'87 Vanagon hesitation, crummy mileage.

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Jivermo
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'87 Vanagon hesitation, crummy mileage.

Post by Jivermo » Sat Oct 10, 2015 1:56 pm

My friend Zeke, out in Seattle, has the following woes:


Symptom:
One to two second hesitation
-- when accelerating under load (incline)
-- when engine is cold
-- worse when fuel tank is low
Poor gas mileage (14mpg down from 17-18mpg)

Attempted fixes:
-- replaced cap, rotor & plugs
-- replaced all exhaust system gaskets
-- replaced temp 2 sensor
-- replaced (borrowed) air-flow-meter
-- replaced (borrowed) ECU
-- checked compression [consistent 145-150 psi all cylinders]
-- checked timing
-- replaced O2 sensor (yet determined if improved mileage)

We also added the suggested capacitor in the AFM last December.
Any suggestions on where to look next?

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Amskeptic
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Re: '87 Vanagon hesitation, crummy mileage.

Post by Amskeptic » Sat Oct 10, 2015 2:37 pm

Jivermo wrote:My friend Zeke,
One to two second hesitation
-- when accelerating under load (incline)
-- when engine is cold
-- worse when fuel tank is low
Poor gas mileage (14mpg down from 17-18mpg)


Any suggestions on where to look next?
Mark current cog position in AFM.

Go three clicks CLOCKwise.
Test.

Better? Do three more CLOCKWISE.
Test and report.

Worse? Go six clicks COUNTERCLOCKWISE from last position (which is net three lean).
Test.
Better?
Report.

Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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krivaswesty
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Location: Spring Branch, Texas
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Re: '87 Vanagon hesitation, crummy mileage.

Post by krivaswesty » Sun Nov 01, 2015 6:44 am

Plug wires as well?

Jivermo
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Re: '87 Vanagon hesitation, crummy mileage.

Post by Jivermo » Sun Nov 01, 2015 7:05 am

Don't know. He is travelling in the southwest, in the van, and I can't teach him right now. I know he did some work to it.

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Amskeptic
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Re: '87 Vanagon hesitation, crummy mileage.

Post by Amskeptic » Sun Nov 01, 2015 12:55 pm

Jivermo wrote:Don't know. He is travelling in the southwest, in the van, and I can't teach him right now. I know he did some work to it.
If he can crisply answer the experiment up there, we might be able to further an online diagnostic track. If we are going to wander around with vague suppositions, we might accidentally stumble upon a solution some time . . . :cyclopsani:

If he is traveling around the southwest, perhaps it is "acceptable" and he was merely too rude to update us.
MTRColin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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