ZDrifter Posted September 5, 2006 Share Posted September 5, 2006 Alright so heres the story. Ive been having fuel issues since I started driving the car. So I did a search, found out that to change the problem of the car running rich you need a aftermarket adjustable fuel regulator. So thats no big deal I get one from Garage 112 here in Portland and they hooked me up by tuning it and getting the fuel pressure just right. I get the car back and it runs great. That lasted for about 2 days until I started putting in my autometer tach. Seems like after I tried installing it that its running worse and worse. I read that the yellow/lavender is the tach signal then found out that you dont use the wire from the ECU since Im using a tach adapter. Anyways this is what the car is doing. When hitting boost it will build rpms slowly and hesitate horribly. Sounds like the car is running rich again but fuel pressure is fine and its not backfiring just sputtering very badly. If I go past 1/4 throttle it will start sputtering. So I figured maybe there is not enough air. So i removed my skid plate since the air filter is near there and it ran considerably better but same simptoms just higher in the RPMS, yea well that lasted for like 3 or 4 hours until it started running worse again. So today I tried running it without the air filter for a short period and still no change. I also checked and replaced all the spark plugs and properly gapped them. I dont know what to try next so any help would be greatly appreciated, Im starting to get down to the wire with going down to college so Im afraid that if I dont get this problem fixed I might have to let her go. Thanks Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted September 5, 2006 Share Posted September 5, 2006 well you said "tried installing the tach adapted" did you mean unfinish? howd that go anyway? only thing i can think of is that you installed your tach adapted incorrecly and/or tampered with the ignition. Now i'm only saying that because you said you had this problem only after you messed with the tach adapter. If it's not that, sounds like there is a lack of air, fuel, or spark. Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 6, 2006 Share Posted September 6, 2006 Maybe you used the wrong wire for the tach, on mine the one for the tach is yellow/blue not lavender, I know for sure I traced those wires several times. Also there are other wires that ARE yellow/lavender coming off there maybe you got the wrong one hooked up. First thing I would try, would to actually use the wire from the ecu instead of whatever you tapped into for the tach adapter, as long as you flip the correct dip switches on the autometer it should work useing the ecu source. You may have tapped into the ignition the wrong way because you problem sounds like an ignition problem. Why do you need to use an aftermarket fuel pressure regulator? if all your stuff on your engine is basically stock, and you stock regulator is working correctly, you shouldn't really need a different regulator to make the engine run right. Maybe your stock regulator was messed up. if you just took an engine out of one car and put it in a different one, it shouldn't have made an aftermarket pressure regulator nessary. Chris Rummel Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted September 6, 2006 Share Posted September 6, 2006 typically no one puts in a stock r33 fuel pump or anything equivelant and go for somthing more over kill. Therefore, youd need a FPR to back down the fuel. Also, another contribution to high FP is if your using the stock hard fuel lines on the car. they are alot smaller ( epecially the return). lower volume= high pressure. Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 6, 2006 Share Posted September 6, 2006 I would say yes to that except that the hard lines on the 280z and the stock skyline are the same 5/16 diameter, so I don't think that is the reason. The walbro, that is commonly used (what I used) is greater volume not greater pressure (although you can get them with both) so I wouldn't think that is it either. I think more likely the cause it because most people don't incorporate the FPCM listed in the wiring diagram under RB25DET only. controlled by pin 104 on the ECM, this was not on my clip and if you get the engine and trann on a pallet you most likely would not have it either. I believe this varies the voltage to the pump, to help control the volume. Since I ran separate lines in 10 gauge the pump will be doing some serious flow. I think if I have this problem, I'll try a restrictor in the line going to the regulator. Other reasons why you could be running rich could be the ecu is in limp home mode, that could cause the type of richness and runablity problems you are having. Usually the main cause is a malfuntioning MAF, check that out and see that it is working properly. An ecu in limp home mode runs like you describe, "very rich and will not let you build revs. You said in your other post that Garage 112 added the regulator and adjusted the timing, I think the timing adjustment is probably cleaned up most of the backfiring and poor running. If it started running rich after again after you added the tach then most likely something in the ignition is amiss, since you didn't mention that you touched the regulator, but it started running rich again. anyway there are some suggestions for you to try. good luck Chris Rummel Quote Link to comment Share on other sites More sharing options...
ZDrifter Posted September 7, 2006 Author Share Posted September 7, 2006 Thanks a lot for the info guys. I am running a SARD fuel regulator because I am also running a walbro 255 and I read in other posts that it helps with the car running rich. I will try totally disconnecting the tach to see if it will make a difference because she is running horibbly. About the tach...Are you guys just getting the tach signal strait from the ECU and not running the tach adapter at all? Quote Link to comment Share on other sites More sharing options...
ZDrifter Posted September 7, 2006 Author Share Posted September 7, 2006 So I totally disconnected the tach today and still no change... It seems like the timing is off again so maybe the belt jumped a tooth?? I just ill have to check that out next. Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 7, 2006 Share Posted September 7, 2006 I have the tach sitting on the dash to go in, and I'm going to run the tach wire from the ecu, really no reason not to, since the Autometer tach will take it's signal from that source just fine. I know that when I had my 240z back in the day (20 years ago) and I added a jacobs ignition to it the stock tach stopped working until I used an adapter, but the autometers are supposed to work using the stock ignition signal without an adapter. by the way the tach wire is yellow with blue stripe not lavender, L is used in the nissan schmatics for Blue, and I think it was just posted wrong. sounds like an ignition problem, to me. Maybe the people that set the timing didn't tighten up the cam angle sensor bolts enough and it moved messing up the timing again. Chris Rummel Quote Link to comment Share on other sites More sharing options...
veritech-z Posted September 7, 2006 Share Posted September 7, 2006 Something I discovered after I took my old gauges out is that Nissan ran the alternator power wire through the volt meter, so taking out that gauge resulted in no alternator. I heard also that the tach on the early cars had the ignition signal wired through it, so a non-functional tach meant a non-functional car. I came across that while searching for alternator wiring instructions. *edit* I just read your sig, and if this is on the 78 rb powered car, you probably shouldn't be having the problem I just described... Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted September 8, 2006 Share Posted September 8, 2006 The RB ECU tach signal wil not work with an autometer tachometer gauge. even with resistors or whatever. I had a 240sx with sr20det and ecu tach signal worked with auto meter gauge, no adapeter needed. so, i thought rb is also direct fire ign. so hech it should work too. I was WRONG. ive done it myself, so save yourself the trouble and forget the ecu signal and use the tach adapter. Zdrifter, It's unlikely that the timing belt jumped a tooth. I think you should make sure all the simple things have been checked before you jump to that conclusion. get an RB25DET factory service manual and towards the end/ appendix there are processes where you can troubleshoot. It never fails for me. good luck Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 8, 2006 Share Posted September 8, 2006 I'm still going to try it, using the ecu signal, did you have the dip switches properly thrown on the back of the tach? What adapter did you use for the autometer tach? Chris Quote Link to comment Share on other sites More sharing options...
ZDrifter Posted September 8, 2006 Author Share Posted September 8, 2006 Alright things I have found out...If I connect my tach to the main power for the coils (white) it bounces from 0rpm to 500rpm at idle and i revv it and it only rises to about 1000rpm. Also it runs very shitty when its cold and it will run like that even if its warmed up but if I stop turn off the car and start it back up it runs better and faster but still popps. Any ideas, maybe bad cold start sensor??? Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 8, 2006 Share Posted September 8, 2006 Do you have the IAC valve hooked up? ie all the plugs pluged in around that? Did you recheck the timing? For the Tach, are you using the Autometer adapter 9117? you should be able to have it work using that. Although I'm going to try the yellow/blue wire which is the tach signal not the yellow/lavender before I invest in the adapter. According to the Autometer website, the cars that need an adapter are coil on plug like this engine is, but this is for the most modern engines that either don't have a tach out or the tach wire is Multiplexed meaning more then one signal is going to the cluster through it. Since the tach signal is dedicated on this one i think it will work. If It doesn't it's not a big deal just means I'll need to get the adapter, but I like to see for myself, before dropping eighty bucks on the adapter. You might want to check the connection for the water temp signal, the one that goes to the ecu, it's the one with two wires make sure it's plugged in. Try using the dianostic trouble shooting in the back of the manual. if you can find a link on here somewhere, it's outlined in a pretty simple if then style format, Hope this helps. Chris Rummel Quote Link to comment Share on other sites More sharing options...
Rumnhammer Posted September 8, 2006 Share Posted September 8, 2006 I just checked the Autometer website on the bouncing problem, make sure your dip switches on the back of the tach are properly adjusted for 6 cylinder operation, it comes from the factory set for 8 cylinder. Chris Rummel Quote Link to comment Share on other sites More sharing options...
poop24 Posted September 9, 2006 Share Posted September 9, 2006 Spencer, what the hell is going on with this bastard child?????? Give me a call and we can check this bitch out.. Adam Quote Link to comment Share on other sites More sharing options...
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