I've wasted a year trying to get my SR running.

[SnaggleToof]

Help me fix my SR! Getting pretty frustrated, missed the whole drift season last year and just pulled the car out of storage from winter.

I bought a swap off a guy, was told it ran great. I changed a couple things, cleaned it up, put it in my car... and I haven't been able to get it to run for almost a year now.

It's an S13 SR20DET, It has 550cc injectors, BC 264 cams, a GT2871R, Z32 MAF and a stock 62 ecu with an eprom tune for this setup. Rest of the motor should be stock internally.

I changed the intercooler setup, buying a brand new PBM setup. I am not running a BOV, but the guy before me was. I bought a brand new harness from Wiring Specialties. It is the SR20DET universal harness as I have a PAINLESS chassis harness. Motor has a brand new alternator.

Now for the problem: (hard to explain because it seems to run different every week, last week I unloaded it off the trailer, it was idling high but I could touch the throttle without it completely going to shit)

When you start car up it seems to run ok, idles at 1500rpm. -17 vacuum, air/fuel is 12-13

It will idle like this forever, until you blip the throttle. Touch the gas a tiny bit and the rpm drops to 900, vacuum to -8, air fuel goes stupid rich (10.0) and it sounds like it's running on 3 cylinders, blowing clouds of black smoke out the exhaust. Turn off the car and restart it and it idles smoothly at 1500rpm again, until you blip the throttle, then back to bogging.

Things I've checked:

Mechanical timing is correct, and CAS is timed properly to 15 bdc.

Replaced crank angle sensor, replaced spark plugs twice, replaced igniter, replaced coolant temp sensor, tried 2 different MAFs. All 4 injectors are firing, all 4 plugs are sparking. I've double checked my grounds, and didn't see any vacuum leaks when spraying the engine bay... But it's possible I could miss one.

Fuel pressure is set at 42 psi, and I'm using 91 octane (was told it was tuned for 94, but don't think it should make a difference at idle)

If I unplug the MAF, idle stays about the same.

http://i1011.photobucket.com/albums/af233/SnaggleToof/Mobile%20Uploads/20140513_192747.jpg (http://s1011.photobucket.com/user/SnaggleToof/media/Mobile%20Uploads/20140513_192747.jpg.html)

[OBEEWON]

Get your tune read and make sure it is proper. As a matter of fact try a stock ECU. 550's and Z32 can run proper on a stock ECU. Give that a try and see if it at least fixes your irratic load issue. If it does then your tune is bad. Also check the connector to the ECU is very tight. Not just the bolt tight. Push down on the plastic connector.

Did you degree the cams? They give you a sheet with the specifics of the exact cams you buy when you get them. Sometimes you have to get an adjustable cam gear to get them right.

But I think something is up with your tune.

[wussmonster]

+1 for checking the tune. Unless it came with paperwork you have no idea what's on there.

Sent from my XT603 using Tapatalk 2

[SnaggleToof]

I will try to get my hands on another ECU, might be tough though. I actually had a problem where the car wouldn't start at all... took me a few days to find that the ecu plug wasn't tight ha, so yeah, it's tight now.

My brother seems to think my intake is the problem, saying it's too short, messing with the MAF readings. Maf is only about 8 inches away from the turbo. He thinks it should be longer. Would this make a difference though? I unplug my maf and the idle doesn't change. It hesitates for a full second when you first pull the plug, but then it goes back to how it was.

I am also getting a spare iacv to try, I will make a proper (longer) intake and try the iacv. Will keep an eye out for a ecu. Any other suggestions?

[jr_ss]

Your brother is right. You need more than 18" down stream of your MAF, having it too close to the turbo will effect the MAF voltage readings. I'm not saying this is your only problem, but part of it. Another problem is the BC cams, they suck. If you haven't degreed them like Obee said, they aren't helping the situation. Find some stock cams, you don't need the BC's anyway for anything under 400hp. If you insist on keeping, find some adjustable cam gears and get the degreed, as they are known to be off a few degrees from centerline, which will cause vacuum and idling issues.

[Mr.Doback]

If your MAF unplugged doesn't change anything, I would think that means your car is running in Open Loop, hence why it is running rich.

While the car is running, have you tired unplugging one coilpack at a time to see if the car changes? I know you said new plugs, but coilpacks can send issues too.

[SnaggleToof]

Yes, I pulled each one individually and the motor noticeably ran worse for each one.

Even tried different coil packs.

[OnTheChip]

Check your TPS voltage with throttle closed. Should be between 0.4 and 0.5V.

[Dboyizmlg]

Your brother is right. You need more than 18" down stream of your MAF, having it too close to the turbo will effect the MAF voltage readings. I'm not saying this is your only problem, but part of it. Another problem is the BC cams, they suck. If you haven't degreed them like Obee said, they aren't helping the situation. Find some stock cams, you don't need the BC's anyway for anything under 400hp. If you insist on keeping, find some adjustable cam gears and get the degreed, as they are known to be off a few degrees from centerline, which will cause vacuum and idling issues.


+1 on this.

Agree

[williamb]

Check your TPS voltage with throttle closed. Should be between 0.4 and 0.5V.

Check this. TPS causes high idle and bogging if adjusted wrong or broken.

[SnaggleToof]

Car running or off?

[williamb]

Key on, engine off. I can't remember which wires at this moment. If you search on here you should be able to find out.

[accoupe]

I know you said new harness but you might check harness from MAF to ECM since you have tried a new MAF just to double check. Also like stated above TPS could be suspect.

[SnaggleToof]

Adjusted tps, it was set at 0.62, adjusted to 0.45
In the middle of making new intake, will try after.

[SnaggleToof]

Long intake and tps adjustment done, runs a million times better. Thanks for the TPS tip bros.

[Om1kron]

aem ems infinity, throw away piece of shit rom tune ecu.

[SnaggleToof]

AEM ems? Ew. When I upgrade it will be haltech.

[Dboyizmlg]

Glad it worked out for you.
That short intake is a common issue...

[OBEEWON]

Nice. Turbulence in the MAF. jolly good.

[wiring specialties]

Glad to hear that you got it running better. Your setup looks very clean.
How are you liking the SR harness (http://www.wiringspecialties.com/s13sr20dets13.html)?

[SnaggleToof]

Wish I got the newer tucked pro version. When I ordered it I was told the newer/better version was almost ready. Ended up waiting like three months and said screw it haha.

Overall the harness is very nice. Pretty happy with it.

Really wish I had that fancier/smaller loom though.

[Kingtal0n]

Put all the stock equipment back on the car, oem wiring maf injectors ecu etc...

and see if it runs like stock. that will help you narrow down the sort of problem you face.

because if you have a perfectly good running STOCK engine, then now you know its your: wiring/ecu/injectors/maf see what I am saying?

Then keep all that stock stuff handy for diagnosing future issues. Always a good investment. And always re-sells for full value.

[jr_ss]

Put all the stock equipment back on the car, oem wiring maf injectors ecu etc...

and see if it runs like stock. that will help you narrow down the sort of problem you face.

because if you have a perfectly good running STOCK engine, then now you know its your: wiring/ecu/injectors/maf see what I am saying?

Then keep all that stock stuff handy for diagnosing future issues. Always a good investment. And always re-sells for full value.

Did you read the thread at all? It's already been sorted, your late to the party.