8.3 (mechanical) Intake Preheater Problem

Topic: 8.3 (mechanical) Intake Preheater Problem (Read 1178 times) previous topic - next topic

8.3 (mechanical) Intake Preheater Problem

November 23, 2023, 04:30:29 pm

Hey guys, need some help. Mike and I are still working on my 98 270 with the 8.3. We have been fighting a slow starting issue since I got it, even with 2 new batteries. So, we checked the relay and it is working but we are concerned about the fuel shutoff solenoid. Mine looks like it might be missing a wire coming out of the top as I only have one wire connected. Can someone who has a 8,3 snap a picture of yours showing how the wires look coming out of the top of the solenoid. i have attached a schematic showing this solenoid. Thanks everyone.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #1 – November 23, 2023, 05:39:15 pm

The fuel solenoid needs 2 wires to operate if it is internally grounded and could have three wires which
would be the ground, One wire is the pull in circuit and the other wire is the hold in circuit.
The intake preheater only works when it is cold. I don't know what temperature it comes on.
When I had an 8.3 mechanical it would fire up after the first cylinder hit top dead center and
when the temperature got below freezing it was hard starting.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #2 – November 23, 2023, 06:02:55 pm

Quote from: oldguy – November 23, 2023, 05:39:15 pm

The fuel solenoid needs 2 wires to operate if it is internally grounded and could have three wires which
would be the ground, One wire is the pull in circuit and the other wire is the hold in circuit.
The intake preheater only works when it is cold. I don't know what temperature it comes on.
When I had an 8.3 mechanical it would fire up after the first cylinder hit top dead center and
when the temperature got below freezing it was hard starting.

Thanks Peter, I will relay this info to Mike. I know mine only has one wire coming out of the top. It looks like it had two male spade connectors but one is broken or bent over.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #3 – November 23, 2023, 06:24:58 pm

I don't know how the solenoid even works with one wire. Pull the solenoid in mechanically and
see how it start.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #4 – November 23, 2023, 06:41:09 pm

Your diagram of fuel shutoff does not relate to your coach if you have the C8.3 non computerized engine. Around 1998, Foretravel started switching to the ISC computerized 8.3 engine.

If you have the mechanical C8.3, just cable tie the solenoid to full up (open) position and start. Cut wire tie to stop engine. Many have done this tie/cut routine for many weeks of travel until replaced.

Solenoid has one 12v wire that is hot with ignition (hold up solenoid IF it has been pulled up with next wire, and one wire that is hot when starter is cranking (pull up solenoid).

Not sure what you are seeing. . .

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #5 – November 23, 2023, 07:35:19 pm

This engine has fuel that goes to an injector that is right at the glow plugs (there are 2) located in the intake. The fuel relay that supplies fuel to these 2 injectors is not opening as there is only 1 wire hooked to it. As stated by Zack the other terminal is bent down and we have not been able to find a wire that should be connected to this spade lug hid in one of the cable looms. The relay that controls the power to the glow plugs was frozen up and not energizing when the ignition switch was turned to run possession. Now that we have got that relay fixed we have lost control voltage to this relay. So we have a couple of problems that we need to iron out.

If we can get the intake air warmed up it should start a lot better as we tool a Prestolite torch and used it to warm (read warm) up the air that is inside the plenum that goes from the CAC discharge to the intake. Once it was warmed up the engine fired up with no problem. The print that Zack posted is half of what we have to go on so if anyone has any prints of this area drop us a note.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #6 – November 23, 2023, 07:41:46 pm

Try pulling the fuel shut off up manually like was suggested and see if it starts better.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #7 – November 23, 2023, 07:44:13 pm

Quote from: red tractor – November 23, 2023, 07:41:46 pm

Try pulling the fuel shut off up manually like was suggested and see if it starts better.

No that didn't help but a great suggestion.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #8 – November 23, 2023, 07:47:39 pm

Well shoot

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #9 – November 23, 2023, 07:52:32 pm

I have found out just now that this system is an "intake flame heater" system. There should be a print that is labeled as such. This was an alternative to the normal grid heater.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #10 – November 23, 2023, 08:32:38 pm

Mike do you have Quick serve? It should show that system for that ESN

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #11 – November 23, 2023, 08:36:39 pm

Here is the system this engine has. Just stumbled across this and it sure looks like the fuel solenoid has only one wire so we may be onto some good info. So it may be internally grounded.

https://www.foreforums.com/index.php?action=dlattach;topic=16490.0;attach=11048
https://www.foreforums.com/index.php?action=dlattach;topic=16490.0;attach=11049
https://www.foreforums.com/index.php?action=dlattach;topic=16490.0;attach=11244
https://www.foreforums.com/index.php?action=dlattach;topic=16490.0;attach=11245

Zack, this will give you something to look over and dream about. Remember small bites.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #12 – November 23, 2023, 08:39:04 pm

Quote from: bbeane – November 23, 2023, 08:32:38 pm

Mike do you have Quick serve?

I have never been able to make QS work for me as I am not a computer person.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #13 – November 23, 2023, 09:03:41 pm

If you like send me the ESN I'll see what I can see

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #14 – November 23, 2023, 09:24:45 pm

I beleave this is what you are looking at

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #15 – November 23, 2023, 10:13:00 pm

Mike
Does any of this apply to what I have?

The flame start system is available on the C Series automotive engines only with either a 12-VDC or 24-VDC electrical system.
The flame start system burns a small amount of diesel fuel in the intake manifold to aid starting in cold ambient temperature conditions. The system also operates in a post-start mode to reduce white smoke.
The intake cold-start control module monitors engine temperature. When the engine temperature is greater than 7°C (45°F], the flame start system will not be activated. Below 7°C (45°F], the system will operate as follows:

Preheat Cycle
When the engine temperature is below 7°C [45°F], turn the ignition key to the RUN position. When the key is in this position, the WAIT-TO-START lamp will illuminate for approximately 25 seconds. The engine should not be cranked until the WAIT-TO-START lamp shuts off. If the engine is cranked before the preheat cycle is complete, the process is aborted. The controller is reset each time the ignition is turned off.

Engine-Starting Cycle
When the WAIT-TO-START lamp goes out, the preheat cycle is complete. Depress the accelerator pedal all the way to the floor and crank the engine. The engine must be cranked within 30 seconds. If the engine is not cranked within 30 seconds, the preheat cycle needs to be repeated (step 1 ).

Post-heat Cycle
Post-heating occurs as the flame plugs continue to burn while the engine is running. Post-heating helps warm the engine faster and eliminates white smoke. Post-heating times are determined by the engine temperature upon start-up.

Cummins Inc.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #16 – November 23, 2023, 10:56:34 pm

Zack, this system is on a friends 96 8.3. Easy to tell if you have that system vs the electric grid heater system.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #17 – November 24, 2023, 07:05:29 am

100% sure that the flame heat system is what is on this coach.
Bruce, that info confirms that the solenoid has only one wire. Now to figure out what is not working properly. Could be a bad ground to a bad control module.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #18 – November 24, 2023, 09:15:20 am

Fuel,air and compression should start your engine,asking the obvious first,do you have a full tank and it would help if you
could give us a list of things you have done while"fighting the problem",may want to check out Larry"b "s site he has upgraded
fuel solenoids and you may get some info there.If you have the Bosch mechanical fuel pump you may have a overflo spring problem.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #19 – November 24, 2023, 09:41:08 am

John,
The coach will start, idle, and run.
Fuel tank has fuel and has been removed to change out fuel lines.
The fuel prime pump has been checked and is working properly
Over flow spring and check valve have been checked and replace in the past But we may replace it again
We are in the process of cleaning all the grounds not only on the battery cables but the electronic grounds for things like the King Control.
This is when found that the intake heater isn't working.
We have no prints that cover this that came with the coach.
When we supply heat to the intake air plenum it fires right up.
If we get the grounds cleaned up that control the glow plugs for the intake heater that may fix the problem. The thing is there seems to be at least 5 or 6 grounds that we haven't found yet from the research last night.

Mike

We have not pulled the starter yet as that may be coming up.
We need to get to a stopping point as I am going to be gone for a few weeks due to holidays.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #20 – November 24, 2023, 10:29:15 am

Mike , hard to find info on that heat system on the Cummins site as far as trouble shooting.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #21 – November 24, 2023, 10:47:00 am

Quote from: Pamela & Mike – November 24, 2023, 09:41:08 am

Over flow spring and check valve have been checked and replace in the past But we may replace it again

If you are going to remove the overflow valve suggest you replace with Tork Tek adjustable model...worked great right out of the box on our coach.

Cummins Adjustable Overflow Valve by Tork Tek - OFV010

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #22 – November 24, 2023, 11:33:08 am

Sorry I thought you you had the grid heater. When I had an 8.3 engine I had to change the glow
plugs and I can't remember where I bought them as Cummins couldn't supply them.

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #23 – November 24, 2023, 07:09:06 pm

Well big thanks to Forum member Dave Larson as he has a coach with the same engine set up as we have here. After several phone calls and some computer time we have enough info to at least troubleshoot this issue. For those with the 8.3 you might think about looking at which system you have for your preheat as we were surprised as we didn't find this one with the grid heater.

Mike

Re: 8.3 (mechanical) Intake Preheater Problem

Reply #24 – November 24, 2023, 07:27:21 pm

Quote from: Pamela & Mike – November 24, 2023, 07:09:06 pm

For those with the 8.3 you might think about looking at which system you have for your preheat...

I think that would only apply to the computer controlled 8.3L engines? The totally mechanical C8.3 (like ours) doesn't have any kind of intake manifold preheater. It does have a engine block coolant heater, of course...

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