Causes of a miss

[dave110]

Started up today to hook up my trailer for the next morning. It was chilly so I left it idle about 5 min. to give the batteries a charge because I knew I would only be moving a short distance. Got under my trailer and got a hiccup. While dropping the trailer on it did it twice again. Pulling up my hill to turn around it did it once under load and was fine after that. I'm hoping it was a fluke and I'll find out tomorrow if it continues, but I'm just wondering what to look for. I'm leaning towards something electrical but would like to hear from others. Truck ran fine the day before.

[Mopar1973Man]

Typically it's injectors getting tired and becoming pissy. I would suggest pop testing to verify. I've had two sets fail the same way.

[dave110]

That's good news! I was needing an excuse for some 7x8or 9's. It does have more of a haze at idle when cold than it used to. So you had a miss as well?

[Mopar1973Man]

Injectors... My 60s failed the same way.

[Dieselfuture]

Assuming you checked ac noise from alternator and fuel pressure is good and no codes then injectors could be a problem. I believe mine went the same way too, just randomly started to miss. Though it was vp but had no codes, so changed injectors and it got better but then expirienced same miss and discovered too much ac current. Fixed alternator and been good for few years now. Few months ago I had a similar miss just once, hoping nothing bad.

[dave110]

Yes, I should have mentioned FP is 20psi, AC is in check, and no codes. I'll see if and how often it does it again and report back. Good to know about the injectors. One thing I wanted to upgrade anyway.

While we're talking injectors. I have genuine Bosch cores to send in. Would it be advisable to have nozzles put on my bodies as apposed to getting aftermarket units? I'm thinking that would be about the same price as buying a whole unit in aftermarket but I'd still have Bosch bodies. I'm assuming the bodies are the same just the nozzles are different. Would DAP do that? Does it even make sense?

[dripley]

DAP sells them both ways, with and with out Bosch bodies. The aftermarket require no cores and the ones with Bosch bodies require cores. You can still have the Bosch bodies and send yours in for the core.

[dave110]

Took it for a pretty good trailer pull run today and it didn't miss a beat. I agree that injectors are on their way out. My long idle yesterday morning made it noticeable. I'll wait until DAP gets their pop test machine fixed and order some 7x8.5s???

 

[Mopar1973Man]

As long as the rail pressures are above idle pressure then they typically don't miss. So that why the towing trip they worked fine but at idle the randomly skip.