Fuel Injector Question

[euromaniac]

**I have spent hours on the search feature with no definitive answer**

Late 1980 M90 Motor - 635CSI Euro

I was flogging the car on the freeway two days ago stretching her legs. Cruising at 115 the car stumbled and I let off and coaxed her gently home.
In the morning, I checked the plugs and ignition components and everything checked out - just changed the plugs and wires a week prior.

I started diagnosing the fuel injectors. Starting from the firewall back 5 of the 6 injectors read 14.9 Ohms with the last Injector reading 3.2 Ohms. She is stuttering and vibrating once running and it is clear that the injector on that cylinder is the culprit. I pulled the injector and it is a Gray color no name reman with RIN 152 written on the side. I found a seller but cannot find any specs on it. All others (#2 - #6) are redish/orange and say Python on the side with the number 24. **Also checked fuel relay (good) and fuel filter (newish).

Modifications worth noting:

Cat Cam
IE Rockers
Miller MAF
WAR Chip

The car does run rich and always has a rich exhaust smell but at WOT runs lean - per dyno results. I'm wondering if the previous owner has the wrong injectors as they seems high impedance vs. the low impedance on the #1 cylinder. Car idled and ran fine but not super smooth.

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https://i.ibb.co/9HzFwcL/FI.jpg

The gray reman (RIN 152) is the old style FI that connects to the fule rail via the 2" rubber hose vs. where the fuel rail connects directly to the top of the FI's.

The car was originally L-Jet so it has the old style fuel rail. The PYTHON (orange) have 2" rubber hoses connected to the top with a hose clamp to accommodate the older rail.

5 Pythons and 1 RIN 152. The nose of the nozzle is also 1/4" longer than the Pythons. These both click on and off with 12volts of power but they have different impedances. Also, the python has a 4 hole nozzle design and the RIN 152 is a single port nozzle with a different spray pattern.

I want to buy 6 brand new FI's for this motor taking into consideration the MODs listed above. Please lend me your insight and experience. I need the car back on the road before summer is gone.

[bpoliakoff]

What ECU are you running? I forget, but are the original Ljet injectors low impedence? If so what are the replacements.

[euromaniac]

ECU is from a 735 according to the previous owner. WAR chip installed.

From searching, the early Euro cars '79-'82 were low impedance. That is in stock form. Running a MAF and the Mods I listed has me turned to the forum here to help me out.

I've upgraded to the Motronic dizzy so have assumed the '85 and up Euro injectors "may" work but I think those are also low impedance. M cars got the high impedance FI's.

Experts?

[bpoliakoff]

The early Motronic 1.0 injectors were low impedance So if you have gone to a later ECU you should be running hi impedance injectors. While you are at it, you should run Mustang injectors which use 4 hole pintle caps and give a much better spray pattern. You should also be running `a Motronic fuel rail but that is only if you have the later style manifold.The other part of the equation is if you have gone to Motronic 1.1 from Ljet, Is the FPR Motronic? The Motronic needs a 3bar FPR and if you haven't upgraded that, that should be done. Are you running a Motronic TPS and throttle body?

[euromaniac]

Which mustang injectors i.e. year/model?

High impedance makes sense as 5 out of the 6 are 14.9 ohms.

I currently have a 2.5 bar fuel regulator on the rail and yes it is from an LJet car with the early Euro manifold. I have the motronic throttle bottle and TPS with a Miller MAF.

Should I bump the regulator to 3? How many lbs. are the mustang injectors you speak of? The pythons in the car are 24#'s.

[bpoliakoff]

go to five0 motorsports or witch hunter They are the go to guys for injectors and injector rebuilding. Any of the FI Mustang injectors will work but you will get more definitive answers there. You need 3 bar with Motronic 1.1 or 1.3 and you should be high impedance yr

[euromaniac]

I talked to Bruce at FiveO and he recommended the 24# Bosch Gen III's that are indeed for the mustangs with the 4.6L.

The issue is the diameter of the FI body. Newer injectors are slim body and I have a Euro E12 based intake and L-Jet fuel rail.

The big rubber donut, metal bracket, and retainer clip is what is used to mount the FI's to the intake. The fuel rail floats above connected only by rubber hoses to each FI, and intake/return lines.

If you put in newer FI's from a late model mustang, how did you mount to the E12 intake?

We have the same car.

[bpoliakoff]

You don't unless you do some custom machining on the LJet manifolds. Why don't you just switch to a later Motronic manifold? they are cheap and all over the place. Your build is getting to convoluted

[Pasocb]

Having similar vehicles, I have been following this post with interest.
Euromaniac, have you confirmed what DME / ECU you are currently running to verify that high impedance are in fact what you should be running?
I believe Bert has provide good advice with the available information.
Our cars have low impedance injectors configured for both types of fuel rails, but I would like to learn more about the original application for high impedance injectors that fit L-Jet manifold (as your car apparently now has).

[euromaniac]

You don't unless you do some custom machining on the LJet manifolds. Why don't you just switch to a later Motronic manifold? they are cheap and all over the place. Your build is getting to convoluted

The car stays original. The build is simplistic. I need 24# injectors for a l-jet manifold - it's as simple as finding l-jet 24# injectors.

[euromaniac]

Having similar vehicles, I have been following this post with interest.
Euromaniac, have you confirmed what DME / ECU you are currently running to verify that high impedance are in fact what you should be running?
I believe Bert has provide good advice with the available information.
Our cars have low impedance injectors configured for both types of fuel rails, but I would like to learn more about the original application for high impedance injectors that fit L-Jet manifold (as your car apparently now has).

The ECU is from a '85 733 with a WAR chip. High impedance injectors are correct for the ECU. The car was tuned for the 24# injectors in it. It needs to be replaced like for like. Miller is defunct and tuning the WAR chip ia major PITA and I don't have WIN XP with the software. Until I go stand alone, I have to make what's there work.

[bpoliakoff]

Years ago, a guy on the firstfives forum,(E12) machined his Ljet manifold to take the Motronic injectors. IIRC he did it himself on a drill press. If not for you, find a small one man band machine shop and have it done. It isn't major surgery