro external pump. Motor is stock besides tomei pon cams, pacesetter header, and a straight piped exhaust. Now onto the problem.

Car starts right up on cold start, however it sounds like it runs on 3 cylinders, engine shakes a ton, have to keep feathering the throttle to keep it alive, after 30 seconds or so it will idle on its own but the idle will jump up and down. After it surges for about 5 minutes it will then hold a steady idle at 1500rpm. Once the car is fully warmed up. It actually doesn't drive half bad. It has a nasty dead spot under 5% load that makes the car buck like crazy. I figured this is due to me messing with the preload of the MAF and the timing. I messed with those because the car ran like absolute garbage before.

I Tried checking timing on the car and I've used two different timing guns and can not getting a reading on the pulley. Yes I had the check box shorted and on cylinder #1.

At this point I have no idea what to do. Could it be the Maf is bad? I also noticed the 02 sensor on the exhaust manifold is cut. Does the stock ECU depend on 02 feed back to run properly? I've been looking for some one knowledgable in SoCal that I can pay to diagnose my car and no one has stepped up. So if you guys know anyone please send them my way!

notnilc20
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Re: 4age running rough, I'm stumped, pls help

Postby notnilc20 » Mon Dec 12, 2016 10:04 pm

I'm no expert but sounds like a timing issue.....why can't you get a reading on the crank pulley?

Also the wire on the o2 sensor is cut? The o2 sensor reading determines your air fuel mixture so that could be a big part of your problems.

subiedrake
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Re: 4age running rough, I'm stumped, pls help

Postby subiedrake » Mon Dec 12, 2016 10:21 pm

I dont suspect it to be timing because it runs pretty good once its all warmed up, and i as for why im not getting a reading i have no idea. two different guns and both did the same thing, the timing mark just goes slowly around the whole pulley. The 02 sensor sounds like what could be causing all of this but i dont know for sure if the 02 relays info to the ecu on these cars, some times they are there just to monitor smog. if that is the case i have no idea where this wire should tie into then. i didnt do this swap and its not exactly super clean either

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jondee86
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Re: 4age running rough, I'm stumped, pls help

Postby jondee86 » Tue Dec 13, 2016 1:29 am

subiedrake wrote:... the timing mark just goes slowly around the whole pulley.

Not sure how this can happen :? The timing light is just a strobe that triggers off an
inductive pickup that you clip onto the #1 spark plug lead. Each time the plug gets a
spark, the light flashes, and it will do that at near enough the same time in every second
rotation of the crank. If the engine is running OK, the crank timing mark can't just
wander off on its own.

The only movement you should see is a bit of twitching around at constant rpm, and
the crank pulley mark moving away to the left when you rev the engine... but it will come
back when the engine slows down. If yours wanders around in a circle, it can only be due
to the crank pulley somehow being loose on the crank.

Check the crank pully bolt for tightness, and reach down in there and see if you can move
(rotate) the pulley on the crank without the crank moving.

Cheers... jondee86

PS: Yes, the ECU uses the O2 sensor to adjust the mixture. I believe, but don't know for
sure, that the engine will run rich if the sensor is not connected.
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totta crolla
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Re: 4age running rough, I'm stumped, pls help

Postby totta crolla » Tue Dec 13, 2016 2:21 am

The timing mark issue sounds a lot like the outer part of the pulley (with the timing mark on) is slipping on the inner part of the pulley that is bolted to the crank.
Almost impossible to set the ignition timing when this happens.

Deuce Cam
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Re: 4age running rough, I'm stumped, pls help

Postby Deuce Cam » Tue Dec 13, 2016 5:22 am

Have yyou jumped the diagnostic port to check for cel's?

davew7
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Re: 4age running rough, I'm stumped, pls help

Postby davew7 » Tue Dec 13, 2016 5:59 am

To verify the timing mark on the crank pulley, stick a screw driver down number one plug hole and slowly turn the crank. when the piston reaches TDC, your notch on the crank pulley should be very close to your zero timing mark on the cam cover. My crank pulley's outer ring had moved about 25 degrees. I temporarily filed a new notch in the outer ring, to set the timing, then bought a new solid alloy pulley. Dave W

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Jeonsah
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Re: 4age running rough, I'm stumped, pls help

Postby Jeonsah » Tue Dec 13, 2016 8:11 am

If there is a sensor that is critical to the engine running correctly that is not working, then it it needs to be fixed. Otherwise you are trying to guess one problem while another is happening.

O2 Sensor needs to be hooked up. After some googling:
http://club4ag.com/tech-data/tech-specs ... -ecu-pins/

It appears the O2 wire is a single wire connected to the ecu at pin #13 on the 18pin connector.

allencr
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Re: 4age running rough, I'm stumped, pls help

Postby allencr » Wed Dec 14, 2016 1:26 am

WHAT'S the compression????
Wadda the plugs look like????
What happens to each cylinder when a plug wire/injector is pulled when running????

Forget the timing light, it's only good for having to pass an emissions test, or for checking that the spark advance is working, that's all.

Set the timing for the smoothest & fastest idle that you can and then dial it back/retard it a bit, around 5-10mm of the dizzys diameter, after you know that the compression is OK, and the cyls. are all fireing about equally.
Then
If it pings/pinks/spark knocks/detonates a little with the fuel of your choice when being abused - accelerating/WOT at 2000rpm in 3rd gear - then either STOP ABUSING IT or retard the timing a bit or use higher octane fuel. If it doesn't ping, advance the timing turning the distributor body against the rotor's direction, and try again till it does.

subiedrake
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Re: 4age running rough, I'm stumped, pls help

Postby subiedrake » Wed Dec 14, 2016 2:58 am

Thanks all the responses you guys rock, so first thing I'm going to do is perform a compression test, if that checks out solid, then I'm going to verify TDC on cylinder 1 and see where it lands on the crank pulley. After all that is solid and timed and if it still runs weird, then it sounds like the 02 would be the main culprit. It's completely disconnected. If I were to run no 02 on my Subaru per say, it would run like absolute garbage. So I don't see why this wouldn't be the same way

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Re: 4age running rough, I'm stumped, pls help

Postby sirdeuce » Wed Dec 14, 2016 7:38 am

Check your electrical connections as well. A loose electrical supply or ground can cause a lot of problems. And, if you didn't know this, the igniter/coil mount/clamp grounds the ignition system. Make sure that it's bolted tightly to the chassis.
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