'87quest Posted July 1, 2014 Report Share Posted July 1, 2014 (edited) I just installed my new Walbro and my car seemed to run fine with the stock maf, but I didn't drive it around much. I just installed my new translator and gm maf and I've got it to idle fine with the settings aux:0 base:0 and idle:3. When I try to drive around it falls on it's face and the fuel pressure drops way low which has never happened until with the new maf. and it goes all the way lean on my wideband. I've tried to adjust the base dial to help but it just gets worse on each click. I've been trying to get it to run right for a few days now but I'm stumped. Any help would be greatly appreciated.. I've also read through every maft forum I can find on here but I'm not finding anything helpful. Thanks in advance! Drake Edited July 1, 2014 by '87quest Link to comment Share on other sites More sharing options...
speedyquest Posted July 1, 2014 Report Share Posted July 1, 2014 Was it running perfectly before installing both the pump and translator? Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 Yeah it ran fine never dropped fuel pressure or anything. Ran a little lean because of the bigger turbo and other upgrades I've done so that's why I wanted to go with the maft so I could sort of tune it in better. Link to comment Share on other sites More sharing options...
TexasQuest Posted July 1, 2014 Report Share Posted July 1, 2014 Did you have the stock maf or dsm maf in your cosmo intake before? Could be the ecu not adjusted to the airflow change yet possibly. Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 Stock maf. I just don't get why my fuel press is dropping way low.. I think if that would stay set at 40ish if be fine. But it idles around 35 (normal) but when I drive around drops down to 20 or even 10 just loses all pressure for some odd reason. I want an adjustable fuel pressure regulator but i don't think that's the answer Link to comment Share on other sites More sharing options...
TexasQuest Posted July 1, 2014 Report Share Posted July 1, 2014 An adjustable regulator would help for aftermarket injectors but your right I doubt that would cure the issue. Have you adjusted the mid-throttle dial any since you said that's where your issues are at while cruising? Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 Yes I've tried that too. It's weird when I start it up and let it warm up its fine for a while I can drive around and try to get my translator tuned in but then after a bit it loses fuel pressure and that causes everything to go down hill. I just don't get why I'm losing fuel pressure! Is there something that I could've messed up changing my fuel pump?! It's driving me nuts Link to comment Share on other sites More sharing options...
ucw458 Posted July 1, 2014 Report Share Posted July 1, 2014 (edited) Did you throw away the cone filter before the pump or keep it? That filter is ONLY for the stock pump. On aftermarket pumps it partially blocks the pump inlet and starves the pump. Did you re-wire the pump? The stock wiring is too small for a 255 pump. You will get voltage drop from the resistance and may see 10 volts or less at the pump. This wears out pumps quickly and gives reduced flow. You need to run a fused 10ga wire from the battery to a relay in the trunk. Then from the relay to the pump. Use the stock pump power wire (black with yellow stripe) to turn on the relay. Give the new pump a 10ga chassis ground. Don't use the stock ground. This allows the pump to get full voltage and enough amps to run properly. Even stock pumps benefit from this. Edited July 1, 2014 by ucw458 Link to comment Share on other sites More sharing options...
importwarrior Posted July 1, 2014 Report Share Posted July 1, 2014 the pump should have nothing to do with the MAF-T do you have a fuel pressure gauge?if so you can pinch the return line to see if the fuel pressure spikes to 90 or more PSi instantly. if you snap the throttle the engine the pressure gauge should remain constant at the set pressure. it should not dip lower. if anything it might clime a few psi once you release the throttle as in press down and let off the gas as fast as possible. Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 Ucw, I did not see the come filter when I had the tank out. I'm not even sure what those look like, it seemed to be just a formed rubber hose before the new pump. But I did not re wire anything. Could the wiring cause this? What kind if a relay would I need? And what size fuse? The Walbro whines pretty loud could that be because of the wiring not keeping up as well? I was hoping not to have to drop the tank again but I will if I need to. Import warrior, yes I do have a fuel pressure gauge. It's electric and is inside the car with my wideband and boost gauges. It always read between 35-40 before the Walbro.aybe I should've ran the stock pump until it quit but I thought the Walbro was a good upgrade. I'll try pinching the return line next time i am with the car. I know the gauge should not dip down when I press the throttle but that's the problem. It'll be fine for a few min of driving then all of a sudden I'll give it some gas and blah blah blah she loses all press and leans out. Thanks guys Link to comment Share on other sites More sharing options...
ucw458 Posted July 1, 2014 Report Share Posted July 1, 2014 A 20 amp fuse on the re-wire is fine. Pump whine is just the way the pump is. You can lessen it by using rubber or silicone between the pump and the mounting bracket. But you may never get rid of all the pump noise. The cone filter usually gets stuck in the hose and looks like this. http://img850.imageshack.us/img850/551/sdc12291.jpg A standard automotive relay like this one works just fine for the pump re-wire. You can find them online or at any parts store. http://www.parts-express.com/Data/Default/Images/Catalog/Original/330-073_HR_0.jpg Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 I did use the rubber around the new pump. But I didn't see that come filter anywhere. I'll check and see if it didn't stay in the old pump otherwise I guess I'll drop the tank again and recheck there. Alright I'll get the stuff it need and hopefully get some time to rewire it tonight. So do I just ditch the factory wiring that's mounted on the tank? Just use the black/yellow wire the run the relay? Thanks man Link to comment Share on other sites More sharing options...
ucw458 Posted July 1, 2014 Report Share Posted July 1, 2014 Yeah just the black with yellow stripe. That's the pump + wire. Use it to activate the relay. While the re-wire may or may not fix your problem,... without it the pump will never give you 100% of it's rated flow. You can run a thicker + wire to the trunk like an 8ga or 4ga if you want for future stereo upgrades or batt in trunk if you plan on doing them. Saves you from running another wire later. I'm doing the re-wire on mine in a few days because I just installed a bosch 044. I'm running an 8ga wire to the trunk for some amps that will go in later. Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 I already have a 4 ga amp wire ran to the trunk which I no longer use so I could use that to save some time but wouldn't that be overkill? I don't plan on have any amps or subs again so I could eliminate the big wire and run a new 10 gauge Link to comment Share on other sites More sharing options...
ucw458 Posted July 1, 2014 Report Share Posted July 1, 2014 Overkill yes but it wont hurt anything. Run the wire you want. Link to comment Share on other sites More sharing options...
StarquestRescue Posted July 1, 2014 Report Share Posted July 1, 2014 (edited) You need to pull the fuel pick up from the tank and replace the in tank filter. This is a dealer item that can be gotten from engine machine service. At the same time you can check the hose from the pick up to the pump for obstructions like the already mentioned cone filter that should be removed with the aftermarket pumps. While the pick up is out shine a flash light in the tank to check for dirt that may clog or re clog the filter. You also should check that the polarity to the pump is correct, as i believe some one once wired a pump up back wards and had the same problem. (the pump made a little pressure running back wards, but could not keep up) The rewire is a worthy mod that many here could benefit from, but it will not fix a sever fuel pressure problem like you are describing. You should be able to do the work i mentioned through the access cover in the hatch. Edited July 1, 2014 by StarquestRescue Link to comment Share on other sites More sharing options...
'87quest Posted July 1, 2014 Author Report Share Posted July 1, 2014 I just had the tank out and cleaned it up inside.. looked a lot better than I expected and I replaced the in tank screen with a universal one from oriellys. I uses the solid black for the - and the black and yellow wire for + so I think the polarity should be correct but I got everything I need to rewire it I'll try that tonight and see if that helps. I also found the cone filter. Still stuck in my stock fuel pump. Any other ideas I can try while I'm there? Thanks a lot guys Link to comment Share on other sites More sharing options...
CarlosFley Posted July 1, 2014 Report Share Posted July 1, 2014 geez, why must I always ffind out of that one mod I have to do until AFTER I've put the tank back up and all Link to comment Share on other sites More sharing options...
StarquestRescue Posted July 1, 2014 Report Share Posted July 1, 2014 (edited) I replaced the in tank screen with a universal one from oriellys.Do you have a link to that? I never heard of using a universal in tank screen on these cars. The rewire is not going to fix it. Though you could have a bad crimp on a slice or ring terminal. Recheck the polarity markings on the end of the pump. And what about the black box (resister) that was used on the stock pumps? Is that still there or did you eliminate That? I do not retain those. Edited July 1, 2014 by StarquestRescue Link to comment Share on other sites More sharing options...
'87quest Posted July 2, 2014 Author Report Share Posted July 2, 2014 I'll look for the part number on the box of the in tank strainer.. It took a little modification but just trimming on a bench grinder. I did leave the resistor. Should I delete that during the rewire? I'll also make sure the polarity is correct when I run the new wires but I know I used the solid black as ground.. I guess I'll know when I get this done. Thanks for the help SQRescue Link to comment Share on other sites More sharing options...
ucw458 Posted July 2, 2014 Report Share Posted July 2, 2014 Recheck the polarity markings on the end of the pump. And what about the black box (resister) that was used on the stock pumps? Is that still there or did you eliminate That? I do not retain those. That's not a resistor, it's a capacitor. The capacitor inside is hooked to both wires. It's there to prevent pump noise in the radio. But just like the one on the ignition coil it can be eliminated without any ill affects. Leave it in, take it out, makes no difference. Link to comment Share on other sites More sharing options...
TexasQuest Posted July 2, 2014 Report Share Posted July 2, 2014 There was a Wix filter part number for the in tank filter floating around a long time ago. Link to comment Share on other sites More sharing options...
'87quest Posted July 2, 2014 Author Report Share Posted July 2, 2014 Ahh thanks for clarifying. I'll tap into the wire before it for my new relay signal wire. Link to comment Share on other sites More sharing options...
StarquestRescue Posted July 2, 2014 Report Share Posted July 2, 2014 That's not a resistor, it's a capacitor. The capacitor inside is hooked to both wires. It's there to prevent pump noise in the radio. But just like the one on the ignition coil it can be eliminated without any ill affects. Leave it in, take it out, makes no difference.Yes it does make a difference. Because when i checked voltage on the pump side i had less voltage then on the harness side. So in the trash it went. If i recall both wires on the pump side of the box look the same, so care must be taken not to mix the wires up. Link to comment Share on other sites More sharing options...
'87quest Posted July 2, 2014 Author Report Share Posted July 2, 2014 I'll eliminate it then! Link to comment Share on other sites More sharing options...
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