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GA 2 SR
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127 Posts
Discussion Starter #1
Hey, I had a question..(Well a couple). Here are my issues, I am doing a GA16DE to JDM SR20 swap, I got the engine in and every thing but the problem is my timing and idling. The symptoms are backfiring and jumping idle when trying to time it making it impossible. I have purchased a new MAF and done the grounding...no help, new Nismo adjustable fpr...no help, swapped out the fuel rail and injectors...no help, adjusted the distributor, new IACV..no help, adjusting screw...no help, swapped two sets of spark plugs gapped for .035 and .044...guess what......no help, tried to time it but the idle continued to jump from 1000rpm to approx 1700rpm, the timing light catches the timing mark and then it jumps........so I was reading on the forum about the timing chain jumping. I removed the VC according to the Haynes manual and turned my crank to #1 TDC to see if the silver marks on the chain lined up with the dimples on the cam sprocket and they did not. I am thinking that my last resort is to replace my tensioner with the newer version (and possibly purchasing a new timing chain) and line up my timing chain according to the manual. My question is has anyone run across this issue??? Can you shed any light on me? I just need help so I can enjoy the power of the SR20DE. This has been a dream project for me since 2001 and I finally got the funds and courage and a garage together to do it.
 

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The Boost Bear..Rawr!
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3,055 Posts
The timing chain marks/dimples will only actually line up with each other every few 1,000 rotations. Nothing to be worried about there.

Plus, if you wanted to replace your chain, it is a PITA!! Ask me how I know.
 

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GA 2 SR
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127 Posts
Discussion Starter #3
How will I know if the timing chain has jumped? What are the symptoms...cause I've tried just about everything with no luck.
 

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Registered
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945 Posts
put a loooooong metal rod in number one spark hole, turn over slowly until it is resting at top dead center, if the valves are open, try one more revolution, both inlet and exhaust valves should be closed and with the pips on the cam gear pointing as the manual says, if it is one tooth out there will be a ten degree error, that will stand out a mile.

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #6
Has anyone else ran into this problem.......I know its not just me. Am I jumping the gun here and misdiagnosing a simple fix. It is about to drive me crazy
 

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tried to time it but the idle continued to jump from 1000rpm to approx 1700rpm, the timing light catches the timing mark and then it jumps
If your timing (and idle) is jumping while your trying to read it your probably not in timing mode. I would not jump to conclusions about it being out or off until you get the idle straightened out.

I'd check for vacuum leaks first before pulling the motor apart those will cause it to sputter and possibly not idle properly.

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #8
If your timing (and idle) is jumping while your trying to read it your probably not in timing mode. I would not jump to conclusions about it being out or off until you get the idle straightened out.

I'd check for vacuum leaks first before pulling the motor apart those will cause it to sputter and possibly not idle properly.

Mike
SO would a vacuum leak also cause the car to pop and backfire as well. This set up is the 91-94 JDM SR20. There was one line coming out from a small circular valve on the drivers side where the charcoal canister would be if it was an original SR20 but it is a GA16 which just contains that small circular black valve. The line I think used to hook up to the EGR system so I went ahead and put a screw in it to block it off...no luck. On these JDM's there really isn't too many places for vacuum lines unless I'm mistaken however I will look again.
 

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SO would a vacuum leak also cause the car to pop and backfire as well.
Yes it will. Those are the most common signs of a vacuum leak.


This set up is the 91-94 JDM SR20. There was one line coming out from a small circular valve on the drivers side where the charcoal canister would be if it was an original SR20 but it is a GA16 which just contains that small circular black valve. The line I think used to hook up to the EGR system so I went ahead and put a screw in it to block it off...no luck. On these JDM's there really isn't too many places for vacuum lines unless I'm mistaken however I will look again.
Give it a good look over. Ohter possible areas to consider are where the injectors connect to the intake manifold, vacuum bung under the throttle body, throttle body gasket, intake runner gaskets, under the intake manifold and really anyplace where a vacuum line connects to the intake. Make sure every hose is accounted for or plugged up if not connected to anything.

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #11
To add to more drama to my swap project, when I try to blip the throttle under the hood and via pedal I get nothing...it sounds like its choking and bogging. I let the car run for about 7 mins and I noticed smoke.... looked under the car and right after the cat it was hot orange, took out the spark plugs and they were black like the car is burning too rich. All in all I'm still looking at this as a great learning experience along with Murphy's law. Can anyone give some technical advice? Pizza and beer is on me if your advice works, i'll deliver in my SR swap...Lol!
 

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GA 2 SR
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127 Posts
Discussion Starter #12 (Edited)
The Revs wont go past 1700-1800 according to my timing gun. I unplugged every thing (TPS, IACV) so the car would just use the computer to idle but still no luck. The funny thing is I'm probably bypassing the simplest thing, I will continue to search though. I will use the spray method to check for a vacuum leak. I removed my throttle body and cleaned it and I put on a new gasket, I also removed my intake manifold and looked for cracks and put on a new gasket, I removed my IACV and cleaned it and the plunger and made sure I was getting voltage. I've been searching for this Gremlin but he keeps hiding.
 

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Thats free revving rite? Have you checked the codes on the ecu to see if it's coming up with anything? Usually if it won't rev past 3k it means the ecu is putting the car in safe mode so it won't destroy anything. This is usually cause by a problem with one of the sensors (maf mostly).

Hows the car put together? You running the SR wiring harness and ecu?

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #14
Thats free revving rite? Have you checked the codes on the ecu to see if it's coming up with anything? Usually if it won't rev past 3k it means the ecu is putting the car in safe mode so it won't destroy anything. This is usually cause by a problem with one of the sensors (maf mostly).

Hows the car put together? You running the SR wiring harness and ecu?

Mike
Yes I have about 8 codes: I dont know all off hand because i'm at work right not but i'll try to recall them: evap canister and or solenoid, map sensor, MAF sensor, O2 sensor bank 1, auxillary valve, emissions system. Thats all I can think of for now. The ECU comes from a manual 98 S-ER which I bought from ebay...I verified the serial number matched up to the correct year according to the Jim Wolf PDF, Matrix cone filter, hotshot headers, magna flow round cat, 2.25 pipe connected to a bomz wanna be apexi muffler.
 

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maf and the bank 1 o2 sensor could be the problem. One problem could be that your using a 98 se-r ecu. The 98 ecu's have more emissions equipment than the 95-97 se-r ecu's.

I gather you are using a 95-97 se-r wiring harness correct? I would try to source a 95-97 se-r ecu off of here and give it a try. Even if it doesn't solve your problems it will clear out a bunch of the emissions code crap and give you a better idea of what is causing the problem.

Back to the maf and o2 codes.. your %100 they are both hooked up to the correct plugs on the wiring harness?

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #16
maf and the bank 1 o2 sensor could be the problem. One problem could be that your using a 98 se-r ecu. The 98 ecu's have more emissions equipment than the 95-97 se-r ecu's.

I gather you are using a 95-97 se-r wiring harness correct? I would try to source a 95-97 se-r ecu off of here and give it a try. Even if it doesn't solve your problems it will clear out a bunch of the emissions code crap and give you a better idea of what is causing the problem.

Back to the maf and o2 codes.. your %100 they are both hooked up to the correct plugs on the wiring harness?

Mike
But the car is a 98 the harness is a 98 purchased from JGY. The MAF and O2 is hooked up to the wiring diagram from a Haynes manual. If The 95-97 ECU will run it I will get one, hey I've tried everything else. Trial and Error
 

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I see. Your positive it's a 98 harness then? I'd stick with the 98 ecu. If you look on JWT's website they have a page the shows how to install a <98 ecu into a 98 car. If you check it out you will see the wiring harness has a few differences from the <97 harness. Namely the rear o2 sensor and some other emissions crap. (these should not effect the cars ability to run and idle correctly though..)

I really don't know what else to tell you to check. With the difference in the 98 ecu and harness it could be a few things. All the sensors should work on it fine so that should be ruled out. But it is also highly unlikely that the timing is off.

What distributer are you using? The jdm motor used the obdI external coil distributer where as the 98 ecu and harness uses the internal coil distributer. If you have to obdI style distributer in it you will run into problems.

Mike
 

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GA 2 SR
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127 Posts
Discussion Starter #18
I have a 95-98 dizzy that I bought from Andreas Miko. I will try the 95-97 and wire it up. Thanks a lot for your advice and help Mike...You'll be the second to know when I get her running right. Peace
 

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No problem and good luck!

Before you try the <98 ecu you should check out JWT's site and see if it will even make a difference in your case. The sensors that are effected in the ecu swap are not engine function critical and are probably not even connected on your car.

Mike
 
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