Hesitation while Cruising, '74 2.0l D-Jet |
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Hesitation while Cruising, '74 2.0l D-Jet |
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. |
Nogoodwithusernames |
Jun 18 2021, 09:32 AM
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#2
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Member Group: Members Posts: 239 Joined: 31-May 16 From: Nor-Cal Member No.: 20,051 Region Association: None |
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. Is that a new TPS? Why are the slots in the mounting screw heads all messed up? No this was my existing TPS, just cleaned the traces of the board. Is the rotational alignment the same as when you pulled it out? @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. 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. @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. |
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