Hello guys I hope you can help me out here. I have an 86 sedan deville and of course it has the notorious HT4100 in it. It set for almost a year and a half without being started so I ended up replacing the air pump because it was pretty much locked up. I also did a complete tune-up, cap, rotor, plugs, wires, air filter, pcv valve, fuel filter, and changed the oil. Before I had done the tune-up I had the car running for a very short period of time. After I did the tune-up the car wouldn't start, so I messed with it for a while and then I replaced the module that is inside of the distributor, under the rotor. After I did this the car started up and ran great...for about a hour and a half. Then I was just sitting there messing with the radio and the car shut off and hasn't started since. Oh yeah I forgot one thing, while I had the car running for that hour and a half the service engine soon light was on and that didn't make alot of sense to me seeings how I had just serviced it. But anyways like I said the car hasn't started since. I took the new module off this morning and got it tested at Napa and it tested good. I was leaning towards getting a pick-coil but instead I got the condensor assembly and tried it. No luck. So now my question is should I just go ahead and replace the pick-up coil or is there some way for me to be sure that it is the pick-up coil before I spend more money for nothing. That's the biggest problem right now, my lack of funds, and I've already spent $240 on the car that I don't have and the pick-up coil is about $50. I really need to get this car running and soon. It's always ran great and this is the first real problem that I've had with it other than the air pump which was no big deal. Also when I check the codes the only ones that I come up with are E95, E90, F80, and F85. Some of them aren't even valid codes that I know of. Also there's some P20 to P30 thing that comes up when I hit the one button. Any idea what that is? I have no idea about any of this and it's really starting to piss me off and burn a hole in my pocket, so hopefully somebody that knows what they're doing can help me out. I would greatly appreciate it. Thanks

Ignore the codes, they likely are nothing right now.

Check voltage on the BATT terminal to the HEI. Is it getting power? Is all the connectors reconnected? Is the rotor turning when you crank it? Is the rotor there? (yeah, I know, dumb question, but it got me once.... ONCE....)

What tools do you have? Any multimeters? I don't know the 86 underhood well, is there a maxifuse loose or blown?

the pickup coils can be intermittant, messing with the wires can do it in. You can check it with a multimeter. Connect it to the leads that connect on the module. Have someone crank the engine and monitor the voltage on the dwell scale or the DC volts scale.

Let us know what you find.

The distributor is fed directly by the ignition switch, whereby the power goes to that from a fusible link under the hood.

I'd agree with NODIH here. If there is no power to the distributor, then that is where you start. If there is, then it is in the distributor. The module controls the spark directly until the engine starts, then the ECM takes over sprk control with it mapped out advance curves.

Mike

Ignore the codes, they likely are nothing right now.

Check voltage on the BATT terminal to the HEI. Is it getting power? Is all the connectors reconnected? Is the rotor turning when you crank it? Is the rotor there? (yeah, I know, dumb question, but it got me once.... ONCE....)

What tools do you have? Any multimeters? I don't know the 86 underhood well, is there a maxifuse loose or blown?

the pickup coils can be intermittant, messing with the wires can do it in. You can check it with a multimeter. Connect it to the leads that connect on the module. Have someone crank the engine and monitor the voltage on the dwell scale or the DC volts scale.

Let us know what you find.


Ok here goes, I have power to the HEI, at least I think so. There are no connectors unhooked. The rotor is turning and of course the son of a bitch is there. Hey it's Ok I've done worse so don't feel bad. I didn't check the maxifuse but there is power to the dist. I checked the pick up coil, at least I think I checked it right and I wasn't getting any power. Could you maybe clarify exactly how to check it so that I know if I did it right? Anyway if I did do it right than I guess that is the problem so how hard is it to replace and how do I do it. If you don't tell me exactly how than I'll end up taking more apart than needeed. Also is there anything else it could be? Like maybe the pickup, the thing with wires from the wiring harness that goes into the dist. I don't know but I have to go. Thanks

What was the condition of the coil? Is it set in its home properly? Was it corroded on its contacts? would not be uncommon for either a coil or the pickup to go bad. For the most part unacceptable levels of resistance in either is what has tended to make modules go bad for me in any car, oh yeah, that and revving way beyond what the system was designed to fire on. lol.


-The Cadillac Rancher