What does ohm testing my injectors tell me?

I assume it has no relation to finding a leaking injector?

Mine all ohm within .2 of 16.8...

 

that number seems to be in tolerance.

I just read a thread about a guy's method for cleaning his injectors- think it was in the engine mod section - he uses a 9vdc power supply and carb cleaner and a rubber tipped blow gun attchemnt on his air compressor - say's the result he has seen are tremendous. poor mans inj cleaning

I would think that if you took the 9vdc out of that process you could see it the injector is not seating completly.

 

In your case you learned that the coil resistance is very uniform, nothing else. Measuring d.c. resistance of a coil is about as useful as **** on a bull, it will only find GROSS coil failures. Since the ECM pulses the injector coil, a far far more valuable coil measurement is done with an impedance bridge which will tell you the inductance and the ,"Q", which is a measure of the coils total electrical losses, d.c. resistance and magnetic field losses. For instance, a coil with a turn to turn short cannot be found with a d.c. ohmeter, but shows up like a thumb busted with a hammer on an impedance bridge.

 

Just re-read my manual, and it says one of the ways to tell if you have leaking injectors is if you have wet/fouled/rich plugs.

I guess that means I have three that are shot, and one questionable one...

So...

Should I be contacting Rich at Cruizinperformance to rebuild my 9 injectors?

 

I ohm tested some Multecs all within spec. But some leaked, two of them would not flow at all, and two of them were pissing a thin stream of fuel, instead of the cone shaped spray. That scenario could be a big problem to diagnose.


I discovered this by finally mounting the injectors and drivers side TPI rail upside down and watching the spray pattern.

 

I vote yes. I'm very please with what he did with mine. He'll also give you a report like this.... RANSOME BERRY
6432 CARSON DR
OLIVE BRANCH, MS 38654

Date: 7-13-06
Vehicle: 92 CORVETTE
Model: 280 150 945
Injector serial #: 607131-607138


Preliminary Test Results
Test pressure = 43.5 psi Injector No.
1 2 3 4 5 6 7 8
Test 1. Injector Resistance 14.8 14.7 14.8 14.7 14.7 14.7 14.8 14.7
Test 2. Leak Down Test (Pass / Fail) P P P P P P P P
Test 3. Spray Pattern (Good / Fair / Poor) G G G G G G G G
Test 4. 60 Second Pulsed Flow Delivery (mL) 85 84 83 84 85 84 84 84
Test 5. 100mL Pulsed Volume 100 99 98 99 100 99 99 99
Test 6. 15 Second Static Flow (mL) 88 88 87 87 88 88 88 88
Test 7. 100mL Static Flow 0 0 0 0 0 0 0 0
Approximate pound-per-hour flow 30.1 30.1 29.76 29.76 30.1 30.1 30.1 30.1

Test Results After Service
Test pressure = 43.5 psi Injector No.
1 2 3 4 5 6 7 8
Test 1. Leak Down Test (Pass / Fail) P P P P P P P P
Test 2. Spray Pattern (Good / Fair / Poor) G G G G G G G G
Test 3. 60 Second Pulsed Flow Delivery (mL) 86 87 85 86 87 87 87 87
Test 4. 100mL Pulsed Volume 99 100 98 99 100 99 99 99
Test 5. 15 Second Static Flow (mL) 90 90 89 89 90 90 90 90
Test 6. 100mL Static Flow 100 100 99 99 100 100 100 100
Approximate pound-per-hour flow 30.79 30.79 30.45 30.45 30.79 30.79 30.79 30.79

Parts Replaced
Pintle Caps Seals O-Rings Screens Hoses Clips
8 0 16 8 0 0

Comments
Tests performed at 0.700 specific gravity.

 

I contacted Rich, and he gave me an excellent price. He also rebuilds the 9th/cold start injector- which is out of production, so I decided to get that done.

Should I replace the FPR while I have the plenum torn apart? Seems logical since the plenum is going to be off, and that FPR is most likely an original.

 

You'll probably tear the diaphram trying to remove it. It sticks to the aluminum. Wouldn't hurt to try removing the cap to inspect it, if that's not also stuck.

 

I've never even looked at one before... Do I just replace the diaphram? or do new ones come as a whole unit?

My fuel pressure drops from 38psi (within spec range of 34-39), to about 15 almost instantly. I am thinking I could be leaking from multiple points. Also the vacuum tubing on the FPR smells of gasoline after inspecting them.

 

My Aeromotive FPR went out and I emailed them about possible rebuilding it. Here's the reply... Sorry, no. That is the old design, which was changed to incorporate new diaphragm materials that became required as the new fuel formulations were rolled out in the spring and summer of 2002. You’ll need a new regulator, it’s available under the same P/N through any Aeromotive distributor.



Brett Clow

Technical Support

Aeromotive, Inc.

7805 Barton St.

Lenexa, KS 66214

913-647-7300 Ext. 109