SmokinFive9 4x4

Ok. Well, I don't like computers. I'd rather watch guages and and such myself that way I have a better idea of what's going on. So, everything on my truck is completely manual. The ecm is there, but the only thing it controls is the "wait to start" light. which just flashes because there's no sensor in the manifold anymore. My question is this. I have the manifold heater solenoid wired to a switch in the cab but other than just guessing at the temp, I really don't know when the right time to turn it off is. is there a way I can use the old switch to make it go off automatically when it's supposed to? Just like a radiator fan switch that comes on at a certain temp and goes off at another? If there's no way to use the stock one, what temp is the manifold supposed to be before the heaters go off?
Same with the fuel heater. I don't have that hooked up at the moment, is it supposed to be on all the time that the truck is running or just at startup/warmup?

Thanks,
Ian

Haulin_in_Dixie

Your engine does not have an ECM. It does have a PCM on the firewall. Don't know why you want to remove it. Has nothing to do with the engine running.

Lil Dog

If its a 90, the PCM is behind the battery..

As far as the timing of the heater etc.. Uh , the PCM does a pretty good job of that. There must be some other reasons you pulled all the "automatic" controls, but at this point, the PCM does the best job of judging fuel heater etc..

BTW the heaters pulse (which I think you are aware) and don't stay on for more than 30 seconds maximum during cold start at -30.. And continue to pulse at intervals determined by the computer at the temperature at the time of the start. The heaters only cycle for a certain time period and then shut off completely regardless of the intake manifold temp.

J-eh

SmokinFive9 4x4

Well PCM, not too much for names, I know the motors not controlled by it, but the heaters are. Main reason I don't have one is that the motor's(or most of it) is from a 94, the truck's a 90 first gen, 1-ton 318 truck. The actual cab is from a 86. It's all messed up. I had stuff layin around, so I put one good one together I used a painless wiring kit to start out and build around it. So the stock wiring is basically gone, and I looked at the schematic for the PCM and thought about trying to reintegrate it, but figured manual control would work jsut as well and be much work.
I did assume the intake heaters were controlled by the manifold temp sensor. The heater for the fuel, I have no idea how that works. I've never had a problem with it, but I've never driven it through a winter either, so I didn't know if those things were absolutely essential to run in cold weather, or just a luxury or what. I know they help, but will it hurt without them. I do run PS additive in it with every tank but is that enough to keep the fuel good in cold weather?

So. There you have my motives. I ussually leave the intake heater on for about 15-20 seconds before startup and it seemed to work just fine. Just wondering if there's a better way. The fuel heater I didn't mess with because I have no idea how hot it gets and if I leave it on too long I didn't know if it would get hot enough to actually ignite something.

?

BIGBADBOB

The 89 CTD just had a small control box on the firewall for the grid heaters. It was simple, maybe find one of those. Good luck.

Lil Dog

Well that certainly helps out on the install.. That was quite a project to handle..

I don't have much info on the fuel heater system.. I think you are right however that the fuel heater is more of a luxury for those that are on the edge of the gelling of fuel and don't use additives.. I don't know if I would worry about it if you haven't had any problems so far.

As far as the intake heater goes, I don't know how you would set up a controller for that other than trying to get the guts out of an 89 or 90 truck.. I think the brains for the intake heater was in the controller in the dash with all the indicator lamps in it. The indicator panel over the heater controls.. Now don't quote me on this but that is what I was told about my 89 waaaay back..

But the heater grid is only controlled by the computer for time on vs. start up temperature reading and then to keep cycling the heaters for a certain time frame.

Lil Dog

D'oh.... Bob was faster...LOL..