AEM EMS hiccup at after 5k

datrip · Jul 20, 2009, 08:51 PM

The car is a built block peak boost 35r 03 viii. All the basic bolt ons, Buschur double pumper, AMS FPR Kit, RC 1200cc inj's, AEM 3.5bar map sensor. The car drives great, idles great, with perfect compression numbers, but with a hiccup after 5k RPMs. I have to many data log files that I can supply to anyone interested in taking a look. Thought it was spark plugs, changed them 3 times with different heat ranges and gaps. We thought it was the FPR on its way out so we got an AMS fpr kit. The issue only lasts for less than a second but the AFR goes rich and it stutters slightly then pulls hard again. Here are the things we are thinking of testing/trying now:

- I would assume that the AEM and the sensors are ok, but both would need to be investigated.

- It would be worth checking to make sure the trigger wheel on the crank isn’t damaged (I doubt this is the case since the signal errors aren’t consistent)

- It could be anything ranging from: wires crimped, broken wire inside insulation, electrical interference requiring a filter to filter out the noise (I’ve seen this on Scion TCs with AEM FICs).

Any and all help with this issue would be greatly appreciated. I am hoping to find someone that has had an issue like this that can offer some advice. I am going to post this here as well as in the AEM EMS specific field. Thanks all in advance as I just want to get my tune finished. Car has been sitting for nearly two months now while trial and erroring on it.

MZP@TeamD · Jul 22, 2009, 02:57 PM

First when did it start happening?did you do anything to the car?
second what kind of ignition system do you have in the car?
Third post one of the logs so we can see whats going on.

awdboosted · Jul 22, 2009, 03:00 PM

To lean.. To much timing.. In one cell
or
a drastic change between cell in that area.

That’s my bet

datrip · Jul 27, 2009, 09:41 AM

Replaced the crank sensor, re-sealed the oil pan and its working perfect after 5 pulls this morning. I will keep all posted if it fixes it after another 5 pulls today.

GTVEVO · Jul 27, 2009, 12:00 PM

Quote:

Originally Posted by datrip

Replaced the crank sensor, re-sealed the oil pan and its working perfect after 5 pulls this morning. I will keep all posted if it fixes it after another 5 pulls today.

Hope so, keep us posted.

mike 99gsx · Jul 29, 2009, 10:24 AM

My bet is that you have a boost leak after the map sensor. I would pressure test the car and specifically look for a leak at the injector seals and intake manifold gasket.

datrip · Jul 30, 2009, 10:49 AM

Crank sensor fixed the issue. Next issue came into play. Couldn't go over 26psi...ended up being a tear in my main line off the intake manifold. Got that fixed and then the next issue comes into play......(at this point I am starting to dislike my Evo)the dyno plot shows that it ramps up about 30-40hp above what it should be at(spikes) and then falls back to normal. We thought it might have been the clutch slipping, but then it went away and didnt come back for 15runs. The entire time though the power was up and down. One run would be 490, the next 550, the next 515, the next 540, next 500....it was very inconsistent.

datrip · Aug 2, 2009, 05:01 PM

Any thoughts EVO Guru's? I am replacing the cam sensor Friday and will test to see if that was the issue. Only other thing is that it could be is the clutch.

datrip · Aug 6, 2009, 07:26 AM

No ideas anyone?

GTVEVO · Aug 6, 2009, 12:42 PM

Well if it was the clutch you should see RPM ramp up in the logs and on the dyno so if you aren't seeing this I would doubt its your issue. If the power is just inconsistent it could boil down to several things. Keep in mind if you tune isn't consistent it will cause inconsistent power. This is where I would start experimenting if all recorded/logged elements check out well.

datrip · Aug 7, 2009, 09:15 PM

Thanks bud. It was ramping up though, and then dropping back down. Oddly, it didnt do it every time though.