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1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 12:26 pm
by jcarrick
Hey guys,
So my wife is driving my 90 these days and it is getting close to 400k miles on it. The thing is champ and really has never let us down. Occasionally it has an issue where it will die at idle when coming to a stop or something, but usually cleaning out the IAC takes care of that. It started doing this again so I cleaned out the IAC, which for the most part fixed the idling issue, but it is now stumbling and feels like it has no power while cruising down the road. It idles fine and doesn't seem to misfire, just stumbles down the road. Does anyone have some ideas to point me in the right direction on fixing this?
-Jon
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 12:41 pm
by DE80q
Have you upgraded your injectors yet, or are they still the problematic OEM ones?
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 12:42 pm
by jcarrick
They have been upgraded to 034's injector kit
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 1:00 pm
by jcarrick
Also, the fuel pump is quite noisy, but it's been that way forever and never had an issue
-Jon
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 1:12 pm
by dana
i would bet its the knock sensor(s). I've used these cheep ebay sensors with success a couple times. Not sure if they actually detect knock, but they keep the ecu from pulling timing and making it stumble.
http://www.ebay.com/itm/NEW-Bosch-Knock ... e5&vxp=mtr
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 1:50 pm
by PRY4SNO
I was gonna say FP or knock sensors.
Looks like I'm a little late to the party haha
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 9:26 pm
by jcarrick
Any way to test the knock sensors? How many are there? Thanks for the link Dana!
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 10:54 pm
by loxxrider
There are two if it's anything like the 3B (and I think it is).
Re: 1990 20v 90 stumbling while cruising?
Posted: Mon Feb 16, 2015 11:30 pm
by jcarrick
That's what I thought. I think my AAN had two as well. I should be able to get home Friday and start figuring out what is actually wrong with this thing. I will also get those knock sensors ordered
-Jon
Re: 1990 20v 90 stumbling while cruising?
Posted: Tue Feb 17, 2015 1:30 am
by PRY4SNO
Yes, two knock sensors.
Best bet is to upgrade to the later bolt-thru kind vs. the native 7a style.
Re: 1990 20v 90 stumbling while cruising?
Posted: Tue Feb 17, 2015 2:38 am
by ChrisAudi80
When was the last time the O2 was replaced? They generally don't go more than 100k.
Re: 1990 20v 90 stumbling while cruising?
Posted: Tue Feb 17, 2015 3:17 am
by jcarrick
PRY4SNO,
I think those are the ones Dana sent the link to on eBay in the 5th post, right?
Chris,
I personally have never replaced it. This thing really never misses a beat, it just runs and won't quit, ha. I guess it's time to start showing it some love. It looks like I'll be ordering an O2 sensor and some knock sensors for sure
-Jon