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jbclem Samba Member
Joined: November 04, 2011 Posts: 165
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Posted: Sat Jun 09, 2018 5:06 pm Post subject: 1993 Eurovan starts running rich at 23.5 mph |
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My neighbor's 1993 Eurovan won't pass smog. The mechanic replaced the O2 sensor but that didn't help. He took it to another mechanic who ran it on a dyno and discovered that it started running rich at 23.5 mph. Suspecting a defective computer, they tried a used computer (the correct part number) and that didn't make any difference. They still suspect the computer but no one wants to buy a new one and have to eat it if it doesn't fix the problem.
The HC is at 200, the CO at 5.5. The 5v signal is at 4.75v.
This car was towed to the original mechanic for a blown head gasket(it was purchased (sight unseen) for a low price because of this), so there is no history on it, and I wonder if there might have been something done (wires mixed up?) during the head gasket repair that is causing this problem.
Can someone suggest possibilities, places to look for this kind of problem. Any particular wires that could have been switched during the repair? Right now the mechanic is stumped and I'm trying to help out.
John |
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postjosh Samba Member
Joined: November 20, 2017 Posts: 135 Location: NYC
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Posted: Sat Jun 09, 2018 9:19 pm Post subject: Re: 1993 Eurovan starts running rich at 23.5 mph |
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i’m no expert but did anyone check the pcv valve? _________________ '93 EV Wkndr – 5 cylinder – 5 speed - 280k+ miles |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22568 Location: NYC/Upstate/ROW
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Posted: Mon Jun 11, 2018 3:49 am Post subject: Re: 1993 Eurovan starts running rich at 23.5 mph |
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You need someone who can monitor injections length and o2 sensor voltage, not just throw parts. The time spent seeking out this expertise will be well spent. Find someone local who does tunes and see if they know VAG stuff. _________________ .ssS! |
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markcm2 Samba Member
Joined: September 02, 2015 Posts: 505 Location: Bellingham, Washington
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Posted: Mon Jun 11, 2018 8:53 am Post subject: Re: 1993 Eurovan starts running rich at 23.5 mph |
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My go-to for fueling issues is a MAF check.
I cannot recall if a MAF signal was visible on the 1993 but generally speaking, a 3rd gear hard pull should result in a grams/second reading of about 80% of the vehicles rated horse power. VAGCOM has a logging function for this. My method is to find a high visibility freeway on ramp, have someone start the recording and accelerate hard through 2nd and 3rd providing it is safe to do so, then check the recording to see your peak g/s.
Coolant temperature sensors are also known for causing issues with fueling, another function you can see (open vs closed loop) on later vehicles but may not be available on OBDI of the 1993. Coolant sensors are usually only about $15. |
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volkybus Samba Member
Joined: November 03, 2013 Posts: 480 Location: CASTLETON VT USA
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Posted: Tue Jun 12, 2018 3:31 am Post subject: Re: 1993 Eurovan starts running rich at 23.5 mph |
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Does it foul plugs? Have u checked the fuel pressure? Bill |
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volkybus Samba Member
Joined: November 03, 2013 Posts: 480 Location: CASTLETON VT USA
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Posted: Mon Feb 04, 2019 8:30 pm Post subject: Re: 1993 Eurovan starts running rich at 23.5 mph |
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volkybus wrote: |
Does it foul plugs? Have u checked the fuel pressure? Bill |
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