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View Full Version : SR Hesitation, etc. Please confirm.


fredbblakemore
09-10-2005, 09:52 AM
I'm experiencing the hesitation, stumbling, and overall weak performance issues explained by many other zilvians. I'm in the process of going through the FSM, old tech threads, etc. to dianose/fix the problem. Below are some comments and questions. Let me know if you have any feedback.

1. Phase2's explanation for setting base timing has either been removed or I have the link wrong (http://www.store.yahoo.com/phase2motorsports/howtosetcaso.html). Does anyone know another "how to" aside from Phase2 and the FSM? I want to read as many write-ups as possible to make sure I'm setting things right.

2. I think I've eliminated the TPS as the culprit. I have a zeitronix wideband/datalogger that's connected to the TPS line on the ECU. The datalogger software reads a minimum value of 7 or 8 and a maximum value of 90. Seems legit.

3. When the engine is set to 15BTDC, it seems to idle okay but once you touch the throttle (either medium or wide open) it really bogs and feels like it wants to stall. I'm going to reconfirm the method of checking the timing with the FSM (warming up, revving, disconnect TPS, etc.) and make sure that I'm getting good readings. I'm using a cheap (Actron Incudive CP7507) timing light as suggested.

4. When the engine bogs (after touching the throttle from idle), the wideband reads really rich. I suppose this could be a few things. Air leak to the intake manifold, timing of ignition, bad ignition (coil packs?), too much fuel from injectors, etc. I'm going to start checking each of these individually. When the bogging ends, the wideband is reading around ideal.

5. When the timing is advanced to (what I think is) about 30BTDC, the hesitation and stumbling is mostly gone down low but the top end (3.5K+rpm) still has no power. I can see steady, full boost of about 7lbs. (on this shitty test meter I'm using) but there is no pull. This sounds like timing to me but I'm not sure.

6. The CAS cover was cracked so I opened it up and inspected the wheel. Everything looks perfect. I rigged it up temporarily (until I can order a new cover). What's the easiest way to check for a faulty CAS?

7. My E5 ECU has no LED inside. WTF is up with that? Is there another way to check the diagnosic shiz?

8. I've tried a few MAFS. One from my S13 SOHC which ran fine before I pulled it, and one from S13 SR. Engine performs the same way with both so I think it's unlikely that the MAFS is the problem.

Here's some info about my setup:
-S13 BlackTop SR
-E5 ECU
-wiring done professionally by a reputable guy
-cometic metal head gasket
-blitz intake filter
-S14 T28 turbo
-medium sized FMIC
-MR turbo manifold
-full 3" exhaust
-stock injectors
-Koyo aluminum rad.
-SPAL dual 11" electric fans

Let me know what you think. Thanks in advance for your help.

ask52
09-11-2005, 10:32 AM
I had a problem with my Apexi bov sticking. made the car bogg out and not run well overall. Not sure if this helps :wavey:

fredbblakemore
09-11-2005, 11:03 AM
Thanks for the tip. I replaced the BOV and flanged pipe with a sealed pipe and it did not improve anything. I'll keep looking...

sr240mike
09-11-2005, 12:34 PM
searchy search search, every week there's a post with sr20det hesitation in the title and every week the same answers are posted. I dunno why your ecu doesn't have the led inside but if your wiring is correct the check engine light should blink the code.

fredbblakemore
09-11-2005, 01:39 PM
The only time I see the CEL on is when I'm cranking to start the car. When I move the small idle adjust screw on the ECU according to the code checking method, I see nothing. Since there's no LED inside the ECU, I can't check the codes. Bad ECU?

sr240mike
09-11-2005, 06:08 PM
Its not an idle adjust screw. Here's the method that would normally work. Turn on ignition without starting car, turn screw all the way clockwise wait 4-5 seconds then turn it all the way back, the Cel on the dash should start flashing. IIrc the ecu's without cel light attached were remanufactured or tuned ecu's. Does the ecu have any stickers on the front or daugherboards inside?

caall99
09-11-2005, 06:57 PM
alot of blacktop ecu's do not have a check engine light, and i believe they came that way from the factory. My blacktop ecu, and my buddy's blacktop ecu, both don't have the check engine light, and we know for a fact that they are not tuned, or remanufactured.

fredbblakemore
09-11-2005, 09:42 PM
Thanks for the info folks. caall99, are you still able to pull the codes by looking at the CEL in the cluster? I can't seem to do that even. My lenghty follow-up post is below:

That FSM is my Bible. Honestly, it's not the easiest document to navigate in digital format, especially when sitting in the car, trying to browse around on the laptop. I'm going to print it out (at least the "EC" section) and use it to check voltages and operation of my sensors at the ECU as soon as possible.

It's very strange that the car wants to run well (better) when set above ~30 or 40 BTDC. I started messing around with the location of the CAS gears and got it to run decent in that range but I decided to set it back to the FSM directed location and focus on my sensors/ecu. It's a real bitch living in Michigan where 62's and E5's are mostly non-existant. I think I got a bum ECU. It has no LED inside and it won't flash the CEL. The only time I see the CEL on is when I'm cranking to start the engine. That leads me to think I should check with a known working one but really the only way for me to do that is buy another one. It's also possible that the wiring for the CEL is incorrect I suppose.

Also, I realized that when the TPS is connected and the throttle is opened, the ECU will retard the timing for some reason. I know that BASE timing should be set and observed with the TPS disconnected, following the FSM instructions (I've done it a million times already.) However, when the TPS is plugged in, I'd expect the ECU to advance the timing as the throttle is opened and the RPMs rise. I'm seeing the timing retarted to as much as 0 degrees. When this occurs, my wideband is reading rich as hell (9.5-11 ish).

Logically, I just can't put these clues together to make a diagnosis. I can tell the TPS is reading becaues the wideband datalogger (which also connects to the TPS) reads valid values ranging from 8% to 90%. The MAFS has been changed between two "known good" units with no effect. The stock O2 sensor was used and then I tried changing to the simulated narrowband output of the wideband O2 sensor. No effect.

Throttle body and IACV were cleaned using carb cleaner, IACV screw was adjusted and tinkered with, all had really no effect. I relocated the battery to the trunk. To make sure I had good grounds, I added 2 more ground wires (in addition to the original one) from block/intake manifold to chassis ground. Battery is grounded well to the chassis in the trunk.

So, the other things I need to confirm are CAS, coil packs, ignitor, wiring (done professionally so I doubt it's the issue), ECU. If I'm missing anything or you can think of a possible solution, please let me know.

Also, I'm continuosly searching for past similar problems. I'm finding that once people fix their issue, they don't post a follow up and discuss what actually fixed the problem...

I like to type. Type type TYPE. Typie Typie Type. Tpyie Type Type.

illmatik53
03-06-2006, 05:34 AM
fCuk man.. my car is doing something similar.. is it normal for your BOV to be outputting black shit? my bov sits above one of the hoses for the intake and like the outlet releases the air onto it. I noticed that there is like a black gunky buildup on the hose that the BOV is blowing air onto.

anyhow, i change my MAF and i didn't get any results. I tightened teh spring on my BOV and it started to drive a little better, but not noticeably. I didn't get the problem when i was in neutral, but now i get the problem in neutral too. i think i'm about to just take my car to Blue Stage and let them work on it, cuz it's starting to drive me nuts. i already changed spark plugs, did an oil change, change the oil pan gasket (cuz i thought maybe it was losing oil pressure cuz there was a small leak around the oil pan), tested a good maf, cleaned out my intake filter.. i dunno.. i don't have the time to work on the car anymore.. and i'm trying to get rid of it too.. *sigh.. anyways, anyone find out what other fixes there are?

1992 Silvia K's
SR20DET Red Top
Greddy BOV
HKS turbo timer
Fujitsubo cat back Exhaust
Blitz intake
Defi Boost Gauge

The boost gauge acts a little wierd, so i'm thinking my BOV might be bad.. when i accelerate, my needle should be doing nothing but going up, but i watch it take dips and it goes back down.. so i'm thinking it might be a vacuum leak.. my initial assumption is that the spring in my BOV is broke or has lost it's tension.. *shrug.. thinking about restoring original hot pipe and getting rid of my BOV..

SR20d2fourT
03-06-2006, 10:09 PM
Try checking for boost leaks. If not then check to see if all your cylinders are getting spark. Try the little things first, it usually pays off.

illmatik53
03-07-2006, 12:35 AM
is it possible for your BOV to be leaking the boost though? and if so, is the internal spring replaceable? or should i just seal it off and re install the stock hot pipe and use the original BOV for a little while to be safe?

illmatik53
03-07-2006, 03:32 AM
so i went to Nissan Blue Stage here in okinawa. The mechanic there told me to check 4 things and in this particular order.

1. Ignition Coil Pack

2. Power Transistor

3. Fuel Pump

4. Crank Angle Sensor

I have about a weeks time to check all this. =(. I'm going to try and fix it before i sell it. In any case, anyone interested in buy a 1992 Nissan Silvia K's redtop SR20DET. after i fix it of course. If you're in the okinawa area, hit me up.

slider2828
03-07-2006, 11:58 AM
Yah, I had that problem when my ignitor was going bad. So basically see if you can check your ignitor with another known good one that might be the problem. Check your spark plugs because after a few misfires of the engine, spark plugs can go bad very quickly. I don't think its a vacuum hose issue or your car would idle like shit, but I would check all connections for piece of mind anyways. Check definitely for intake leaks, like the SMIC connections and all your air connections. But first and for most I would SO check your ignitor, that thing goes easily because the harness ground supplied to the ignitor sucks hardcore, hence I grounded mine to the chassis.

And to answer your question, the crank angle sensor has a resistance and voltage in which your FSM in the electrical section will tell you what is the max ohms and the min ohms when you turn it. So basically you take a volt meter and put it on ohms and just turn it very slowly and check your voltage.

I don't think fuel pump because it wouldn't run rich like that, unless you have an aftermarket FPR in which you should know the pressure should be at 38-42psi at all times unless you flowing 275+

Hardly ever see coil packs go bad.... But what I would do is check your grounds in your car. Coil packs and ignition firing is directly connected to how well your grounds are situated.

Good Luck.. I think I covered most of your questions.

illmatik53
03-07-2006, 11:55 PM
damn dude.. u are one smart fella.. i'll let you know the results.. i'm actually kinda fed up with the car and might sell it and let the guy know what the problem is.. *sigh..

illmatik53
03-07-2006, 11:56 PM
btw.. is the power transistor the ignitor for the coilpacks? the one that's located on the right side (when looking at the engine from the front of the car) and is bolted down to the wheel well.. like right below the stock boost filter?

illmatik53
03-14-2006, 11:44 PM
so i was getting my car inspected.. and they said a screw was missing.. and i was like what? it turns out that a screw broke on the turbo housing.. so i think that is where my boost leak is coming from.. i am going to go to nissan to get the screw today.. hopefully that is what the problem is..