Cleaned HFCM, now losing FP
- Thread starter 6speedsd
- Start date
Seems most likely that air is causing the gauge flutter. The faster the fuel moves under demand, the more air.
Question; how would an injector oring allow in air? Im trying to visualize it, but the pressure at the oring is positive and hes reported no fuel in oil.
Have you sampled fuel supply in various points in the plumbing to see if there's air? Perhaps pre-upper filter, post injector rail/pre regulator, post regulator, etc.
Question; how would an injector oring allow in air? Im trying to visualize it, but the pressure at the oring is positive and hes reported no fuel in oil.
Have you sampled fuel supply in various points in the plumbing to see if there's air? Perhaps pre-upper filter, post injector rail/pre regulator, post regulator, etc.
6speedsd
New member
Koeo gauge holds steady. No fluctuation at all.
I talked to my injector builder a little today and he too seems to think it's a failing oring. Said it would take a substantial leak to cause the volume of fuel needed to dilute the oil, or even make it smell like fuel. A leaking oring would let pressure drop as the fuel is being pushed past the oring instead of pressurized in the rails.
When I got home tonight, I pulled the stock fpr spring and brass seat out of the filter housing just to see what would happen. I had regulator set at 70psi before. With the spring out, pressure went up to 74-75. Anyways, I dropped it back to 70. At idle, gauge is still fluctuating 68-70. Apparently that wasn't causing any issues...didn't think it was, but tried anyways.
I haven't checked pressure at any other points, but I certainly will before pulling injectors.
Sent from my SAMSUNG-SM-G900A using Tapatalk
I talked to my injector builder a little today and he too seems to think it's a failing oring. Said it would take a substantial leak to cause the volume of fuel needed to dilute the oil, or even make it smell like fuel. A leaking oring would let pressure drop as the fuel is being pushed past the oring instead of pressurized in the rails.
When I got home tonight, I pulled the stock fpr spring and brass seat out of the filter housing just to see what would happen. I had regulator set at 70psi before. With the spring out, pressure went up to 74-75. Anyways, I dropped it back to 70. At idle, gauge is still fluctuating 68-70. Apparently that wasn't causing any issues...didn't think it was, but tried anyways.
I haven't checked pressure at any other points, but I certainly will before pulling injectors.
Sent from my SAMSUNG-SM-G900A using Tapatalk
It would not allow air in per say, but would allow pressure to drop, and if it was in the first stages of failing, would have an inconsistent pressure drop. My truck was doing yhis prior to putting my new injectors in, had lowish pressure that would drop to 45ish psi with an air dog 2. It was also dumping some black smoke on a neutral run up in a stock tune. When i tore it apart, found #5 injector had started burnng the white o ring, bottom section was pretty black, copper washer was ok. No noticeable fuel in the oil, no overfilling of oil. Just suggesting it from past experience as all other options have been about exhausted.
6speedsd
New member
I'm going to put a gauge in at the factory test port this evening. That'll show me pressure before the heads...regulator (where I've been checking it now) is after heads. Not sure if that'll show me anything, considering this is a looped system now, and if my mind is wrapped around this right, a drop in pressure after injectors should also show a drop before...? But then again, maybe I'm thinking about it wrong.
Just want to definitively exhaust EVERY option before I start yanking injectors out.
Sent from my iPad using Tapatalk
Just want to definitively exhaust EVERY option before I start yanking injectors out.
Sent from my iPad using Tapatalk
:thumbsup:
Ok, gotcha
6speedsd
New member
Gauge ran to test port. Still dancing around at idle, which I figured it would be, but had to try at least. I'll run it tomorrow hooked up there just to see if there is ANY difference.
Sent from my iPad using Tapatalk
Sent from my iPad using Tapatalk
6speedsd
New member
Tell me about it.
I'm actually starting to wonder about my regulator. It's been unusually loud lately for some reason..like, hearing it inside the truck when I'm sitting at a light or something. I looked up some reviews on the particular model I have, and there were a few instances of guys in the turbo gasser world having issues with pulsations, gauge flutter (one guy even mentioned 7-10psi fluctuation)...says the issue is because that model has a thin diaphragm which can't stop pulsations. Makes sense thinking about it. I considering buying an El Cheapo regulator just to throw on there to test if that's my issue. Either that or getting a few fittings to cap off the lines coming from the back of my heads, and run the supply side back like factory...basically doing away with the RR and my regulator.
Sent from my iPad using Tapatalk
I'm actually starting to wonder about my regulator. It's been unusually loud lately for some reason..like, hearing it inside the truck when I'm sitting at a light or something. I looked up some reviews on the particular model I have, and there were a few instances of guys in the turbo gasser world having issues with pulsations, gauge flutter (one guy even mentioned 7-10psi fluctuation)...says the issue is because that model has a thin diaphragm which can't stop pulsations. Makes sense thinking about it. I considering buying an El Cheapo regulator just to throw on there to test if that's my issue. Either that or getting a few fittings to cap off the lines coming from the back of my heads, and run the supply side back like factory...basically doing away with the RR and my regulator.
Sent from my iPad using Tapatalk
6speedsd
New member
I doubt I can get that lucky, but I'll check it out.
Just watching some stuff yesterday, noticed something odd. It drops some as you accelerate, and will drop significantly if you stand on it, as it's been doing all along. However, while just cruising at a constant speed, anything under 70mph and the gauge fluctuates about 2psi. Say 68-70. The minute you hit 70, it starts fluctuating 5-10psi. It'll go 70 to 60, up and down constantly. Slow down to 68-69 mph, and it settles out. There isn't enough of a load change over that 1mph to cause it to do that if it's a bad injector oring...I don't think anyways. Now, this was while reading pressure at the test port, and not off my regulator.
Sent from my SAMSUNG-SM-G900A using Tapatalk
Just watching some stuff yesterday, noticed something odd. It drops some as you accelerate, and will drop significantly if you stand on it, as it's been doing all along. However, while just cruising at a constant speed, anything under 70mph and the gauge fluctuates about 2psi. Say 68-70. The minute you hit 70, it starts fluctuating 5-10psi. It'll go 70 to 60, up and down constantly. Slow down to 68-69 mph, and it settles out. There isn't enough of a load change over that 1mph to cause it to do that if it's a bad injector oring...I don't think anyways. Now, this was while reading pressure at the test port, and not off my regulator.
Sent from my SAMSUNG-SM-G900A using Tapatalk
6speedsd
New member
Very little rpm difference.
Ok, here is the fun part. Rode out to help a buddy with a truck today. Ride out gauge was hooked to sender in test port on fuel filter. Like I mentioned, 70mph and up she fluctuates like crazy....5-10psi. Ride home, moved the gauge wiring back to the sender off the regulator. Guess what....no more crazy fluctuation at 70mph plus. Still bounces a couple psi, but not the erratic 5-10 above 70. I don't quite understand that one.
At first I thought maybe engine vibration was causing an erratic reading off the sender, but that wouldn't explain it only doing it at 70+.
I need to just order that Cheapo regulator and see if my current one is at fault. Go on and rule that out once and for all.
Sent from my iPad using Tapatalk
Ok, here is the fun part. Rode out to help a buddy with a truck today. Ride out gauge was hooked to sender in test port on fuel filter. Like I mentioned, 70mph and up she fluctuates like crazy....5-10psi. Ride home, moved the gauge wiring back to the sender off the regulator. Guess what....no more crazy fluctuation at 70mph plus. Still bounces a couple psi, but not the erratic 5-10 above 70. I don't quite understand that one.
At first I thought maybe engine vibration was causing an erratic reading off the sender, but that wouldn't explain it only doing it at 70+.
I need to just order that Cheapo regulator and see if my current one is at fault. Go on and rule that out once and for all.
Sent from my iPad using Tapatalk
Last edited:
6speedsd
New member
Wiring issue to what? I've confirmed the pressure drop with a pair of mechanical gauges as well.
It'll stay in the 60's as long as I don't go over like 30%pedal. Anything over that and it drops. I'll drop into the 30's if you stand on it hard enough.
Sent from my SAMSUNG-SM-G900A using Tapatalk
It'll stay in the 60's as long as I don't go over like 30%pedal. Anything over that and it drops. I'll drop into the 30's if you stand on it hard enough.
Sent from my SAMSUNG-SM-G900A using Tapatalk
6speedsd
New member
I have not. Major fluctuation only occurs when reading at the test port on the filter housing, pre-injector. Reading pressure at my regulator... post-injector... does not show that fluctuation. That part is starting to make me think it's not an oring issue.
Also noticed when it was fluctuating so bad above 70, I'd see as high as 75psi on my gauge. Regulator is set at idle at 70psi, so im.not sure if pressure really is somehow spiking that high, or if that's the gauge just over sweeping above 70...sort of a momentum type of thing if that makes sense. I'm still wondering about the regulator though.
Correct. Filters have actually been changed twice since this all started. Once initially, then again about a month later.
Sent from my SAMSUNG-SM-G900A using Tapatalk
Members online
No members online now.