SR20DET Misfiring, Running Rich, Poor Boost - Page 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ultimateirving · 06-15-2013, 11:21 AM

Quote:

Originally Posted by Mark Slide Squad

Ok, please take some friendly advice as I am trying to help you out here. I have been working on SR20's since 1998 (no BS) and have put together many SR20's since that time. If you take a look at the factory FSM from Australia, it will show you that all shims are NOT the same. They come in about a dozen different thickness'. The top of the valve will NOT be equal height to all other valves on the head, period. Due to tolerances in machining of the height of the valve, the valve spring retainer, and the valve seat itself, the height where the shim sits will vary. Whoever told you that all shims are the same height clearly doesn't know wtf they are talking about. Please do yourself a favor, DOWNLOAD the factory service manual. Study it. Read the section of measuring/setting valve shim clearance. If you don't understand it, I would recommend taking your car to an experienced shop that knows about SR20's.

And your car will start fine with the oil pressure in the lifters if you bled them, not sure what you mean with that part. As long as your battery is ok, the lifters won't affect the car starting. Zilvia has so much bad information on here, it's terrible. One person says something, and all of a sudden everyone believes it. If you don't believe what I am telling you, again, look at the FSM. If your valve shims aren't set correctly to each other, you WILL break/crack/throw a rocker arm, cause severe valve train wear, etc. Good luck.

Dorn i know this is your daily, but he is right. When you put the head back together its important to make sure these are all setup correctly. And even though its going to take more time and effort. Do yourself a favor and research learn what needs to be done so that ur SR will be reliable.

Danger_Dorn · 06-15-2013, 11:33 AM

As far as the hydro lifters go I was under the impression that if there is not enough oil pressure, then they will not pump up thus giving me a PITA when trying to start. I understand all of the above. I cant really afford to pay 175 bucks for a damn tool though or to make one. They "But your engine is going to go brrrrrrRRRRAAAHHHH! BOOOM!" but I think trial and error will prevail here.

Mark Slide Squad · 06-15-2013, 11:41 AM

Quote:

Originally Posted by Danger_Dorn

As far as the hydro lifters go I was under the impression that if there is not enough oil pressure, then they will not pump up thus giving me a PITA when trying to start. I understand all of the above. I cant really afford to pay 175 bucks for a damn tool though or to make one. They "But your engine is going to go brrrrrrRRRRAAAHHHH! BOOOM!" but I think trial and error will prevail here.

Thanks @ultimateirving, you understand the importance too.
You can get an old busted lifter for probably $5, and a drop indicator for probably $20. Then you can take apart the old lifter and JB weld the drop indicator stem into it. Total cost of tool: $25. You just spent all that money rebuilding the motor and have an SR20, so I am sure you can afford $25 to make the tool! If you want to be stubborn and think what we are saying isn't important, than more power to you. When your freshly built engine breaks/throws more rocker arms, it's going to cost you a lot more than $25 to fix it. Some people only learn by their own mistakes I suppose. Cutting corners only costs you in the long run when building a motor. Think about why your engine threw a rocker arm to start with. Yes, it's because you didn't spec the shims out.

Danger_Dorn · 06-15-2013, 01:30 PM

Yeah I will probably end up making one. Thanks for the time and patience guys. Ummm embarrasing question but here goes. IF I left the rocker arm out could I drive it if I went easy on it? I'm a Marine and sometime I HAVE to go to work at a moments notice. This happens quite often. Will I kill it just driving on it nicely? I dont want to but I already was driving it for a week like this not knowing it lol.

Kingtal0n · 06-15-2013, 01:40 PM

Here is some knowledge from experience:

#1 I Once ran an SR20 with every single lifter empty (no oil, only air) and it ran perfectly normal, except for 2 things:
a: it made a horrendous ticking noise at all rpms that was very obviously coming from the valvetrain
b: it put chatter marks on all the valves by the retainers, apparently they were bouncing on the seat once in a while.

it made no difference with how the engine starts.

As to starting an SR20, here is some info...

The sr20det ecu (and even the power FC ecu, but NOT the AEM EMS) cranks all 4 cylinders to one compression stroke before it will start. If you listen carefully, you should hear 4 compression strokes (chug chug chug chug VROOOM!!!) is the typical reliable sr20det starting mechanism. If it takes MORE than 4 compression strokes, check the ORANGE wire ("start" signal) first for proper wiring as this is the most common wiring mistake people will make that affects starting characteristics. iirc that wire is a 12V signal off the ignition switch, but I could be wrong so look it up first.

Summary:
-lifters being full of air/oil have no affect on starting characteristics,
-4 compression strokes THEN start is the sr20 way

Kingtal0n · 06-15-2013, 02:03 PM

Quote:

Originally Posted by Danger_Dorn

Yeah I will probably end up making one. Thanks for the time and patience guys. Ummm embarrasing question but here goes. IF I left the rocker arm out could I drive it if I went easy on it? I'm a Marine and sometime I HAVE to go to work at a moments notice. This happens quite often. Will I kill it just driving on it nicely? I dont want to but I already was driving it for a week like this not knowing it lol.

do not drive it without the valves operating properly.

Danger_Dorn · 07-11-2013, 02:28 PM

Update: Found out the shop I took it to had the shims and guides switched so the rocker arms werent seating...switched it all over and havent had a problem since other that my now fuel problem. I'll just add it here so I can bother Irving some more.

NEW PROBLEM:

Everything is great except my AFR. I'm running pig rich. I hava an AEM uego wideband and sometimes at idle or cruising it will be at a 13 to 15 but usually it just sits at the max of 10. I think I figured out the problem but I just want a 2nd opinion (this is where you come in Irving lol). I have an Walbro 255lph and the original stock FPR. My vac lines are secure with no known vac leaks. I guess what I'm getting to is my stock FPR could be old and unable to deal with the new fuel pump right? So If I get a new AFPR with a gauge i should be able to dial it down so this isnt a problem anymore right? I have checked the rail and there are no bends. I am also using the KA fuel filter which shouldnt be a problem.

I have a baby on the way so I'm trying not to break the bank. I have found universal AFPR for like 30 bucks. Input appriciated guys. Thanks

Kingtal0n · 07-11-2013, 05:10 PM

Quote:

Originally Posted by Danger_Dorn

Update: Found out the shop I took it to had the shims and guides switched so the rocker arms werent seating...switched it all over and havent had a problem since other that my now fuel problem. I'll just add it here so I can bother Irving some more.

NEW PROBLEM:

Everything is great except my AFR. I'm running pig rich. I hava an AEM uego wideband and sometimes at idle or cruising it will be at a 13 to 15 but usually it just sits at the max of 10. I think I figured out the problem but I just want a 2nd opinion (this is where you come in Irving lol). I have an Walbro 255lph and the original stock FPR. My vac lines are secure with no known vac leaks. I guess what I'm getting to is my stock FPR could be old and unable to deal with the new fuel pump right? So If I get a new AFPR with a gauge i should be able to dial it down so this isnt a problem anymore right? I have checked the rail and there are no bends. I am also using the KA fuel filter which shouldnt be a problem.

I have a baby on the way so I'm trying not to break the bank. I have found universal AFPR for like 30 bucks. Input appriciated guys. Thanks

No, the fuel pressure regulator is not an issue if it is working properly. I Have used the OEM regulator with many walbro 255 pumps. it COULD be bad, of course, but anything can be BAD. IF it is good, there is no issue.

Why then does it sit at 10:1? couple of options.

1.Your wideband could be wrong. (check the plugs)
2. boost leak ( of course ) free to check and diagnose do this first
3. wrong / bad maf (almost never but worth pointing out)
4. bad regulator (as stated) easy to find and change an OEM regulator
5. assuming you have OEM ecu OEM Injectors OEM Maf etc... If not then there is a whole slew of other possibilities

start with that

Danger_Dorn · 07-11-2013, 06:21 PM

thanks for the speedy reply. This will be a long one. Brace yourselves.

Current Diagnosis
1. I have stock everything on a freshly rebuilt motor. Rebuild contains bearings, rings, metal hg, arp hg studs and rod bolts ect basically all new internals.

2. I dont think the wide band is wrong I have had it in there for less than 1000 miles positioned in the test pipe. It is an AEM uego and I have never heard of these things going bad. Plug my mpg is like 11 with black smoke at a high rev with gas smell out the pipe so I am in fact running juicy.

3. I checked spray of the injectors a while ago and again listened with a screwdriver everything checked out so that likely isnt the issue.

4. I havent checked the maf recently but i highly doubt thats it. I have a WS harness so wiring has checked out and I replugged the plugs

5. I have checked for vac leaks and found nothing. I can boost just fine up to 11psi as usual. Just slightly boggy probably due to the afr.

6. The only thing else it could be is a poor regulator. I was just going to buy the cheap godspeed universal one with the gauge on it and go from there. Not many SR's here on Camp Lejeune so I'll have to go hunting this weekend.

Thanks again for the help I'll keep you updated.

Kingtal0n · 07-11-2013, 07:31 PM

you need to boost leak check it. air leaving after the maf sensor is what you are looking for, not vacuum leaks. Fill the plumbing with air pressure (15psi or so) with the engine off and listen for leaks.

Danger_Dorn · 07-14-2013, 04:35 PM

Well, cleaned the MAF and its better. Cruising at -4 vac I sit a a perfect 14-15.5 afr, but when I acc it goes to 11 to 12.5 which is to be expected. Nex question is do you think I would benifeit from taking out my 02 sensor and cleaning it?

Kingtal0n · 07-14-2013, 05:06 PM

Quote:

Originally Posted by Danger_Dorn

Well, cleaned the MAF and its better. Cruising at -4 vac I sit a a perfect 14-15.5 afr, but when I acc it goes to 11 to 12.5 which is to be expected. Nex question is do you think I would benifeit from taking out my 02 sensor and cleaning it?

wow #3 wrong/bad maf. its almost never the maf but, good job. how did you clean it if you dont mind me asking?

No do not clean the o2 sensor. They are cheap and easy to replace. I assume you mean the narrowband sensor. Your factory ecu should adjust the a/f ratio while cruising in closed loop using the narrowband as indicated by your wideband around 14.7:1.

you CAN try unplugging the narrowband and checking your cruise a/f ratio without it plugged in on the wideband. That would tell you how far off your base map is from ideal, based on maf sensor voltage, since that is the only variable that really matters on a stock engine in your situation. I used to carry around a few maf sensor hot-wires (just the plastic part with the hot-wire) and change them out looking for the best match. The one that gives you 12.5:1 during WOT at 7PSI and that will allow you to cruise in 5th at 65mph around 14.8:1 with the narrowband disconnected is the one you want.

It should read mid 11's if you go over 12psi of boost though. Depending on the turbocharger. If you see anything in the high 12's or 13's change out the maf until you find one that works. Either that or your fuel pump is weak (might need a hard-wire 12V source that is a typical problem)

fyi you do not want anything in the 11's at or below 7psi of boost- this is a waste of fuel. 12.5:1 is about as rich as you want to go when running 7psi from any turbocharger.

Danger_Dorn · 07-15-2013, 04:45 AM

I unscrewed it from the two screws on top and sprayed some airflow cleaner on it a few times and then allowed it to dry.

I have a t25 with an hks internal wastegate and I hit 12 psi WOT. My fuel ratio goes to 12.5 ish so I think we're golden

Thanks again King. I appriciate the help. I do beleive this would be a good to keep hanging around zilv-izzle

Danger_Dorn · 07-15-2013, 04:50 PM

Well I'm still being picky. My next question is as follows

My cruising AFR is from 14 to 15.5 which is good. My only issue is now when I get on it...not WOT but like half throttle to keep up with traffic at a light my AFR is in between like 10.9 to 13. Is this normal or too rich? I'm kind of aiming for gas mileage right now. Some helping facts might be that I have a t25 so it spools right at 2k rpm... what do you think?

Kingtal0n · 07-16-2013, 12:41 AM

Quote:

Originally Posted by Danger_Dorn

Well I'm still being picky. My next question is as follows

My cruising AFR is from 14 to 15.5 which is good. My only issue is now when I get on it...not WOT but like half throttle to keep up with traffic at a light my AFR is in between like 10.9 to 13. Is this normal or too rich? I'm kind of aiming for gas mileage right now. Some helping facts might be that I have a t25 so it spools right at 2k rpm... what do you think?

short answer:
It sounds good

long answer:
When tuning for part throttle with a stockish turbo I like to see these air fuels:
4" vacuum: 14.0:1
2" vacuum: 13.7:1
0psi: 13.5:1
2psi: 13.1:1
4psi: 12.9:1
7psi: 12.7:1
10psi 12.4:1
12psi 12.2:1 "(no longer part throttle)"
15psi 11.9:1 ""

these are all conservative, a little too rich, very safe if the timing is right, but somewhat lean enough to conserve fuel at part throttle.

Danger_Dorn · 07-16-2013, 02:46 PM

Well I paid more attention today when sitting in traffic. When getting on the gas like 1/4 throttle or anything to keep up with traffic it goes straight to 10 then holds until I return to idle where it corrects to 14 ish. So i guess it just goes rich whenever im acc....?

Kingtal0n · 07-16-2013, 03:37 PM

Quote:

Originally Posted by Danger_Dorn

Well I paid more attention today when sitting in traffic. When getting on the gas like 1/4 throttle or anything to keep up with traffic it goes straight to 10 then holds until I return to idle where it corrects to 14 ish. So i guess it just goes rich whenever im acc....?

like i said already try different maf sensors they all work differently despite being "identical"

Danger_Dorn · 07-16-2013, 03:58 PM

yeah the only problem is that nobody around here that I know has an sr20.

Kingtal0n · 07-16-2013, 04:18 PM

Isnt that a #62 or E5 ecu? If so use a SOHC KA maf hot wire. Any junkyard...

Danger_Dorn · 07-16-2013, 08:21 PM

It's a redtop so yeah wouldnt a single cam KA one work? Good point. I'll have to go scavenging. It completely slipped my mind.

Danger_Dorn · 07-23-2013, 09:32 AM

So I definitely think its the MAF. I went WOT from 1st all the way through 4th and it pulled great. My afr was like 10.5 which is too rich I believe but still better than lean. After conducting said shinnanigan I came to a slow at a stop light where my car suddenly decided to bog down really hard. I was trying and my afr was like 13 but I wasn't getting hardly anywhere. My turbo was spooling and everything but it was BARELY accelerating. To me this sounds like a MAF issue especially with my 13mpg and rich acceleration (10.0 at times). Does everyone agree this is a MAF issue? And why would it only do this after being WOT? This isn't the first time this happened.

Danger_Dorn · 08-22-2013, 07:42 PM

The problem was my TPS was incorrectly adjusted so now its good. Also ign. timing was off and I had oil in my spark plug holes from a snapped center valve cover bolt (fixed with jb weld lol). Also had a vac leak in my IACV. Replaced the Maf and between all of that I guess I fixed it. Just for future reference for anyone that has this problem

06-15-2013, 01:40 PM	#35
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	Here is some knowledge from experience: #1 I Once ran an SR20 with every single lifter empty (no oil, only air) and it ran perfectly normal, except for 2 things: a: it made a horrendous ticking noise at all rpms that was very obviously coming from the valvetrain b: it put chatter marks on all the valves by the retainers, apparently they were bouncing on the seat once in a while. it made no difference with how the engine starts. As to starting an SR20, here is some info... The sr20det ecu (and even the power FC ecu, but NOT the AEM EMS) cranks all 4 cylinders to one compression stroke before it will start. If you listen carefully, you should hear 4 compression strokes (chug chug chug chug VROOOM!!!) is the typical reliable sr20det starting mechanism. If it takes MORE than 4 compression strokes, check the ORANGE wire ("start" signal) first for proper wiring as this is the most common wiring mistake people will make that affects starting characteristics. iirc that wire is a 12V signal off the ignition switch, but I could be wrong so look it up first. Summary: -lifters being full of air/oil have no affect on starting characteristics, -4 compression strokes THEN start is the sr20 way __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

07-11-2013, 07:31 PM	#40
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	you need to boost leak check it. air leaving after the maf sensor is what you are looking for, not vacuum leaks. Fill the plumbing with air pressure (15psi or so) with the engine off and listen for leaks. __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

07-16-2013, 04:18 PM	#49
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	Isnt that a #62 or E5 ecu? If so use a SOHC KA maf hot wire. Any junkyard... __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

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06-15-2013, 11:33 AM	#32
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	As far as the hydro lifters go I was under the impression that if there is not enough oil pressure, then they will not pump up thus giving me a PITA when trying to start. I understand all of the above. I cant really afford to pay 175 bucks for a damn tool though or to make one. They "But your engine is going to go brrrrrrRRRRAAAHHHH! BOOOM!" but I think trial and error will prevail here.

06-15-2013, 01:30 PM	#34
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	Yeah I will probably end up making one. Thanks for the time and patience guys. Ummm embarrasing question but here goes. IF I left the rocker arm out could I drive it if I went easy on it? I'm a Marine and sometime I HAVE to go to work at a moments notice. This happens quite often. Will I kill it just driving on it nicely? I dont want to but I already was driving it for a week like this not knowing it lol.

07-11-2013, 02:28 PM	#37
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	Update: Found out the shop I took it to had the shims and guides switched so the rocker arms werent seating...switched it all over and havent had a problem since other that my now fuel problem. I'll just add it here so I can bother Irving some more. NEW PROBLEM: Everything is great except my AFR. I'm running pig rich. I hava an AEM uego wideband and sometimes at idle or cruising it will be at a 13 to 15 but usually it just sits at the max of 10. I think I figured out the problem but I just want a 2nd opinion (this is where you come in Irving lol). I have an Walbro 255lph and the original stock FPR. My vac lines are secure with no known vac leaks. I guess what I'm getting to is my stock FPR could be old and unable to deal with the new fuel pump right? So If I get a new AFPR with a gauge i should be able to dial it down so this isnt a problem anymore right? I have checked the rail and there are no bends. I am also using the KA fuel filter which shouldnt be a problem. I have a baby on the way so I'm trying not to break the bank. I have found universal AFPR for like 30 bucks. Input appriciated guys. Thanks

07-11-2013, 06:21 PM	#39
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	thanks for the speedy reply. This will be a long one. Brace yourselves. Current Diagnosis 1. I have stock everything on a freshly rebuilt motor. Rebuild contains bearings, rings, metal hg, arp hg studs and rod bolts ect basically all new internals. 2. I dont think the wide band is wrong I have had it in there for less than 1000 miles positioned in the test pipe. It is an AEM uego and I have never heard of these things going bad. Plug my mpg is like 11 with black smoke at a high rev with gas smell out the pipe so I am in fact running juicy. 3. I checked spray of the injectors a while ago and again listened with a screwdriver everything checked out so that likely isnt the issue. 4. I havent checked the maf recently but i highly doubt thats it. I have a WS harness so wiring has checked out and I replugged the plugs 5. I have checked for vac leaks and found nothing. I can boost just fine up to 11psi as usual. Just slightly boggy probably due to the afr. 6. The only thing else it could be is a poor regulator. I was just going to buy the cheap godspeed universal one with the gauge on it and go from there. Not many SR's here on Camp Lejeune so I'll have to go hunting this weekend. Thanks again for the help I'll keep you updated.

07-14-2013, 04:35 PM	#41
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	Well, cleaned the MAF and its better. Cruising at -4 vac I sit a a perfect 14-15.5 afr, but when I acc it goes to 11 to 12.5 which is to be expected. Nex question is do you think I would benifeit from taking out my 02 sensor and cleaning it?

07-15-2013, 04:45 AM	#43
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	I unscrewed it from the two screws on top and sprayed some airflow cleaner on it a few times and then allowed it to dry. I have a t25 with an hks internal wastegate and I hit 12 psi WOT. My fuel ratio goes to 12.5 ish so I think we're golden Thanks again King. I appriciate the help. I do beleive this would be a good to keep hanging around zilv-izzle

07-15-2013, 04:50 PM	#44
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	Well I'm still being picky. My next question is as follows My cruising AFR is from 14 to 15.5 which is good. My only issue is now when I get on it...not WOT but like half throttle to keep up with traffic at a light my AFR is in between like 10.9 to 13. Is this normal or too rich? I'm kind of aiming for gas mileage right now. Some helping facts might be that I have a t25 so it spools right at 2k rpm... what do you think?

07-16-2013, 02:46 PM	#46
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	Well I paid more attention today when sitting in traffic. When getting on the gas like 1/4 throttle or anything to keep up with traffic it goes straight to 10 then holds until I return to idle where it corrects to 14 ish. So i guess it just goes rich whenever im acc....?

07-16-2013, 03:58 PM	#48
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	yeah the only problem is that nobody around here that I know has an sr20.

07-16-2013, 08:21 PM	#50
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	It's a redtop so yeah wouldnt a single cam KA one work? Good point. I'll have to go scavenging. It completely slipped my mind.

07-23-2013, 09:32 AM	#51
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	So I definitely think its the MAF. I went WOT from 1st all the way through 4th and it pulled great. My afr was like 10.5 which is too rich I believe but still better than lean. After conducting said shinnanigan I came to a slow at a stop light where my car suddenly decided to bog down really hard. I was trying and my afr was like 13 but I wasn't getting hardly anywhere. My turbo was spooling and everything but it was BARELY accelerating. To me this sounds like a MAF issue especially with my 13mpg and rich acceleration (10.0 at times). Does everyone agree this is a MAF issue? And why would it only do this after being WOT? This isn't the first time this happened.

08-22-2013, 07:42 PM	#52
Danger_Dorn Zilvia Member Join Date: Oct 2012 Location: Jacksonville NC Age: 30 Posts: 265 Trader Rating: (0) Feedback Score: 0 reviews	The problem was my TPS was incorrectly adjusted so now its good. Also ign. timing was off and I had oil in my spark plug holes from a snapped center valve cover bolt (fixed with jb weld lol). Also had a vac leak in my IACV. Replaced the Maf and between all of that I guess I fixed it. Just for future reference for anyone that has this problem