ZZ3Astro

Vapor lock at what location? Inside the pump impeller?

Interesting finding tonight... I've been chasing hard start from the beginning. I just discovered the +12v feed to the coils is only active when the fuel pump is on. I was chasing down the power wire to the coil packs because a friend who works on a lot of Holley EFI systems told me he has seen this problem when the coil power wire is too close to other wiring from the ECM. I was trying to verify which pin was the +12v feed at the coil sub-harness and couldn't find any at all. Finally I set the meter up and cranked the car and saw +12v come up. I then put an LED light on that pin and cycled the key. Sure enough, it lit up with the fuel pump prime then went out! No wonder the long cranks before it will fire.

Is this the proper way to wire a Holley system?? I don't know, I paid the experts to figure it out. Guess since I've already gone through half the wiring I might as well read up on the rest of it..

ZZ3Astro

https://images.holley.com/271r968-1a.jpg


Well I guess they did it 'right' according to the LS1 harness instructions. Anyone else have experience with this system and powering LQ coils directly from the fuel pump relay? Funny thing is the subharness instructions say give it a 20A circuit but the Dominator instructions say the fuel pump on the same relay (if you choose to run it from that relay) can be a max of 10A. Maybe it's a 30A relay. Either way if LS/LQ coils can send so much noise back into the system why would they power it from the relay built into the harness?

Street Lethal

iTrader: (16)

Vapor lock in the fuel rail. The car was driving fine during the test runs, was idling fine in the garage when you got back, but then fuel pressure suddenly dropped, and the engine died. Regulator was hotter than usual. Hard starting afterward. Second pump was triggered, pressure was restored, but the engine still didn't want to start and run. The next time that happens, especially on a hot day, try purging the fuel rail by depressing the schrader valve watching for vapor release, then restart. It sounds like a check valve issue, because this wasn't the first time that this has happened if I remember correctly...

- Rob

ZZ3Astro

No Schrader on these holley rails, but they are flow through, in one rail and out the other with an external regulator. If it's locking anywhere it is probably at the pump head.


The only thing I have left at the moment is to look at the power and ground for the coils. Holley recommends powering the coils on the fuel pump relay. I will try bypassing that and powering them from a separate feed. Also the coil ground is supposed to go directly to the block. I don't see that yet, will look for it this morning. Everything else is by the book though and I'm sure he ran the ground per instructions. Everything else by the book except they didn't verify which coil went to which cylinder and that was what I had to re-pin for.

Street Lethal

iTrader: (16)

Double check your check valves. The moment you stated that the regulator was hotter than usual, and that the first pump you can hear working but no pressure build up, and the second pump was triggered with pressure being restored but still no starting nor running, it essentially underlined vapor lock. Hotter than normal day, temps were rising pretty fast during your driving, and everything was fine up until that point of idling in the garage for a long period of time...

- Rob

ZZ3Astro

I really need to put some kind of fuel cooler on the return line. If I could get the analog gauges working I could actually keep an eye on the fuel pressure while I'm driving. I have the MFD but not easy to read a digital pressure while trying to drive it under boost.


Meanwhile since the low boost tune is not too bad I took out my anger on the old front tires!

Street Lethal

iTrader: (16)

Be grateful it's nothing major Steve. Fix the fuel pressure issue which really shouldn't be that difficult to do, and send the gauges back to Holley for them to test themselves. I on the other hand am down to a short block because either my Cometic MLS gaskets are no longer holding, or the rings are toast in the one and three cylinders. So yeah, be grateful it's nothing major. Could always be worse...

- Rob

ZZ3Astro

Alright so here goes..


Running the coils off the jump box seems to have resolved most of the issue. During a three minute test I did observe one glitch. I did confirm the power to the coils/injectors is a separate feed from the main ECM power. I also found that the coil ground was to the chassis NOT to the block as instructed. I grounded it correctly but made no difference.


I also discovered the Holley EFI Analog Fuel Pressure gauge is, in fact, reading the OIL pressure. Not sure if there is a fix other than replacing that gauge. Not a good experience with these gauges that is for sure.


So next I'll try to filter the power with a capacitor on the coil feed, I guess.

no new tires

So what did 9K buy again?

DIGGLER

iTrader: (1)

why was the LS even being mentioned with these guys? there should be plenty of documentation with the holley for a sbc with individual coils. i have a friend that ran that setup.

on the fuel issue, did you hear any bubbling or pressure in the tank?

anesthes

iTrader: (12)

Car just doesn't want to get finished.

You are a patient man though, if I had even half of these problems that thing would be on its way to China right come back as several washing machines.

86CamaroDan

9K for that type of work? wtf? Nobody will ever work on my own stuff, EVER, for reasons just like this. All that money and your doing it over again anyway. Im in the wrong side of the business if they got you for 9K on that type of install.

Drac0nic

I'd get some ferrite and wrap a few turns around it.

In terms of the oil pressure I'd check connectivity to the sender. They're both 90 ohms if OEM GM so chances are it's hooked up to the wrong sender.

ED:Also some flat braided grouding strap all over the place couldn't hurt things if you're just running wire.

Orr89RocZ

iTrader: (20)

Interesting. I was under impression that coil and injectors were just assigned to pins for cyl 1-8 for v8 harness and that firing order was programmable in the holley. Did not think repin was necessary

I havent gotten this far yet with mine but will be checking holley wiring now

Street Lethal

iTrader: (16)

Does the Holley software see the same oil pressure drop, or is it just the gauge? If the software is showing oil drop prior to engine shut down, well then you found the problem. I still think you're experiencing vapor lock on the hotter than normal days, but if the system see's a sudden drop in oil pressure, pretty sure Holley would have it kill the fuel pump as a fail safe. If it's just the gauge itself, then yeah, burp your fuel system. How did you run your pickup sender? Are you running the stock check valve? How many fuel filters are you running?

- Rob

anesthes

iTrader: (12)

The firing order is programmable.

I'm confused.

-- Joe

ZZ3Astro

I have about 6k in the Holley parts through a source at 10% over cost. That's all of the harness components, 5 small gauges, 2 large and one small MFD, O2, pressure sensors and the Dominator ECM. I spent right at 2900 with the shop to install the ecm, main and subharnesses, wire up the gauges, reroute and terminate the rear mount battery cable all the way to the starter, build relay panel for the fans/fuel pumps, install main battery cable circuit breaker, wrap the crossover and downpipe and make new front brake lines (hard lines) to fit the tubular crossmember.

ZZ3Astro

I agree, it was vapor lock affecting the fuel pressure.

ZZ3Astro

The firing order issue was this:


As an example Holley ECM expects Coil #1 to go to pin B21


On a standard LS/LQ Coil Harness 150 series connector (the one that goes to 4 smaller connectors the plug into each coil) I believe Pin B is cylinder 1, C is 3, F is 5 and G is 7. The specific pins do not matter for this example. The point is on my car the cylinder attached to the coil on a particular pin is DIFFERENT than an LS because my coils are remote mounted and organized in a way that makes it easy to know what coil goes to what cylinder.


What this shop did was ignore my request/statements and figured LS Coil Harness, LS wiring. Yes you can adjust the firing order in the software. It needs to match the engine's actual firing order. It's not there to correct wiring mistakes. The injector sequence follows this order as well.

ZZ3Astro

I am ignoring all analog gauges due to the glitches and incorrect readings. The MFD and laptop show the fuel pressure drop yes.


I am unaware of a fuel pump shutdown commanded by low oil pressure in this system as a default. If there is one that could be something to consider, however the fuel pressure drop is very slow when it happens and it maintains about 7-9 psi as it tries to run.. and it won't restart once it happens until it cools off a bit.


Running one inline billet filter (can't remember which one but it wasn't cheap). Only check valves I'm aware of are the pumps themselves and whatever they have inside. Aeromotive 340s

Orr89RocZ

iTrader: (20)

What is your fuel pressure normally?

Drac0nic

Actually as a question do the sensor grounds tie to a common point? I'm wondering if the ground isn't that great or if you're missing a couple of them. I mean, it could make it so the gauges "pull" on one another and would likely contribute to noise too.

ZZ3Astro

Fuel pressure is set to 43 psi base.


Draconic keeping in mind these are can bus gauges, the individual gauges would not be affected by sensor ground issues. That said, it's an off the shelf Holley EFI harness for tpi engines so the grounds are all tied together at a central location AFAIK.

Orr89RocZ

iTrader: (20)

If you dont add a cooler try 55-58 psi base

DIGGLER

iTrader: (1)

i watched your last couple vids and wanted to add a thought on the noise issue... the can/sensor wiring should be nicely separated from power wires. in car audio, the standard is to run rca/low level wires down the center of the car, heavy power cable down once side of the car, and speaker wiring down the opposite side of the car. i have firsthand experience with alternator whine due to power cable running alongside rca cables. induced noise really comes into play when you have wiring running in parallel to each other, not so much when crossing one another like a T.

so basically, make sure the low level wiring is far away from any heavy current wires and especially the plug wires.

ZZ3Astro

Diggler - he ran the CAN wire across the top of the dash away from everything else so he did good there.

The MSD noise filter arrived yesterday. I had a few minutes yesterday to hook it up to one of the two LS coil harness extensions... so the main power feed Y's just before the two plugs, which the extensions plug into. I decided if I was going to cut any wires it would be on those extensions. I ran the car with the filter on the one side it seems to be enough to dampen out the noise that was going back down the feed wire. I may still wire the other side as well but I'm going to drive it first and see what happens. The two minute idle test had no glitches. I have a feeling even with both sides hooked to the filter that I would still benefit from installing another filter on the main power feed wire of the Dominator as well.
Hoping to get a chance to drive it some today.

anesthes

iTrader: (12)

I know what you mean now, but that's not what I thought you meant.

Cyl 1 is Cyl 1, doesn't matter if it's an SBC or LS1. Ford numbering is different.

I didnt' think you meant they wired CYL 1 to a pin that wasn't CYL 1. (or ignition driver 1 rather).

They should have followed your plug wires to know which coil was which.. I don't get how they screwed this one but, I suppose I'd have to see it. I realize you mounted your coils in a odd spot, and to make your plug wires work your coil connectors might not be what they expected. But they should have traced it out.

-- Joe

ZZ3Astro

I asked them to trace it out, and I pointed out the cylinder ID tags on each plug wire right at the coil end. The question was the 1->4 connector because with the coils demounted from the factory bracket, the subharness came off and the connectors are not labeled and the middle ones can easily reverse location. I could have and would have easily traced it out and plugged them in the correct order but I was paying someone else to do it. They are not easy to dismount or access all of the coil harness plugs as they are kind of stuck up in the nose a bit. I told them I had no idea which coil went to which pin and to please trace it out.


Drove the car.. broke down immediately due to fuel pressure while the car was still warming up. Definitely cant be vapor lock. I was making a turn though, and fuel was down a good bit (should be at least 2 gallons left though). I added 10 gallons after a successful restart and drove about 10 miles with no issues including 12 psi no issues holding 11.0:1 AFR. I stopped at a store and had a start issue and had to flood clear, but it had CLT of 210 deg so I reduced start-up fueling at that range and it started right up. When I got home it died in the drive way and I just happened to be looking at the FPR gauge and I saw it drop off to 7 psi as it died. For now I'm going to reverse the order of the pumps. I'm going to make the secondary become primary and see if it ends up with the same problem. If so, its vapor lock. Otherwise pump #1 is bad.


I barely need the second pump when I'm in boost so I can get away with #2 having issues - it probably won't have the issue in the short time I'm in boost anyway. I'd like to consider E-85 capability when I upgrade the fuel system so I'd rather not buy a pump just yet.


Car has endless attitude that is for sure.

DIGGLER

iTrader: (1)

2 gals is pretty much empty imo since the lines and such probably hold nearly a gallon. Probably best to keep at least a half tank in there at all times. Pumps die quickly if starved

Orr89RocZ

iTrader: (20)

If it happens again with pump 2, try jackin pressure to 58 to combat vapor lock. 4th gens with return less style did this

ZZ3Astro

Pump 2 did the same thing. I'll try the pressure thing next. Today it shut down during a hard decell. Second pump got it moving again.


Car is running hotter than before and I can't figure out why. It is in the low-mid 90's here and that isn't helping, but it's running 215-220. Has plenty of coolant. Maybe the thermostat is acting up after sitting for a while. I went about 10 miles and it never over-heated but 215 is too hot for me. Timing while cruising is in the high 20's so it might be worthwhile to increase into the low 30s and it might reduce temps some.


Car is spinning those tires pretty readily but it still feels sluggish with the timing so conservative. I really need to swap those valve springs and the plugs are fouled from whatever they were doing to get the car started, so I'm just going to do springs and plugs at the same time in a couple of weeks. Long way to go with this car especially if the higher PSI doesn't fix fueling.

Orr89RocZ

iTrader: (20)

Yeah def jump timing lol high 20’s is idle timing lol you are putting alot of heat into the exhaust side and surrounding engine bay

How do you control the second pump? Wot switch? Hobbs? 58 psi base will reduce flow of pump 1 some so may need to turn on number 2 earlier

86CamaroDan

You running inline pumps or intank?
CLT of 210 is hot? stock t stat doesnt even open untill 195

Orr89RocZ

iTrader: (20)

I ran my car at 210-215 in the hottest of days but would lke to keep under 200 lol rad and fans werent capable in 90 deg heat but fine under that

86CamaroDan

Mine dont even turn on untill 205. temp fluctuates between 190-210

ZZ3Astro

In-pump tanks yessir... heck yeah 210 is hot! Hot on the floorboard and too hot for the fuel system it seems. Idk how the stock setup was so happy going to 238 but I like seeing 180-190 max. Car is much more comfortable and overall seems to like it better.


Second pump comes on at 3 psi via Holley system (formally via Hobbs). I think the issue is being compounded by the high flow of the 340 and excessive heat soak. From what I am reading, the Aeromotive 340 (I have in tank) pumps are compatible with PWM. So what about the idea of setting up a PWM port that modulates the pump rpm based on MAP or fuel demand? This would substantially reduce fuel flow at cruise and hopefully keep tank temps lower, reducing the likelihood of vapor lock at the pump-head.


I think I would just run both pumps all the time in that scenario. All I would have to do is replace one relay with a solid state relay and repurpose the second fuel pump relay trigger wire as PWM. This would also give me insurance against a single pump failure. Thoughts?

ZZ3Astro

Wow.. timing is wayyy off the megasquirt numbers. I just added 15-25% across the board to get it in the same range. I'm hoping this makes a big difference on underhood temps. Turbo spool was certainly very lame yesterday.

Orr89RocZ

iTrader: (20)

You hear about hot pumps and hot fuel alot with these cars but i have yet to experience it.

I wonder if its just bad pumps everyone has received or what. I only ever ran 1 pump at a time and cant see that causing much heat. I would think engine bay heat soak causes most of the fuel heating but thats just a thought

If the pumps can be pwm controlled that would work great.

86CamaroDan

I was just talking about PWM controllers with my buddy tom last week. Aeromotive has a nice one available.

+1

ZZ3Astro

A couple of years ago when I was battling high fuel temps I took my hood off.. it made no difference to fuel heating at all. Still scratching my head on that one.

Orr89RocZ

iTrader: (20)

Eh probably related to air flow over the car, doesnt really aid in the cooling of top end and the direct heating of the intake and rails of the hot coolant thru the intake greatly offsets the free air hoodless effect

Want an experiment try drilling heads so coolant goes around the intake manifold externally, and block the coolant passages. Should keep intake much cooler

Orr89RocZ

iTrader: (20)

Also if its vapor lock in the rails the higher pressure will help combat the vaporization/boiling off of the gas

But hot fuel pump cavitation will need a cooler

Street Lethal

iTrader: (16)

Steve, that will not make a difference. A radiator with no fan, but with air hitting it from the front through an open grill while driving will not lower the coolant temperature as fast as you would think, not to mention the temperature will not increase as fast as it would when exposed and not contained because of system pressure. The air is simply not moving fast enough. Not enough pressure. It takes the fan to reduce temperature being located directly next to the radiator where the coolant "splits" in which reduces the temperature, because that is where the heat dissipates. Now, when you factor gasoline vaporizing between 160 and 210 degrees depending on its' very makeup; ethanol, fuel grade, etc, throw in the added heat from your turbo headers reaching well above 1000 degrees not too far from the fuel rail, the fuel in the pressurized system can only withstand so much, and as you increase the heat, whether through a skewed timing table, hot engine bay, or just a very hot day, the gasoline will vaporize that much faster. Removing your hood does nothing, because it's not enough air to overcome the pressurized system when your're driving. If it was, then we wouldn't need turbo's, we'd just open the intake at the throttle body and remove the hood. If only lol...

- Rob

ZZ3Astro

Street Lethal, the thought was that the under-hood heat soak was contributing to the fuel heating but yep it was more the radiant heating from the engine itself and the turbo headers and turbo than ambient heat that was getting to the fuel.


I'm going to be on PWM very soon with this setup since it really doesn't cost much to do so. Very interested to find out what happens with fuel temps and the issues I've been dealing with all this time.


Took the GTR out last night to dinner... wow I have to ask myself why I bother with the Iroc at all. Ice cold air, no rattles, amazing braking and unbelievable acceleration, all at the push of a button! The only thing I can come up with is the sounds the Iroc can make with the cutout open! LOL

Street Lethal

iTrader: (16)

Steve, you are not the only one dealing with this headache, believe me. Lots of street turbo cars head to the track and suffer from vapor lock. I emphasize street because there is a difference from someone driving it occasionally, as opposed to someone driving it every single day, especially in Florida. Cars w/turbo's purposely come from the factory with the headers as low as possible for a reason. Guys want to get fancy with their setups forget, or never consider, the byproduct of heated fuel. If you're now concerned with possible fuel slosh, which I don't feel is the case, but if you want to kill a few birds with one stone, pull the in tank assembly, install an external pump that can handle your horsepower needs, and run your lines accordingly. Lose the TPI fuel lines, and lose the TPI fuel filter altogether. Go with the tried and true Aeromotive 1000 w/the Holley system controlling it...

- Rob

ZZ3Astro

Rob, more or less I'm planning to upgrade the heck out of the fuel system. I'm not sure if I want to go with a single pump and if I want to go in-tank or external. I really like the idea of redundant pumps. I think just upgrading fuel line sizes and going to PWM alone would put me in a much better situation. That said I won't rule out going to a A1000. Especially like the new brushless pumps from Aeromotive.

DIGGLER

iTrader: (1)

seems like more volume moving through the rail would help with a radiant heat issue from headers causing vapor lock in the rail? i know the pumping of the fuel itself makes heat, but maybe a cooler and plenty of fuel in the tank would take care of that.
am i wrong?

i have run an a1000 and it worked fine, but i think i would prefer in tank pumps for a street car.

Street Lethal

iTrader: (16)

I agree Dig, I'm running an intank pump and wouldn't consider doing the external pump for my car. Steve mentioned fuel slosh though, and I think he is concerned about that being a possibility, that's why I threw that out there. Still curious to visually see how he is running the four lines from the fuel tank. Normally you'll find; feed, return, charcoal canister (vapor), and check valve. He removed his charcoal canister just like I did, but I'm curious as to what he did with that line. Did he just plug it up? I added another check valve on that line after cutting it shorter back by the stock fuel filter location to help the tank release any excessive vapor build up from the increased exhaust temps, and zip tied the two check valves together for easy access to them...

- Rob

anesthes

iTrader: (12)

I'm lost in the threads..


What's the target crank HP for this build now, Steve?

I'm running a single 410lph in tank. I don't have e85 available locally so I'm sized for pump gas.

I ran braided ptfe fuel and return. It runs along the frame and then goes up the trans tunnel and into the fuel rails. Lines are sleeved with thermal barrier.

I gotta put some lighting in the race car trailer but I'm close to being ready to tow it up and beat on it at the track. I think it will pass trch.

-- Joe

Street Lethal

iTrader: (16)

Steve needs to burp his baby, she's been crying for years and needs a pat on the back. Just like throwing 600 horsepower at the stock ECM code, adding that much power and heat to a stock oriented fuel system was never going to work without revamping quite a few things. The check valve that came with the car was just enough to avoid vapor lock for two hundred horsepower, but adding triple the power and heat to an already restrictive check valve is, umm, well, it's going to build up.

Where's the tums lol...

- Rob