Won't Rev over 2,200 RPM? - FIXED

[Adam]

Not sure what is happening here. I thought it might be a fuel delivery issue, but I've changed both the WVO filter and the diesel filter and it looks like I'm getting decent flow through my sight glass filter both and after the IP. The van just won't rev faster than 2,200 RPMs even with my foot to the floor in Park or Neutral. Which means my current top speed is about 20km in 1st because the gears won't change. My wife suggested it might be my tranny flkuid which I'll check right now. Any other suggestions?

[EricN]

Simple things that you can check.

Plugged exhaust: put your hand by the tailpipe while it is being revved. If it feels wimpy, a baffle could be broken inside the muffler.

Throttle adjustment: Turn it off, open the engine compartment, push the accelerator to the floor, make sure the throttle wheel on the IP is going full stroke.

Air intake blocked somehow: Seen rats build nice nests in airboxes causing lack of revs.


Less simple things. Not worth trying to diagnose/guess at without seeing the truck as the list will do nothing except get you in a panic but hey, just for my own amusement, here it is:

T-belt skipped
IP/governer issue
Cam wiped out
etc. etc.

[mararmeisto]

...[p]lugged exhaust: put your hand by the tailpipe while it is being revved. If it feels wimpy, a baffle could be broken inside the muffler...

Not sure that exhaust back pressure is an issue for a diesel engine - it doesn't rely on it. That being said, I imagine that if it's completely blocked it could pose an issue.

[loki]

my vote is for the throttle cable being loose or stretched. so ya while running and the "hood" up move the throttle manually on the IP and see if you can get more rpms that way.

[Adam]

I drove it down to Victoria and back last night without much of an issue. It was sluggish on the return, but I thought it was a clogged WVO filter. I just got in from trying to take some video illustrating that I couldn't rev over 2,200 RPM and then it went to 3,000 to just prove me wrong. So I took it out for a spin and was able to shift into 2nd with a lot of effort, but my top speed was still only 30km/h. After coming in to eat a bit then going out to check the exhaust back pressure (with is good) I was able to rev to 3,500 now in Park. So maybe my fiddling helped the situation a bit, or the warm engine helps.

EDIT: I just got in from another test run where I was able to rev to 3,900 in Park and sspeed up to 60km/h. The shifting is very delayed from 1st to 2nd and I don't think I even made it into 3rd, just drove along at 2,8000 RMPs doing ~60km/h until I got scared I was going to wreck something.

I did check the throttle cable and playing with it manually with the hood up doesn't give me any more RPMs. That was my hope originally that something was obstructing the throttle and preventing it from opening up all the way, unfortunately it doesn't look that easy

[delicat]

G'morning Adam!

On the throttle cable there's a little rubber boot, pull it off and you'll see the cable going inside a tube (facing towards the back). On the cable there should be a metal knob that needs to align with the entrance of the tube. Doing so will adjust your shifting points.

Might not be the full solution but may be part of it if you're having hard time shifting...

Good luck,
David

[Adam]

Hey David, Thanks for the feed back. I was fooling around with that knob because the casing surround it was all cracked, but it didn't seem to help.



I drove it this morning and there is a total lack of power going up hills on either WVO or diesel. I had to drive up the hill to my place at 15km/h. Sometimes I was able to get the revs up to 2,500, other times I'd be lucky to get 1,500. It almost feels like a fuel delivery issue, but I checked all the points in the WVO system and they look clean. The only thing I can think of is that something made it past my in-line glass sight filter (which is after my Pollack valve and right before my IP) and is restricting fuel flow. I think it time to drive it up to CCAuto, as soon as we get our other vehicle insured.

[EricN]

Dont muck around with the shift cable as David has suggested. The reason your shift points are delayed is you are using alot more throttle to get yourself moving. This allows more throttle valve pressure on the back side of the spools in the transmission. Coupled with lower governer pressure due to a lack of speed, the transmission "thinks" you are accelerating hard and is delaying the shift. Pull the fuel delivery hose off the IP and turn the veggie on so your transfer pump is pumping, see what kind of flow you are getting. Then go to the vegmax, open the drain and do the same thing, compare the flow. If it comes out good, then there is something up with the IP.

[Adam]

Hey Eric, I did check out my WVO flow at all the junction points: before the aux pump, after the aux pump, before the VegMax, through the VegMax, after the VegMax, changed the VegMax filter, before the Pollack value and after the value. I was initially having WVO flow issues, but it looks like all that checking fixed the WVO flow, but not the over all problem. The symptoms are almost like the clogged filter problems I've had in the past, but not quite. The van won't stall, it just has no power.

I dropped it off with Glen at CCAuto today so hopefully he'll have an easy solution for me tomorrow. He seems to think it might just be a cable, but it was nothing that that I could see from looking at the engine bay. I did also notice some belt squeeling on the painfully slow 45km drive up to Coombs. That might be related to my home alternator fix that I performed a month or so ago.

[after oil]

i am sure glen and his band of jolly good chaps will get to the bottom of your problem adam.
i thought of a similar problem i had with my nissan diesel, and it came down to a tiny air leak that occurred only under pressure i.e. when i was givin' it full throttle.

[Adam]

Glen and his crew got it figured out. It was an internal failure of my IP, cause still unknown. CC Auto dissected the IP trying to find the cause but nothing was obvious. I was concerned that it might be cause by my b50 use or the WVO system, but right now there is no evidence of that. No gunk, no broken internal bits, it just doesn't work. They are sending it off to a specialist to get rebuilt, hopefully that will shed some light on the cause.

[dfnder]

well at least you are on track to driving normal again, sorry to hear about the cost

[after oil]

i am having this same problem! adam did you ever get an idea on the ultimate cause? guess ill have to go over and see glen the mad scientist...

[Adam]

I got a 'new' used IP which fixed the problem. Glen sent the old IP off to be rebuilt, but I never heard back from him about the ultimate cause of the IP failure. His initial suspicion was that it was WVO related, but he said after look at the IP there was no clear reason as to why it failed, he was expecting to see some WVO gunk in there, but he didn't. I haven't heard back on what the rebuild shop had to say.

[after oil]

lets hound him and see what we can find out. mine is another WVO van and suspicions are aroused around here... but lets not raise the terror alert just yet.