INJ1 Fuse Blowing

[Paul Workman]

Originally Posted by Dynomite

No....... The other Zs are running perfectly and these coils had a lot of miles so will just toss them. Like Lee said in our duscussion (he had same issue with INJ1 fuse) he re-loomed injector wires and issue was solved. He does not know how exactly he fixed the issue (INJ1 fuse blowing)

I am in same boat as Lee
I have a clue but do not know exactly.


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Wooohohohoo... That sounds like a Lukas Electronics kind of peoblem, Cliff! It is a Lotus, after all...

[Dynomite]

Originally Posted by Paul Workman

Wooohohohoo... That sounds like a Lukas Electronics kind of peoblem, Cliff! It is a Lotus, after all...

Well......this Lotus just will not quit now as I have been trying for several days to blow INJ1 fuse. It maintains 1200 Ohms on the down side and the LT5 runs perfectly.

Of interest and indicating where the INJ1 issue might be......... was last time watching the Ohm meter measuring down stream electrical resistance from INJ1 fuse while disconnecting electrical under the Plenum (INJ1 had failed and showed zero ohms on down side) the Ohms came back as I disconnected the 14 pin DIS connector.

The 14 Pin DIS connector (8 pins are used) has 4 wires with original (stock) mechanical crimped splices down by rear of block just before large Wire Loom. I disconnected the large Loom clamp and raised the loom just even with the windshield wiper motor. I cut those mechanical splices and slipped heat shrink on the cut wires and then soldered the wire ends. Heat shrink slips over the soldered splice and with some heat will insulate the splice. I then put it back together temporary and took a ride with no issues. I then removed the Plenum one more time and installed new wire looms on all electrical wires.



Installed New Red Wire Looms on Coil Driver wires, EGR wire. secondary MAP wire, and the Crankshaft sensor wire connected to rear of DIS. Just cleaning up all wiring (Some of the New Wire Looms contained multiple Connector Wiring). Installed new wire looms on Injector Wires as well.

The key is to install the wire looms such that no connector is under any kind of tension at any time and with the wire looms on each wire there should be no wire contact with anything under the plenum.

The INJ1 Fuse issues are summarized here INJ1 Fuse

Did check secondary operation by grounding Pin 17 on the ECM Green plug. With key on and with finger over vacuum line going to secondary Map sensor the secondary canisters functioned perfectly.

New Coils.................................................. ......................New Wire Looms (Red)





See Also:
Under the Plenum
The Four Minute Plenum Installation

[Paul Workman]

Originally Posted by Dynomite

Well......this Lotus just will not quit now as I have been trying for several days to blow INJ1 fuse. It maintains 1200 Ohms on the down side and the LT5 runs perfectly.

Of interest and indicating where the INJ1 issue might be......... was last time watching the Ohm meter while disconnecting electrical under the Plenum (INJ1 had failed and showed zero ohms on down side) the Ohms came back as I disconnected the 14 pin DIS connector.

The 14 Pin DIS connector (8 pins are used) has 4 wires with original (stock) mechanical crimped splices down by rear of block just before large Wire Loom. I disconnected the large Loom clamp and raised the loom just even with the windshield wiper motor. I cut those mechanical splices and slipped heat shrink on the cut wires and then soldered the wire ends. Heat shrink slips over the soldered splice and with some heat will insulate the splice. I then put it back together temporary and took a ride with no issues. I then removed the Plenum one more time and installed new wire looms on all electrical wires.



Installed New Red Wire Looms on Coil Driver wires, EGR wire. secondary MAP wire, and the Crankshaft sensor wire connected to rear of DIS. Just cleaning up all wiring (Some of the New Wire Looms contained multiple Connector Wiring). Installed new wire looms on Injector Wires as well.

The key is to install the wire looms such that no connector is under any kind of tension at any time and with the wire looms on each wire there should be no wire contact with anything under the plenum.

The INJ1 Fuse issues are summarized here INJ1 Fuse

Did check secondary operation by grounding Pin 17 on the ECM Green plug. With key on and with finger over vacuum line going to secondary Map sensor the secondary canisters functioned perfectly.

New Coils.................................................. ......................New Wire Looms (Red)





See Also:
Under the Plenum
The Four Minute Plenum Installation

Nice write-up, Cliff!

BTW, I never saw a mechanical splice that I liked. And, I never looked at a pin/cylinder connector that wasn't gold flashed with less than suspicion. (I use dielectric grease on them to retard oxidation.)

[Dynomite]

Originally Posted by Paul Workman

Nice write-up, Cliff!

BTW, I never saw a mechanical splice that I liked. And, I never looked at a pin/cylinder connector that wasn't gold flashed with less than suspicion. (I use dielectric grease on them to retard oxidation.)

Just for your additional information.......I also found original stock mechanical splices on the Drivers side Injector Wire Harness between the last injector by the fire wall and main wire loom captured in the Clamp attached to rear of block. I did not replace those original Injector Wire Harness splices simply because it is NOT an easy job to get down in that area with a soldering gun, wire stripper, Heat gun, or electrical tape. The mechanical splices on the Injector Harness did look well separated.

I did manage to replace four of the 14 Pin Connector Splices between the 14 Pin Connector and the main wire loom captured in the Clamp attached to rear of block. I removed the mechanical splices and used Solder, Heat Shrink, followed by electrical tape to connected the exposed ends of each wire (overlapping the bare wire ends about 3/8 inch on each side of the splice). The solder took very well saturating the two bare wire ends.

[32valvesftw]

Cliff,

Do you think we all have these suspect splices on our cars?

[Dynomite]

Originally Posted by 32valvesftw

Cliff,

Do you think we all have these suspect splices on our cars?

Interesting question....I checked another LT5 wire harness I have on the wall (from a 90 or 91) and yes....it also contained these splices. The splices are interesting as they are swedged/crimped metal clips that are crimped over overlapping ends of bare wire as you can see in the photos. These Crimped wire ends are in turn wrapped with a silly cloth wrap about 1.5 inches long that is relatively loose and can be removed by cutting lengthwise with razor blade. Keep in mind this is a 95' with more going on under the Plenum (EGR and MDP).



I am not saying these splices caused INJ1 to blow as it appears only a shorted wire could do that. The spices although in somewhat poor condition did not appear to be in contact with associated spliced wires. I will say when I got done soldering the overlapping ends and sliding heat shrink over the splice with some heat it is like night and day on the continuity of the resulting splice compared to the original mechanical splice. And.....most importantly, the stripped wire ends (stripped 3/8 inch on each overlapping wire) took solder very well saturating all strands of the bare wire ends.

One more point........These four splices on the 14 Pin Connector Harness each had two wires coming from the main wire harness within the clamp attached to the rear of the block going into one wire going on into the 14 pin DIS Connector. The only way to do that is to splice the wire.

[XfireZ51]

First of all, great work and documentation on this Cliff. Second, are u suspecting these are OEM splices? Do the appear to match the splice methodology illustrated in the FSM?

[Dynomite]

The splices are definitely OEM splices and the FSM does not seem to indicate where splices are located but I recall Dave suggesting to check splices inside the car or maybe outside also. Further, the only wires spliced are those wires where two wires are spliced into one.

I rechecked my on the wall 90'/91' wire harness and the 14 pin DIS connector wire harness does have identical appearing splices but did not check if identical wires within the harness.

Again I am suggesting these splices did not appear to contribute to a short blowing INJ1 fuse but could contribute to a discontinuity in electrical signals.

And...... The Drivers side Injector harness (and maybe passenger side also) contains similar splices between last injector and main wire harness.

I doubt anyone has peeked inside the wire looms of these wire harnesses


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[GOLDCYLON]

CLiff is she good to go?

[Dynomite]

Originally Posted by GOLDCYLON

CLiff is she good to go?

Seems that way....good to go....and NEW Plates