93 svx bizaare power surge (i think)

[sdjeff]

Ok, here goes..

93 Svx I got it for a song on a rebuilt title. Runs like a dream except that it didn't start reliably. Soooo.. I re did a large portion of the electrical incuding the alternator wiring and the fuse box itself. it was basically fubar. I was a mechanic for a long time and electrical was my specialty.

anyway, Things were fine for a couple months then bam, i turned the key, the engine started missing, knocking and backfiring bigtime, The AC went out and it immediately overheated.

I went through everything and the only supect part seemed to be a blown AC fuse. I replace it and The AC is fine. No apparant loss of power and the engine smooths out a bit at higher rpms. its not an idle issue, checked that. The cooling fans don't kick on. I checked everything and the fans, relays and fuses are all ok. I replaced the temp sensor and still no result. There is nothing wrong with the head gaskets, radiator, water pump, thermostat or hoses. The check engine light is not on, the light itself works. I went over the wiring i did and its all kosher.

The thing that gets me is all this, the blown AC, the engine issues and the cooling fans not working all happened at once. I don't know if the ECM is blown, I dont have access to a scanner. And I have no clue where the suspected surge could have come from. I'e worked on everything from Geo metros to Ferraris and I'm lost on this one.

Any suggestions would be much Appreciated.

[oab_au]

Originally Posted by sdjeff

Ok, here goes..

93 Svx I got it for a song on a rebuilt title. Runs like a dream except that it didn't start reliably. Soooo.. I re did a large portion of the electrical incuding the alternator wiring and the fuse box itself. it was basically fubar. I was a mechanic for a long time and electrical was my specialty.

anyway, Things were fine for a couple months then bam, i turned the key, the engine started missing, knocking and backfiring bigtime, The AC went out and it immediately overheated.

I went through everything and the only supect part seemed to be a blown AC fuse. I replace it and The AC is fine. No apparant loss of power and the engine smooths out a bit at higher rpms. its not an idle issue, checked that. The cooling fans don't kick on. I checked everything and the fans, relays and fuses are all ok. I replaced the temp sensor and still no result. There is nothing wrong with the head gaskets, radiator, water pump, thermostat or hoses. The check engine light is not on, the light itself works. I went over the wiring i did and its all kosher.

The thing that gets me is all this, the blown AC, the engine issues and the cooling fans not working all happened at once. I don't know if the ECM is blown, I dont have access to a scanner. And I have no clue where the suspected surge could have come from. I'e worked on everything from Geo metros to Ferraris and I'm lost on this one.

Any suggestions would be much Appreciated.

the engine started missing, knocking and backfiring bigtime, The AC went out and it immediately overheated.

Hard to say,but you may have had a voltage regulator failure, that has allowed the max voltage to go very high (18V), blow fuses and things. It does happen.

Harvey.

[SoCal LS-L]

Originally Posted by oab_au

the engine started missing, knocking and backfiring bigtime, The AC went out and it immediately overheated.

Hard to say,but you may have had a voltage regulator failure, that has allowed the max voltage to go very high (18V), blow fuses and things. It does happen.

Harvey.

+5, that exactly what i thought too. If the wiring was fubar then it could easily short the alternator to ground and otherwise tweak the diodes or field control to give your system high or bad voltage (alternating current).

[davew833]

I sent you a PM- I'm also in Salt Lake City. There are a couple of us here.