Fuel injector Prob. 77 280z

[jagnew3]

Hmmm could be I guess, but it has always powerd up when I trip the shutter, and only seems to happen when I really romp the throttle. Could it maybe still be running, but at a lower voltage, causing it to lean to 0? And if it did this, why does the pump activate imediately, only w/o pressure? It truly is like the pump runs dry. I don't know how these aftermarket pumps do with priming, maybe it is for some reason going dry and taking forever to re prime. It's bizzare , I'll check them over real good Bob, it just does'nt feel right. I got my 1977 FSM on cd today..maybe, someplace in the 670+pages is the answer..

[Jeff Bolin]

there is a problem with trying to just run the gas through the filter the are only a few ways that I have found to make the fuel pump run. you can either jump the fuel pump relay, you can go direct to the fuel pump its self ,if you have a power source IE a good battery and jumper leads and hook direct to the pump. or you can go the long way and figure out how to jump the oil pressure switch and the alternator switch. Both of the latter are what tells the pump to run when the key is turned.( I bet you noticed that the pump didnt run until you turned the motor over huh) and just kicking the starter won't make it either, since the fuel pump relay does not latch (on). But when you do succeed in getting the pump running ,there will be a considerable amount of fuel running all over the place believe me. For this little problem I went to Home Depot and bought a length of that clear plastic tube and ran it from the filter back to the tank filler then kick off the pump and watched the fuel flow. If you still have issues with rough starts you might want to look at the cold start injector. or the switch that controls it . you know where the cold start injector is located but the switch is located just below the thermostat housing it is the larger hex nut in the housing the other is the water temp sender. I forget what the exact name for the thing I think it is called a thermaltime switch but I am sure, some one here can tell you. Any way you can't miss it.Look right under the hose attached to the housing and radiator. those are the two ususal suspects for rough idle that and of course dirty injectors but you took care of that issue. If you have any other questions I am real good with this silly fuel injection system I have a 77 280 2+2 these things are a kick in the pants the motors are almost bullet proof. as long as the oil is pumping you got no worries hahaah take care

jeff bolin

73 capri 2600

74 capri 2800

73 MGB roadster

77 280z 2+2

88 ranger XLT

92 transport

04 toyota 4 runner

and boats and motorcycles and kids and dogs and cats

hahahahah

have a ama(Z)ing day

[jagnew3]

Thanks, Jeff. It has always started great. I already have runn an entire tank of fuel through the filter, using the long hose after the filter, while making the pump run by holding the air flow sensor shutter open. Worked like a champ. The problem is the car starts great, the thermotime switch does it's job, then the idle slowly comes to 900, and the car runs great...a little low pressure, but running great. As long as I don't stomp it. When I do, the car goes lean, fuel pressure drops, and will not recover..like someone shut down a door in the pump supply line., I let it sit, and I trick the pump into pumping, and finally the pressure comes back up..and we go through the whole thing all over again.. For some reason the pump stops pumping fuel. I think when I punch it, the pressure (due to low volume) can't keep up and it drys the pump out. and then the pump needs a while to re prime...because there is a restriction. That or either the TPS or the AFS are for somereason shutting down the pump, and it uses all the fuel and can't get re primed.. It's a lot of fun. I drove it for an hour and had no trouble...until I romped it..then it started this crap again..

[Jeff Bolin]

take a look at the pressure regulator at the pump or look at the fuel rail pressure regulator or the vacuum line to it

you might want to pull the lower hose of fthe tank and make sure it isnt partially blocked that happened to me it was bad gas sludge i cleaned that out and all is good on that end

BTW how are you measuring fuel pressure>?

if your pump is starving I would pay close attention to the lower supply line

if the tps goes bad you will get a surging motor I had that about 3000 rpm it would surge I found the contacts were corroded I cleaned the same and used silicone grease and bingo no more tps issue the afs can cause your pump to die out if the switch contacts are some how fouled (dirty corroded)

but I would make sure your fuel delivery is good first then work my way forward

be safe have an amaZing day

by the way I am running an aftermarket pump also I didnt need to prime it all

[jagnew3]

I have a pressure gauge installed between the filter and the regulator. I kinda enjoy being able to monitor it. I wish there was one in the dash. I installed a new regulator (rail) yesterday, and with it new vac hose and line hoses. The new regulator seemed to smooth the engine (though it was pretty smooth already). I am checking the fuel line from tank to pump tonight, but there will be no driving, as there is too much snow on the ground, and This Z will never see it as long as I own it, I truly feel like something is plugging, collapsing, or the like..we'll see. If I clear something out I should see a rise in pressure I would think.

[sblake01]

I don't think there's a clog anywhere. Been there done that. It would act differently. If that 'aftermarket' fuel pump is a Master E8312 from Parts America and their affiliates, you may have added to your problems. The throttle position sensor, thermotime switch, cold start valve etc. won't make the fuel pressure drop. There is no pressure regulator at the pump. Jeff B., maybe you mean the fuel damper? And as for the other point, even if there was a clog, you'd still hear the pump trying to ... well, pump. Now, Jeff A., by air flow sensor, I'm sure you mean Air Flow meter. There are contacts there that are part of the system that runs the fuel pump and there's a good chance that your problem lies there. You've changed a few parts and still basically have the same problem. You say it runs fine when you open the flap on the AFM. You need to check those contacts and make sure they are clean and functioning properly. But don't just throw parts at the problem. Read your FSM especially in the area of fuel system trobleshooting. Sure, all those ways that Jeff B. suggested will make the fuel pump work, but what good does that do when it doesn't work when connected properly?

[jagnew3]

Steven..I missed you. Any ideas why when it goes into this state of o pressure, the pump won't pump fuel...even though it is running? I think that the Air flow meter is playing a trick, but I can understand why, even if it's the main cause, the pump won't pump for bit (though it's running) when I open the air flow meter shutter manually...The pump runs and runs..but sounds like it has no fuel. I'll take a good look at the air flow meter, but that stuff inside is prolly a bit too exotic for me.

[jagnew3]

BTW it's not that pump..it's most likely the same aftermarket one avail through NAPA though. What are the problems other have had with thiers? This one is running good, is quiet and did give me some improvement, though it still aint right.

[mriz]

The only thing I can add because I just went through an idle problem (corrected with Steve's help)is to do the pin tests on the ECU connector from the FSM. Some tests cover the injector circuit,cold start valve ect.. Kept me from chasing parts.Hope it helps.

[sblake01]

I don't know about the one from Napa but the pump I mentioned (from Parts America) has no check valve and thus would bleed down the pressure as soon as it stopped pumping. IMO, OEM is the only way to go there. If the pump 'runs and runs but it sounds like there is no fuel' as you say, then I stand corrected on what I said earlier. The fuel pump is self priming so maybe there is a clog somewhere prior to the pump. But, then again, like I said, I don't trust aftermarket pumps. Let me know what you find out when you check the line between the tank and the pump.

[jagnew3]

Thanks to all, especially you Stephen, You are what is keeping this fun. Your encouragement for me to use the service manual is appreciated. I do the same thing when people are shade treeing their sea doos. It's great to fix something, but better to understand it. I think the issue of pump pumping vs pump running was a misdirection/ communication on my part. It does run when I trip the shutter, but will not pump fuel....for a while..then does. Last night I did check over the Air flow meter, and I believe it to be sound. I did clean all the contacts, and the connector. BTW I could not get the thing to do it last night, but I didn't drive it either. However, that said overall pressure is down since the last time this happened. It's now running about 30-32, goes down a bit when I rev the engine, then as I let out it rebounds to around 38 for a second..then rests at 30-32 again. It was pushing about 36 before the trouble came back (remember I put 45 trouble free miles on it before it started again.)..I say came back because this is about what it was doing with the old pump...before I wrecked it..

Here is the link to the pump Stephen

:http://napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=BA&PartNumber=1528029&Description=Fuel+Pump+(OE+Electric+In-Line+Type)

I think that is a check valve at the end with the electrical hook up, but I only assumed it, I didn't check, and I didn't ask Btw I didn't pay anything near that price...I get a big napa discount, as my shop does $3500-$4000/ mo. in parts with them. (ofcourse being that it's napa, $4000 is two packs of spark plugs, and oil filter, a shop towel and some armour all at Napa )

Anyhow I'm gonna change my fuel filter..again, and clean fule pick up line up a bit, and see if we get anything better. There is no strainer on this pump...though it is made to accept one, and I am looking for one (mine was missing) and it could be it has sucked a bunch of stuff up. we'll see. Thanks againg for so much great advise. If you know who's selling the oem strainers please let me know. How much pressure gets put on the line comming out of the tank...could I put a valve and my glass inline filter the as a temp way to watch what goes through there?

[jagnew3]

Sorry, bad link Here's napa part number BA1528029