Hi everyone!

Normally I'm in 1st Gen. world, (see my sig.) but my mother-in-law has a problem with her 98 24V D3500. And being such a swell son-in-law, I've volunteered myself to 'fix' it. What she doesn't know won't hurt her .

Seriously though... When accelerating from a stop, the truck is totally gutless. WOT results in stalling, so a gradual increase is called for to get her rolling. Once moving, at around 35 - 40mph it's alright, and there's good boost and acceleration from there. It's the lower end that's the trouble.

The truck's done close on 190k miles, and as far as I know hasn't had anything touched/adjusted, e.g. valves, pump, injectors etc. So it could just be a combination of all of that, PLUS the fact that it was once topped off with 87 octane. Thankfully not by me! The engine was fully cleansed immediately after, but I can help wondering what long-term effects may have resulted...

Anyway, any and all ideas would be appreciated. The truck doesn't owe anything, so I'd like to at least get it running right, if not 'better' (heeheehee) than before.

Thanks in advance.

Keran

 

Check your lift pump pressure and volume. Next comes a VP44 perhaps.

 

Might also check all the boots on every joint in the intake.

 

Ahhh I'm hoping just the LP, but I think you may be right. I don't know about the VP44, but I do know the VE on my truck is good for at least 500k miles. Would the petrol eat away at o-rings, seals etc, thus causing drop in pressure? It was only in there for a couple of hours, then got drained and flushed. Still...

Thanks for the reply Dozer!

 

Thanks wurkenman, I need all the suggetions I can get. And besides, this is educational as well as fun! This is, I'm guessing, to check the engine's getting enough air! Boost isn't cutting in 'til around 1500rpm, although that's pure guess work as there's no boost guage. I know... to really nail this I need gaugesgaugesgauges!

Anyway, keep those suggestions coming!!

Cheers!

Keran

 

Well mine has been like that since new, so what RPM does it start to pickup at? Mine is gutless till 1450 rpm fuels to 1975 then it is petering out, rarely will it fuell past that point! This last injector pump helped alot! The two vp44's before that the best way to discribe it's fueling would be most of the time it would make the motor rev and scream but no power from idle! I have some ideas that aren't popular PM me if you wish?

 

Might be the Map/boost sensor.

 

Is this truck a manual?

 

No, Auto. NV5600 I think, but not 100% on that. D3500 SLT. O/D, I/C power everything etc etc...

 

Please bear with my newbie self, but what and where is the map/boost sensor? This is different to the current, (OEM) chip? I've wondered about that, the chip just not telling the pump to send enough fuel. I get a puff of smoke at start up, but apart from WOT there's no smoke at all, so it's certainly not over fuelling. Which is why I'm thinking LP/IP.
Of course, as I said previously, nothing has been done to this truck. It could just be the fuel filter for all I know. I get back home tomorrow, so will start on the basics first over the next few days.

Thanks for all the replies and advice everybody! I sure appreciate it.

Cheers!

Keran