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-   -   Fuel injectors clogged? (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/fuel-injectors-clogged-14154/)

Dr. Switch 08-07-01 05:01 PM

Fuel injectors clogged?
 
I just swapped engines, the replacement is a nice unit that sat on a shelf for a long time but had near zero miles on it. After taking it apart and cleaning it up, I put it in and it wont start.
It has lots or spark, good compression, fuel presure and a good battery to spin the hell out of it. It starts briefly with starting fluid, so I think its not getting any gas. Could the injectors be completely clogged up from sitting so long? I soaked them for a while in cleaner but didn't have them tested or anything before i put it back together.
Any fuel injection experts out there? Cause I'm a complete idiot in that dept.
Bill

HAILERS 08-07-01 08:27 PM

Could it be that the engine that is in the car is one who's injectors are the low impedence (about 3ohms) and the impedence of the new engines injectors is high impedence(12 ohms)? It does indeed sound like they are not operating. What year car is this? What year car did the new engine come out of? Then again it could be something else. If you pull all the plugs out and spin the engine over for ten to fifteen seconds do you get a fuel mist out of the plug holes? If not it just ain't injecting. Check ohms value.

Dr. Switch 08-07-01 10:02 PM

Thanks, I didn't think about the ohms thing....both motors are from an '87 Rx, or so I'm told. And when I spun it w/out the plugs......no fuel mist. I did notice that the injectors have a raised bump that coresponds to a dent in the connector and on the old motor the bump was centered on the plug, and on the new motor the bump is offset to one side.
I will check the resistance next.
Bill

HAILERS 08-08-01 12:29 PM

Sounds like the injectors are the wrong ones especially when you mentioned the offset tab on the connectors. That offset I'm sure was to make the design idiot proof so you could not put the wrong injector on. They were wrong. I can put that plug on either injector. Done did that before. OOOps, what did I just call myself? If you have a wiring diagram you can ohm the injectors out from the ecu. As I write this I forgot what your car is, n/a or turbo. If n/a the secondaries are not hard to get to. Even if they were the right ones they play no part in starting so they could be good and the primaries bad. Cannot win.

Dr. Switch 08-08-01 09:31 PM

You are the man!!!
I checked out the impedance and as it turns out the old injectors- 3 ohms, the new injectors-13 ohms.
I switched them out and the sumbitch fired right up.
Now, why would the two engines have different injectors? They both came from an 86 or 87 car I think. The injection system doesn't have the "VDI" manifold which means its pre-89 right...
Anyway, is there a way I can still use these injectors? I hate to run the old injectors with 160,000 miles on them when I have four nearly new ones sitting there. Is it as simple as switching the resistor block? or changing the ECU?
Could I wire three 3 ohm resistors in paralell w/ each injector to bring the impedance down to 3 ohms? I'm so confused.
By the way, if you are ever in Florida, I owe you a few beers.
Thanks again,
Bill

RETed 08-09-01 07:34 AM

Mazda changes from low- to high-impedence fuel injectors mid-year for the 1987 models.&nbsp I think the cut-off date was 07/87 in terms of build date...



-Ted


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