Fuel Injector Removal

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I need to check my injectors to see if any are leaking. I contacted Detroit Diesel to see if they could test them without removing them, but they said that’s not possible. Since it’s a 360-mile round trip to the nearest Detroit Diesel location in Montgomery, I’m considering pulling them out myself and having them tested at a local injector shop.

Is this a task I can handle on the 8V92 engine without too much trouble and frustration? Are there any specific pitfalls I should be aware of?

Also, what’s the best place to purchase Detroit Diesel parts like fuel injectors? Should I contact the corporate office, one of the regional offices, or a service center? Thanks!

Dale Farley
Dale & Paulette

“God loves you and has a plan for your life!”

[MyPrevost]

This situation is a bit of a mixed bag. Yes, you can pull out the injectors, and in some ways, DDEC injectors are easier to handle than mechanical ones since fewer components need to be removed with them. Generally, getting them out isn’t the issue.

However, the challenge comes when it’s time to reinstall and adjust them. What makes you suspect they are leaking? If it’s fuel in the oil, the problem is more likely due to the fuel supply or return tubes. Additionally, a failed seal on the fuel gear pump could cause fuel to leak back into the engine case via the blower aux drive.

As for where to purchase injectors, there are many options, especially for rebuilt ones. A good injection shop can test your current injectors and either sell you rebuilt ones or repair the ones you have. Many truck service centers, like Peterbilt, Kenworth, and International, also serve as Detroit Diesel service centers and may have injectors in stock.

Believe it or not, you can find new injectors on eBay, but if you’re not completely certain about what you need, this could be a risky way to go about it.

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Jerry,

The reason I’m suspecting that one or more injectors might be leaking is that after letting the engine idle for a few minutes, I notice a cloud of white smoke when I accelerate. Detroit Diesel suggested this could indicate a leaking injector, and others on the forum have supported this as a likely cause.

I’m surprised to hear that the injectors need to be adjusted upon reinstallation, especially since they’re electronically controlled. I haven’t found any details in my manuals about this, but Detroit mentioned that the injectors are located under the valve covers. In my experience with other diesel engines, the injectors have always been external.

Dale & Paulette

“God loves you and has a plan for your life!”

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Yes, if the injectors are leaking from the tip, that confirms my suspicion. And I understand now that they are indeed located under the valve covers.

I’m not trying to dissuade you from tackling this job, but I wanted to point out that to access the injectors on one side, you’ll need to loosen the exhaust manifold expansion joint that connects to the turbocharger inlet. This connection often becomes seized over time. Unless you have experience doing this or a well-equipped shop to work in, it might be wise to consider having it done by Detroit Diesel or a local service shop.

You also have to think about the possibility of getting everything back together and then finding out it won’t start. That could mean calling out a DD service truck or having to haul it in with a wrecker, which is definitely not ideal.

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Dale,

I’m not entirely certain about the DDEC-controlled 8V-92, as most of my experience comes from working on the mechanical versions. When I had those, I did all my own valve and injector adjustments. However, accessing the injectors typically involves removing the Jake brakes and exhaust rockers/bridges, which means you’ll also need to readjust the lash and rack afterward.

If you’re considering tackling this job, just be prepared for the extra steps involved.

Shelly

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Dale,

These are the reasons I previously suggested trying a fuel additive injector cleaning method. Many auto dealers and repair shops have used this approach with good results, and it might be worth considering as a first step. I recommend checking with the DD shop to see if they utilize this cleaning method and what results they typically achieve. While I’m not necessarily advocating for it, I think it’s worth looking into before deciding on further steps.

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Well, all the feedback has given me plenty to think about. I want to avoid any complications with the exhaust system since I know how challenging that can be if anything is seized. I wasn’t aware that removing the injectors would affect the Jake brake or valve settings, and I wouldn’t feel comfortable trying to adjust them afterward.

I may look for a local shop that has experience with my specific engine. Unfortunately, there isn’t a DD shop within 150 miles. I’ll also ask if cleaning the injectors with an additive is a viable option.
Dale & Paulette

“God loves you and has a plan for your life!”

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Dale,

The turbo inlet pipes aren’t slip joints, so they should come off without too much trouble. The covers will also be manageable, and you can access everything from the rear of the coach if needed. I know this from experience because I serviced my Jake solenoids once, and it was quite straightforward.

That said, I’m not entirely convinced that tackling the injectors is the best route for you.

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Dale,

If you have a hand pump with a pressure gauge, you can connect it to the fuel filter since there’s a port available for that. By pumping diesel into the lines, you can monitor the pressure over time to see if it drops. I watched my Detroit Diesel technician use this method to identify a leak in the line under the cover, and it was quite effective.

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Even if you have Detroit Diesel handle the job, make sure to check your jake brakes before heading out on a long drive! When I first got my bus, I had a tune-up and injector replacement done at DD, but afterward, my jakes didn’t work.

I took it back, and they informed me that the “jake connectors were not making good contact.” In my terms, that meant they forgot to reconnect the jake connectors!

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The fuel port is located at the base (actually the top) of the fuel filter that’s mounted on the left rear of the water pump. You can access it by removing the plug with an Allen wrench. If you can adapt to it, one of the best and easiest tools to use is a handheld pump-up sprayer.

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