VEMS 1.8t 630cc coldstart problems

Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 10:31 pm

You think I might have corrosion in there giving some juice to the iac motor? It is in the car since 1999 lol, I'm going to try and unplug it on the next break but I thought the TPS was used to keep the car running too?

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Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 10:35 pm

The iac works when I adjust the ref dc , it raises and lowers air/rpm as it should.

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Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 10:50 pm

I disconnect the map line it's at 100kpa as it should be, I calibrated the TPS and wideband last night too, no difference.

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Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 10:56 pm

It's still waste spark setup too but I didn't think that had effect on idle rpm?

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Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 11:05 pm

I disconnected the TPS/iac and the rpm still sits at 1000rpm after warmup is done

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loxxrider · Post by **loxxrider** » Fri Feb 06, 2015 11:10 pm

Yeah, I just wanted to know if the IAC is blocked off what the idle is like. It's just nice to be able to eliminate one part of the problem. If you can verify that the idle stays at 1000 RPM with the IAC fully closed, then you know the problem is with timing (either ignition or cam). Have you verified that timing is zero'd?

Urtorsen · Post by **Urtorsen** » Fri Feb 06, 2015 11:52 pm

loxxrider wrote:Yeah, I just wanted to know if the IAC is blocked off what the idle is like. It's just nice to be able to eliminate one part of the problem. If you can verify that the idle stays at 1000 RPM with the IAC fully closed, then you know the problem is with timing (either ignition or cam). Have you verified that timing is zero'd?

I zerod it as always and checked it thorougly before pulling the tensioner pin, but I'll check it again. It starts on the button (when above 20f outside) and runs without a hiccup, the only thing I needed to do to get my AFR on point from the get go in December was bump the req fuel up. You don't think it's anything to do with the head being ported??

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loxxrider · Post by **loxxrider** » Sat Feb 07, 2015 12:02 am

I don't think that'd stop you from idling below 1000 RPM. I'm just about out of ideas at this point, so hopefully others can chime in. Have you posted your configuration or a log?

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 12:38 am

No but I will do.

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 12:38 am

Thanks for your input!!

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 6:22 pm

So I unplugged the throttle body and took it off. The plate is never closed fully. I thought it should be closed when engine off or unplugged

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 6:26 pm

I can push it closed that little bit by hand from the lever outside. Maybe it has slipped a gear

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 6:27 pm

It springs back open when I manually close it the same as when I manually open it

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loxxrider · Post by **loxxrider** » Sat Feb 07, 2015 6:50 pm

Not sure how its supposed to be. Have you tried pushing it closed more when the car is running? Since there isn't a maf now, it shouldn't be a problem to do that.

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 7:01 pm

So from searching it's supposed to be slightly open , probably Incase it fails, but how can I pull it closed direction a little to get desired lower rpm as the oem must do???

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loxxrider · Post by **loxxrider** » Sat Feb 07, 2015 7:12 pm

Can you just push on it with your finger while it's running with open throttle body?

I think we might be going in the wrong direction here, but it's worth a try to eliminate it.

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 7:20 pm

Yeah i can unplug it and push it that little bit in the close direction(just like when I took it off the car earlier)with the plate from outside and it does shut it enough to kill the engine. I've searched and found that the AEB throttle body is meant to be cracked open a hair. I don't run any tip or vac lines or recirc valve just the bare essentials off the manifold vac lines.

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 7:25 pm

The pwm only moves the iac motor in one direction?

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loxxrider · Post by **loxxrider** » Sat Feb 07, 2015 7:29 pm

Yeah, I believe so. Well, does pulling more timing out make it run poorly?

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 7:50 pm

I went down to 7.5 but I don't like doing that as every where I've looked people run 10 minimum at idle. I'll go through everything better when I have more time. Like you said maybe it's the wrong place to look but good to rule it out. I want to find out if the oem ecu pulls it closed completely. Il buy one from the breakers to see if I can modify it to close a touch more

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 7:51 pm

Even with pulling timing to there it won't go below 900 hardly

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 8:17 pm

I'll triple check everything else then come back to it.

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 8:20 pm

Maybe I have a slight vacuum leak somewhere else or this head isn't 100%. I have checked and I'm at the proper vacumn that people usually see.

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Post by **Marc** » Sat Feb 07, 2015 8:32 pm

I've never had success controlling the 1.8t gear drive idle motors. try disabling it and using only timing control. adjust the cable stop if it needs more static idle air.

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 9:19 pm

I can use it to control the idle but with everything disabled and only using the timing idl control it still won't let me go below 900, it never needs more idle air when warm only less. It's steady as a rock just won't let me go to the 850rpm warm idle setpoint. All I'm using right now after it gets warm is the timing advance iac. The ref dc for iac I drop to zero after it gets to 55 deg

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