CAT 3208 Wiring Diagram (Alternator, Fuel System, Parts)

Pictures often explain mechanical and electrical systems a lot better than words can. When you get the right diagrams you should be able to figure out where every component is and make the right repairs.

One of the best places to go for a wiring diagram for your 3208 CAT engine is CAT itself. They should have those diagrams handy and should be able to send you one. Make sure to check the owner's manual to see what diagrams are included in its pages.

To see a multiple number of diagrams, just continue to read our article. It presents as many diagrams as can be found. Just keep in mind that there are many applications for this motor so our diagrams may not be the ones you will need.

Finding CAT 3208 Wiring Diagrams

This can be a problem as many of the ones found on the search engine’s image results page either are blurry or may be mislabeled. It is hard to trust the label unless you have it in today’s world, people will put anything up on the internet.

The best places to go would be to an experienced CAT mechanic or dealer. They should have these wiring diagrams on hand as their employees would need access to them.

The only problem with these sources is that they may be reluctant to copy and hand them out. You will have to talk to these people directly to see what they can do for you.

CAT is another option. Contacting the company directly may provide positive results. Another good place to go will be a marine, RV, or other truck forum that talks about the 3208 engine.

Often, other members place diagrams in their posts to help their fellow members. The key to accessing those diagrams is that you usually have to sign up. Sometimes you have to make a post and ask, then you could be directed to another thread that contains the diagram you need.

The final place to look would be to ask a friend who owns an RV, truck, or boat with a 3298 engine.

CAT 3208 Alternator Wiring Diagram

The following image is a picture of the most common alternator system used with the 3208. It may not be like the one you have but it provides you with a starting point.


This is a simplified diagram that provides the key points to connect your wires. It is possible that CAT has designed the wiring to be different for each of the many applications it uses for this engine.

This is why we tell you to contact CAT. Your specific set up may require a different wiring diagram than a friend will have. Or talk to your mechanic to help you track one down that is model specific for your vehicle or boat.

The internet is not always going to be your friend and the diagrams you find may not help. Also, the top of the results pages are dominated by the threads from different discussion forums asking the same questions.

CAT 3208 Starter Wiring

The following diagram is also found on this web page. The difference between the two is that the one on the search engine result’s page does not have the legend accompanying it.


To get to the legend for this diagram, you have to go to that web page and scroll down till you see the subsection ‘wiring diagrams’. If you do not want to do that, here is the legend for you.

12 Volt Starting And Charging System With Electrical Engine Protection Panel

(1) Off, Start Switch. (2) Control panel magnetic switch. (3) Water temperature sending unit. (4) Oil pressure sending unit. (5) Starter solenoid. (6) Starter motor. (7) Hourmeter. (8) Water temperature gauge. (9) Oil pressure gauge. (10) Battery. (11) Ammeter. (12) Fuel shutoff solenoid. (13) Alternator regulator. (14) Water temperature shutoff switch (normally open). (15) Oil pressure shutoff switch (normally closed). (16) Alternator.

We suggest going to that web page because it has other valuable information that you may be able to use.

CAT 3208 Fuel System Diagram

This is a basic diagram that contains all the elements for this specific application of the 3208 engine:

Here is the legend that is found underneath this diagram:


Sleeve Metering Fuel System (SMFS) Fuel Flow Schematic

(1) Fuel priming pump (closed position). (2) Fuel priming pump (open position). (3) Return line for constant purge valve. (4) Constant purge valve. (5) Manual purge valve. (6) Fuel injection nozzle. (7) Fuel tank. (8) Check valve. (9) Check valve. (10) Check valve. (11) Fuel inlet line. (12) Water separator. (13) Fuel filter. (14) Fuel line. (15) Fuel transfer pump. (16) Fuel bypass valve. (17) Camshaft. (18) Fuel injection pump housing.

See the rest of the legend at this link.

CAT 3208 Injection Pump Diagram


This gives you a basic idea of what the pump looks like. Unfortunately, most diagrams coming up in search engine results pages do not provide the legends.

If you want to know how to remove and repair this part of the engine. Here is a link to some step by step instructions as well as pictures so you can see how those steps go.

Also, if you need other help with troubleshooting this injection system, here is a link to a troubleshooting manual with a top view diagram of the system. It is an 8-page document with a list of problems and possible sources.

The last page has these few words of instructions:

The problems in this chart are problems that do come about and are normally called "low power." These problems are not necessarily more common than engine problems , but they are possible problems which you need to read and check before an engine is disassembled.

Read all of the items but make sure the first four are checked completely before making any engine test.”

CAT 3208 Fuel Shut Off Solenoid Wiring Diagram

Here is a colored diagram that may be clearer than a black and white image:


Again, we must say that these images are just for one style. The 3208 was produced for 20 years and had many applications so the images may not reflect what you own.

Make sure to contact CAT for model specific diagrams that will help you out. Also, if you own an RV do not be put off by the many marine results you may get when you do your own searches.

Sometimes the marine diagrams will work for your specific 3208.

3208 CAT Engine Parts Diagram

Here is one diagram option to look at. We suggest that you do your own search for your specific version of the 3208. it did come in three different versions so there will be tweaks done by CAT:


This diagram gives you an idea of what to expect when you want to work on your 3208. Check your owner’s manual if you have one. There may be a parts diagram in it or there may be a parts manual online that will show every part in this engine.

One reason you may not find anything online is that CAT may not want DIY mechanics working on their engines.

CAT 3208 Belt Diagram

This is probably the clearest and easiest diagram to understand out of all the ones we placed in this article:


installed so ignore that portion of the diagram if you don’t.

Removing and replacing belts is not that tough. The key is to get the proper tension on them so that there is no slippage or noise. If you do hear some noise, after testing the belts, tighten them up a little bit more.

CAT 3208 Fuel Pump Diagram

Here is the diagram with the legend. We are not sure if the lettering is going to be clear enough to read or not. Everything is labeled correctly and you should have a clear view of how to put the belts back on your 3208 after taking them off for repair work. Your RV or boat may not have the supercharger.


There are other images online but most of them do not come with a legend. This should provide you with a good idea of all the parts in the fuel pump and where they go.

Some additional words

Finding good images online is not always an easy task. You can never be sure if the person placing the diagram online has labeled it correctly or not. The best thing to do if you are not sure about any diagram is to show them to your mechanic and see what they say.

Or contact CAT and ask them to send you what diagrams they can. The company should still have the 3208’s diagrams on file as that engine is still going strong over 20 years after its final production run.

If they do not, make sure to visit those different discussion forums to see what has been placed in their threads.

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