My SR runs, but it wont idle and it dies

[srJOEYdet]

Hey gang,

Thanks for all the help, I got my ECU, and now it runs!!!!

But it idles like crap. It will randomly sputter from anything between 200 rpm to a little over 1200 rpm. It just shakes around. It shakes like it has a deap cylinder, the whole car vibrates. I have verified my vacuum lines, and I am running an autometer boost gauge. The gauge won't get out of vacuum. (-hg) And the car is REALLY sluggish. I think slower than my old KA. And unless I have my foot on the gas to keep it running, it just sputters and dies.

This was all with nothing but a vacuum line from the I/C pipe to the wastegate. One thing I checked was putting in the factory boost controller. I plugged the little green box in, and had a vacuum line from the I/C pipe to the box, and than one from the box to the wastegate. The only difference I noted was that it seemed to backfire more.

On the good side it has EXCELLENT oil pressure...


Joey

[srJOEYdet]

I checked out my spark plugs. They were brand new, and now have about ten minutes of use with fuel. THey are slightly blackened (normal) axcept for the electrode, which is a whitish grey color. Is this normal?

Also, my replacement ECU is not very average looking. take a peek for yourself...

http://www.imagestation.com/picture/sraid81/p854443899d72d138787848c9669c04e4/faff2a14.jpg

http://www.imagestation.com/picture/sraid81/pa91d90348dbc15d77dab294f2790fd74/faff2a11.jpgTo me, it looks like it was tuned by a shop. If this is true, I could have been tuned to advance or retard timing a little, assume premium gas, or it could have been set up to run a garett T3/T4 for all I know. Is this what you guys think?

[240Dave]

http://www.pdm-racing.com/features/plugs.html

You guess is as good as mine on the ECU :confused:

[DudeYourSoOOJDM]

Check timing.
do you have a fuel pump? how is the voltage to it?
how are the coilpacks?
MAFS?

I wouldn't even try to drive it if it's doing what your describing.

Search for troubleshooting topics on here and FA......this has been discussed a whole lot.

[Bill Roberts]

Joey, is your pipes to and from the intercooler "air F u c k i n g tight"??

Clean the MAFS. Do this by VERY carefully taking a cotton swab and alcohol to the winding bar...but barely let it touch it and blow lightly to dry. Dislodge a winding, and hummmm...

The KAE MAFS will work from what I read.

Next, Injectors. They got to be CLEAN...if their is any of the old gas soot and sludge from them sitting. It will run like azz. I am a fan of Techron by Chevron. Autozone and Discount auto has techron as well as other gas stations. Try a bottle. It is like lighter fluid.

Next.

Defective high speed sensor. You know the speed sensor? It has been reported that this can go bad at the tranny and cause a misreading. Oily connection can do it. Just another thing to check.

Finally, the gauge cluster. Could it be that your tach resistance could be off due to a bad ground and this will cause an adverse reaction to the ecu? Also, did you replace the fuel pump? Stock FP is inadaquate...filter too.

Did you drain the gas tank and make darn sure that water and moisture did not enter the system while you were installing the engine?

Ok...chomp on that a while.

OH...Battery cables and grounds...so important that the charging system and alternator is doing its thing...and the igniters..and good solid new pluig wires.

Chomp Chomp..

[srJOEYdet]

Dave- PDM was the first place I looked for my plugs. They have been confirmed normal, so no problems there. But PDM says nothing about white electrodes. I think just because they aren't worn enough.

Hypershift-the one thing I don't know how to check is timing. but I am going to rule out other trouble-shooting untill I get a stock tuned ECU.

Bill- The I/C pipes are VERY tight. I am running over 20 PSI at 5k rpm. I am not going to run the car again untill I get another ECU in it. I will clean the MAF soon. I suppose running some techron won't hurt. The speed sensor. Mine is intermittent. My speedo only works sometimes. Along with the speedometer on my A'pexi rev/speed meter. I am using the USDM one...

I have a walbro 255 lph in tank pump and a 300ZX filter. I have not drained the tank, but I only had a little in the tank, and the car was in the garage the whole time. Plus I filled it with premium today. same symtoms.

Charging system is in great shape. I have a clean battery, good alkalinity, (or specific gravety, I had a shop test it!). My volt meter on my turbo timer reads 12.x after the car sits, and 14.x while it is running.

Here is what I have concluded: (hypothetical situation)
Some guy decides to run a T4 with 770CC/mn injectors. he wrecks his car, venus gets half of it, they send the ECU to some whiney kid up north. (ME) on a stock car, this ECU would run a lot of boost, and run very lean, since bigger injectory require less of a pulse for the same fuel as stock 360s.

So! I get his ECU, and my car will run 20 PSI at 5000 rmp, it also runs so lean that it overheats, and it wont idle. All this lean combustion can lead to pre-detonation. That's why I am going to wait to take it to school and show it off.

Also, I think the ECU is set up for the stock MAF, since it is running a code 55 through the dignostic mode. Code 55 is all OK.

Thanks for all the help guys.

Joey

PS: I have searched a lot... What are reasonable EGTs? (engine gas temperatures) Mine get up to alsmost 800º. I think that seems pretty high. It is because I am running lean though.

[Bill Roberts]

20LBS of boost is insane!

Joey, you got to get that clip running aroung 7 to 9 in a full rawhide mode. Man..Lean kills the engine. That is just way way too much boost for this point in this. You must get it stock "acting" to get things balanced and into kilter. It is not kosher at this point with that must boost. Hopefully the techron will open the injectors some to allow the richness to increase...otherwise...damn...that is just way way too lean for now. Please don't kill your engine under that lean condition...it will kill it. Keep it under 3700 until that is figured out.

The irratic speedo is a key element.

the Ecu is a send return device. A multiple feeback-loop if you will running at 16 bit computing power. The speed sensing must be solidifyed to have accurate feedback for the remaining circuitry of the device.

Lets stay with this and I will monitor your progress.

I just hope I can help on this side of the glass...and remember, I run N/A...although I have turbo knowledge, I will never be the last work..but hopefully I can get you into something that points toward the several culprets at this stage. Lets look at this from a logical POV..

[Kid Zelda]

Timing .. timing timing .. do it man

[Joel 180]

I hope thats not a stock T25G you are running 20psi on... thats a fast way to completely destroy it! :)

[srJOEYdet]

It was spiking to 20 PSI, at around 5K, which is when detonation made me let off the gas, and I promptly ended my test drive. The boost is not linear at all. When I was driving it around, it was running vacuum below 2K, and than it would climb to about 10ish at 4K, than rush up to 20 and detonation started. The ECU was "Sent out on Monday" but I am tracking it, and it was received a little south of Sacramento on Thursday afternoon. And I am north of Sacramento... odd?

Anyway, I also found out that somehow I was running rich. I moved the car into the garage the next day, and It was puffing so much black smoke. And of course I could smell the unburned gas out the tailpipe. I just thought it was running lean, since it was heating up so bad, and since it wouldn't idle, and it sputtered, ect.

I found out that you can run hot from being too rich too though. So that explains the heat. Must have had higher voltage injectors or something. That would make the stock ones run the car too rich.

Joey

[720_datsun]

Originally posted by srJOEYdet
Hey gang,

Thanks for all the help, I got my ECU, and now it runs!!!!

But it idles like crap. It will randomly sputter from anything between 200 rpm to a little over 1200 rpm. It just shakes around. It shakes like it has a deap cylinder, the whole car vibrates. I have verified my vacuum lines, and I am running an autometer boost gauge. The gauge won't get out of vacuum. (-hg) And the car is REALLY sluggish. I think slower than my old KA. And unless I have my foot on the gas to keep it running, it just sputters and dies.

This was all with nothing but a vacuum line from the I/C pipe to the wastegate. One thing I checked was putting in the factory boost controller. I plugged the little green box in, and had a vacuum line from the I/C pipe to the box, and than one from the box to the wastegate. The only difference I noted was that it seemed to backfire more.

On the good side it has EXCELLENT oil pressure...


Joey if it smokes alot. like alot of white/blue smoke then it could be a blown ring or vavle seal. same thing happend to my truck. truck shakes likes hell and if im not on the gas it wont stay running, aslo idles rough.

[mbmbmb23]

srJOEYdet

Why dont you take a close up pic of the ECU so maybe someone on this board can translate what it says. Maybe it has the tuner specs listed on it?...or in the least a name of the place that tuned it and a serial number so you can call them and see what they did to mod the ECU.

You could always send the ECU off to an SR tuner who can plug in the ECU and read what its tuned to.


-m

[Emperiorjack]

Check to see if the egr valve is stuck open.

[mbmbmb23]

If the price is right....just buy a backup ECU and give it a try.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33596&item=2435587511

[Emperiorjack]

Originally posted by srJOEYdet


Anyway, I also found out that somehow I was running rich. I moved the car into the garage the next day, and It was puffing so much black smoke. And of course I could smell the unburned gas out the tailpipe. I just thought it was running lean, since it was heating up so bad, and since it wouldn't idle, and it sputtered, ect.

I found out that you can run hot from being too rich too though. So that explains the heat. Must have had higher voltage injectors or something. That would make the stock ones run the car too rich.


Do you have a misfire?