Holley Sniper EFI Planning and Installation

[Cooter_76]

Looking great Cooter! Did you have any issues with the kick down interfering with the valve cover? I did with my Lokar kick down, and ended up having to install a spacer under the throttle body.

I didn't have any valve cover issues, but I'm re-using the small phenolic spacer I had under the Edelbrock carb.

 

[Cooter_76]

Yesterday afternoon I managed to mount the fuel pump and started bending hard lines.

Glad I bought 25' of hard line, as I've already scrapped a fair bit as part of the learning process.

 

[Cooter_76]

I decided to run the return line along the outside of the driver's side frame rail and use a Tee to tie-in to the filler vent.

After searching everywhere for a fuel-rated tee that had two 5/8" outlets and a 3/8" outlet, I gave up and went with a 5/8" x 3 fitting. So I have a section of 5/8" running up the frame rail, then used a reducer to 3/8" flex line, then hard line. It's not elegant, but it should get the job done.

 

[Cooter_76]

The wiring was a bit of a mess. The Sniper needs a "clean" 12V wire that is hot in Start and Run. I had a blue wire coming out of the firewall that met this need, but it was already hooked-up to the + side of the coil and the Duraspark box. After discussing it in this thread and talking with Holley's tech support, I decided to run the blue wire to a distribution block. From there I have a wire going to the Duraspark, one to the coil and a another going to a relay that is connected to the wire on the Sniper. Eventually I'd like to have the Sniper control timing, so this will likely change when the Duraspark is eliminated.

 

[Cooter_76]

Once everything was hooked-up I went through the Sniper quick start guide and followed the instructions to set the engine parameters using the hand-held controller. Found a slight fuel leak at one of the connections and was able to remedy by tightening a clamp.
The Bronco fired right up, but was idling between 2200 and 2500 rpm. I only ran it for a minute or so, then shut it down. A buddy is coming over this evening to put a second set of eyes on everything before I do any more testing.

 

[Cooter_76]

Well, tonight did not go as well as I had hoped.

After experiencing the high (2200-2500) idle speed at the initial startup, I called Holley's tech support. The tech guy suggested I turn the idle screw counter clockwise 1/2 turn at a time to get the idle down. After one full turn, the idle dropped to about 1400 RPM. He said I should let it idle at that speed until the engine came up to 160 degrees and modify from there. If that didn't solve it, the next step would be to look for a vacuum leak. The IAC should read between 2 and 10%.
Later, my buddy Rob came over. After the engine warmed-up, I tried turning the idle screw back & forth. The IAC would sit at 0%, then suddenly shoot up to 50%+ and the engine would die. Couldn't get it to idle well below about 1,000 RPM. We decided to leave it there and let it learn, but it would just run for a few minutes and eventually die.
We thought it might be a fuel issue. I only had a few gallons of gas in the tank, and the fuel pump sounded a bit funny. Managed to drive it to a nearby gas station and put 7 gallons in it. Went for a drive down the road and through the neighborhood. It seemed to drive well until idling down the street. It died right in front of my house.
Got it in the driveway and we were sitting there watching it run and die. I don't have a fuel pressure gauge, but we were watching the flex line by the firewall. It would sort of surge back & forth, then go limp just before the engine died.
What's weird is that it will run fine at higher RPMs, but it does not want to idle. I guess my next steps are to get a fuel pressure gauge and take some vacuum and timing readings as reference points.
I'm all ears if anyone has suggestions on where to start trouble-shooting.

 

[Cooter_76]

I managed a bit of improvement today. After reading this article and following his steps for setting the idle speed, I was able to get the engine to idle around 850 rpm with the IAC showing between 2 and 10%. That's still 100 RPM higher than the target of 750, but it seemed to run much smoother and didn't stumble.

 

[Cooter_76]

When I first installed the Sniper, I followed the video from CJ Pony parts and used a tee fitting to connect the brake booster and PCV valve to the vacuum port on the back of the throttle body. When I took it for the first drive last Thursday the brakes were rock hard, so this morning I picked-up a barbed fitting at Home Depot and installed it in the plugged port on the front of the throttle body. I'm now using this to pull vacuum to the PCV and have a separate dedicated hose to the back of the throttle body for the brakes. The brakes are now back to normal.

 

[Cooter_76]

I took an extended test drive earlier this afternoon and was feeling good. The EFI pulls hard under acceleration and idles nice and smooth. The kickdown cable is functioning well also. I took it for a 20-mile drive, with a mix of back roads, interstate and stop & go surface streets. Everything was going fine until it stumbled pulling away from a stoplight a few miles from home. I had to feather the gas to keep it from dying. Coolant temp had risen to about 200 degrees at this stop light. It ran fine from there until I got it in the garage. When I tried to re-start it, though, it would run for a few seconds and die. When it was running, the Air/Fuel gauge on the display turned red and was reading ~35%.
I suspect the fuel and/or pump may be getting too hot when sitting in traffic. I checked the pre-filter temp with an infrared thermometer and it was reading 123 degrees. The outlet fitting on the pump was reading 119. I have no idea if those readings are too high. Tried to start it again 10 minutes later. It would run, but stumble a bit and the idle was sitting around 1100 rpm.
I have a fuel pressure gauge en route from Amazon, and it should be here Wednesday. Less than 2 weeks before the LEBC Round Up...

 

[RADO]

Sounds like you're making progress for sure! From all my research, whether you use the Fitech or Sniper, there's always a bit of tuning/troubleshooting to get the system running smooth. I'm running Fitech with the same fuel pump as you.

I would consider heat wrapping your exhaust near the pump. Fiberglass heat wrap is easy enough and will help a lot if you suspect the pump and fuel is getting too hot.

 

[Cooter_76]

I would consider heat wrapping your exhaust near the pump. Fiberglass heat wrap is easy enough and will help a lot if you suspect the pump and fuel is getting too hot.

Not a bad idea. Thanks!

I called Holley again this afternoon to get some advice. For the hot start issue, they suggested it could be a bad O2 sensor. Apparently this can be tested by running it in open loop mode the next time that happens. If the problem goes away under open loop, then the O2 sensor may need to be replaced (under warranty.)

I also asked about the high idle (can't seem to get it down below 850 rpm.) He said it could be a vacuum leak, or perhaps I have a more street/strip oriented cam. I have all new vacuum lines, so the only spot I would think could be leaking would be at the front or back of the intake manifold. No idea what cam I have (or whether the engine has been bored.) More things to tinker with...

 

[Cooter_76]

It's been a frustrating week full of bonehead moves. %)
After tinkering with the Bronco on Monday, I apparently left the ignition key on. Went out Tuesday afternoon to find the battery completely drained. I tried jump-starting, but the coil was fried.
Thursday I picked-up a new coil and some heat wrap for the exhaust. Got the engine running and checked timing & vacuum just for reference. Initial timing is set at 14 deg BTDC. Vacuum gauge was reading 15, which is about all I've ever been able to get out of it.
Went for a drive, and it was running rough. Wouldn't shift into 3rd. Got home and discovered I'd accidentally pulled one of the transmission vacuum lines off the tree on the manifold. Easy fix. Tried to start it again and nothing. No power to anything, including the headlights. ?:?
Finally traced it to a fried fusible link. Hopefully this was related to leaving the key on earlier in the week.
So today I picked up a new fusible link from Napa. I'm starting to know the guys at all the local auto parts stores by name. Hopefully I can get some garage time this weekend.

 

[Cooter_76]

Success!?!

Today I replaced the fusible link and sleeved the fuel line before the pump with heat shield (in addition to wrapping the exhaust pipe.) Also installed a fuel pressure gauge. Took the Bronco out for several test drives under different driving conditions and have not experienced any hot start issues. Fuel gauge is showing 100+ PSI. The exhaust wrap makes a significant difference, compared to the driver side exhaust. I'm cautiously optimistic that the issue has been solved!

 

[Broncobowsher]

100+ PSI sounds like the fuel pump is dead headed. is there any fuel in the return line? For this style EFI I expect to see ~45 PSI, maybe 65PSI max on some systems.

 

[Ol'Blue]

100+ PSI sounds like the fuel pump is dead headed. is there any fuel in the return line? For this style EFI I expect to see ~45 PSI, maybe 65PSI max on some systems.

Yup! My Sniper runs 58-62 psi. Holley recommends 60 if I remember correctly. 100 psi sounds way too high.

 

[Cooter_76]

Yup! My Sniper runs 58-62 psi. Holley recommends 60 if I remember correctly. 100 psi sounds way too high.

100+ PSI sounds like the fuel pump is dead headed. is there any fuel in the return line? For this style EFI I expect to see ~45 PSI, maybe 65PSI max on some systems.

Good points. I pulled the return line at the throttle body and tried to blow into it. There was a lot of resistance and some air came back out when I stopped.
Then I removed the gas cap and tried again. This time it was much easier to blow through the line. Gas cap on or off doesn't have any affect on the fuel pressure gauge when the engine is running. It's pretty much pegged.
I also opened up the vent line closer to where it tees into the tank. There was some fuel in the line. I'm running 3/8" flex and hard line from the throttle body to within 2' of the tank, then 5/8" flex to the tee into the vent by the filler neck. There shouldn't be any resistance in the line itself. Maybe the tank is becoming pressurized?
Something tells me I'm going to get to spend another 20+ minutes on hold with Holley again on Monday...

 

[Broncobowsher]

Pull the line off the EFI. Run a different line into a 5-gallon gas can. Key on. Check pressure. If now correct, start engine and check again.

What you need to figure out is if the problem is in the return line or in the EFI.

Remember the EFI is a closed loop. It draws off the gas tank a little more than it puts back. Leaving the gas cap on/off won't make a difference. It makes a difference when you blow because you are adding to the tank volume without removing anything.

 

[Cooter_76]

Pull the line off the EFI. Run a different line into a 5-gallon gas can. Key on. Check pressure. If now correct, start engine and check again.

I tried this test this morning. There's a slow, steady stream of gas from the return. No noticeable change in pressure.

Seems this would point to a faulty pressure regulator in the EFI? Maybe this has something to do with not being able to get the idle down below about 820 RPM and the strong gas smell in the garage? Has the fuel pump been overheating because it's working too hard?
Or is my $20 fuel pressure gauge junk? Should I just trade my Bronco for a used TJ and a flat-billed cap?:-[

 

[Skiddy]

Should I just trade my Bronco for a used TJ and a flat-billed cap?:-[

LOL I had to laugh at that, no please don't do that unless you sell me your bronco;D
I wonder since your fuel pressure is so high that maybe the regulator can't control it

 

[tirewater]

Is there a place to get the official specs for the bosch fuel pump? Internet talk says the pump is a 90-100 psi pump while Holley specs a 60psi pump. You may want to bypass the efi just to test the pump without the regulator.

As it stands, your pressure gauge is pegged, so we have no idea what actual psi it's providing.