This is a continuation of my post of 3/4/04 "Solve this..etc". Please see for complete background. Basically, I have a 91 Seville which will not start. Cranks O.K. but does not fire. Spark, fuel, filter and pump appear O.K. After three weeks of frustration, I found that the 2 fuses for the injectors in the fuse box under the hood, blow every time the engine is cranked. Although they did blow twice before during my three weeks of working on this, now they will blow every time I crank the engine. One side of the fuse(s) reads 12volts with the ignition on and open (no voltage or resistance) with the ignition off. The other side of the fuse reads 2 K-ohms with ignition on or off.

My (very skimpy) schematic shows wires from the ECM (PCM) directly to the injectors (one wire per injector) and continuing with one wire per injector to the two fuses that are blowing....and of course through the fuses to batt.

I assume the 2 K-ohm reading is the load of the injectors. Tho, I have no idea, this seems to be reasonable??????

My question: what happens during cranking that would blow both fuses? I thought at first that maybe one of the injectors (or wiring) was shorted to ground (only during crank). But there are 2 seperate fuses, each of which only connects to 4 injectors. A short to ground of one injector wouldn't blow BOTH fuses.

Anyone have any ideas....or run across this before?? Thanks all.

itzalgud

I would think you have to check first for the short to ground. I would say two fuses, two shorts. And go from there. I think the PCM supplies ground to fire the injectors, so the short would likely be on the positive end of the injectors, or the injectors themselves. At least start there.

Probably explains the hot converter as well. A couple of injectors are stuck and flooding the engine.

Thanks for the reply, Lawrence. It just seems odd that there would be two shorts in two seperate circuits. I think your idea that the injectors are somehow causing this is probably right. Maybe I should just go ahead and replace them. The car has 115,000 miles so I guess it wouldn't hurt even if they do not fix the problem. I'll post if I find the problem.

itzalgud

Thanks for the reply, Lawrence. It just seems odd that there would be two shorts in two seperate circuits. I think your idea that the injectors are somehow causing this is probably right. Maybe I should just go ahead and replace them. The car has 115,000 miles so I guess it wouldn't hurt even if they do not fix the problem. I'll post if I find the problem.

itzalgud


Uh...throwing parts at a problem rarely solves the problem, is expensive and causes a great deal of frustration..... do a little more diagnosis....

Go to the top of the engine and unplug the 8 electrical connectors that are at the injectors. Each fuse supplies 12 volts to 4 of the injectors directly....so...one side of each of those injector terminals should have 12 volts to it all the time. Disconnect all 8 connectors and put new fuses in. If the fuses are OK then check for 12 volts at each of the connectors on one pin. Each should have 12 volts if the fuses don't blow.

If the fuses blow again even with the injector connectors disconnected then there is a short in the wiring harness between the fuse and the injectors. If the fuses do NOT blow with the injectors disconnected then start hooking up one injector at a time and see which one(ones) cause the fuse to blow and work from there.

Are you sure the other work done on the car didn't pinch the engine wiring harness somewhere??? That commonly happens when things like trans service is done....the engine harness is pinched between the trans and engine when it is bolted together and that blows fuses and such.

Were the injectors "cleaned" or anything or was any sort of solvent or cleaner run thru the tank recently?? The fuel flows directly thru the wire windings inside the injectors so any solvents can eat the insulation off the wire windings of the injectors causing them to short and blow fuses. The longer the solvent sits in the injectors the more damage it can do. If solvent was run thru them and then the car sat while you worked on it the injectors could have been ruined by the solvent/cleaner/gas treatment.