afterfire and hesitation

885.0conv · Sep 13, 2009

Is there an easy way to get to the wires off the EEC, I want to measure a ref voltage can I take the wires off the still get the 5V ref or does it have to be plugged in. I'm still getting 31(KOEO) and I get the 5V on the EGR and the voltage changes when the plunger goes in. I am thinking the voltage is not getting back to the computer. Also I hear a ticking sound on the pass. side on the backside of the engine. I am getting a vacuum on the EGR at idle which is not suppose to be there (maybe EVR gone bad?) and I get a 244 (KOER) which the book says cylinder balance test. I am just wondering where to go from here. Thanks for any info.

HISSIN50 · Sep 14, 2009

You should not have two and three digit codes. An aero fox uses two digits.

What's your baseline position sensor reading at idle? Spec is below ~0.60V IIRC, but if it's above 0.40V that can cause issues.

It seems to me that the EGR should be disabled with a code 31. For the EGR opening at idle, I'd look at a bad vac switch, as you noted.

If you think the sig wire from the position sensor to the EEC is open, disconnect both connectors (at the EGR valve and the EEC's connector) and do a continuity test. It should be almost nill.

You could also test the voltage on that pin while everything is connected. The voltage at the EEC should match that at the sensor.

885.0conv · Sep 17, 2009

I am getting .636V. I borrowed my fluke from work so I know that reading is good. I replaced the EGR vacuum solenoid and now there is no vacuum to the EGR at idle. I am still getting the afterfire and bad gas smell but I think the ticking noise I heard by cylinder 4 is an exhaust manifold gasket leak because I can smell exhaust as soon as I start it up. I am getting a 23(KOER) so I will have to adjust the TPS. Do I adjust it when the engine is warmed up or at first start also what should it be.

HISSIN50 · Sep 18, 2009

For the TPS, it doesn't matter. Testing it KOEO on a cold engine is just fine. Look for it to baseline under ~1.5V. If it's anywhere near 1.0V (give or take a tenth) I'd leave it alone.

885.0conv · Sep 18, 2009

I set my TPS to 1.0V and the error code went away. Now when I run the KOER test I get 4 lights to start then 1, 2, 4, 4, 1, 2, 4, 4, which to seem like it says 244 which in the book it says is a cylinder balancer test issue. But since you said that there is no 3 digit codes I would not know.

885.0conv · Sep 19, 2009

I went off the assumption that the codes were 12, and 44. So in the book I have it says error 12 is the idle air controller. When I took the controller off it was nasty. I took it to work and used the ultrasonic on the valve part not the electronic part to clean it. Now the car will not start does this mean I need a new IAC.

HISSIN50 · Sep 19, 2009

It would seem logical. Never clean an IAC unless prepared to replace it.

If you hold the throttle open a little bit while cranking, it should start.

885.0conv · Sep 20, 2009

I replaced the IAC seems to run a little betteralso did the fuel filter since it has been two years (6000 miles) just to be on the safe side and since it is cheap. Another question, with my setup when should my power kick in? Its slow from 1K to 3K and at 3K it takes off up to 5K when the tranny shifts under WOT.

885.0conv · Sep 20, 2009

I finally got all my error codes to disappear. The afterfire has settled down but I still get the hesitation til 3K-3.5K and then it takes off. It seems that at half throttle and WOT act the same til 3K. I measured the TPS and it goes from 1.0 to 4.7 at WOT and it is smooth. The only I see is the ticking sound come from cylinder 4 area. I moved the dizzy up to 20 base timing and the ticking went away but that seems like a lot. The ticking sounds like either a stuck lifter or an exhaust leak. Is there a way to check if it is a certain one?

liljoe07 · Sep 20, 2009

20 BASE!!!!!!!!!!!!!!!!!!!!!!!!!

With the SPOUT out you set it to 20°.

Have you drove it like that?

885.0conv · Sep 20, 2009

No I have not drove it, just moved the dizzy to where it would go away and checked the base timing and it was at 20. I recently replaced the oil pan gasket, water pump, and timing cover gasket. I didn't disconnect the exhaust from the heads so the leak might be the header gasket. When I went to do emissions the test would not take because there was a major exhaust leak. I checked the header bolts and 6 of them were loose. I tightened them up and the engine bay got quieter but the ticking by cylinder 4 was still there.

885.0conv · Sep 21, 2009

I replaced the header gasket on the pass. side and the ticking went away but I still have the hesitation and afterfire is only went I snap the throttle. I cant think of anything else to check for.

885.0conv · Sep 22, 2009

I am going to get a fuel pressure tester from autozone and see what it says, would a failing ignition coil do this, mine is the stock one. Also would a stock replacement be good or do I need an upgraded one with my setup and will the dizzy (stock), wires (stock style replaced two years ago (6K miles)), and plugs (bosch +4 ) be okay with the upgraded coil.

HISSIN50 · Sep 22, 2009

A small window of hesitation and then return to normal performance all the way to WOT would not indicate a coil or ignition part failure per se.

In any case, I would not run plat plugs.

If running lean, you should get lean code(s) if you're driving the car very much.

Have you looked for leaky wires at night? IIRC there was a TSB on wire routing (it involved a cross-fire).

ID89GT · Sep 22, 2009

Swap to some autolite plugs

liljoe07 · Sep 22, 2009

Posted via Mobile Device

Ditto, get the Bosch +4's outta there.

Autolight 3924's, gap to .045 and let her rip.

885.0conv · Sep 22, 2009

Ok I will do that, I guess I got fooled with the ad about more gaps is better but now that I think about it the can only be one spark at a time.

liljoe07 · Sep 22, 2009

Posted via Mobile Device

I'm a firm believer that 20 base is way to much. Depending on load conditions, the ECM can add up to 18 degrees more timing. That's puts you at 38 depending on the load.

What were you trying to get to go away by setting the Base timing to 20?

885.0conv · Sep 22, 2009

There is a ticking sound coming cylinder 4 area. I was thinking it might be a header gasket leak but I changed it and it is still there. So it might be a stuck valve. I turned the dizzy to see if the ticking would go away and this when I noticed the base timing of 20. I returned it to 12 which is where it is normal at I am afraid to drive it at 20.

liljoe07 · Sep 22, 2009

Rocker or lifter is the likely cause.

You have TW heads, so are the Stud mount or Pedestal Mount?

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