Had the 914 out a couple times this weekend and noticed some hesitation while at light throttle cruising, say at like 25-30mph in 3rd.
I just recently did a valve adjustment and checked timing per the manual, had to clean up the points a little bit as one side had a little bit of a 'tit' starting to grow.

Other than the hesitation it seems to be running well still, maybe a bit on the warmer side compared to what it used to be? (Also first time out this summer, ran it a few times this spring when it was nice and cool) But it has good power, and no audible changes in tone.

What should I be checking first? Timing looked like it was right on the mark with vac line off and at about 3-3.5k rpm so I don't *think* that's the issue.

Check your throttle position sensor (TPS) for alignment & circuit board wear. BTDT.

Maybe it’s just me , but 25-30 in third is too slow. Try second at that speed.

I agree, Throttle Position Sensor was my hesitation and bucking problem. I cleaned it and it came back so I replaced it with used sensor and so far it is running much better. Long term plan is a new board from 914 Rubber

Thanks for the tips, I will check on the TPS. That would be a nice easy fix for sure.

Isn't 3rd recommended in the manual for that speed? I know my VW is, and it's only got 4 gears. *edit for clarity* my 914 has 5 gears, my VW has 4 gears and cruises 25mph in 3rd gear just fine. Thus thinking out loud shouldn't the 914 also be able to do the same since it has a bigger motor AND more gears?

Cheers to all for the replies! I'll report back with results either way.

If this is a 914, it has a 5 speed in it. There were no 4 speed 914s.

In case you have and aftermarket gear knob with no pattern, First is to the left and rear.


Clay

Also, toss a couple drops of oil in the top of the distributor shaft, under the rotor. It lubes the weight pivots. There should be a small piece of filter-like material in there.

It can do 25mph in 3rd gear, but if you're at ~2800rpm or below you should be downshifting or you're lugging the engine.

That’s my point exactly. You’ll prolong engine life by making a habit of cruising at 3000 rpm or above.

Some guys rotate their tach so 3K RPM is at TDC.

Alright I'll bite, this is going a bit off topic of what I was originally asking but...

VW's owners manual page showing gears and speed ratings. (This is a T3 VW, with D-jet FI on a 1.6l)
https://www.thesamba.com/vw/archives/manual...ype3/page31.jpg
3rd gear is perfectly suited for low speed cruising. (At this speed, while just cruising, the load is low. If I were to climb a hill or want to accelerate quickly? Duh. Downshift.)

Another page of the VW owners manual showing that stock 3rd gear is 1.26:1 (same as the stock 901 box I believe?) and final drive is 4.125 vs the 901 at 4.43
https://www.thesamba.com/vw/archives/manual...ype3/page62.jpg

Thus if VW says it's safe to cruise at 25 in 3rd and the 914 will be at about 200rpm higher AND has .4 extra liters of UMPH behind it then I'm calling it good.

Driving the 914 in 3rd gear at 25 is not lugging anything. Again, there is hardly any load on the motor at that speed.
Now am I gonna do 20mph up a 40% grade in 3rd gear? Heck no.
Will I cruise around town in 3rd gear so I can hear more than just the motor screaming behind me? Heck yes.

Another data point for those still interested, my VW (has a 1.7l T4 in it) will barely reach 250°F-275°F head temps cruising around town in 3rd gear. Now on the highway is a different story, then the motor has much more load and needs the fan speed up to keep up with the extra heat.



Anyways, I digress. Back to the issue of hesitation at low load cruising (Regardless of speed, it did it at 50mph in 4th as well. It just wasn't as noticeable.)
I will check out the TPS and clean or replace as needed, then re-install and adjust per the manual and see how that does.

Just for reference

Doesn't this depend on how many beers you've had?

The general rule-of-thumb I've been told (Chris Foley) is always keep it above 3000 under load.

That follows my anechdotal observations of the effects on CHT. Any time it's a hot day and I'm "lugging it" below 3000 the CHTs get into the high 300s. I really don't like that:

http://www.914world.com/bbs2/index.php?sho...mp;#entry377466

@GregAmy
paying forward, someone shared the ontology of the phrase “rule of thumb” with me about six months ago, and it changed when I use it.

“A modern folk etymology holds that the phrase is derived from the maximum width of a stick allowed for wife-beating under English law, but no such law ever existed”

BTW. I had the same hesitation issue on our 73 2.0 with new TPS. Needed to pull the distributor and service/rebuild.

Good info, thanks. Generally speaking, I use a smaller stick but if we're actually allowed a larger one then all the better.

This a must do as the weights get gummed up and stick without those drops of oil

Absolutely under load is no question! No disagreement there at all, I was only talking low load scenarios, as that's when my little hesitation issue is popping up.




I am pretty sure I did a bit of oil there, but it probably wouldn't hurt to pull it out and clean the whole distributor. It probably needs a new rotor and cap anyways. What's the best source for a good quality cap and rotor these days? I'm not sure I would trust some cheap replacement anymore...



I also pulled out the TPS last night, and it was a little dirty but none of the traces are worn. I cleaned it up and I'll put it back in and adjust it once I get my multimeter back.

Following as I'm troubleshooting a what sounds like a similar bucking problem at part throttle. I've replaced the TPS board with a new one from 914 Rubber. I've also installed new coil, cap, rotor, points, plugs, wires, vacuum lines, and had the injectors rebuilt.

Okay got the TPS back on the TB but the adjustment procedure doesn't seem to have worked quite right. (Photo attached)

In the book the TPS only has 4 connections, mine has 5. At first I used the same terminal numbers to do the adjustment but there is never continuity between pin 14 and 17 anywhere in the adjustment range.

Popped the cover off the TPS and also looked at the plug in the engine bay and maybe I'm supposed to use pins 17 and 12? Did the procedure with the multimeter on those pins but now the arm never hits the stop, and the middle "finger" never makes it back to the pin 17 pad on the circuit board.

Is there a different procedure for the 2.0 D-Jet? Did I totally mis-understand the directions in the manual?

(Gist of the procedure in the book is when pins 14 and 17 have continuity, turn the TPS back anti-clockwise to ticks and tighten it down.)

Click to view attachment

2.0L TPS have 5 poles (cavities), but only four wires, one cavity is empty.. All 914 D-Jet harnesses have only 4 wires at the TPS.

17 & 12 (on the TPS) are the contacts to switch on the idle circuit in the ECU, hence the need for continuity. The other two wires handle acceleration based enrichment. When the TPS is not at idle, then the sensors take control and not the ECU.

Is that a new TPS? Why are the slots in the mounting screw heads all messed up?

Thank you for that diagram!

The manual I was going off (Clymer I think?) had me rotate the TPS the other way after reaching 0 ohm. I'm glad I had the cover off to see that it would never reach the idle pad which is what made me ask about it.

Will follow this procedure and report back.




After seeing how that does I would also like to do an ignition system tune up with new cap, rotor, wires, and plugs since I don't know how long ago that was last done.

No this was my existing TPS, just cleaned the traces of the board.

mine had that bucking as well for years, thought the TPS board would be “worn” but the marks on it were just oxidation on the trail of where the feelers ran. cleaned with an eraser spotlessly like yours and bam, no bucking at all. i will bet you will have a nice smooth running motor now.

Is the rotational alignment the same as when you pulled it out?

Your hesitation at light throttle cruise is most likely a symptom of a marginally lean fuel mixture. Increasing the fuel pressure by a pound might be sufficient to mitigate the problem. A more suitable fix is adjusting the MPS, but isn't as simple as adjusting fuel pressure.

As for minimum rpm under load - I use 2600, but I wouldn't want to drive up a steep hill at that rpm.

Alright, last night I followed the diagram Jeff posted, took it for a drive around town and the hesitation seems to be fixed.

I do want to go through the top end and do some cleaning and new gaskets. Things like check the PCV and AAR, new TB gasket and breather tower gasket, as well as the ignition system tune up I mentioned previously. Having the air filter box off I realized the motor is pretty dirty and could use a going-thru.





@windforfun , no that photo was after I followed the manual's directions for adjustment. After following the diagram Jeff posted it is now lined up with the marks from previously. Or very nearly at least.




@ChrisFoley thank you for that input, I'll check the fuel pressure when I go through everything else, haven't done that in a couple years probably. I should also make sure the idle mixture is correct too while I'm at it.

Well it's been about two years, life is busy as we all know, and messing with other hobbies and moving etc etc. I'm trying to get this running better again. It was a bit better for a while, but I also wasn't driving a ton and it wasn't so bad to be bothersome. I think it's gotten a bit worse now after not being driven as much.

I can remember how nice it drives when it's in tip top shape and would like to get it there again.

Especially now that I have been driving the 914 to work a lot more lately since my 98 Isuzu pickup daily doesn't like to start on our cold (relatively) mornings we've been having. (If anyone has any thoughts on this too I'm all ears! cranks and cranks and cranks but won't catch till it's warmed up. Coil going bad?)


Over the weekend I checked timing, and fixed a possible vacuum leak at the stupid stacked elbow coming off the plenum. (Why not just have two nipples coming off the plenum???) The rubber was getting a little hard on the elbow so I used a dab of oil safe RTV to glue in the brass tubes since those were a bit loose.


Do I just go through everything again, TPS, distributor (clean and lube)? Doing everything over just feels like

Perhaps I'll unplug the TPS on the way home to see if that could be the cause.

One thing I haven't done is check fuel pressure in a long while. I haven't adjusted it either but perhaps the regulator has lost a bit over the years?

The temp sensor in the head is new, I believe 914 rubber brand, as of a few years back.

I have been reading d-jet posts in Volvo forums and they have even named the part throttle miss it is so common (mapt? Or something like that). I found disconnecting my tps results in no part throttle miss however I suspected it was the idle circuit turning on and resulting in lean conditions. Not the accelerator pump section. I am currently of the opinion that it is likely a combination of that idle circuit and advanced timing. I ran out of season before I could do more testing though.

Is it hesitating again? In your post from 2 years ago you said it was fixed. Was it ok for the past 2 years and started acting up again or is it a new/different issue?

Emery - I'll disconnect the TPS before I head home and see if there is any change worth noting.

RJames - I don't think it was ever 100% fixed but it was better for a while.

Agree with Clay. I'd pull the distributor, disassemble, clean the old grease, re-grease and put it back together. You may just have the disks sticking in the distributor.

Chris

Report back after driving with TPS unplugged. Yesterday on the way home (low 60s F) it seemed to do much better. Idle seemed to suffer a bit, but that's not surprising since it would never go on the idle circuit.

This morning I also left it unplugged on the way in this morning (mid 30s F) and the hesitation came back, though possibly not as bad as before.

So it sounds like it might be a combination of the TPS and distributor, so I'll go through both of those again just like last time. Maybe I missed something last time, or didn't put enough oil on the weights.

I'll find out and report back, I appreciate everyone's input. Not working on these things every day I have a vague idea of how the system works but not always good enough to diagnose an issue. And all my manuals are in a box somewhere yet to be unpacked as well.

Two things I did to reduce/eliminate hesitation on my D-Jet 2L:

- Replace the TPS board;
- Couple drops of oil down the top of the disty shaft to lube the weights (that's supposed to be a regular maintenance item anyway)

The third one was to convert it to Microsquirt, but I'd suggest the first two are easier... - GA

Yeah, gunky dizzy could definitely do it. I have a 123 but I also have a 2056.