OK...I am going to try to answer the last few posts all at once...so here it goes. As far as I can tell, I am holding steady fuel pressure except for a fuel fluctuations/missing/bogging/whatever when I try to rev.

I have tested all 6 of my coil packs and they arc to ground. My BOV is the HKS one that came with my other (stock, I assume) and both hoses are hooked up (back and side). If I unplug the one on the side, the idle rises. I am only guessing but that seems like a normal response, and might indicate that vacuum is good. (??). Other than that, I don't have a vacuum gauge, so I'm not sure how to test it.

As for the ECU: Here is a pic of my ecu. The first five numbers on the model number are the same first five numbers that Datascan looks for. I don't know if this is a stock ecu, because of the Access sticker on it. (the other ecu in the pic is just one that I bought off ebay a year ago, but I don't think anything is wrong with my ecu). My clip came with the Access ecu though...please tell me if it is stock, or what is special about it:



MAF: It's readings in datascan, seem very normal. It is stable and low at idles and rises when revved. However, I WILLLLLL try to unplug it and check for response. What is the expected GOOD response, and what are the BAD responses??

Injector-related problems: When I took out all of my injectors, the O-rings looked great on them...NO signs of wear or tear. I will recheck to make sure that they "re-seated" correctly. I just wanted to mention that my fuel pressure holds steady at an idle, so I am guessing that o-rings would cause low pressure at all times. PS. When I pulled the injectors out, I "tapped" all the junk out of the top of them. If anything, I would suspect that an injector itself is bad/leaky.

I'll be checking alot of things tomorrow or monday when I am off work and I will repost the current status then. In the mean time, I would love more great suggestions/responses like these to point me in the right direction. I am also DEFINITELY going to be putting a voltage-meter on my fuel pump wires, so that I can see what happens to voltage when I rev...just another suspicion whether my ECU is telling the fuel to cut out on me.....

--TJ

Do you still have your stock fuel pump and FPR? If so... try reinstalling those and see how it runs... with light reving and idle the stock pump will be ok... I'm wondering about your FPR... at least change out the FPR and see if there is a change...

Sounds like you might actually be flooding if it dies out with reving... before you found the plugs black it sounded lean due to needing starter fluid but now with the black plugs it's looking like it's the other way around

rbsileighty wrote:Do you still have your stock fuel pump and FPR? If so... try reinstalling those and see how it runs... with light reving and idle the stock pump will be ok... I'm wondering about your FPR... at least change out the FPR and see if there is a change...

I will if I can find it..I'm not the type to throw anything away. I still have my 300zxTT MAF and spare ECU that I bought in trying to troubleshoot this. Know anyone that needs em?? lol

rbsileighty wrote:Sounds like you might actually be flooding if it dies out with reving... before you found the plugs black it sounded lean due to needing starter fluid but now with the black plugs it's looking like it's the other way around

I think that was a mix between olddddd gas, high fuel pressure, and when it wouldn't start it was because I had blackened the plugs. But it was definitely the new plugs and new gas that got it past the "only start with starting fluid problem." I've got it set lean at 32psi now, just to (hopefully) keep it from flooding and blackening the plugs again.

HOWEVER....now my problem is that it still hesitates and bogs out when I rev even a little. I also notice that my fuel pressure wavers a little bit, even set so low, when I rev a little bit. I am going to check voltage response on my fuel pump wires later today after I wake up. If my voltage drops when I rev, what should I assume??? (I have my own theories on this, but I don't know enough about mechanics...lol)

--TJ

I still really think you're probably flooding it when you rev somehow... which is why you might want throw the stock fuel stuff back in to at least show that's not the problem

Are you saying you have your base fuel pressure (idle) at 36psi?

rbsileighty wrote:I still really think you're probably flooding it when you rev somehow... which is why you might want throw the stock fuel stuff back in to at least show that's not the problem

Are you saying you have your base fuel pressure (idle) at 36psi?

no...my base fuel pressure is set around 32 because I think that is an easy enough mark for my pump to hold steady. I figure that if my pump can't keep up pressure at 32, then I definitely won't build and hold 36, but I'll try other things today. I've gotten about 4 hours of sleep and I'm about to go get started testing it again...

--TJ

So you have a blow of valve with stock rb ecu...might sound dumb but that could cause it to run realy badly when reving the Ecu thinks the air is coming back threw the intake with the recuculating valve but wit the blow off its just blowing out. the esu expects it back in but not receiving the incoming air..On my Rb20 i was changing the plugs and forgot to hook up the main pipe on the recirvulating valve that shot the air back to the intake and on rev she ran realy badd jumping hesitating and shaking...just look it over might help

Ok...I am doing a little testing...

1..fuel pressure drops when I rev up to 3000 or more2..will bog at 2000 rpm if I rev slowly3..voltage (grounded to the pump ground wire) on the fuel pump is steady at 11.8v, even when revving high...so voltage is steady...should it increase when fuel demand increases??

4..battery voltage when idling (even with jumper cables still on it) is steady at 14.2v

Other testing:

I unplugged my MAFS and the idle dropped and the car died.

I unplugged the AAC and the idle jumped (iirc)

Datascan oxygen reading is still steady at 33....NEVER CHANGES A BIT....so

I unplugged my exhaust o2 sensor and nothing changed.

any answers to these??

also, my car has a voltage drain in it somewhere (alternator related??)...I came back to it 2 days later and the battery is completely dead (brand new battery)

moso240 wrote:So you have a blow of valve with stock rb ecu...might sound dumb but that could cause it to run realy badly when reving the Ecu thinks the air is coming back threw the intake with the recuculating valve but wit the blow off its just blowing out. the esu expects it back in but not receiving the incoming air..On my Rb20 i was changing the plugs and forgot to hook up the main pipe on the recirvulating valve that shot the air back to the intake and on rev she ran realy badd jumping hesitating and shaking...just look it over might help

moso240, here are some pics of my rb20. Please look at my BOV that came with the car and tell me what u think....as far as I know it is a stock setup..

http://www.angelfire.com/ar/SP....html

Ok...Well I didn't figure anything else out tonight and it is too late for me to continue. I used my crappy digital camera to (try to) record a silent video of my fuel pressure gauge dropping when I rev...

http://s268.photobucket.com/al...2.flv

My rpm's are reaching 3000+ rpms 12 seconds into the video right when the video is cutting off. The fuel pressure gauge is the lower gauge on the left pillar....

Carl, here is a pic of my fuel injector...looks pretty much the same as an injector from a KA...



--TJ

I will try to remember to make a daylight video of the rpms and fuel pressure drop...sorry about that crappy video...

--TJ

How did you set your fuel pressure? Please go step by step...

mine did the same thing, a cut wire to something with the starter made mine not want to crank/idle, it was on the pass side in the fender so u gotta take the pass side fender out idk if its the ame prob, i dout it but..

it was a red wire that was cut idk what it was to tho lol it was red with little dots on it lol

rbsileighty wrote:How did you set your fuel pressure? Please go step by step...

I am using a fuel pressure gauge and fuel pressure sending unit. The sending unit is mounted in a "T" on the fuel inlet side (as opposed to the FPR mounted on the fuel-OUT return line).

Once I get the car to warm idling (not that it matters I think, but the engine was warm), I look at my FP gauge, and then go to the Nismo FPR and adjust accordingly; with vacuum: 37psi now.......without vacuum: ~43psi.

I hate that you can't quite see my tach in that crappy video. But I only revved one time (in the last 3 seconds or so). I revved hard (to bypass that 2000rpm bog when slow-reving) and it made it to around 3000rpm before it seems to miss; almost simultaniously the fuel pressure drops to around 20psi; then it backfires and will balance out at idle speed (if I have let off of the gas pedal)..

Did you see the FP gauge drop like a rock when I revved hard in the video?

--TJ

The blowoff isnt going to be a problem. I was running the crushed 1st gen and mine started ran great.

The battery drain problem can come from many places. Make sure your glove box light goes off when its shut, make try and pull your radio fuse and let it sit for a couple of days and see what that does. I had a horrendous drain on mine also, and the radio wiring ending up being the culprit. Also you can look in the RB section for one of my threads where it tells you how to test the mA draw while your car is off. Just start pulling fuses until you get the correct mA reading. Should be around 20-30mA if nothing is causing a parasitic drain.

As for the idling, have you checked your timing? Also, make sure like many of them said to check your maf connections. Also, look on your postive battery terminal and youll see two plugs. One of which comes from the alternator. Make sure that these connections are clean and true because that also gave me a problem. Your oxygen sensor should not be THAT steady. You should get some sort of fluctuation under a load, how ever minuet they may be. You're going and assessing the problem correctly, so we'll find it soon.

Ok..here is that daylight video of my fuel pressure dropping. Unfortunately, my crappy little digital camera can't get the timing right. This time, I floored it in neutral and my revs were hitting 5000rpm at the beginning of the video. But also rewatch it and notice that, at that point, my fuel pressure gave in, dropped, and bounced back immediately once I let off of the pedal...

http://s268.photobucket.com/al...5.flv

I have a whole lot of o2 sensor reading from my multimeter, but I'll post them later (in case anyone actually knows what the normal readings are for comparison).

HERE IS THE REASON I AM POSTING NOW: THE BIGGEST CLUE OF ALL??????????

I didn't give it much consideration before, but: My clutch and brake pedal feel REALLY weak!!! Everytime I pump my brake, my idle is affected and improved!!!!!! Can anyone please connect these dots???? Can one single thing cause low pressure (vacuum??) AND fuel pressure shortage???

perhaps a bad checkvalve/brake booster combo is causing a massive air leak.plug the brake booster port and see how that goes.

Carl H wrote:perhaps a bad checkvalve/brake booster combo is causing a massive air leak.plug the brake booster port and see how that goes.

ummm...brake booster port?? The general area is the big black thing in the driver's side engine bay on the firewall, right? but do I just take off which hose and plug it?? Am I plugging the brake booster or the hose that I disconnect?? or both?

The fuel pressure reallllly drops when driven. I just moved it a few feet..lol

s13_240_rb20 wrote:
ummm...brake booster port?? The general area is the big black thing in the driver's side engine bay on the firewall, right? but do I just take off which hose and plug it?? Am I plugging the brake booster or the hose that I disconnect?? or both?

The fuel pressure reallllly drops when driven. I just moved it a few feet..lol

well, I unhooked the main hose running from the brake booster. The engine was off when I unhooked the hose, and it released pressure.

Upon starting the car, that hose has alot of suction (vacuum) and it looks like the fuel pressure builds normally but very slowly loses pressure when that hose is removed from the brake booster and it (the hose) is plugged off. So where do I go from here? Time to get a VAC/Boost gauge just to get more readings??

I never saw the point of getting a boost gauge before because I have no plans of upgrading the turbo or upping the boost from the stock 7...

--TJ

it almost sounds like the fuel pump isnt staying engaged when you start the car...perhaps your wiring is at fault.

Carl H wrote:it almost sounds like the fuel pump isnt staying engaged when you start the car...perhaps your wiring is at fault.

fuel pump voltage stays steady at 11.8volts, even when revving. I have mentioned way earlier in this thread that it seemed kind of low, but even when I applied battery voltage, I think the problem persisted.

I can hear my pump running regularly, but I have ALWAYS thought that it was weird that ALL my fuel pumps sounded so loud..lol But then again it is a hatch and it's right there.

How much voltage should I be getting to the fuel pump for a 1990 hatch. I am probing the (iirc) blue wire for ground and white wire for POS+ on the fuel pumps harness plug.

EDIT: This is a better question, I think: How much voltage does my Bosch 040 need for it to work at "optimum performance"?? The Bosch was an upgrade I did about 8 months ago for some reason I forget.

I think my car was losing power at upper RPM's a long time ago (when drivable) and I probably upgraded to the Bosch, and then my problems got worse....I just don't remember...Thinking about it that way, maybe it is wiring. My 11.8volts might have ALMOST been enough to run the Walbro's but not nearly enough for the Bosch...I may go back and rewire a direct GND and Batt voltage to the pump and try it, but I think I have already tested that plenty...

--TJ
Modified by s13_240_rb20 at 4:28 PM 2/25/2008

Do your lights dim and such when you rev?

Do you still have the Walbro? I'm still in favor of running the old setup since it looks like a glitch in the new one

Your fuel pressure problem might also be the hose in the tank that goes from the pump to the top of sending unit. You might have a loose clamp or a split hose. Your idle issue when pumping the brakes sounds like you have a bad diaphram in the booster and when you push the brakes the cut opens up.

I don't have the walbro's anymore. I gave em away. Anyone have a spare pump? lol still interested in what voltage a bosch needs to run best...

mott6904 wrote:Your fuel pressure problem might also be the hose in the tank that goes from the pump to the top of sending unit. You might have a loose clamp or a split hose. Your idle issue when pumping the brakes sounds like you have a bad diaphram in the booster and when you push the brakes the cut opens up.

How do I test for a bad diaphram?? or do I just figure out how to disassemble it and look at it?? lol

I've thought of that connection too already. I'll double check it anyway, but it doesn't seem to fit into my theory of it holding fuel pressure when the car is turned off...

--TJ

How is your pump wired again? Exactly... not at the pump but at the ECU/chassis however you wired it

You basically tested the brake booster allready. When you pushed the pedal down the idle changed. You might also hear the vacuum leak but not all the time. It sounds like a wiring problem then for the fuel pump or maybe a bad fuel pump. Do you have a spare pump... stock or anything to replace it with?

I don't have another pump lying around...wish I did..got one I can borrow?? lol

I'll check my engine bay harness tomorrow for how i spliced it in during the swap...

--TJ

Im with Mott on the diaphram assessment. Junk yard you a new booster and get rid of that problem. Or you could just osplit into it and cure that problem yourself. (Please no duct tape.)

As for the fuel, why not just use a stock fuel pump? They're good and steady in the mid and higher 200's for power. Most likely you're only sitting about 200-210 right now. Ditto for checking the wiring and Ill meter my fuel pump and o2 when I get home today and tell you what Im running at so you have a base for your testing.

s13_240_rb20 wrote:I don't have another pump lying around...wish I did..got one I can borrow?? lol

I'll check my engine bay harness tomorrow for how i spliced it in during the swap...

--TJ

Make sure you read through this:zerothread/92829

Does your ECU light stay on when you crank?

90_rb20 wrote:
Ill meter my fuel pump and o2 when I get home today and tell you what Im running at so you have a base for your testing.

Thanks, in advance, for the wiring testing. I definitely NEEEED something to compare to. Please be sure to tell whether you ground to a wire or to chassis/battery ground. I also noticed that my o2 harness plug carries voltage on the 2 outside wires when I put the black probe on them but, more oddly, my POS probe on the POS battery post, so please check that way also...I did resistance testing on the sensor and harness (seperately) yesterday also, so I can compare some results there also if you can.

--TJ

rbsileighty wrote:
Make sure you read through this:zerothread/92829

Does your ECU light stay on when you crank?

ecu light goes out

The two outside wires on the connector are the power and ground for the 02 heater and the middle is the signal wire. If you put your multimeter on volts depend on what you kind you have it should adjust to mill volts and then back prode the middle wire and see what it reads. If you rev the car up to about 2000 rpm it should jump around from 200 to 800 millvolts. If it doenst change at all then you have a bad o2 sensor.