AEM EMS problems on turbo lude.... - Honda Prelude Forum

H22UK · 04-10-2008, 07:44 AM

I’m having problems with getting my Turbo lude to start and idle using the AEM EMS 30-1020. It had been fine with starting in the past but I had it re-tuned a few weeks ago to try and cure the stalling problem it had since the ems was fitted and an awful flat spot in the dyno graph. I though it was ok when I picked it up from the tuner but the stalling/starting problem now seems to be worse!

Not that it makes much difference but here is my setup.

UKDM 1998 5th Gen H22A5 (185bhp) 10:1 comp (our version of US base model)(BONE STOCK INTERNALS)

Turbonetics T3/T4 ball bearing turbo .63AR
Treadstone cast manifold
Turbonetics evo wastegate
Turbonetics raptor BOV
Treadstone TR8 fmicTreadstone
alu charge piping
Custom silicone couplers
Treadstone oil feed/return kit
Custom 2.5” downpipe
2.25” straight through (catless) exhaust
RC 550 saturated injectors
Walbro 255 pump
NGK grade 7 iridium plugs
AEM EMS 30-1020 (tuned without electronic boost control)

When I try and start the car it will crank over without any hint of firing up UNLESS I tap the gas pedal. When I do this it will start almost imediatley but will usually die unless I lift the rev’s to around 2k then let off the gas. It will then continue to idle fine. It seems that it’s most likely prone to stalling when the engine is hot and is usually caused by the Fan cutting in but sometimes just cuts out when slowing to a stop. Ive watched this happen countless times and it seems that the rpm’s dip naturally when the fan cuts sometimes to around 400-500rpm and if it doesn’t stall it will take a good few seconds to regain the 950rpm idle target. I have tried to cure this by playing with the target graphs etc and it has help a bit but it’s still not 100%.

I have checked for vacuum leaks etc etc, I’m convinced it can be cure withing the EMS itself.

So to all AEM wiz kids, any idea’s what I could try .….? I’m still learning the aem software btw. I would take it back to the tuner but he’s 100miles away and I’m pretty skint atm.

Thanks Guys

D_Ludesions · 04-10-2008, 11:04 AM

Sounds like a fuel issue when starting up to me. Have you tried posting up your question on the AEM forums? Aempower.com and go under forums, they are usually pretty helpful over there.

Artifex · 04-10-2008, 11:43 AM

Actually, there were some 1020s which had a factory defect. They came configured incorrectly, and would not idle the car. This could be your problem. I had a 1020 briefly, and I had to send it back to AEM to get it serviced.

Where did you get the ECU? Was it sitting for a long time?

H22UK · 04-10-2008, 02:49 PM

Cheers Guys, Yeah the ecu was sitting for ages and i brought it 2nd hand from a guy off preludepower. I will ask about the 1020 idle issue on the aem forum. I think it is fuel related aswell, although i could also be the ems struggling to contorl the idle stab valve for whatever reason. It had started fine before though.......

Artifex · 04-10-2008, 03:39 PM

Actually, I bet it is the idling ECU problem. I had the exact same symptoms, and I could even get the car to run if I tapped the gas. All the early units had this problem. Unfortunately, you have to ship it to AEM in CA to get it fixed.

What is your unit serial #? If it is less than about 140, I would bet you an E-beer that is the problem.