Somebody please help with RB20. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

jeremymc45 · 10-24-2014, 10:03 PM

I have a 89 skyline gts-t. I drove it for a couple weeks and i was having problems with what seemed to be fuel cutting around 4200 rpms. So i took the COMPUTER out and it reads MEC-R109 also has a chip in it. Well now the first 4 to 5 starts it starts up and dies. Then after that it stays running but poorly. It has no throttle response, it acts like it is hitting a rev limiter around 3 grand. So i unplugged the maf sensor and it will not start without it. When i get it running i can unplug the tps and it runs the same as well as the maf sensor as well nothing changes but maybe 200 rpms and it goes up thats all. The little red led light in the computer blinks as well as the exhaust temp gauge on the dash. They just keep blinking all the time and will not throw a code. I just dont know what else to do I looked at my wiring and it all seems to be in tact. Stock engine and trans only thing aftermarket would be a blitz fmic. Any advice would greatly be appreciated.

Kingtal0n · 10-24-2014, 11:46 PM

Well lets get you pointed in the right direction first.

1. Inspect visually everything of course, but I cannot do that (pictures of the engine?)
2. Compression test, inspect plugs (pics of plugs?)
3. if you own a leakdown tester + compressor do that as well (might as well)
4. If the engine appears filthy, clean it. Literally get under the hood with some solvents and wipe everything until you can see clearly where any new liquids are appearing.

Now we can start thinking about the way the ecu is thinking. A blinking light in the computer might be a warning that the chip is not installed properly or not reading right. Perhaps the ECU is on some kind of backup fail-safe map. At this point you either need to replace the computer, or try removing the chip. It would also help to cross reference the part# on the maf with the computer and find out what the OEM part #'s for everything should be. The fact it only runs with the maf installed is of small significance as well, but it does not tell us much other than the ecu is at least aware of the maf.

Other than this, the only other thing you can do is check for boost leaks, and start checking the voltage/resistance of all the various sensors and comparing those numbers to proper values, and checking continuity at the ECU for each. It also wouldn't hurt to check your fuel pressure, change the filter, do a basic tune-up etc...

Sileighty_85 · 10-24-2014, 11:49 PM

If you mean the Catalytic Converter light is flashing then your Cat is probably clogged. Rip that bitch out

jeremymc45 · 10-25-2014, 07:12 AM

Ok I have not yet taken the plugs out will do that here in about 10 minutes. I've checked for vacuum leaks and boost leaks there isn't any. The cat is already cut off the car and the o2 sensor is in the pipe. Changed fuel filter but have not yet checked for fuel pressure yet since it is burning so rich. It's pretty much when you can give it throttle over 3000 rpms its just leaking it right out of the exhaust lol. I've tried the cam sensor it wont stat without that plugged in. The tps, iac, and so on will run without it plugged in just takes a little longer to start but you can tell a difference in the rpms when you plug it back in.

S13alldayyo · 10-25-2014, 05:22 PM

Probably the MAF is shot

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jeremymc45 · 10-26-2014, 07:34 AM

For the maf sensor car will not run untill it's plugged in as well as the cam sensor. The other sensors unplugged one by one the car will start just takes longer for it to. Thats when you can hear the difference in the rpms when you plug them back in one by one.

*brndck* · 10-26-2014, 09:28 AM

Did the car even run right since you've owned it? Did you just buy it?

omgRWDgoodness! · 10-26-2014, 10:30 AM

RB20DET is your problem. R25 or -26 should straighten things right out.

jeremymc45 · 10-26-2014, 10:39 AM

I should say the car at least ran and I could drive the car when I got it. Now I can't. My plugs are dark black like I said its burning really rich now. Im upgrading to the the 25 next year. I would like to enjoy the car a little more before I put it up for the winter. I have no boost leaks or vacuum leaks checked all that again today. Took the maf sensor off and cleaned it as well.

l adam l · 10-26-2014, 07:32 PM

i'd check the ecu, if you could find someone around with a stock ecu thatd probably help. those chipped ones do go bad sometimes...

also rb25s run for about ~800 no trans from most importers with maf, wiring harness, and ecu.

jeremymc45 · 10-27-2014, 07:02 PM

Im going to buy a new ecu and probably get nistune as well. For the rb25 im getting the whole neo swap. There not to much atleast it just starting to get cold here.

10-24-2014, 10:03 PM	#1
jeremymc45 Join Date: Oct 2014 Location: Ohio Age: 34 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	Somebody please help with RB20. I have a 89 skyline gts-t. I drove it for a couple weeks and i was having problems with what seemed to be fuel cutting around 4200 rpms. So i took the COMPUTER out and it reads MEC-R109 also has a chip in it. Well now the first 4 to 5 starts it starts up and dies. Then after that it stays running but poorly. It has no throttle response, it acts like it is hitting a rev limiter around 3 grand. So i unplugged the maf sensor and it will not start without it. When i get it running i can unplug the tps and it runs the same as well as the maf sensor as well nothing changes but maybe 200 rpms and it goes up thats all. The little red led light in the computer blinks as well as the exhaust temp gauge on the dash. They just keep blinking all the time and will not throw a code. I just dont know what else to do I looked at my wiring and it all seems to be in tact. Stock engine and trans only thing aftermarket would be a blitz fmic. Any advice would greatly be appreciated.

10-24-2014, 11:49 PM	#3
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	If you mean the Catalytic Converter light is flashing then your Cat is probably clogged. Rip that bitch out __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

10-25-2014, 07:12 AM	#4
jeremymc45 Join Date: Oct 2014 Location: Ohio Age: 34 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	Ok I have not yet taken the plugs out will do that here in about 10 minutes. I've checked for vacuum leaks and boost leaks there isn't any. The cat is already cut off the car and the o2 sensor is in the pipe. Changed fuel filter but have not yet checked for fuel pressure yet since it is burning so rich. It's pretty much when you can give it throttle over 3000 rpms its just leaking it right out of the exhaust lol. I've tried the cam sensor it wont stat without that plugged in. The tps, iac, and so on will run without it plugged in just takes a little longer to start but you can tell a difference in the rpms when you plug it back in. Last edited by jeremymc45; 10-25-2014 at 08:26 AM..

10-26-2014, 10:30 AM	#8
omgRWDgoodness! Zilvia FREAK! Join Date: Jul 2009 Location: Palm Beach Gardens, FL Age: 33 Posts: 1,498 Trader Rating: (48) Feedback Score: 48 reviews	RB20DET is your problem. R25 or -26 should straighten things right out. __________________

10-24-2014, 11:46 PM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 41 Posts: 4,828 Trader Rating: (17) Feedback Score: 17 reviews	Well lets get you pointed in the right direction first. 1. Inspect visually everything of course, but I cannot do that (pictures of the engine?) 2. Compression test, inspect plugs (pics of plugs?) 3. if you own a leakdown tester + compressor do that as well (might as well) 4. If the engine appears filthy, clean it. Literally get under the hood with some solvents and wipe everything until you can see clearly where any new liquids are appearing. Now we can start thinking about the way the ecu is thinking. A blinking light in the computer might be a warning that the chip is not installed properly or not reading right. Perhaps the ECU is on some kind of backup fail-safe map. At this point you either need to replace the computer, or try removing the chip. It would also help to cross reference the part# on the maf with the computer and find out what the OEM part #'s for everything should be. The fact it only runs with the maf installed is of small significance as well, but it does not tell us much other than the ecu is at least aware of the maf. Other than this, the only other thing you can do is check for boost leaks, and start checking the voltage/resistance of all the various sensors and comparing those numbers to proper values, and checking continuity at the ECU for each. It also wouldn't hurt to check your fuel pressure, change the filter, do a basic tune-up etc...

10-25-2014, 05:22 PM	#5
S13alldayyo Zilvia Addict Join Date: Mar 2012 Location: Florida Posts: 653 Trader Rating: (3) Feedback Score: 3 reviews	Probably the MAF is shot Sent from my iPhone using Tapatalk

10-26-2014, 07:34 AM	#6
jeremymc45 Join Date: Oct 2014 Location: Ohio Age: 34 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	For the maf sensor car will not run untill it's plugged in as well as the cam sensor. The other sensors unplugged one by one the car will start just takes longer for it to. Thats when you can hear the difference in the rpms when you plug them back in one by one.

10-26-2014, 10:39 AM	#9
jeremymc45 Join Date: Oct 2014 Location: Ohio Age: 34 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	I should say the car at least ran and I could drive the car when I got it. Now I can't. My plugs are dark black like I said its burning really rich now. Im upgrading to the the 25 next year. I would like to enjoy the car a little more before I put it up for the winter. I have no boost leaks or vacuum leaks checked all that again today. Took the maf sensor off and cleaned it as well.

10-26-2014, 07:32 PM	#10
l adam l Zilvia Member Join Date: Feb 2009 Location: Murfeesboro, TN Age: 35 Posts: 254 Trader Rating: (0) Feedback Score: 0 reviews	i'd check the ecu, if you could find someone around with a stock ecu thatd probably help. those chipped ones do go bad sometimes... also rb25s run for about ~800 no trans from most importers with maf, wiring harness, and ecu.

10-27-2014, 07:02 PM	#11
jeremymc45 Join Date: Oct 2014 Location: Ohio Age: 34 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	Im going to buy a new ecu and probably get nistune as well. For the rb25 im getting the whole neo swap. There not to much atleast it just starting to get cold here.