Clifton Posted March 17, 2007 Share Posted March 17, 2007 Yes, you are certainly correct, I am running lean there. I'm still running the same fuel map that I just stole from someone else to get the car running. I never bothered to tune the rest of the map because it was just hitting that wall really fast anyways, so I'm not under WOT very much anymore . From what I saw TPS was 100. Save the file you have (file, save as) and just make a new one, try it, if it doesn't work just open the previous one and burn to ecu. I have atleast 100 maps from saving the previous when I change anything. Quote Link to comment Share on other sites More sharing options...
X64v Posted March 17, 2007 Author Share Posted March 17, 2007 What I meant was during normal street driving (it's my daily driver) I don't hit WOT much anymore with this problem hanging right there. I've tried tuning up through 150-160 ve at 4krpm and above with the same results. And I'll get my current .msq file up in a few hours before I go to work. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 17, 2007 Share Posted March 17, 2007 I think it's your fuel supply line. Many people have problems using the stock feed line on injected engines with originally non-injected cars. It's a simple fix, switch your supply and return line (make the supply line the bigger of the two). I've heard of this problem with both MS'd and OE injected cars (L28's swapped into 240z's and 260z's). Apache Junction is on the way from Flagstaff to Tucson right? If you want some help I'm heading back to Tucson this weekend and could stop by if you want. Mario Quote Link to comment Share on other sites More sharing options...
X64v Posted March 17, 2007 Author Share Posted March 17, 2007 It does this with a full 3/8" feed from tank to rail as well. And I'm getting 60gph free flow/50gph @ 36psi through the 5/16" feed. That's double what the injectors can use, even at 100% duty cycle. Yeah, it's just east of phoenix. If you're taking I-10 from phx to tucson, I'm about 45 minutes east. If you're taking the 60 to the 79 through florence, I'm right off the 60. PM me if you feel like stopping by, you're welcome to. Quote Link to comment Share on other sites More sharing options...
X64v Posted March 17, 2007 Author Share Posted March 17, 2007 Here's my current .msq file. MSnS-E verison 029t. current msq.zip Quote Link to comment Share on other sites More sharing options...
74Adam Posted March 18, 2007 Share Posted March 18, 2007 This is probably unrelated, but there is a guy over on the ignition/electrical forum that is having the 4000 rpm cutout because he accidentally cut his O2 sensor wire and resoldered it. http://forums.hybridz.org/showthread.php?t=120063 Just thought it was an interesting coincidence. Hope you get this resolved soon so you can get back out to enjoying your car. Quote Link to comment Share on other sites More sharing options...
GrommitZ Posted March 18, 2007 Share Posted March 18, 2007 I had a 4k cut out that drove me crazy for months. It turned out to be my distributor dizzy. You're probably running lean at 4k because spark is cutting out. Have you noticed that your car cuts out at about 4k regardless of load? You could rev it to 4k in neutral with no load or speed up a hill until you hit 4k with the same cut off even though you have vastly different fuel requirements. I found a rebuilt l28et distributor, but I hear people have been installing z31 dizzies inside the l28et distributor body. You're running lean because spark is cut, causing the unburnt oxygen to pass through to the o2 sensor. Quote Link to comment Share on other sites More sharing options...
X64v Posted March 18, 2007 Author Share Posted March 18, 2007 I GOT IT! FINALLY! I had my father listen to the fuel pump while I manually grounded the injectors, and he could hear the fuel pump kick down a good bit (engine was off. While the engine was at WOT this was inaudible). I hooked the pump up to another vehicle with jumper cables, and started the car....nailed 7k before I could even let off the gas! Thank you all for all your help. I was THIS ----><---- close to putting the su's back on. I'm glad I did not, as this would have eatin away at me forever. Veritech - I know you're running a 280 that's already got the correct fuel pump wiring, but try what I did...with your simptoms being so similar to mine, it certainly wouldn't hurt to try. Thanks again all, Sean Quote Link to comment Share on other sites More sharing options...
olie05 Posted March 18, 2007 Share Posted March 18, 2007 So was your fuel pump wired inline with the injectors or something? -or- was your battery so weak that the injectors opening drained voltage that much? Quote Link to comment Share on other sites More sharing options...
X64v Posted March 18, 2007 Author Share Posted March 18, 2007 My fuel pump was running through the original wiring harness (single 12 gauge wire from the battery running everything). I have my injectors coming off a 10 gauge wire from the same terminal. I think they were sapping most of the power from there when their pulse width got up there (even though I'm running peak and hold). I'm just about to run another 10 gauge from the battery to the fuel pump (through a fuse and relay, of course). That should fix it. Quote Link to comment Share on other sites More sharing options...
veritech-z Posted March 18, 2007 Share Posted March 18, 2007 My fuel pump is wired on a dedicated switch with new wires....I'm glad you were able to get your bugs worked out, but I suspect I've got some funny spots in my fuel map...I just don't have the time right now or anyone to ride shotgun with me to do a little street tuning. Quote Link to comment Share on other sites More sharing options...
X64v Posted March 19, 2007 Author Share Posted March 19, 2007 Well, looks like all is not as well as it seemed... I ran new wiring for the pump: 10ga straight off the + starter terminal, into a 30a fuse block w/10a fuse, into a 30a relay, then more 10ga wire to the + terminal of the pump. - terminal of the pump through about 4 inches of 12ga wire (didn't have any more connectors for the 10ga) onto a screw I welded on to the chassis for a ground. Well, the problem persists. It's now occuring around 5000-5500, but it's still there. The thing that made me mad was when I hooked up the pump to an external power source again (1997 chevy van (while running), jumper cables from it's battery directly to 12ga wires coming off the pump) it didn't do any better. That's exactly what I did last time to make it rev fine in neutral, but now it won't... Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 19, 2007 Share Posted March 19, 2007 You are getting closer. It sounds like you need to rewire some stuff. Make sure all your MS grounds and battery grounds are connected to the engine block with a large cable. In another post, I listed what I plan to do for my wiring. I am going to make a ground terminal block for ALL system grounds. The ground central "manifold" will be directly connected to the engine with a hefty braided cable. BTW, use shielded wire for the fuel pump. Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 19, 2007 Share Posted March 19, 2007 You are getting closer. It sounds like you need to rewire some stuff. Make sure all your MS grounds and battery grounds are connected to the engine block with a large cable. In another post, I listed what I plan to do for my wiring. I am going to make a ground terminal block for ALL system grounds. The ground central "manifold" will be directly connected to the engine with a hefty braided cable. BTW, use shielded wire for the fuel pump. Yes, grounding is very important, so don't skimp on ground wires. There is no need to run shielded cable for fuel pump power. In electronic systems, power leads to high power devices are not shielded (like a pump or motor). Very low amplitude signals are. That is why the VR sensor cable is shielded. For you guys running ZXT distrubutors, it is also a good idead to shield the signal wire from the distributor to the MS even though it is a +12v square wave. Nissan shielded it. The idea of the shield is to keep noise from effecting low amplitude signals, not to keep noise inside the power lead of a high power device. It cheaper and easier to do it that way too (easier to shield little wires, than big ones). Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 19, 2007 Share Posted March 19, 2007 The stock wire for my ZX fuel pump was shielded, so I replaced the wiring with a heavier shielded wire when I switched to the Walbro pump. That sheilding may have been due to the original pump being controlled by the Fuel Pump Control Module. Not sure why, but it was shielded. Thanks for the tip on the dist. signal wire being shielded. I will definitely take ALL precautions. X64v, I was thinking about this. Even though your pulswidths in your datalog seem correct, that only means that the MS is doing it's job and sending out the signal. It doesn't necessarily mean that the injectors are actually performing the duty that they are asked to do. I wonder if B&G are going to be integrating fuel pressure monitoring into future units. That would be really helpful in the datalogs. Although, the O2 sensor is already telling you, "fuel is missing". Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 19, 2007 Share Posted March 19, 2007 Ok, lets try a different direction... You're using a narrowband O2. It is possible to fool a narrowband. A sudden way rich condition (such as a misfire) can show up as a lean condition on a NBO2. That is why you can't really tune with them, and I remember a while back (before WBO2s were this cheap) that people recommended the O2 sensor AND a EGT gauge, so that you could cross check conditions between gauges. I'm thinking your spark might be cutting out. It could be a dying ignition module or coil, or too much spark plug gap, semi-fouled plugs, or just running way rich in your fuel map. Mario (I couldn't stop by on my way down because I left too late, but at least I'm closer now, though I have midterms this week) Quote Link to comment Share on other sites More sharing options...
X64v Posted March 19, 2007 Author Share Posted March 19, 2007 When I said I had it, I didn't explain the test I did. I probably should have. This is what I did: cut the inj1 and inj2 wires just after where the 3 injector wires merge into the one wire. I then joined those two wires together, and wired a short lead onto that, basically giving me full manual control of the injectors. I took the outlet off the FPR and routed it into a fuel can. I turned the key to on, and then I would ground the injectors for a couple seconds at a time. When the injectors weren't grounded, the pump flowed 50gph just fine. But when I grounded the injectors (effectively simulating 100% duty cycle), I could hear the fuel pump kick down, and there would be absolutely no fuel coming out of the fpr. So what I did then was wire the fuel pump to another running vehicle via jumper cables, and try the test again. Viola, gobs of fuel coming out the fpr return even under 100% duty cycle. But now I'm having trouble getting the pump enough power on the car. I will be running a number of tests and trying different things in the next few hours. I'm basically just gonna set up the manual injector control again, and keep trying different ways of wiring the pump until I can get fuel out the return with the injectors open (cranking the engine a bit in between to clear all that fuel, and keeping a jump vehicle running and hooked up to the battery so I always have full operating voltage). And it's cool Mario, I was just wiring most of the day anyways. I will be down sometime in the near future to tour the UA engineering college; if I'm still having problems, we could meet afterwards and take a look. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 19, 2007 Share Posted March 19, 2007 How are you powering the pump? For a non EFI car I would use a relay with a feed from the battery, controlled by the MS box, with some nice wire to the rear. Have you tried swapping the supply and return lines? In your tests it might show it flows enough but at the same time you could really be straining your pump causing it to sometimes work and sometimes not. Argh new problem in my car... I'm leaking fuel out the back... damn evap hoses... Mario Quote Link to comment Share on other sites More sharing options...
X64v Posted March 19, 2007 Author Share Posted March 19, 2007 I ran new wiring for the pump: 10ga straight off the + starter terminal, into a 30a fuse block w/10a fuse, into a 30a relay, then more 10ga wire to the + terminal of the pump. - terminal of the pump through about 4 inches of 12ga wire (didn't have any more connectors for the 10ga) onto a screw I welded on to the chassis for a ground. It does this with a full 3/8" feed from tank to rail as well. . Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 19, 2007 Share Posted March 19, 2007 Sorry, lack of sleep + programming for several hours has been killing my brain... It might be ignitions related then... how do your plugs look? Mario Quote Link to comment Share on other sites More sharing options...
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