RedRocketZ28

iTrader: (19)

Could a vent issue cause this? Right now I obviously have my stock feed line as the return. The middle port on the bucket is EVAP correct? Well this is no longer going anywhere and is dumped. The other port is the stock return side? This is wide open currently. Do I need this capped? I can't remember if it used to be or not. It had been awhile since I have had to open up the trap door.

Ryans99ls1

iTrader: (16)

You dont need it capped. I was an idiot when i put mine together and put my return on the evap hole. All it did was blow that check valve into the tank. My return was wide open as well, no issues

RedRocketZ28

iTrader: (19)

Thanks man. Grasping at straws here!

RedRocketZ28

iTrader: (19)

Update time. I drove the car down to a buddies house this weekend. We threw another walbaro 255 in it and wired it up. I knew it didn't need more fuel but I was desperate at this point. Once that was installed we jumped the hobbs to make sure all the pumps were running. Took it for a drive, and more of the same like I figured. Fuel pressure won't rise in boost, and it starts running away lean up top. Next, I replaced the vacuum line off the FPR with the push-to-connect hose and fitting like the rest of my lines are. That made no change.

So, we started checking voltage. Only thing I changed from last year in the wiring was relocating the battery to the trunk. Volts while running are around 13.1 so I figured all was well there. Checking the volts at the battery shutoff it was showing 14.1 while car was running. Checked the volts at the pump wiring with all of them running showed 12.1. Is this too low? I am not a wiring guy by any means but I still think it's a volt issue when getting into boost. With the 3rd pump on, under boost it drops to mid 12's voltage wise on the sncaner. With only two pumps it doesn't drop at all. Next step is to check voltage at the pumps when in boost. We ran out of time Saturday to complete all the tasks.

So far, I have tried a lot obviously. Does it sound like a wiring issue? I only have a couple of grounds on the entire car. There's one coming from the driver's side head to the frame. Then the battery to the rear seatbelt bolt that holds it to the body. Do I need to possibly add more grounds?

What about a PCM issue? I can no longer control certain things via the scanner in HPTuners. I can't change timing or the AFR when it's running and I used to be able to. Here's a weird one too. We took the car out and did some hits on 12-13 lbs. AFR's dipped into the 11's so I thought we were making progress. I added a touch more fuel to it and on the same boost level it was back in the 12's. All of this is not making any sense at all.

Any more thoughts on some things to check out? Sometime this week I plan on checking voltage at the pumps in boost.

stevieturbo

13.1v at the battery with the engine running is poor. I'd be wanting to see the full 13.8-14.4v or thereabouts. Basically whatever you measure at the alternator, it should be very very damn close at the battery.
If not, fix the wiring.

And likewise, I would be wanting to see pretty damn close to this at the pumps too. The more pumps you add, the more current they will draw and the more substantial the wiring needs to be. Wiring, connectors everything.

One ground from battery to chassis should be ok. But it needs to be substantial, and to good clean bare metal.

Likewise, engine to chassis.

Any other ground takeoffs like for pumps...again, proper sized and always to good clean metal, or if battery or engine block is more convenient...either/or.

I prefer sourcing wiring for fuel pumps from the alternator, unless there is a substantial cable from alternator to battery, in which case battery would be fine.

Chances of a faulty PCM is slim.

Are injector pulse widths increasing as per your changes, yet AFR's reducing ? Are you sure the engine is running correctly, and there are no misfires ?

Did you resolve the return line, so it was a straightforward open and unrestricted return to the tank ?

RedRocketZ28

iTrader: (19)

I am using 1/0 cable from alt to battery, from fuse block to starter, and from starter back to switch. The 13.1 volts while running is according to the scanner. At the battery it was showing 14.1, likewise at the switch. The pump wiring though was showing a decent drop. It was 12.1 with all the pumps running and voltage on the scanner dropped into the mid 12's.

Injector pulse widths are increasing the same on both banks. They seem to show a rise with the added fuel, as well does the duty cycle, but the engine isn't receiving the fuel. I know there is not any misfires, and the engine appears to be running the same as it did before this issue. Just AFR's going lean and fuel pressure not rising. It does not smoke, has good vacuum at idle, and sounds healthy.

I have not done anything with the return line. I assume it is flowing well though as turning on all 3 pumps the same time shows a very small increase in fuel pressure at idle. It maybe goes up 1 or 2 psi.

Ryans99ls1

iTrader: (16)

With this being such a tough issue to tackle, you cant leave anything on the table. Bypass the filter in the return so you can be absolutely positive its the cause. Pull it and put rubber hose in place as a quick test.

RedRocketZ28

iTrader: (19)

Good point. I will do that as well.

stevieturbo

You did confirm the pumps/reg are able to make pressure ? ie mityvac applying pressure to regulator ?

Can toy stick a pressure gauge onto the regulator reference port and take it for a drive ? Tee local to the regulator itself.

It just sounds so weird fuel pressure doesnt rise at all...as if it isnt getting a signal ?

RedRocketZ28

iTrader: (19)

Have not hooked up anything to apply pressure yet. However, I cranked the fuel pressure up at idle and it climbs as it should according to my dash mounted gauge.

I will try to get something hooked up and monitor pressure that way as well. Something else to try.

It rises sometimes, and other times it does not. Base pressure is set at 60 psi with vacuum source unplugged. On spring pressure only (showed 8-9 psi on logs) it rose to 65 according to the gauge. Crank up the boost, and it won't make it over base pressure. Voltage on scanner shows the same 13.1-13.2 volts. Could still be dropping at the pumps though correct?

So...next things to try are:

1. Check voltage at pumps under load/boost.
2. Check pressure at regulator like you mentioned.
3. Get rid of the return filter
4. Check voltage all over the car and add/clean grounds if need be.
5. Try another FPR? The aeromotive one I tried was only good for 70 psi. I had that set at 60 psi base but only running on wastegate spring. Could it still have been too high for that particular regulator since it was only good to 70 psi max?

Would it be a good idea to unhook the fuel line from the bucket to filter and from the filter to rail and blow out with compressed air? Maybe something clogging it? Outside of the things mentioned in my list, replacing all the fuel lines would be a last ditch effort. If I did that I would go to -10 feed and use the existing -8 feed as my return.

I never thought that changing the oil and trans fluid would cause me so much headache.

stevieturbo

You are wasting your time reading voltage off a scanner. That only tells you voltage at the end of the wiring to the ecu. Not the pumps.
At present, who cares about the rest of the car ?...you're only interested in the pumps

You need to apply pressure to the regulator and see if that aspect even works at any time.

Just run a temporary return line from regulator to tank...even if it's long hose shoved back into the fuel filler spout. Just make sure it's free flowing

But check the above first.

98Camarod

iTrader: (43)

When you set the base pressure, it's with the vacuum unplugged. So once you hook it back up it will drop to less than 60psi depending on your vacuum. It rose to 65psi, that should be close to the required 1:1 rise.

Have you tried a different alternator?

RedRocketZ28

iTrader: (19)

Right, it drops to 54-55 when plugged back in at idle. Driving around it drops to 52-53. Should it drop on a complete 1:1 as well? For the life of me I can't remember if it did last year when all seemed well. I am pulling 10-11 inches of vacuum at idle and driving around it will be 14-16 at times. Base pressure has always been around 60 psi with this setup. As soon as it gets into boost it will rise to 59-60 then either hold around there or drop a bit. The other night when it rose to 65 the AFR was 11.8. Should be around 11.1-11.2. That was on 9 lbs of boost or so. Kicked it up to 12-13 lbs. and pressure wouldn't rise above 60 and AFR's shot up to the high 12's, low 13's. I even took it a step further, which was dumb, and hit it with 18 lbs. for a brief second and when I saw the AFR's jump into the 15's I immediately let out. Failed to mention I also put my buddies AEM wideband in it since mine gave me an error code again.

Also, with the 3 pumps kicking on, the voltage at the scanner will drop to mid 12's. Never did this with just two pumps. Have not tried a different alternator due to the fact it was showing 14.1 volts at my battery shutoff which is coming directly from the alt. On a cold start I get 13.5-13.6 volts and it drops to the 13.1 range when the car warms. This is from the gauge, not directly from the alt with a volt meter. Is that about normal? I suppose trying a different alt would rule out that as well.

stevieturbo

Fuel pressure should track manifold pressure 1:1

So yes on vacuum, it should fall, on boost it should rise. With only 9psi boost, I would expect it to rise by 9psi for sure.

With 30-40psi boost...I wouldnt have that same expectation...even if in theory it should.

As there is no real need to be running 60psi base, you could try dropping fuel pressure to say 45psi ( no vac attached ) and see if fuel pressure tracks manifold pressure better.

You'll need to bump the fuel tables a little to bring mixtures back in check.

Walbro's and most pumps suck over 70psi or so....although really they shouldnt be struggling so bad in this case, especially with 3 of them

But get the mityvac onto that reference port and see how fuel pressure behaves when you add some pressure.
Even do it when driving with some fuel being used if it helps

But should also say....the relatively small fuel pressure numbers you're talking about, really wouldnt explain such large changes in AFR

When you say you're watching injector pulse widths increase...are these definitely IJPW's as seen at the injector, after any compensations have been applied ?
Not just a base table of some sort ?

RedRocketZ28

iTrader: (19)

I am not positive on the injector pulse width. It is whatever HPTuners looks at in the scanner. I couldn't tell you if that is after any compensations have been applied. Suppose that's a question that needs to be answered.

My tuner actually suggested 65 psi base fuel pressure but it was set at 60 ever since I have had the 127# injectors in it. I am on E85 and my injector duty cycle was in the 80% range on 14-15 lbs. last year with the smaller turbo and cam.

It's hard to watch the wideband, the fuel pressure, road and speedo when doing a pull on the street. I have a speeding ticket which confirms that from this weekend . I had a buddy drive my car the other day while I watched the gauges and scanner. Anyway, the fuel pressure seems to do funky things. Sometimes it drops well below the base 60 psi, other times it will rise a bit, and other times it sits right around the base 60. No rhyme or reason to what it does.

stevieturbo

**** watching gauges...datalog !

If you have no means of datalogging and must watch manual gauges..set up a video camera or something.

Watching anything other than the road is a recipe for disaster

RedRocketZ28

iTrader: (19)

I have hptuners and do data log. I would rather not stay on the throttle if it starts running away lean.

stevieturbo

Not saying to stay on the throttle. But the logs will contain the data you need, and you can review it any time.

You'll also have logs for future reference. It's always handy to keep logs to refer back to, especially when having problems.

98Camarod

iTrader: (43)

Something to think about here as well, my autometer electric fuel pressure gauge went out this past season. Have you checked with a mechanical gauge to verify the fuel pressure?

I have my base pressure at 43.5lbs and it drops to 39lbs at idle and rises with exactly 1:1 ratio as it should.

x2 and definitely don't try to watch gauges. Verify that the gauge matches at idle to what the scanner says and when you rev it and then roll out. You don't have to run through all the gears or anything to get the data that you need.

stevieturbo

The problem occurs under load. So any tests must be carried out then. Obviously not taking it to the point of causing damage though