Big Problems With Kenne Bell Fuel System and FRPP 80lb Injectors

Rickyll7

Member
Dec 16, 2005
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Sorry, but this is quite lengthy.

I just installed my Kenne Bell kit with boost-a-pump and the KB modified fuel rail adapter for my 98 return fuel system on my car with some FRPP 80lb injectors.

The car runs like total crap now. It smelled pig rich and vibrated like hell. It wouldn't idle. If I revved it, the vibrations and fuel smell only got worse. I shut it down promptly.

I decided to start with checking the fuel pressure. I read an even 39 psi with no vacuum. I pulled 22.5 inches of vacuum with a vacuum pump and the pressure went down to 30 psi, so I think the pressure regulator that came with the kit along with the adapter plate are both working great.

However, before plugging in the fuel pressure gauge, I had to depressurize the system. To do that, I unplugged the fuel pump cut-off switch in the trunk and started the engine to run the fuel out of the rails. When I started the engine, it ran perfectly, idled, and revved fine for about 5 seconds before it ran out of fuel.

I tried it again a few times with the pump plugged in and unplugged, each time it ran like crap with fuel pressure and ran great without it until it ran out of fuel.

I am running the SCT Pro Racer package with a Livewire tuner. Before the blower, I had the car running great with a bunch of mods such as comp XE268 cams, stroker kit, ported PI heads, PI intake, 90mm LMAF sensor, FRPP 24 lb injectors, long tubes, o/r x pipe, just to name a few.

Now I've added the KB and the 80 lb injectors. I have tuned the vehicle with the correct values for the injectors per both fords website and SCT data files. I checked all values to the injector part number, M-9593-LU80. The injectors are new from Suttonhp.com. The injectors are black with a blue stripe at the bottom and hey are EV6 body style and have USCAR connectors, so they check out as being the correct injectors.

I can't figure out where the problem is.

Any ideas?
 
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Doesn't sound like the PCM knows about the 80# injectors, even if the SCT indicates the parameters were programmed.

How can I check that? I've tried retuning it a couple of times and have the same results. I've also tried reloading the injector values into the tune and reloading the tune into the LW and then retuning the vehicle. Same results there too.
 
So lets recap.

The engine runs like crap with the 80lb injectors and fords values for them in the tune (which match SCT values). These values can be found on fords website.

Ford Racing Performance Parts [M-9593-LU80*]
and
http://www.fordracingparts.com/parts/ics/m-9593-lu80.pdf

If I shut off the fuel pump, the engine runs great with the same 80 lb injectors and values with zero fuel pressure in the rails! (measured at zero psi with fuel pressure gauge immediately after start up) Car runs for about 6 seconds with no fuel pressure.

I just tried running the engine with my old 24 lb injetcors and fords values for those in the tune and it ran great.
( http://www.fordracingparts.com/parts/ics/m-9593-a302.pdf )

Any ideas as to what is not working properly between my new 80 lb injectors and the values im using for them?
 
80# is way over kill. I would just stick to the 24#s cause that's probably what Kenne Bell intended in the first place.

My KB came with 36# injectors. AFAIK, that's the minimum for their kits. But I agree, 80# injectors seems like a lot of fuel injector unless the OPer is shooting for a thousand HP.
 
My full kit, 1.7L Intercooled with everything included (Fuel rails, regulator, chip...) and my injectors are 24#... unless I'm reading the color wrong. I wouldn't go higher than 36#. Do they even make a 2.6L that will fit to a 98 engine?

Link to injector colors...

Pics of injectors and their sizes

Pic of my injectors.

KB10.jpg
 
I am going out on a limb here. Isn't there a minimum pulse width an injector can open/close? For a given size injector, there is a minimum amount of fuel that can be delivered with a single pulse.

So is it possible that the injector is soooo LARGE that at minimum pulse, the amount of fuel delivered is much more than an idling engine needs? The tuner can have the correct size, but the injector itself is the limiting factor.

From another perspective, why don’t all performance cars come with 80# injectors? You could have the best of both worlds! A kitten for city driving. A tiger when called for. IMO, the reason is there is a minimum finite amount of fuel a given size injector can deliver.

I suspect that at HIGH horse power levels, the 80#’s would work just great.

If there is a KB boost a pump (BAP) in use, this could make the situation worse.
 
Those are 36 lb injectors from KB. I'm not sure where they get them from. I have pi heads and the kb pi intake. They make a 2.6l upgrade for the pi manifold.

Did you not look at my link? Everywhere I look, those are 24# injectors. I don't think Kenne Bell re-labeled the standard markings on fuel injectors. I will pull my spec sheets and I'm sure they say that too. I think you are mistaken.

'98 is not a PI engine and Kenne Bell does not support PI swaps on NPI engines for their setups so unless you are a better engineer then who builds their setups, I would not suggest such a foolish move unless you have the money to experiment.
 
Did you not look at my link? Everywhere I look, those are 24# injectors. I don't think Kenne Bell re-labeled the standard markings on fuel injectors. I will pull my spec sheets and I'm sure they say that too. I think you are mistaken.

'98 is not a PI engine and Kenne Bell does not support PI swaps on NPI engines for their setups so unless you are a better engineer then who builds their setups, I would not suggest such a foolish move unless you have the money to experiment.

I could be wrong about those injectors, but the KB website itself says that the 96-98 and 99-04 kits come with 36lb injectors, maybe they have changed.

I know the 98 engine is not a PI engine. I put patriot performance stage II PI heads on it myself a few years ago. Kenne Bell may "not support PI swaps on NPI engines for their setups" but they did for me. They sent me all the 98 brackets, parts, supplement instructions I need, along with the 2.1L bolted down to a PI manifold to mate up to my PI heads.

I've got it all running perfectly right now with my old injectors and a tune I wrote myself. I don't know what exactly you are saying is a foolish move on my part, but I doubt I'm the first one to do a PI swap on a 98 mustang or use non stock injectors/sensors/parts and tune the car.

I did the same thing a month ago before I got the KB. I tuned the car myself using SCT Pro Racer Package, LC1 wideband, SCT Livelink dataloger, and SCT Livewire. I tuned it for my 90mm LMAF sensor and FRPP 24 lb injectors along with all my other mods.
 
I am going out on a limb here. Isn't there a minimum pulse width an injector can open/close? For a given size injector, there is a minimum amount of fuel that can be delivered with a single pulse.

So is it possible that the injector is soooo LARGE that at minimum pulse, the amount of fuel delivered is much more than an idling engine needs? The tuner can have the correct size, but the injector itself is the limiting factor.

From another perspective, why don’t all performance cars come with 80# injectors? You could have the best of both worlds! A kitten for city driving. A tiger when called for. IMO, the reason is there is a minimum finite amount of fuel a given size injector can deliver.

I suspect that at HIGH horse power levels, the 80#’s would work just great.

If there is a KB boost a pump (BAP) in use, this could make the situation worse.

The KB BAP only operates at boost levels of 5psi and above. Even if it was somehow running full time, it would make no difference. I've got a return fuel system where a pressure regulator returns any fuel in excess of 39.15 delta psi (fuel rail pressure minus manifold boost/vacuum). I've checked the fuel rail pressure and its perfect. 39.15 psi at zero manifold vacuum (engine not running) and 35 psi with about 15 inches of vacuum in the engine. This means that no matter what the boost or vacuum is in the manifold, the injectors see a fuel pressure difference of 39.15 psi between the rails and the manifold - anything leftover is sent back to the fuel tank.

Perhaps the injectors could be too big to opperate that low, I though that might be a problem. However, I ran the numbers from fords data sheet for those injectors along with the air flow rate of the engine (data log from my ecu). The injectors are opperating above the ford spec for min pulse width and well into the opperating range specified for those injectors.
 
Did you not look at my link? Everywhere I look, those are 24# injectors. I don't think Kenne Bell re-labeled the standard markings on fuel injectors. I will pull my spec sheets and I'm sure they say that too. I think you are mistaken.

I could be wrong about those injectors, but the KB website itself says that the 96-98 and 99-04 kits come with 36lb injectors, maybe they have changed.

There should be a part number on the injector....post it up.
 
The KB-sourced injector in my right hand has the (Lucas) part number D3165BA. According to this site:

Injector Information

The injector information is:

Delphi / Lucas
37 lb / hr. Disc Injectors
Part Number Delphi D3165BA (Lucas old 5203002, Lucas New 621037)
Static Flow Rate: 37.27 lb/hr @ 43.5PSI (300kPa) or 282gm/min
Dynamic Flow Rate: 8.42 gm/pulse - 2.5ms pulse width and 10ms repetition rate
Coil Resistance: 15.9 Ohms / High Impedance / High-Z
 
I did some data logging last night with the 24lb injectors.
Data reflects idling only.

Idle speed: 730 rpm
AFR: 14.6:1
LT Fuel Trims: bank 2=1.13, bank 1=1.02
ST Fuel Trims: Both Oscillating above/below 1.00 (~0.96/1.04)
Spark: Moves around between 21-26 Degrees
MAF Counts: 171-174
Load: .165-.175
Coolant Temp: 184 degrees
Intake Air Temp: 174 degrees
Battery Voltage: 13.4 V

Let me know if you're interested in looking at the files to get a better look at how things are operating.
 
I'm not going to continue in this thread anymore. If you're that smart you should have known the 80# injectors are way out of the specs for your set up (if in fact we are talking about a stock '98 4.6l 2v engine). Smell of fuel and running rich... well yeah!

Good luck...! :flag:
 
I'm not going to continue in this thread anymore. If you're that smart you should have known the 80# injectors are way out of the specs for your set up (if in fact we are talking about a stock '98 4.6l 2v engine). Smell of fuel and running rich... well yeah!

Good luck...! :flag:

The car is not stock, I never said it was and I can't understand why you keep suggesting that it is. In fact, my first post on this thread listed a few of my mods.

As for the 80# injectors being "way out of the specs for your set up"... who said that, and under what justifications and/or facts?

Here are some facts:

The MAF is reading about 175 counts at an idle of 730 rpm. That equates to about 0.9230 lb/min of air (per the LMAF sensor transfer function).

0.9239 lb/min of air for an 8 cylinder engine operating at 730 rpm equates to 0.0003161 lb air/cylinder for one 4 stroke cycle.

With an AFR of 14.64:1, that equates to 0.00002159 lb of fuel required for one injector to fire for that cylinder per 4 cylinder stroke.

The fuel injector break point is 0.00002421 lb of fuel, so that means the injector is operating under the modeled "low slope" (modeled by ford and defined by their specifications which I am using) which is 0.028183 lb/s of fuel per injector.

That amount of fuel at the modeled "low slope" would require a pulse width of 0.0007661 seconds or .7661 milliseconds.

The minimum pulse width that ford allows for those injectors to operate properly is .599 milliseconds.

This all means that those injectors should operate just fine from my engines idle all the way up to WOT (if the injectors are working properly and if fords values are correct).

Those are my calculations using values I've looked up. Maybe I'm wrong. If so, please show me how. I would really like to figure this out without just throwing money at it with different injectors and not systematically determining the root cause first. Everything I have read says that it should run just fine and that is why I'm on this message board, to find out why it's not running fine.

I'm not here for someone to tell me to go out and spend another $400 on new injectors because, "Those injectors sound real big, you should buy new ones!". If I wanted to throw money at a problem looking for a solution, I could have done that on my own. Perhaps then I might deserve being called foolish.

Thanks for the help.
 
Your short (and long, for that matter) trims are right around 1 which tells me the PCM isn't having to grossly account for the undersized 24# injector squirts if the calibration is loaded for 80# injectors.

That is, it still appears to me that the PCM thinks there are 24# injectors and when there are, the trims are right where you'd expect them to be. If you've got the 80# calibration in there then I suggest again that no, you don't have that loaded no matter what you think or what the SCT is saying.

Take the car to a proper dyno tuner (set the valet bypass on the blower and drive with the 24# injectors in it...) and have them assess the scalars.