 Hesitation while Cruising, '74 2.0l D-Jet |
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| Nogoodwithusernames |
 Jun 14 2021, 04:44 PM
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#1
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Member  Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None  |
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. |
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Replies(1 - 19)
| windforfun |
Jun 14 2021, 04:52 PM
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#2
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Senior Member Group: Members Posts: 1,841 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
Check your throttle position sensor (TPS) for alignment & circuit board wear. BTDT.
(IMG:style_emoticons/default/beer3.gif) |
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| KELTY360 |
Jun 14 2021, 05:20 PM
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#3
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914 Neferati Group: Members Posts: 5,036 Joined: 31-December 05 From: Pt. Townsend, WA Member No.: 5,344 Region Association: Pacific Northwest 
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Maybe it’s just me , but 25-30 in third is too slow. Try second at that speed.
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| gonzo54 |
Jun 14 2021, 06:10 PM
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#4
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Orange Crush Group: Members Posts: 226 Joined: 10-May 19 From: Seal Beach, CA Member No.: 23,112 Region Association: Southern California
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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
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| Nogoodwithusernames |
Jun 15 2021, 09:39 AM
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#5
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Member Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None |
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! (IMG:style_emoticons/default/beerchug.gif) I'll report back with results either way. |
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| ClayPerrine |
Jun 15 2021, 09:43 AM
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#6
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Life's been good to me so far..... Group: Admin Posts: 15,523 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille
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QUOTE(Nogoodwithusernames @ Jun 15 2021, 10:39 AM)  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. Cheers to all for the replies! (IMG:style_emoticons/default/beerchug.gif) 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 |
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| GregAmy |
Jun 15 2021, 09:45 AM
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#7
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Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States
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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.
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| rjames |
Jun 15 2021, 11:21 AM
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#8
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I'm made of metal Group: Members Posts: 3,956 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest
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QUOTE(Nogoodwithusernames @ Jun 15 2021, 08:39 AM) 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! (IMG:style_emoticons/default/beerchug.gif) I'll report back with results either way. 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. |
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| KELTY360 |
Jun 15 2021, 11:52 AM
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#9
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914 Neferati Group: Members Posts: 5,036 Joined: 31-December 05 From: Pt. Townsend, WA Member No.: 5,344 Region Association: Pacific Northwest
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QUOTE(rjames @ Jun 15 2021, 10:21 AM) QUOTE(Nogoodwithusernames @ Jun 15 2021, 08:39 AM) 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! (IMG:style_emoticons/default/beerchug.gif) I'll report back with results either way. 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. |
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| windforfun |
Jun 15 2021, 01:40 PM
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#10
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Senior Member Group: Members Posts: 1,841 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
QUOTE(KELTY360 @ Jun 15 2021, 10:52 AM) QUOTE(rjames @ Jun 15 2021, 10:21 AM) QUOTE(Nogoodwithusernames @ Jun 15 2021, 08:39 AM) 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! (IMG:style_emoticons/default/beerchug.gif) I'll report back with results either way. 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. (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) Some guys rotate their tach so 3K RPM is at TDC. |
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| Nogoodwithusernames |
Jun 15 2021, 03:43 PM
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#11
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Member Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None |
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. (IMG:style_emoticons/default/driving.gif) 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. |
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| BillJ |
Jun 15 2021, 04:42 PM
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#12
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Senior Member Group: Members Posts: 1,114 Joined: 4-March 13 From: charlotte, NC Member No.: 15,610 Region Association: None
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Just for reference
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| windforfun |
Jun 15 2021, 05:04 PM
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#13
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Senior Member Group: Members Posts: 1,841 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
QUOTE(BillJ @ Jun 15 2021, 03:42 PM) Just for reference Doesn't this depend on how many beers you've had? (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) |
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| GregAmy |
Jun 15 2021, 05:06 PM
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#14
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Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States
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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 |
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| Jett |
Jun 15 2021, 05:54 PM
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#15
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Senior Member Group: Members Posts: 1,641 Joined: 27-July 14 From: Seattle Member No.: 17,686 Region Association: Pacific Northwest
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QUOTE(GregAmy @ Jun 15 2021, 04:06 PM) 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 (IMG:style_emoticons/default/smile.gif) 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. |
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| GregAmy |
Jun 15 2021, 06:03 PM
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#16
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Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States
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Good info, thanks. Generally speaking, I use a smaller stick but if we're actually allowed a larger one then all the better.
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| Bleyseng |
Jun 15 2021, 07:00 PM
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#17
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Aircooled Baby! Group: Members Posts: 13,035 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
QUOTE(GregAmy @ Jun 15 2021, 08:45 AM) 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. This a must do as the weights get gummed up and stick without those drops of oil |
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| Nogoodwithusernames |
Jun 16 2021, 09:30 AM
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#18
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Member Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None |
QUOTE(GregAmy @ Jun 15 2021, 04:06 PM) 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 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. QUOTE(Bleyseng @ Jun 15 2021, 06:00 PM) QUOTE(GregAmy @ Jun 15 2021, 08:45 AM) 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. This a must do as the weights get gummed up and stick without those drops of oil 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. |
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| scottthephotog |
Jun 16 2021, 10:45 AM
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#19
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Member Group: Members Posts: 187 Joined: 20-November 18 From: Euless, TX Member No.: 22,667 Region Association: Southwest Region |
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.
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| Nogoodwithusernames |
Jun 17 2021, 10:53 AM
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#20
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Member Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None |
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.)  |
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